First Edition 2006 OMAR YAACOB & KOH KHO KING 2006

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4 First Edition 2006 OMAR YAACOB & KOH KHO KING 2006 All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical including photocopy, recording, or any information storage and retrieval system, without permission in writing from Universiti Teknologi Malaysia, Skudai, Johor Darul Tak'zim, Malaysia. Perpustakaan Negara Malaysia Cataloguing-in-Publication Data Advances in marine technology / editors Omar Yaakob, Koh Kho King. ISBN Marine engineering. 2. Naval architecture. I. Omar Yaakob. II. Koh, Kho King Pereka Kulit: MOHD. NAZIR MD. BASRI Diatur huruf oleh / Typeset by OMAR YAACOB & RAKAN-RAKAN Fakulti Kejuruteraan Mekanikal Universiti Teknologi Malaysia Skudai Johor Darul Ta'zim, MALAYSIA Diterbitkan di Malaysia oleh / Published in Malaysia by PENERBIT UNIVERSITI TEKNOLOGI MALAYSIA 34 38, Jalan Kebudayaan 1, Taman Universiti, Skudai, Johor Darul Ta'zim, MALAYSIA. (PENERBIT UTM anggota PERSATUAN PENERBIT BUKU MALAYSIA/ MALAYSIAN BOOK PUBLISHERS ASSOCIATION dengan no. keahlian 9101) Dicetak di Malaysia oleh / Printed in Malaysia by UNIVISION PRESS Lot 47 & 48, Jalan SR 1/9, Seksyen 9 Jln. Serdang Raya, Tmn Serdang Raya Seri Kembangan, Selangor Darul Ehsan MALAYSIA

5 v Contents Preface Contributors Chapter 1 Computer Application in Malaysian Shipyards Yahya Samian, Omar Yaakob and Tay Kho Jim Chapter 2 Chapter 3 Malaysian Ocean Data Collection using Satellite Remote Sensing Omar Yaakob, Kamaludin Omar, Maged Marghany, Norazimar Zainuddin and Mohd Arizam Abdul Wahap A Study on Dynamic Interaction of Ships While in Speed M. Rafiqul Islam, Md. Nazrul Islam and Md. Sadiqul Baree Chapter 4 Bulbous Bow Application for Malaysian Fishing Boat Koh Kho King and Thong Jia Rong Chapter 5 Bulbous Bow for High Speed Displacement Craft M.P Abdul Ghani Chapter 6 Ship Handling And Safety In Restricted Water Adi Maimun and A. Haris Muhammad Chapter 7 Effect of Double Chine on Planing Hull Vessel Performance Adi Maimun, A. Haris Muhammad, Ahmad Fitriadhy, A. Zulkhairullah and S. Vigneshwaran Chapter 8 Ship Detection through Remote Sensing Satellite Omar Yaakob and Mohd Halim Abdul Sideek vii ix

6 vi Chapter 9 Management of Inland Waterway System for Transportation Ab Saman Abd Kader and Kong Kim Fong Chapter 10 The Development and Use of Inland Waterway System for Eco-Transportation Ab Saman Abd Kader and Mohd Zamani Ahmad

7 vii Preface Advances in Marine Technology 2006 is a compilation of 10 papers contributed by Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia academic staff and students based on their past and current research work. The book covers a balanced set of topics of interest in marine technology and related fields. These range from hydrodynamics, transport system management to satellite and information technology. The use of information technology in shipyards is covered in Chapter 1 while an overview of research works using satellite technology for oceanographic data collection is given in Chapter 2. Drawing on the strength of the Department, the next five chapters are devoted to hydrodynamics. Chapter 3 investigates the dynamics of ship interaction, while Chapter 4 and 5 report works on bulbous bow applications. The manoeuvring of ships in restricted seaway presents its own unique problems and these are presented in Chapter 6. Chapter 7 describes the performance of double chine vessels. Satellite technology for ship identification is dealt with in Chapter 8. This is followed by two chapters dealing with inland waterways which have a big potential of evolving into an alternative transport system. The book should serve as a valuable reference on the recent development in advances in marine technology and its related fields. Editors, Omar Yaakob Koh Kho King Faculty of Mechanical Engineering Universiti Teknologi Malaysia

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9 ix Contributors Abdul Saman Abd Kader, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Adi Maimun Abdul Malek, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Ahmad Fitriadhy, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Ahmad Zulkhairullah, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Andy Haris Muhammad Ahmad Fitriadhy, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Kamaludin Omar, Department of Geomatic, Faculty of GeoScience and Engineering, Universiti Teknologi Malaysia. Koh Kho King, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Kong Kim Fong, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Maged Marghany, Department of Remote Sensing, Faculty of GeoScience and Engineering, Universiti Teknologi Malaysia. Md. Nazrul Islam, Department of Naval Architecture and Ocean Engineering, Bangladesh University of Engineering and Technology Md. Sadiqul Baree, Department of Naval Architecture and Ocean Engineering, Bangladesh University of Engineering and Technology Mohamad Pauzi Abdul Ghani, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia.

10 x Mohammad Rafiqul Islam, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Mohd Arizam Abdul Wahap, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Mohd Halim Abdul Sideek, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Mohd Zamani Ahmad, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Norazimar Zainuddin, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Omar Yaakob, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. S. Vigneshwaran, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Tay Kho Jim, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Thong Jia Rong, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia. Yahya Samian, Department of Marine Technology, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia.

11 Computer Application in Malaysian Shipyards 1 1 COMPUTER APPLICATION IN MALAYSIAN SHIPYARDS Yahya Samian Omar Yaakob Tay Kho Jim 1.1 INTRODUCTION Computer application in shipbuilding industry can be traced back to the early 60 s. However, its extensive use in shipbuilding CAD/CAM system only began in mid 80 s following the availability of relatively cheaper computer graphics and introduction of NC machines. Since then, rapid progress has been observed although not as fast as that in other manufacturing industry. This may be due to the fact that shipbuilding is always regarded as a complex job oriented industry together with the conservative attitude of many shipbuilders in venturing into new technology. However, in the present development of computer technology (hardware and software) and its peripherals, networking and communication technology, many modern shipyards have not only use computers to facilitate some of their activity but also have use computer to integrate and coordinate their entire technical and business operation. From simple standalone computer program in the early sixties, many modern shipyards are now adopting the fully Computer Integrated Manufacturing, CIM. Indeed computers will become the heart and brain of the future shipbuilding industry.

12 2 Advances in Marine Technology Global Competitiveness Long before the term globalization came into use, the shipbuilding industry had already been subjected to fierce international competition. With the increasing demand for low ship price, short delivery time and higher quality standards, many surviving shipyards today are either surviving on government project and subsidies or venturing other projects. This could include ship repair and conversion work or other diversified business, or focusing on a very specialized ship with very little or no competitors. In such highly competitive world, any effort to improve productivity is highly valued and computer application is certainly plays an important role Changes in Shipbuilding Environment Over the past decade, the way ships are designed and built has experience the following changes: The ship is to be delivered in shorter period of time that demands shorter construction process and more overlapping engineering works. Design for production concept has been implemented widely, hence considerable increase in engineering works. Higher percentages of engineering works have been subcontracted which lead to significant reduction of shipyard gross revenues. The development computer and communication technology have not only contribute to these changes, but the way computer is used in shipyards has also affected by these changes

13 Computer Application in Malaysian Shipyards STATE OF THE ART Since 80 s many changes and new development on computer application in shipbuilding industry had occurred (Toroja and Alonso, 1999) which can be categorised into four main areas as follow: Development of hardware, software and computer system. Development in information technology. Computer application in marine education Hardware, Software and Computer System The availability of a more powerful, high capacity and relatively cheaper and smaller computer components, and more powerful networking technology has shift the used of large main frame system to the PC based system. On the software development, many CAD/CAM/CAE softwares for shipbuilding were introduced in the market. These softwares incorporate variety of that include: The incorporation of solid modelling and 3-D product model. Finite Element Method (FEM) softwares with better graphical interface and surface definition. The use of virtual reality (Alonso et al., 1997) that allows the designer to virtually immerse in the design and performs real time simulations. The application of computational fluid dynamics (CFD) that enables better comparative analysis of ship hydrodynamic behaviour. The application of robots in shipyards has also increased due to creation of more favourable environment including simplification of robot teaching, higher work piece accuracy,

14 4 Advances in Marine Technology 2006 smaller robot size and weight. Apart from the tools, computer has also changed the system in which the shipyard is operated and managed. From mid 80 s until mid 90 s, many shipyards were familiar with CAD/CAM system. However at present most modern shipyards have already implemented the more integrated system namely Computer Integrated Manufacturing (CIM) system which utilized computers in the integration and coordination of all activities in the shipyard including design, production, management, business etc. utilizing a shared and centralized database. The implementation of CIM (Ross, 1995),(Ross et al., 1997) had been reported to offer several competitive advantages since the success of any shipyard is obviously dependent on all activities and not merely design and production alone Information Technology The very fast pace of communication technology development in the last several decades has also influence the use of computers in transferring information within the shipyards and with outside world. In the present internet technology, shipyards had already able to transfer a vast amount of technical information at high speed and low cost. The development of new digital communication technologies has also created the possibility to access and maintain software from remote sites and performing remote supervision of engineering work through public communication channel via Wide Area Network (WAN). The success of shipyard integration is also closely connected to the development of LAN and WAN (Gomez, 1997) with sufficient bandwidth to cope with the flow of information. Currently LAN is more generally used in many shipyards including small yards due to its simplicity and low cost. Application of WAN which is more complex and costly is more confined to large organization where

15 Computer Application in Malaysian Shipyards 5 concurrent engineering work has to be done from two or more distant locations. However with the introduction of globalization era where more companies will merge and collaborate, and with ever increasing networking capability, the use of WAN is now become essential feature in many yards. Apart from rapid growth on communication and networking technology, the way the information is stored represented and exchange has also changed. Two significant changes that being observed over the last several decades are the use of one single database and standard information exchange. The CAD/CAM system in 80 s and early 90 s used multiple files to store ship information has now moved toward single database that stored total product information which is more flexible, fast and can be accessed almost simultaneously by many users. The database system it self has changed from proprietary database specially developed for shipyard integrated CAD/CAM system into a commercial relational database with standard query language (SQL). One of the most important aspects in information exchange is that the data developed by one system must be able to be recognized by other systems without reducing or distorting it. This demands standardization of data format. The first effort on standard format for describing product design and manufacturing information was Initial Graphics Exchange Specification (IGES) developed in Today many shipyards have adopted a more internationally accepted standard for data exchange format is STEP (standard for the exchange of product data). STEP is designed to operate in the first instance as a neutral file transfer mechanism. Each CAD system must be able to translate the neutral format into native data format and vice versa. Presently several STEP application protocols specifically for ship design, production and operation that have been developed in the last decade (Lofdahl et. al, 1995) had widely been used.

16 6 Advances in Marine Technology SHIPBUILDING SCENARIO IN MALAYSIA There are more than 40 registered shipbuilding related companies in Malaysia. However only few can be categorized as medium size shipyards judging based on international standard, while the rest are either small shipyards or merely boatyards. Most of these yards provide services on new building and repair/conversion work ranging from medium size tanker to a small recreational boat. Some shipyards have also ventured on other engineering activity as part of their diversification strategy. In the present economic situation, Malaysian shipyards mainly survive on repair and conversion work, while profit (if any) from new building is reported to be very low (approximately 1-3% for commercial ship). However for shipyards that are involved with the government projects requiring large quantity of almost identical crafts, a good profit margin is expected. With the implementation of global and free trade, the privilege of getting government subsidies and support is no longer guaranteed. Malaysian shipyards as other shipyards in the world not only have to face a more fierce competition, they also have to survive on their own. Having realized the forthcoming challenge, the government had made early preparation by encouraging and facilitating the upgrading the local shipyard capability. Since the last decade, many of the government project related to shipbuilding has put more emphasis in the Transfer of Technology (TOT) aspect both in term of hardware and the technology knowhow. Among areas that are given higher priority in these TOT programs are the development of local design capability and the application of advance tools/machinery including computers and automation in shipyards. Both of these aspects have been proven to have significant influence on the yard competitiveness and have a long-term strategic importance to the country. While such projects will benefit some shipyards, their effect on others especially small shipyard is not known for certain. The worst scenario that could happen is when the gap between the

17 Computer Application in Malaysian Shipyards 7 large and small shipyards becomes larger, in which it could lead to closing down of the many small yards as they may no longer be able to compete on an even playing field. One of the way to reduce such problem is the used of advance technology including computer hardware and software that are relevant and affordable to local shipyards. A nation wide survey was carried out in order to determine the current status of computer application in Malaysian shipbuilding industry. The survey also intended to find out which computer modules are being used and to see if there is need to develop alternative modules. The result of this survey will be discussed in the following section 1.4 COMPUTER APPLICATION SURVEY UTM Roles Universiti Teknologi Malaysia, UTM being presently the one of the higher institution in Malaysia that run courses in Marine Technology both at undergraduate and postgraduate levels has been quite active in promoting the healthy growth of the Malaysian shipbuilding industry. UTM, through the Department of Marine Technology, supported by the Marine Technology Laboratory is not only committed in producing graduates and professionals in the related fields, but is also actively involved in several research works and consultancy services. One of research interest is the application of modern technology to the shipbuilding industry, both in the hardware and software aspects. This computer technology survey is one the many efforts that contributed to such commitment. This nation wide survey was carried out in order to determine the current status of computer application in Malaysian shipbuilding industry. The survey also intended to find out which

18 8 Advances in Marine Technology 2006 computer modules are being used and to see if there is need to develop alternative modules. The result of this survey will be discussed in the following section Survey Correspondents 27 companies that represent almost all the major and active shipyards in the country have been surveyed and 23 (85%) had responded to the survey. The survey work covered both Peninsular and Sabah / Sarawak areas. The survey questionnaire was divided into several sections which cover the following areas; general particulars and overall computer application in the company, computer application in specific department, purpose and level of internet application, level of computer skill and training method, benefits, problem and future planning on computer application in the company. The survey also includes the question on which computer modules that will serve their immediate need. Out of 23 companies responded, 13 had answered and returned the questionnaire form, one answered through discussion during the visit and the rest via telephone conversations Overall Uses of Computer The breakdown of respondents with regards to their usage of computers is given in Figure 1.1. It was surprising to note that 3 (13%) companies responded that they do not use computer at all in their premises. 17% of the respondents only use computers solely for administration purpose, leaving only 70% of the shipbuilders using computers for their core shipbuilding activities

19 Computer Application in Malaysian Shipyards 9 Not Using Computer 13% Admin 17% Core Activities 70% Figure 1.1 Percentage of computer Application Figure 1.2 shows the use of computer application in various departments. It clearly indicates that the highest application (besides administration) of computer in shipyard is in the design department. This applies to more than 50 % of shipyard being surveyed. Among all the 20 respondents, 7 (30 %) claimed to have their own web sites Design Department 12 shipyards had to some extent employed computers in design and drafting works. The level of design involvement differs from yard to yard but most of them use computer applications in the preparation of detail or production drawing while preliminary design work is often subcontracted to the design companies abroad. The types of ship that are designed locally are shown in Figure 1.3.

20 10 Advances in Marine Technology 2006 Figure 1.2 Computer application in various departments Figure 1.3 Type of ships designed locally The design manpower also varies. Whilst the majority of small yards operate without professional design personnel, some large shipyards have more than 20 designers. On the software application, except for AutoCAD drafting package, the number of ship design softwares used in Malaysian

21 Computer Application in Malaysian Shipyards 11 shipyards is considered very low as indicated in Table 1.1. Most of the design softwares provide a wide range of calculation and design modules including hull form and system design. The level of utilization also differed according to the size of shipyard. For most of large shipyards, the average percentage of software utilization is within 70 to 100 percent, while for small shipyard it is within 30 to 40 percent only. Table 1.1 Softwares used in design departments Production Department Production department normally requires more drafting and labour-intensive work. Softwares are also used in this department, but mostly for drafting and planning tasks as indicated in Table 1.2. Majority of respondents mentioned that these softwares are effectively used at almost full capacity. There are also few shipyards that have implemented limited application of CAD/CAM system. Profile cutting in these shipyards is carried out using CNC

22 12 Advances in Marine Technology 2006 machine that is directly linked to the computer in the design office. Table 1.2 Software used in production department Other Departments Apart from the two departments mentioned above, respondents also named other departments including planning (as separate from production department), Test and Trial, Account and Oil & Gas department. The softwares used in these departments are given in Table 1.3 below. However, no comment was given with regard to the software effectiveness and its percentage of utilization Internet Application The level of the internet application is presented in Table 1.4. However, it needs to be noted that the table does not reflect the actual application in the shipyards being surveyed. This is because

23 Computer Application in Malaysian Shipyards 13 in most cases the person who fills in the survey form only represents him/herself. However the findings shown in Table 1.4 may give some indication on the effective used of internet. Table 1.3 Software used in other departments Table 1.4 Internet application

24 14 Advances in Marine Technology Computer Training The level of computer skills among the workers is divided into three categories i.e. expert, fair knowledge and novice users. Generally, 42 % of them are at expert level whereas fair knowledge and novice user, each stands at 41 % and 17 % respectively. The survey also revealed that most of the computing skills are acquired through self-learning as indicated in Table 1.5. The effectiveness of the training method is given in Table 1.6. Table 1.5 Training method Table 1.6 Effectiveness of training method

25 Computer Application in Malaysian Shipyards Benefits and Problems The list of benefits of computer reported in many survey works carried out world wide is also included in the survey form. The respondents were asked to tick which benefit he or she agrees and the result is shown in Table 1.7. Table 1.7 Benefits of computer The above result indicates the perceived benefits by the respondents and not the benefits actually measured in the shipyard. Most of the respondents believe that computer application could provide some form of benefit to the company. When asked about the problem that faced by the respondent, the following list represent among the most frequent problems encountered:

26 16 Advances in Marine Technology 2006 Too expensive Require in house customization Cannot solve all problems Inadequate experience manpower Low software utilization Future Planning Among future planning cited by respondents are (in order of priority) as follows: Upgrading computer system. Searching for best and cheap software More investment on CAD/CAM and NC Machines. Establishing design department. Training facilities. National Network to share expertise. Clearly, the needs for better and affordable software are high in their agenda Computer Modules Needed The final part of the survey is intended to get some indication of what software or modules that are immediately needed by the respondents. The modules that are high in priority as indicated in survey result shown in Table 1.8 will be given immediate consideration in the research project.

27 Computer Application in Malaysian Shipyards Survey Conclusion Judging from the survey result and present state of the art of computer application in shipbuilding industry, two major conclusion can be drawn: The number of shipyards in Malaysia that use computer for the core activity (design and production) is still very low. Even to those shipyards that use computer, the level of computer utilization in most of these shipyards is far from the present level of the developed countries. It is also quite reasonable to conclude that the status of computer application in Malaysian shipbuilding industry is somewhere between 15 to 20 years behind most of the American and European shipyards. Table 1.8 Required Computer Modules Software / Modules Priority H M L Powering Hydrostatic/Stability Structural Scantling Hull Form Website Propeller Load Line 2 0 0

28 18 Advances in Marine Technology FUTURE SUGGESTIONS With the exception of one or two respondents that have some reservation on computer application, most of them believe that computerization will bring benefits to their organization as already reflected in the survey. However the problems and constraint that have been put forward during the survey are among the factors that hindered them from doing so. Having this perspective in mind together with the suggestion made by the respondent during the survey, the authors intend to put forward some proposal that could encourage and enhance the application computer in our shipbuilding industry Correct Attitude First is to have the correct attitude toward computer application. The purchase of hardware and expensive software should not be done simply because it is a luxury thing to have or trend to follow that merely to impress the competitor/client that the company has the up-to-date technology. Any investment on computer should have a clear objective that is to generate profits in whatever forms. On the other hand do not expect computer to bring immediate cash, as it requires time for familiarization and customization during the early stage of its implementation Design Capability In shipbuilding industry, the application of computer has always started in design office. Hydrostatic software is among the first module that was developed to assist the design work. One of the

29 Computer Application in Malaysian Shipyards 19 main reasons that computer application is considered very low is because not many shipyards in Malaysia are involved in design work. With the exception of one or two shipyards, most of the design work is either subcontracted or purchased mainly from foreign companies. Although the government has already insisted on local design especially for boat 15 meter and below, while one or two shipyards take this challenge seriously, majority of them prefer to seek a quick solution abroad. A serious and collective effort is therefore urgently needed in order to promote the development and use of local design. Design development not only requires facilities but most importantly it requires pool of technical expertise. While some shipyard has the opportunity and fund to send their technical staffs for training abroad, small shipyard has to work closely with the local higher institution. Since it is not economical for every shipyard to start developing their design office, it is therefore suggested that the government should establish a concept of National Ship Design Centre to promote and facilitate the development of local design. The benefit is quite evident. It is not only promoting the local product, the money that otherwise flow to the foreign companies can be used to improve the local shipyard capability and above all it has a strategic important as we no longer always need to rely on foreign countries Development of Local Software One of the problems highlighted from the survey is most of the existing software are expensive to purchase and to maintain. Not only the purchase price is high with considerable amount of training and annual licensing fee; it is also expensive to maintain the experts to run the software. Furthermore, only approximately % (as indicated in the survey) of these expensive packages is utilized in shipyards. Although there is a number of cheap design software available in the market, the quality and reliability

30 20 Advances in Marine Technology 2006 are not known for certain. An alternative solution is to develop local software that is more suitable and more flexible to our local need. An initial step has already been taken by UTM researchers in promoting such effort, which will be discussed in the next section National Think Tank Group Another suggestion proposed here is the creation of a forum or think tank group to discuss the development of computer application in Malaysia. This forum or group should be represented by a wide spectrum of shipbuilding industry which at least includes shipyards, ship design consultants, government agencies, classification societies, universities, software developers and also representatives from information technology sector. This is very much duplicates of what has been done in many developed nations sduring the early stage of computer application in shipbuilding. As a start, AMIM together with UTM and some government agency could be the most suitable platform to initiate this effort. 1.6 DEVELOPMENT LOCAL SHIP DESIGN SOFTWARE Another serious effort is the research project on the developments of local ship design and calculation software. It is mainly aimed for local shipyards and for educational and training purposes. The software will be developed on module basis as a stand-alone which will later integrate together utilizing the centralized database as illustrated in Figure 1.4.

31 Computer Application in Malaysian Shipyards 21 Figure 1.4 Software main interface This software is intended to be more flexible, easy to use with self-explanatory information and manual and hopefully cheaper than the existing software. The software is kept and maintained in UTM but will be allowed to be accessed from remote location. This will enable (with some form of agreement) small shipyards to download or execute any module whenever and wherever required without the need to purchase the entire package. It also eliminates the maintenance cost and with the on line expert service it could further reduces the need of expensive expertise in the yard. Apart from providing the tool, UTM can also become the centre of providing information, data or any related material that can assist the design work and with the present networking technology this can be done almost virtually. Several stand-alone calculation modules including hydrostatics, intact stability, powering for fast craft, structural scantling have been developed. Once the hull form design module is completed the integration process will be carried out using the ship geometrical information as the basis for centralized database. With the small amount of financial allocation, limited time (2-3 years)

32 22 Advances in Marine Technology 2006 and handful of inexperience research assistant, it is quite impossible to develop a complete package equivalent to existing package. Nonetheless, it is expected that the outcome of this research project will at least provide a strong platform and clear direction for any serious and collective effort of developing our own software to be carried in the near future. 1.7 CONCLUSION Computer application, although may not be the answer to all problems, can play an important role in the development of shipbuilding industry in Malaysia. However, the result of the survey has clearly indicated that in general (with the exception of few large shipyards) the computer application in the local shipyards is at infancy stage. In view of the globalization era, where more fierce international competition is expected, a serious and collective effort is inevitable. Several suggestions have been put forward in this paper in order for us to discuss, argue, agree and act upon. A research work on the development of local ship design software carried out in UTM is an indication that the first step of a long and challenging journey has already started 1.8 ACKNOWLEDGEMENT The authors wish to thank the following organizations and individuals for their support and contribution: MPKSN, IRPA committee, Research Management Centre and Department of Marine Technology, UTM. Special thanks also to all shipbuilding companies for their cooperation and support during the survey work without which this paper will not come to existence.

33 Computer Application in Malaysian Shipyards REFERENCES Alonso, F., Garcia, L., Brunet, P., (1997). Virtual Reality and Ship Design, ICCAS 97, Vol. 2, Gomez, P., (1997). Telematics: A Challenge to Concurrent Engineering, ICCAS 97, Vol. 2, Lofdahl, R.H., Martin, D.J. et al., (1994). The NIDDESC Ship Product Model: The STEP Solution, Journal of Ship Production. Ross, J. M., (1995). Integrated Ship Design and its Role in Enhancing Ship Production, Journal of Ship Production, February Ross, J. M., and Horvath, J. A., (1997). Shipbuilding CAD/CAM/CIM: How World class Companies are applying the State of the Art, ICCAS 97, Vol. 1, Toroja, J. and Alonso, F., (1999). Developments In Computer Aided Ship Design and Production, The Royal Institute of Naval Architects, London.

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35 Malaysian Ocean Data Collection Using Satellite Remote Sensing 25 2 MALAYSIAN OCEAN DATA COLLECTION USING SATELLITE REMOTE SENSING Omar Yaakob Kamaludin Omar Maged Marghany Norazimar Zainuddin Mohd Arizam Abdul Wahap 2.1 INTRODUCTION Oceanographic data is required for most coastal science and engineering applications. Examples of such data include wave heights, wave periods and sea level variability. Waves are generally the most important environmental factor producing forces on offshore structures. The design of offshore structures used for oil and gas present problems, due to environmental hazards from wind and current forces and the weight of the structure. In traditional design techniques the structure is first designed to withstand the most severe conditions which it is likely to meet in 50 or 100 years. Thus, as well as an estimate of extreme wave conditions; the statistics of all waves throughout the year have to be specified. In addition to wave heights and wave periods, sea spectra are also important input in analysis of ocean structures. Wave data is also seen in ocean renewable energy work, particularly in development of wave energy devices. Accurate

36 26 Advances in Marine Technology 2006 prediction of wave heights, periods and probability of occurrence are required to determine the performance of these devices. Long-term sea level height variations are an important indicator for climate changes. Detection of sea-level variation will enable us to predict effects of environmental concerns over global warming. Over a long period, coastal tide gauges have provided the main technique to measure sea level changes. The limited number of tide gauges and their respective locations has hampered a more comprehensive monitoring of such effects. This Chapter reviews traditional methods of obtaining such data and presents new remote-sensing-based methods which can improve the accuracy and comprehensiveness of such data. In this age of globalisation, cooperative work between Universities and research institutions from various countries are becoming a norm. The Chapter also includes a description of two examples of research collaborations undertaken by Universiti Teknologi Malaysia (UTM) in gathering ocean data using satellite remotesensing. 2.2 WAVE DATA SOURCES Wave data are traditionally obtained through wave buoys or visual observations records. Buoy measurement is considered to be one of the best sources of information since it measures wave directly, however it has a disadvantage of limited number of deployments for vast area of the oceans. In Malaysia, there are very few operational wave buoys and thus there is a heavy dependence on visual observation records such as that published Marine Meteorology and Oceanography, Malaysian Meteorological Service, for example MMS (1999) and by British Maritime Technology (1986). A description of these data has been presented in papers by Yaakob et.al. (2004), (2004a). The accuracy, reliability and comprehensiveness of such data which is based on voluntary reporting have often been questioned

37 Malaysian Ocean Data Collection Using Satellite Remote Sensing 27 for example by Sinkai and Wan (1996). Because the visual data usually come from ship reports in main shipping routes, these data bring up some shortcomings due to observation itself. Firstly, the wave height reported in adverse climatic conditions tend to be overestimated by the observer and secondly, more ships sail in good weather conditions consequently samples are biased toward lower wave height values. The result is that this sample does not fit accurately of the lognormal model, which is usually appropriate for wave study, when the observations reported as calms are included in the sample. Besides wave heights and periods, wave spectra are also required to describe the distribution of energy in the waves. This is required especially in carrying out sea keeping analysis of floating vessels. In Malaysia, the study of ocean wave spectra is only carried out in UTM. The work is reported in Omar et. al (2003) and Adi et. al (2006). They reported field measurement of ocean waves and ship motions and derived sea spectra from the measured data. The studies concluded that Pierson-Moskowitz spectrum shows the best correlation to the measured data in Malaysian waters. The weakness in this study is the limited amount of data gathered. The sea spectra obtained are based only on short-term data measured in a few locations over a few hours. In addition, due to limitation in the measuring instruments, no directional effects are taken into consideration. 2.3 LOCAL MEAN SEA LEVEL DATA Southeast Asia region is characterized by its unique geographical and geophysical settings. It shares continental and archipelagic parts. The archipelago consists of thousands of islands. The entire area is located in the boundaries between two continents, Asia and Australia, and between two major oceans, Pacific and Indian Oceans. Most of Southeast Asian countries are bordered by sea and a large number of populations inhabit low lands in coastal areas.

38 28 Advances in Marine Technology 2006 Due to the aforementioned facts, better knowledge of sea level behaviour in this region becomes important. There are several factors that may cause the sea level height vary from time to time, i.e. local processes, ocean circulation change, global and regional climate change, and geological processes. Long term sea level height variations are a valuable indicator of global climate change. There are several possible negative impacts due to the sea level rise to coastal environment in the future such as beach erosion, inundation of land, increase flood and storm damage, increase salinity of coastal aquifers, and coastal ecosystem loss. Therefore, an understanding of past and future changes in sea level and related ocean are important in coastal management. During the past centuries, coastal tide gauges have provided the main technique to measure sea level change. There are two main problems faced in monitoring regional sea level changes by using tide gauge in the region: Only few tide gauge stations provide long records, mostly belonging to Thailand and Malaysia. Uneven geographical distributions because the tide-gauge stations are usually installed on coastal areas and there are no long term records from the deep ocean. Furthermore, the stations in Indonesia are very limited in number, so the Indonesian waters are not well covered by tide gauge observation. Local mean sea level (MSL) in Malaysian seas has traditionally depended on tide gauges. A network of continuously operating tide gauge stations has been established since 1984 along the coastal areas of Malaysia. The main objective of the establishment of the network is to enable continuous time series of sea level heights to be obtained for the purpose of establishing a vertical datum for the nation. The available tidal records and their MSL values are given in Figure 2.1. Analysis of this data shows that trends do exist in the sea level

39 Malaysian Ocean Data Collection Using Satellite Remote Sensing 29 height around Malaysia and varies quite significantly from one location to another. Also, the linear trends of the MSL variations are positive, indicating an overall rise in the sea level around the coast of Malaysia. Height(m) Kukup Port Klang Bintulu K. Kinabalu Sandakan Lahat Datu Tawau Tg. Keling Johor Bahru Tioman Tg. Gelang P.Pinang Tg. Sedeli P.Langkawi Geting Lumut Cendering Figure 2.1 Yearly mean sea levels measured by tide gauge stations in Malaysia 2.4 OCEAN WAVE DATA THROUGH REMOTE SENSING Space borne sensors such as satellite altimeters provide long-term and continuous coverage of wave and wind fields of the world oceans. One of the first satellites that used altimetry technology in the measurement of sea levels was the Seasat A. In the 1990s with more complex and advanced imaging and altimetry systems, radar remote sensing has become a more significant tool and has been utilized by the ERS- 1, Geos-3 and TOPEX/Poseidon

40 30 Advances in Marine Technology 2006 satellites. Details can be found in Fu and Cazenave (2001). In 1992 TOPEX/Poseidon satellite altimetry mission was launched and its mission was ended in Since then it was replaced by Jason-1. Both satellite missions provide the most precise altimetry data when compared to others. In UTM, studies on satellite remote sensing are carried out in the Department of Marine Technology and in the Faculty of Geoinformation Science and Engineering. The use of satellite remote sensing to obtain wave data is carried out in two directions. First, research work is continuing to deal with satellite altimetry to obtain wave heights and periods and secondly, Synthetic Aperture Radar (SAR) images are used to derive sea spectra Wave Heights and Periods Data To obtain wave heights and periods, satellite altimetry is used. Yaakob et.al. (2004, 2005) reported work currently being carried out at Universiti Teknologi Malaysia to derive wave heights and wave periods for Malaysian sea areas. This work was carried out as part of collaboration programme under Japan Society for Promotion of Science (JSPS) Core University Cooperation Program in Marine Transportation Engineering. The group consists of members from Hiroshima University, Universiti Teknologi Malaysia and Bogor Institute of Agriculture. In Malaysia, the project is supported by the National Oceanographic Directorate at the Ministry of Science and Innovation. The work in UTM is based on data gathered from TOPEX/Poseidon (TOPEX) satellite. The method consists of accessing data from the TOPEX website and processing using some algorithm to obtain wave heights. Since TOPEX data do not include wave periods, work in UTM mainly focused on developing methods for derivation of wave periods from TOPEX data. Data is presented in scatter-diagram format familiar to engineers. The data is being processed and will be made available to the internet. A

41 Malaysian Ocean Data Collection Using Satellite Remote Sensing 31 trial website has been completed. Most of this work has been reported by Omar et. al (2004, 2004a). It has been shown that more comprehensive data can be obtained for all sea areas using satellite altimetry data. Comparison with presently available data based on visual observation has shown encouraging results. The data provided by satellite can be used to derive wave periods, which can then be used to obtain joint probability distribution of wave heights and periods. Three methods to derive wave periods were studied. The results indicate that the method proposed by Hwang et. al (1997) produced similar trends with the local measured wave heights and periods distribution data Derivation of Sea Spectra Another group in UTM is studying possibility of developing ocean wave spectra using SAR images. Studies in derivation of wave spectrum are based on processing of Synthetic Aperture Radar (SAR) images. The work in this area has been reported in Maged and Mansor (1997) and Maged (2001). The Synthetic Aperture Radar (SAR) produces an image of the sea surface and the analysis starts by a 2D spectral analysis of subsets of the image. The following section provides an example of application of such method. Figure 2.2 shows the regions of interest that is used to model the wave spectral information. The wave spectral information is extracted from the average of the 12 sub-images; each sub-image was 512 by 512 pixels. The average sub-images spectral information were used with quasi-linear and velocity bunching model. Figure 2.3 show the comparison between in situ wave spectra, observed ERS-1 wave spectra, and velocity bunching models. These wave spectra were presented in polar plots. These circular areas indicate individual wavelength peak

42 32 Advances in Marine Technology 2006 spectra propagation. The wavelength unit is meter (m). These scales indicate the change of wavelength spectra in the circular areas with distance of peaks from the centre being inversely proportional towards its wavelength. The angular position of the peaks indicates the wave propagation direction, which are inherently ambiguities with the 180 opposite direction. This finding confirms the study by Maged et. al (2002) which reported that the Fourier spectrum of single image inherently contains 180 ambiguity in the propagation direction. This means that each wave system is therefore, represented by two radially symmetric peaks. Figure 2.2 Sub-images were used to derive ERS-1 Wave Spectra Figure 2.3(a) indicates that the in situ wave data showed the northeast wave propagated at 15, 30 and 75, respectively away from the azimuth direction (Figure 2.3a). In situ wavelength was found to be between 90 m to 200 m. The ERS-1 observed wave

43 Malaysian Ocean Data Collection Using Satellite Remote Sensing 33 spectra during December 1999 yield 0 away from the azimuth direction. The ERS-1 wavelength spectrum was ranged between 50 m to 300 m. This means that the dominant wave was an azimuthally travelling wave (Figure 2.3(b)). (a) (b) Range Azimuth (c) Figure 2.3 Wave Spectra Models (a) in situ (b) ERS-1 and (c) Velocity Bunching during December 1999 Figure 2.3(c) shows that the wave spectra generated by velocity bunching model yields wave spectra by 58 away from the azimuth direction. The wavelength was observed from velocity bunching

44 34 Advances in Marine Technology 2006 model ranged between 50 to 250 m. The in situ wave spectra peaks are similar to velocity bunching model. The ERS-1 wave spectra yield by 20 away from the azimuth direction. The wavelength was observed from ERS-1 ranged between 100 to 280 m. This indicates that the velocity bunching model produced a better agreement with in situ data compared to ERS-1 observed spectrum. 2.5 OCEAN SEA LEVEL MONITORING THROUGH REMOTE SENSING Although satellite altimetry records are still quite short compared to the tide gauge data sets, this technique appears quite promising for sea level change problem because it provides sea level measurement with large coverage. A precision of about 1 mm/year of measurement global change can be obtained. To improve sea level monitoring in South East Asia Region, a project was initiated to utilise TOPEX/ Poseidon and Jason-1 satellite altimetry data in measuring sea level heights for long term sea level change monitoring purpose. The project is part of South East Asia Mastering Environmental Research using Geodetic Space Techniques programme (SEAMERGES) under the in the field of the application of satellite altimetry technology for earth dynamic monitoring. This programme which is supported and funded by the European Union (EU) brings together four universities: Delft University of Technology (The Netherlands), Universiti Teknologi Malaysia (Malaysia), Chulalongkorn University (Thailand), and Institut Teknologi Bandung (Indonesia). Comparisons between about ten years (January 1993 July 2002) of TOPEX/Poseidon and tide gauge data are analysed. Nine tide gauge stations, 2 stations in Thailand and 7 stations in Malaysia are chosen for the investigation where the TOPEX tracks are nearby to the tide gauge locations, as shown in Figure 2.4.

45 Malaysian Ocean Data Collection Using Satellite Remote Sensing 35 Sea level time series data based on tide gauge and TOPEX altimetry observations at Koh Taphao Noi (Figure 2.5) and Koh Lak (Thailand) have the same characteristics in both variation patterns and linear trend rates. The linear trend differences 1.5 mm/year and 0.1 mm/year respectively. Figure 2.6 shows the variation of sea level obtained from TOPEX and tide gauge in Port Klang and Tioman (Malaysia). Similarity in the pattern of sea level variations indicates good agreements between TOPEX altimetry and tide gauge stations. Due to the narrowness of Malacca Straits, sea level variation at Port Klang area appears to be noisy than other areas. Overall, the differences of linear trend between TOPEX and tide gauge are considered small, within -3.4 to 1.0 mm/year (Table 2.1). K KOH Figure 2.4 Selected tide gauges locations Satellite altimetry records may still be too short to compare with multi-decadal tide gauges but the results discussed above may hardly be comparable to those tide gauges in ten years record. However, the comparison of TOPEX and tide gauges observations showed good agreement, and therefore both techniques are

46 36 Advances in Marine Technology 2006 competitive. Figure 2.5 Sea level variations at Koh Taphao Noi: tide gauge (above) and TOPEX (below)

47 Malaysian Ocean Data Collection Using Satellite Remote Sensing Port Klang - Tide Gauge 50 Tioman - Tide Gauge Monthly Mean Sea Level (cm) mm/year Monthly Mean Sea Level (cm) mm/year Port Klang - Topex 50 Tioman - Topex mm/year mm/year Monthly SSE(cm) 10 0 Monthly SSE(cm) Figure 2.6 Sea level variations at Port Klang and Tioman from tide gauge and TOPEX Location Data Used Linear Trend (Tide Gauge) Linear Trend (TOPEX) Table 2.1 Linear trend of sea level from tide gauges and TOPEX (mm/yr) P.Klang K. P. Tioman Bintulu Tawau Miri Kinabal u Kudat Difference

48 38 Advances in Marine Technology CONCLUSIONS Satellite remote-sensing technology provides a means as a complementary tool to the traditional ways in measuring ocean characteristics. This is very useful particularly for the Southeast Asian region where the measuring stations such as wave buoys and tide gauges are still limited both in number and geographical distribution. This technology is able facilitate the demand for ocean waves and ocean tide data in almost every part of the area. However, satellite remote-sensing records may still be short to detect long term ocean data statistics such as long term sea spectra and sea wave level rise possibly associated with global warming. 2.7 ACKNOWLEDGEMENT The authors wish to thank National Oceanographic Directorate and MOSTI who supported the project under the IRPA programme. Special thanks are due to Division of Marine Meteorology and Oceanography, Malaysian Meteorological Service for their support and assistance. The authors are also grateful to the European Union for its support for the SEAMERGERS programme. Continuing support from JSPS for the wave data study under the Asian Cooperation Programme is also greatly appreciated. 2.8 REFERENCES Adi Maimun, Omar Yaakob, Md. Ahmad Kamal, Ng Chee Wei, (2006), Evaluation of Sea keeping Analysis of a Fishing Vessel using a Wave Buoy and Onboard Motions Monitoring Device, Regional Conference on Vehicle Engineering and Technology, Kuala Lumpur, July 2006

49 Malaysian Ocean Data Collection Using Satellite Remote Sensing 39 BMT (1986), British Maritime Technology Ltd.,. Global Wave Statistic. Unwin, London. Fu, L-L. and Cazenave, A. (ed.), (2001). Satellite Altimetry and Earth Sciences: A Handbook of Techniques and Application, Academic Press, UK. Hwang, P.A., Teague, W.J., Wang D.W.C., Thompson, E.F., Jacobs, G.A. (1997) A Wave/Wind Climatology For The Gulf of Mexico, Proceeding of 7th International Offshore and Polar Engineering Conference, USA. Maged M., (2001). TOPSAR wave spectra model and coastal erosion detection. Int. J. Applied Earth Observation and Geoinformation, (3) (4): Maged, M.M., and Mansor, S.B. (1997). Offshore and Onshore Wave Spectra along Chendering Coastline. Proceedings of 18th Asian Conference on Remote Sensing. October Kuala Lumpur, pp.g-5-1-g-5-6. MMS(1999), Malaysian Meteorological Services Department (MMS), Monthly Summary of Marine Meteorological Observation, 1999, 2000, Omar Yaakob, Adi Maimun Abdul Malik, Koh Kho King, A. Haris Muhammad And Dony Setyawan, (2003), Wave Data Collection And Modelling For Engineering Applications, International Hydrographic and Oceanographic Industry 2003 Conference, Kuala Lumpur, July 2003 Omar Yaakob, Norazimar Zainuddin, Ramli Shariff (2004a), Developing Malaysian Ocean Wave Database Using Satellite Altimetry, 5th Regional Conference on Marine Technology, Johor Bahru, September Omar Yaakob, Norazimar Zainudin, Yahya Samian, Adi Maimun Abdul Malik, Robiahtul Adawiah Palaraman (2004), Developing Malaysian Ocean Wave Database Using Satellite, 1st Asian Space Conference, Chiang Mai, November Shinkai A. and Wan S., (1996). Statistical Characteristics of the Global Wave Statistics Data and Long-term Predictions, ASME, Japan.

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51 A Study on Dynamic Interaction of Ships While in Speed 41 3 A STUDY ON DYNAMIC INTERACTION OF SHIPS WHILE IN SPEED M. Rafiqul Islam Md. Nazrul Islam Md. Sadiqul Baree 3.1 INTRODUCTION As a vessel travels across the water surface, a variable pressure distribution develops along the length of vessel. The pressure rises at the bow and stern and drops along the midsection. These pressure gradients, in turn, generate a set of waves that propagate out from the vessel bow and another generally lower set of waves that propagate out from the vessel stern. The pressure distribution along the hull of a vessel significantly causes lateral forces and horizontal moments to act on the vessel when it passes another vessel or moves in close proximity to other structure or channel bank as because unsymmetrical flow occurs around the hulls. The interacting lateral forces and horizontal moments are complex; continually change while the ships are in the proximity of each other, and dependent on hull sizes, vessel speeds, directions, lateral separation; and water depth. One of the first papers on interaction of floating bodies was published by Ohkusu (1969), where the series expansion method was employed and only heave motion was considered. He extended the classical solution for a single heaving circular cylinder, first developed by Ursell (1949), to the case of two cylinders in a

52 42 Advances in Marine Technology 2006 catamaran configuration. This type of two-dimensional analysis is most relevant to the interactions between adjacent ship hulls in beam seas. More extensive computations and experiments were published in his subsequent paper (Ohkusu, 1970) and a subset of these results is included in a survey (Ohkusu, 1996). Ohkusu (1976) also dealt with the problem for a ship oscillating in the vicinity of a structure by an approximate method. In his results, he clearly illustrated the effects of position of a smaller body on the weather and lee side against a large body. Motivated by practical designs for offshore platforms with multiple columns, Ohkusu (1972) also developed a three-dimensional technique using the eigenfunction expansions for single axisymmetric cylinders to account for their mutual wave interactions. His first paper presented at an international symposium (1974) summarized and extended both of these pioneering contributions, and brought his work to the attention of the international community. Kodan (1984) extended Ohkusu's method (1976) to investigate the effects of hydrodynamic interaction between two parallel slender structures in oblique waves and compared it with model experiments to support the validity of strip method, but the speed effect was not included. The assumption of infinite depth was common to most of the published works in ship hydrodynamics (Garrison, 1974). On the other hand 3D-source distribution technique in most published works has been outlined only for zero forward speed (Faltinsen and Michelsen, (1974), Garrison (1974)). Van Oortmersen (1979) also used the three-dimensional diffraction theory to compute hydrodynamic interactions between two bodies. However, they did not apply their method to ship configurations and did not consider the speed effect either. Loken (1981) analyzed the wave-induced motions and wave drifting forces and moments without forward speed on several close vessels in waves; the results were satisfactory except for the resonance region. Due to lack of computational resources, his work was restricted to simple body shapes represented by rather large panels. Islam (2001) studied Motions and Non-linear Second order Drift Forces of Multi-Body Floating Systems in Waves using 3D

53 A Study on Dynamic Interaction of Ships While in Speed 43 source distribution technique. Ali (2003) studied hydrodynamic interaction and dynamic behaviour of multiple floating bodies using 3D source distribution technique where he employed lid technique for removal of irregular frequency. These research works were also carried out without the effect of forward speed. The works mentioned above may be useful for some practical purposes. However, the speed effect has been not considered, which is important. Chen and Fang (2001) developed a method of solving interaction problem of two adjacent ships moving with same forward speed in waves using three-dimensional approach. But for simplicity again they used Green function and its derivatives with zero forward speed and infinite depth of water. In present paper, 3D source distribution technique and speed dependent Green function have been employed for prediction of forces and motions of closely running ships. 3.2 MATHEMATICAL MODEL Coordinate System and Assumptions Individual ship is treated as a rigid body having six degrees of freedoms. The ship is subjected to hydrodynamic forces due to incident waves and radiated and diffracted waves due to other ship(s). The model focuses on the motion analysis of two ships without mechanical connections.

54 44 Advances in Marine Technology 2006 Figure 3.1 Coordinate systems for two ships advancing in waves. The right-handed coordinate systems are defined in Figure3.1. O a -X a -Y a -Z a and O b -X b -Y b -Z b are fixed on ship a and ship b, respectively, which translate with the forward speed velocity U a and U b. Here same speed (i.e. U =U a =U b ) has been shown for both the ships. The O-X-Y-Z system is the inertial coordinate system. The X-axis points forward, the Z-axis (not shown in the sketch) is assumed to be vertically upward and the O-XY plane rests on the calm water surface. The incident wave angle is denoted as χ. The fluid is assumed to be incompressible, inviscid and irrotational. Then there exists a velocity potential satisfying Laplace equation together with boundary conditions on the free surface, on the body, and at the bottom, and the radiation condition in the far field. The resultant velocity potential on ship a and ship b in the fluid can be written as 6 6 φ = φ + φ + φ + φ X + φ X (3.1) a Ia Daa Dba jraa j = 1 ja jrba j = φ b = φ Ib + φ Dbb + φ Dab + φ jrbb X jb + φ jrab X (3.2) ja j = 1 j = 1 where incident wave potential, jb

55 A Study on Dynamic Interaction of Ships While in Speed 45 φ I g cosh [ k ( z + h )] ik ( x cos χ + y sin χ ) = (3.3) ω 2 cosh( kh ) e e φ Ia, φ Ib : the potential of incident wave on ship a and ship b φ Daa, φ Dba : the diffraction potential on ship a due to ship a or ship b φ Dbb, φ Dab : the diffraction potential on ship b due to ship b or ship a φ jraa, φ jrab : the radiation potential on ship a or ship b due to oscillation of ship a while ship b is fixed φ jrba, φ jrbb : the radiation potential on ship a or ship b due to oscillation of ship b while ship a is fixed X ja, X jb : the response motion of mode j of ship a or ship b, respectively; j=1,2,3...,6 for surge, sway, heave, roll, pitch and yaw. ω e : encountering frequency and is defined as: χ : wave heading angle from X -axis k.: wave number h : depth of water Equations of Motions The boundary conditions and limitation for solving the hydrodynamic coefficients for a parallely moving ship are described by Islam et al. (2008). The equation of motion for a parallely moving ship can be written as: 6 j = 1 m m m m m m m ( M kj + akj ) X&& j + bkj X& j + CX j = Fk, ( k = ), (3.4)

56 46 Advances in Marine Technology 2006 where, M kj m a kj m b kj m inertia matrix in k - mode due to the motion in j - mode, : added mass coefficient matrix of kj, : :damping coefficient matrix of kj, C : hydrostatic restoring force coefficient matrix of kj, X j m : vector containing the three translational and three rotational oscillations about the co-ordinate axes in j -mode. The suffices k, j =1, 2, 3, 4, 5, 6 represent surge, sway, heave, roll, pitch and yaw modes, respectively and m =1, 2 number of ships. The hydrodynamic coefficients are calculated using the mathematical derived by Islam et al. (2008). The set of the linear equations have been solved by Gaussian elimination method. Table 3.1 Particulars of the ships (separated by m from centre to centre) Ship Mariner ship (right, weather side) Series 60 ship (left, lee side) Block coefficient L (m) B (m) T (m) Displacement Ton VALIDATION On the basis of the model a computer program has been developed and computation of wave forces /moments and motions of a ship plying in weather side close proximity of another ship running in the same direction and speed has been carried out. The particulars

57 A Study on Dynamic Interaction of Ships While in Speed 47 of the ships are furnished in Table 3.1. The mesh arrangements of the ships are shown in Figure 3.2. Figure 3.2 Mesh arrangement of the Mariner (right) and the Series 60 ship (left) Non-dimensional Heave Force Present Work Chen and Fang (2001) Fn = 0.14, χ = 45 deg Ship : Mariner Non-dimensional Pitch Moment Present work Chen and Fang (2001) Fn = 0.14, χ = 45 deg Ship : Mariner λ/l λ/l Figure 3.3 Validation of Heave Force Figure 3.4 Validation of Moment The results have been compared with the published results of Chen and Fang (2001) for the ship pair shown in the Table 3.1. The comparisons of the results of heaving force and pitching moment have been presented in the Figure 3.3 and 3.4. In the case of pitching moment author's results and that of Chen and Fang are

58 48 Advances in Marine Technology 2006 very close to each other. How ever in case of heaving forces there is minor difference especially at higher wavelength ratios. These minor differences between present results and Chen and Fang (2001) ones may be due to differences in the Green Functions used. It may be noted again here that Chen and Fang have used zero speed Green Function but in present work Speed dependent Green Function has been used. Due to lack of availability of experimental results comparison could not be made with experimental ones. However, the results obtained employing speed dependent Green function is expected to be more realistic Non-dimensional Sway Force Mariner alone Mariner with Series 60 Fn = 0.14, χ = 180 deg Non-dimensional Heave Force Mariner alone Mariner with Series 60 Fn = 0.14, χ = 180 deg Encountering Frequency (ω e ) Encountering Frequency (ω e ) Figure 3.5 Effect on Sway Force Figure 3.6 Effect on Heave Force 3.4 EFFECTS OF INTERACTIONS Case - I: Ships are running at same speed To examine the effects of ship interaction on the wave exciting forces, moments and motions, some computations have been performed for the same pair of ships mentioned above at head sea condition. The results are plotted against encountering frequency in the Figures 3.5 to Figures 3.5 to 3.9 present Forces &

59 A Study on Dynamic Interaction of Ships While in Speed 49 Moment results and while that of Figures 3.10 to 3.15 present Motions results. Figure 3.5 shows that at head sea condition the Mariner ship experiences almost nil/zero sway force where as in the case of interaction with the Series 60 ship sway force on Mariner increases especially around the encountering frequency 0.8. So there is an influence of interaction effect on sway force. On the contrary, Figure 3.6 shows that heave force decreases due to interaction especially at low frequency. Pitch moment shows almost similar nature of effect of interaction on it (Figure 3.8). Figure 3.7 shows that the Effect of interaction on Roll moment is negligible Non-dimensional Roll Moment Mariner alone Mariner with Series 60 Fn = 0.14, χ = 180 deg Non-dimensional Pitch Moment Mariner alone Mariner with Series 60 Fn = 0.14, χ = 180 deg Encountering Frequency (ω e ) Encountering Frequency (ω e ) Figure 3.7 Effect on Roll Moment Figure 3.8 Effect on Pitch Moment In Figure 3.9 the yaw moment, like that of sway force in Figure 3.5, increases due to interaction at low frequency, especially at the frequency ranging from 0.90 to 1.3. From the Figures 3.5 to 3.9, it is observed that there is significant influence of interaction on heave force & pitching moment especially at low frequency range and negligible influence in the case of sway force, roll & yaw moment. Figure 3.10 shows that effect of interaction on surge motion. It is seen from this figure that at around frequency of 0.50, the surge motion has a sudden rise in contrast to the surge motion of single Mariner. This may be due to the irregular frequency

60 50 Advances in Marine Technology 2006 effect, because in case of surge force there is no influence of interaction and as such it is expected to have no influence on surge motion Non-dimensional Yaw Moment Mariner alone Mariner with Series 60 Fn = 0.14, χ = 180 deg Non-dimensional Surge Motion Mariner alone Mariner with Series 60 Fn = 0.14, χ = 180 deg Encountering Frequency (ω e ) Encountering Frequency (ω e ) Figure 3.9 Effect on Yaw Moment Figure 3.10 Effect on Surge Motion Figure 3.11 shows that like sway force, sway motion too increases at low frequency region and in addition to that high sway motion amplitude fluctuates significantly. In Figure 3.12 heave motion also fluctuates and some sudden jumps are seen, especially at frequency Comparing with Figure 3.6, the heave motion is expected to be less than that in case of Mariner alone. But sudden jumps of heave motion or motion due to interaction and also may be due to irregular frequency or resonance. Figures 3.13 and 3.14 reveal that effect of interaction decreases roll and pitch motions significantly. Figure 3.15 shows that like yaw moment, yaw motion too increases at low frequency region due to interaction with closely running ship.

61 A Study on Dynamic Interaction of Ships While in Speed 51 Non-dimensional Sway Motion Mariner alone Mariner with Series 60 Fn = 0.14, χ = 180 deg Encountering Frequency (ω e ) Non-dimensional Heave Motion Mariner alone Mariner with Series 60 Fn = 0.14, χ = 180 deg Encountering Frequency (ω e ) Figure 3.11 Effect on Sway Motion 1.0 Figure 3.12 Effect on Heave Motion 1.6 Non-dimensional Roll Motion Mariner alone Mariner with Series 60 Fn = 0.14, χ = 180 deg Non-dimensional Pitch Motion Mariner alone Mariner with Series 60 Fn = 0.14, χ = 180 deg Encountering Frequency (ω e ) Encountering Frequency (ω e ) Figure 3.13 Effect on Roll Motion Figure 3.14 Effect on Pitch Motion 1.0 Non-dimensional Yaw Motion Mariner alone Mariner with Series 60 Fn = 0.14, χ = 180 deg Encountering Frequency (ω e ) Figure 3.15 Effect on Yaw Motion

62 52 Advances in Marine Technology Case - II: Ships are running at different speed Another preliminary calculation has been performed for a pair of an LNG carrier and a ship like structure FPSO running parallely at same Froude number (0.10) but at different speed. The respective speed with particulars of the LNG and the FPSO are furnished in Table 3.2. Table 3.2 Principal particulars of the LNG and the FPSO (The lateral distance between the two ships is 8.68 meter) LNG (right) FPSO (left) Speed (Knot) Length, L m m Breadth, B m m Depth, D m m Draft, T m m Displacement, m m 3 Block Coefficient, C b The mesh arrangement of the LNG-FPSO is presented in Figure 3.16 and some of their head sea results (exciting forces, moment and motions due to surge, heave and pitch) of ship LNG with or without FPSO) are presented in Figures 3.17 to 3.22.

63 A Study on Dynamic Interaction of Ships While in Speed Non-dimensional surge force LNG alone LNG with FPSO Fn = 0.10, χ=180 deg Surge Force Encountering frequency (ω e ) Figure 3.16 Mesh arrangement of LNG and the ship like structure (FPSO) Figure 3.17 Effect on Surge Force The figures show in general that the effect of interaction at different running speed is more significant than case-i i.e. ships running at same speed. In case of LNG with FPSO, the peak value in all the cases of motions due to surge, heave and pitch are found to shift towards left to that in case of LNG alone (Figures 3.20 to 3.22). This may be due to maximum values of heave, surge forces and pitch moment, which exist towards left than that in case of LNG alone as shown in Figures 3.17 to CONCLUSIONS From the above results of the two cases and discussions, following conclusions may be drawn: Effects of interaction between parallely moving ships for head sea condition show that for such interaction, lateral (Sway) force and motions and also horizontal (Yaw) moment and motion have negligible influence but in case of heave

64 54 Advances in Marine Technology 2006 and pitch the influence is significant, especially at low frequency range. Effects of interaction are more significant for the ships running at different speed. The program developed for computing the interaction forces/moments as well as motions of closely running ships numerically expected to be able to predict satisfactorily and it may be used for evaluating safe navigation of ships in infinite and finite depth open water / harbours and water ways. It may be used for evaluating safe navigation of other type of movement (overtaking/meeting) of closely running ships Non-dimensional Heave Force LNG alone LNG with FPSO Fn=0.10, χ=180 deg Heave Force Non-dimensional Pitch Moment LNG alone LNG with FPSO Fn=0.10, χ=180 deg Pitch Moment Encountering frequency (ω e ) Encountering frequency(ω e ) Figure 3.18 Effect on Heave Force Figure 3.19 Effect on Pitch Moment Non-availability of experimental data, validation of interaction forces and moments has been made by comparing with available computed results only. Therefore, experimental work is recommended for further research.

65 A Study on Dynamic Interaction of Ships While in Speed LNG Alone LNG WITH FPSO Fn = 0.10, χ = 180 deg Surge Motion LNG ALONE LNG WITH FPSO Fn = 0.10, χ = 180 deg Heave Motion X 1 /ζ a 0.5 X 3 /ζ a Encountering Frequency (ω e ) Encountering Frequency (ω e ) Figure 3.20 Effect on Surge motion Figure 3.21 Effect on Heave motion 4 LNG ALONE LNG WITH FPSO Fn = 0.10, χ = 180 deg Pitch Motion X 5 /κζ a Encountering Frequency (ω e ) Figure 3.22 Effect on Pitch Motion REFERENCES Ali, M.T., (2003). A study on Hydrodynamic Interaction and Dynamic Behaviour of Multiple Floating Bodies. PhD Thesis, Yokohama National University, Japan. Brard, R., (1972). The representation of a given ship form by singularity distribution when the boundary condition on the free surface is linearized. Journal of ship research. Chen Gung-Rong, Fang Ming-Chung., (2001). Hydrodynamic

66 56 Advances in Marine Technology 2006 interactions between two ships advancing in waves, Ocean Engineering 28. pp Faltinsen, O. & Michelsen, F., (1974). Motions of large structures in waves at zero Froude number, Proc. Intl Symp. on the Dynamics of Marine Vehicles and Structures in Waves, London, pp Faltinsen, O. M. & Michelsen, F. C., (1975). Motions of Large Structures in Waves at zero Froude number, International Symposium on the Dynamics of Marine Vehicles and Structures in Waves, Mechanical Engineering, Published in London. pp Garrison, C. J., (1974). Dynamic response of Floating Bodies, Proc. Offshore Technology conference, Paper No. OTC 2067 Garrison, C. J., (1978). Hydrodynamic Loading of Large Offshore Structures, Three Dimensional Source Distribution methods, Numerical Methods in Offshore Engineering, pp Hogben, N. and Standing R. G., (1975). Wave Loads on Large Bodies, International Symposium on the Dynamics of Marine Vehicles and Structures in Waves, Mechanical Engineering, Published in London, pp Inglis, R. B. and Price, W. G., (1981). A Three Dimensional Ship Motion Theory-Comparison between Theoretical predictions and Experimental Data of the Hydrodynamic Coefficients with Forward Speed, RINA. Inglis, R. B. and Price, W. G., (1981). A Three Dimensional Ship Motion Theory: Calculation of Wave Loading and Responses with Forward Speed, RINA (1981) Inglis, R. B. and Price, W. G., (1980). Calculation of the Velocity Potential of a Translating, Pulsating Source, RINA. Islam, M. R., (2001). A Study on Motions and Non-linear Second order Drift Forces of Multi-Body Floating Systems in Waves. PhD Thesis, Yokohama National University, Japan. Islam, M. R., (2008). Effect of Vessel Interaction on Hydrodynamic Forces While Advancing Closely in waves.

67 A Study on Dynamic Interaction of Ships While in Speed 57 The Proceedings of MARTEC. Kodan, N., (1984) The motions of adjacent floating structures in oblique waves. The 3rd International Symposium on Offshore Mechanics and Arctic Engineering. Løken, A., (1981). Hydrodynamic interaction between several floating bodies of arbitrary form in waves, Intl. Symp. on Hydrodynamics in Ocean Engineering, Trondheim, pp Ohksu, M., (1969). On the heaving motion of two circular cylinders on the surface of a fluid. Reports of the Research institute of Applied Mechanics, Kyushu University (Japan), Vol. 17, No. 58. Ohkusu, M., (1970). On the motion of multi hull ship in waves, J. Society of Naval Architects of West Japan, 40, Ohkusu, M., (1972). Wave action on groups of vertical circular cylinders (in Japanese), J. Society of Naval Architects of Japan, pp Ohkusu, M., (1974). Hydrodynamic forces on multiple cylinders in waves, Proc. Intl. Symp. on the Dynamics of Marine Vehicles and Structures in Waves, London. Ohksu, M., (1976). Ship motions in vicinity of a structure, Proc. 1st Intl. Conf. on the Behaviour of OffShore Structures (BOSS 76), Trondheim, pp Ohkusu, M., (1996). Hydrodynamics of ships in waves, Advances in Marine Hydrodynamics, Computational Mechanics Publications, Southampton, UK, pp Salvesen, N., Tuck, E. O. And Faltinsen, O., (1970). Ship Motions and Sea Loads, SNAME, s. 78, pp Ursell, F., (1949). On the heaving motions of a circular cylinder on the surface of a fluid, Quarterly J. of Mechanics and Applied Mathematics, pp Van Oortmerssen, G., (1979). Hydrodynamic interaction between two structures, floating in waves, Proc. 2nd Intl. Conf. on Behaviour of Offshore Structures (BOSS 79), London, pp Vugts, J. H., (1971). The Hydrodynamic Forces and Ship

68 58 Advances in Marine Technology 2006 Motions in Oblique Waves, Research Centre, TNO for Shipbuilding, Delft Report No Wehausen J. V. and Laitone., (1960). Surface Waves", "Encyclopedia of Physics, Vol. 9, Springer-Verlag, Berlin.

69 Bulbous Bow Application for Malaysian Fishing Boat 59 4 BULBOUS BOW APPLICATION FOR MALAYSIAN FISHING BOAT KOH Kho King THONG Jia Rong 4.1 INTRODUCTION Admiral David. W. Taylor was first to introduce bulbous bow to ship design (Bill, 1986). In 1950s, bulbous bow was designed to reduce the drag on large commercial cargo ships. In 1970, bulbous bow was fitted into battleship Delaware, which produced outstanding performance. With model testing and advanced knowledge of hydrodynamics, bulbous bow was formulated to give reduction in fuel consumption over a narrow range of speed and draft. With the success of larger ships, smaller vessels follow attached bulb in order to achieve the same result of reduction in fuel consumption. Bulbous bow application in fishing vessel begins with large ocean trawler and followed by the smaller fishing vessel in the Europe. Malaysian fishing vessels were mainly of traditional design, built using wood by skilful craftsman. It is the purpose of this research to study the effect of bulbous bow design on ship resistance on Malaysian purse-seiner.

70 60 Advances in Marine Technology MODEL AND BULBOUS BOW PARTICULARS The subject of study is a Malaysian fishing vessel, purse-seiner, named Perintis TRF Perintis TRF 1010 is an offshore fishing vessel, purse seiner C2 class, GRT above 70, owned by Universiti Teknologi Malaysia and is currently operated offshore of Terengganu. Perintis TRF 1010 hull form was designed according to traditional fishing vessel of east coast of Peninsular Malaysia and constructed using wood. Table 4.1 Principal particulars of Perintis TRF 1010 in full scale and model scale PRINCIPAL PARTICULARS FULL SCALE PERINTIS TRF 1010 MODEL SCALE MTL 008 UNIT S LOA m LBP m LWL m B moulded m Bwl m Dmoulded m T (above keel) m T (below keel) m C b C p C m Volume Displacement m 3 Weight Displacement kg Wetted Surface m 2 LCG m VCG m Service Speed knots

71 Bulbous Bow Application for Malaysian Fishing Boat 61 Principal particular of Perintis TRF 1010 in full scale and model scale is shown in Table 4.1, with scale ratio of 1:32. Model designation of Perintis TRF 1010 is named as MTL 008. Offset table of bulbous bow is shown in Table 4.2. Table 4.2 Offset Table of Bulbous Bow Half Breath (mm) Height Above Baseline (mm) Station Waterline Buttock Line /2 1 1/ FP / / / / The researcher refer to Bil (1986), Kratch (1978), Watson & David (1998) and Zhuo (2002) to summary a methodology of bulbous bow design for Malaysian fishing vessel (purse seiner) Basically, this methodology of bulbous bow design divide into 3 phases. PHASE I PHASE II PHASE III Procurement Vessel Hydrostatics Data Bulbous Bow Shape and Parameter Bulbous Bow NURBS Modelling Body plan of Perintis TRF 1010 with bulbous bow is shown in Figure 4.1.

72 62 Advances in Marine Technology 2006 Figure 4.1 Body plan of Perintis TRF 1010 with bulbous bow Visual comparison of Perintis TRF 1010 hull form with and without bulbous bow are shown in Figure 4.2 and 4.4. Figure 4.2 Perintis TRF 1010 hull form without bulbous bow

73 Bulbous Bow Application for Malaysian Fishing Boat 63 Figure 4.3 Perintis TRF 1010 hull form with bulbous bow Bare hull of model of Perintis TRF 1010 is shown in Figure 4.4. Model of Perintis TRF 1010 with bulbous I shown in Figure 4.5. Figure 4.4 Bare hull model of Perintis TRF 1010

74 64 Advances in Marine Technology 2006 Figure 4.5 Model hull form with bulbous bow 4.3 MODEL TESTS RESULTS AND FULL SCALE EXTRAPOLATION Resistance test for MTL 008 (model scale of Perintis TRF 1010) had been carried out at Marine Technology Laboratory, Universiti Teknologi Malaysia. Table 4.3 Water density and kinematic viscosity Temperature deg, T ( ) Water density (kg/m3) Water kinematic viscosity (x10-6 m2/s) Towing Tank Sea Water

75 Bulbous Bow Application for Malaysian Fishing Boat 65 Two tests have been carried out: calm water model bare hull test and calm water bulbous bow model test. MTL 008 was tested at m full load draught above keel. Table 4.3 shows towing tank and sea water density and kinematic viscosity used in the research (Lewis, 1988) Model Test Results Form factor value was determined by conducting model tests at very low forward speed, and Prohaska plot was plotted for the determination of form factor value as in Figure 4.6. From the Figure, the obtained (1+k) value is Resistance coefficient from model tests for bare hull condition is shown in Figure 4.7. Resistance coefficient from model tests with bulbous bow attached is shown in Figure Prohaska's Plot Ctm/CFOM y = x Fn 4 /C FOM Figure 4.6 Prohaska plot

76 66 Advances in Marine Technology Resistance Coefficient Coefficient Froude Number (Fn) Cv Cr Ct Figure 4.7 Model test results (bare hull) Resistance Coefficient Coefficient Froude Number (Fn) Cv Cr Ct Figure 4.8 Model test results (with bulbous bow) Model tests result were extrapolated to full scale results by using

77 Bulbous Bow Application for Malaysian Fishing Boat 67 ITTC 1978 method. Viscous resistance coefficient, residuary resistance coefficient and full scale effective power comparison for Perintis TRF 1010 bare hull and with bulbous bow were shown in Figure 4.9 to In Figure 4.9, it can be seen that MTL 008 with bulbous bulb produces slightly higher viscous resistance than bare hull condition, which is due to the increment of wetted surface area. MTL 008 with bulbous bow shows nearly identical residuary resistance at Froude number 0.14 to 0.23, but more significant differences at higher Froude number. Residuary resistance in the model tests are mainly coming from the wave making resistance, which is more significant at higher Froude number (higher speed). Bulbous bow plays important role in reducing wave making resistance, hence the reduction of residuary resistance for model with bulbous bow at higher Froude number. Coefficient Viscous Resistance Coefficient, Cv Froude Number (Fn) Bulbous Bow Bare Hull Figure 4.9 Full scale viscous resistance coefficient comparison Figures 4.10 and 4.11 show the full scale total resistance and effective power comparison of MTL 008 extrapolated to full scale

78 68 Advances in Marine Technology 2006 for bare hull condition and with bulbous bow attached. From the figure, it can be seen that bulbous bow is only effective at ship speed of above 8 knots, more significant at 10 knots and above. At ship speed below 8 knots, viscous resistance is higher than the wave making resistance that is able to be reduced by the bulbous bow, hence the resultant total resistance of model with bulbous bow is of higher resistance than bare hull condition. The percentage in reduction of total resistance at service speed 10 knots between bare hull and with bulbous bow attached is around 7% while at 11 knots maximum speed is around 5% Residuary Resistance Coefficient, Cr Coefficient Foude Number (Fn) Bulbous Bow Bare Hull Figure 4.10 Full scale residuary resistance coefficient comparison

79 Bulbous Bow Application for Malaysian Fishing Boat 69 Full Scale Total Resistance, R TS Resistance (kn) Speed (knots) Bulbous Bow Bare Hull Figure 4.11 Full scale effective power comparison Full Scale Effective Power, P ES Effective Power (kw) Speed (knots) Bulbous Bow Bare Hull Figure 4.12 Full scale effective power comparison

80 70 Advances in Marine Technology Model Test Observation During the model tests, MTL 008 with bulbous bow attached was found to have less wave generated around the bow than bare hull model, shown in Figure This coincides with the model test results of reduction in residuary resistance for model with bulbous bow attached at full scale service speed of 10 knots. 4.4 CONCLUSIONS Study of the resistance and wave making effect of bulbous bow on a Malaysian fishing boat, purse-seiner type, was conducted. The bulbous bow designed by the researcher with length of bulbous bow, L PR = 1.24m and breadth of bulbous bow, B B = 1.16m shown satisfactory results in reducing the wave making resistance, total resistance and effective power through the model resistance test in the towing tank of Marine Technology Laboratory, Universiti Teknologi Malaysia at full load draught 2.145m (above keel) in calm water condition. With bulbous bow, the vessel is able to reduce on full scale resistance and effective power by 7.36 % at 10 knots service speed and 4.85 % at 11 knots maximum speed. At speed above 8.5 knots, the vessel attached with bulbous bow starts showing the benefit reduction of full scale total resistance. At speed below 8.5 knots, there is a tendency increment in the full scale total resistance due to the increment of wetted surface area.

81 Bulbous Bow Application for Malaysian Fishing Boat 71 (Bare hull at 10 knots) (MLT 008 with bulbous bow at 10 knots) Figure 4.13 Model tests at full scale ship service speed 10 knots 4.5 FUTURE STUDY Bulbous bow has shown good reduction in wave resistance in high Froude number for Malaysia fishing boat. Further studies in the aspects of economical, sea comfortable, manoeuvring, and seakeeping tests should be conducted before the actual implementation of bulbous bow design to Malaysian fishing

82 72 Advances in Marine Technology 2006 vessel. The influences of draft (water line) to the location of bulbous bow can also be further investigated. 4.6 REFERENCES Bill, H. C., Bruce, H., Bruce, J., Bruce, H. and Jedd W. H., (1986). Bulbous Bow Design Methodology for High-Speed Ships. Transactions Society of Naval Architects and Marine Engineers. Vol. 94, pp Kracht, A. M. (1978). Design of Bulbous Bows. Transactions Society of Naval Architects and Marine Engineers. Vol 86. Lewis, E. V., (1988). Principles of Naval Architecture: Volume II Resistance, Propulsion and Vibratio. Jersey City, N. J.: The Society of Naval Architects and Marine Engineers. Watson and David, G. M., (1998). Pratical Ship Design. Amsterdam, New York: Elsevier. Zhuo, Y. T., (2002). The Effect of Bulbous Bow to the Resistance and Motion of Vessel. Master. Thesis. Taiwan University.

83 Bulbous Bow for High Speed Displacement Craft 73 5 BULBOUS BOW FOR HIGH SPEED DISPLACEMENT CRAFT M.P Abdul Ghani 5.1 INTRODUCTION The maritime industry is continuing to develop in response to new technology and customer demands. In 1998 the world's fast ferry market has been valued at approximately USD$4.5billion. Currently there are approximately 700 of such vessels around the world. Stena, for example, recently paid around 65M for their latest new vessel (Goodrich 1999). In recent years fast ferries which are capable of speeds in excess of 40 knots in water depth less than 10m has been operational. As high-speed operations move near to sensitive shorelines, complaints from the public on extensive wave wake or wake wash from these fast vessels also increase. Although the leading waves in the wash are very small in terms of wave amplitude compared to storm waves, they have a very long period and build in height rapidly in shallow water at the shoreline thereby causing substantial surges on beaches as well as breaching sea walls at high tide. This wake wash is likely to have environmental effects such as shoreline erosion as well as endangering swimmers and small boats. During 1997, as a consequence of public concern, the Danish Maritime Authority (1997) issued a governmental order which requires that the highspeed craft operator/owner has to show evidence that the ship-

84 74 Advances in Marine Technology 2006 generated waves do not exceed a prescribed wave height criterion in shallow water along the entire route. Similar criteria exist for other regions, such as the Puget Sound, Seattle, some navigable inland waterways in the Netherlands and the River Thames, UK (Hansen 1999). There are other which are equally sensitive to damage such as the Paramatta River in Australia, the Solent (i.e. particularly the route between Southampton and the Isle of Wight), Nantucket, the Mare Island Channel and the East Bay Estuary in San Francisco Bay. Wake wash or normally known as wash results from shipgenerated waves other than wave-making resistance. There is a general awareness of the importance of ship-generated waves in design. However, until recently, ship-generated wave analysis has not been fully considered in design studies except as one of ship's resistance component resulting from the energy expended in generating a wave pattern. As the design spiral is the traditionally accepted way of representing the ship design process, wash was not considered to be a part. The main dimensions and form are clearly fixed by other considerations. One may think of wash as another spoke of the wheel because the elements of design which affect wash are also directly related to ship performance such as resistance, stability, seakeeping, deadweight capacity etc (Abdul Ghani, 2003). 5.2 BACKGROUND Bulbous bows are used on almost all large modern ocean-going ships. It reduces the bow wave thereby making the ship more energy efficient. The bulbous bow actually creates it own wave, which cancels the hull's bow wave. A properly designed bulbous bow can certainly improve the running efficiency of a hull and reduce vertical acceleration. A number of new designs incorporate a bulbous bow and some in service yacht utilizes a retrofitting bulbous bow to improve their performance at sea. This study will

85 Bulbous Bow for High Speed Displacement Craft 75 focus the effect of bulbs on wake wash attributes such as its height, period etc generated by high-speed displacement craft. When low wash is the prime concern, catamaran hull might be an attractive alternative to monohulls, because of their inherent wave-cancelling potential. In the present study the NPL5b hull form series has been chosen as an object for further investigation (Abdul Ghani 2002). The aim of this work is to find the best combination of the existing hull form of the high-speed displacement (NPL5b) and bulbous bow/bulb type that have considerably less wake wash without compromising other attributes such as seakeeping ability and resistance & propulsion of the vessel. The approach of the study is to incorporate different bulbous bow into the existing NPL5b series hull form. The framework of the approach for undertaking the research outlined can be explained by addressing the following three phases of development: First Phase - Bulbous Bow Design. Second Phase - Model Preparation. Third Phase - Tank Testing. Figure 5.1 Type of Bulbous Bow

86 76 Advances in Marine Technology BULBOUS BOW FOR NPL5B HULL FORM Generally the type of bulb or bulbous bow can be broadly classified into three main types as shown in Figure 5.1. The main bulbous bow geometric parameters are volume and protruding length beyond forward perpendicular, L PR. According to the theory of bulbous bow, it has been established that the bulbous bow volume influences the size of the wave that is generated, while L PR determines the phase of the bulbous bow generated wave. In this study, the bulbous bow design was focused on varying the L PR.rather than it cross section. Bulbous bows with circular cross section are preferred for further investigation in relation to wave wash because of their simple construction procedure as well as other advantages. As mentioned by Schneekluth (1987), in his studies on this bulbous bow that the potential danger of slamming effects can also be avoided. This type of bulbous bow also recommended by Kracht (1978) for the slender hull form. It fits well with U and V types of forebody sections and offers space for sonar equipment if required. The diameter of the bulbous bow was chosen based on several design parameters as suggested by Kracht (1978), Hoyle (1986) and Roddan (1999). Consideration of those parameters, the 48mm diameter has been chosen for this particular model for further investigation. Although, the protruding length of the bulb beyond forward perpendicular, L PR is varied but it is not allowed to project longitudinally beyond the upper end of the stem for safety reasons, in consideration of anchor handling, docking and manouevring. Four different bulbous bows have been developed by varying the bulbous bow's projecting length L PR between 20mm and 100mm. These bulbous bows have been designed and faired to the parent hull, whilst the afterbody and the forebody from amidship to 0.3 L PR is kept unchanged. The cross section parameter, C ABT has been fixed at a value of i.e the ratio of bulbous bow cross section area at FP to the

87 Bulbous Bow for High Speed Displacement Craft 77 midship section area. Other bulbous bow details are shown in Table 5.1. Also, others bulbous bow nomenclature as described by Kracht (1978). Table 5.1 Bulbous Bow Parameters Item C LPR C BB C ZB C ABL C ABT C VPR Bulb Bulb Bulb Bulb EXPERIMENTAL WORK All the four model were tested in the Lamont Tank, University of Southampton, UK. The hull of the models was made of Glass Reinforced Plastics (GRP) with epoxy resin. They were built in two halves, one half from station 0 (AP) up to station 8 with their forms maintained as an original NPL5b hull and another half from station 8 to stem which have undergone slight modification in order to accommodate the bulbous bow. These two portions were joined at a bulkhead at station 8 and are removable. Details of the models used in the investigation are given in Table 5.2. The model was towed horizontally at the longitudinal centre of gravity and at an effective height one third of the draught above the keel. The models were fitted with turbulence stimulation studs of 3.2mm diameter and 2.5mm height at a spacing of 25mm. Those studs were situated 37.5mm aft of the stem. No underwater appendages were attached to the models. During the model tests to measure the wash, resistance and trim were also recorded. All tests were carried out in calm water over a

88 78 Advances in Marine Technology 2006 wide range of speeds corresponding to a range of length Froude numbers 0.3 to 0.6. All wave probes were located at the optimum longitudinal position for longest possible wave traces. Table 5.2 Model Particulars Item NPL o NPL b1 NPL b2 NPL b3 NPL b4 L,m B, m T,m , kg LCB, m WSA C B THEORETICAL APPROXIMATION Linearised wave resistance theory has been applied to various hullforms with varying success using the method developed by Mitchell. Although this method does not provide accurate quantitative results, it does provide quite realistic qualitative results for slender forms like the Wigley hull or typical catamarans. The setback in using thin ship theory occurs for broader hull forms near the limit of the thin ship theory. However, the hull form of interest in this task are generally very thin/slender with L/B in the order of more than 10. In this current work a computer program developed by Insel (1990) and updated by Couser (1998) has been used in order to predict wake wash produced by the hull with and without bulbous bow theoretically.

89 Bulbous Bow for High Speed Displacement Craft RESULTS Wave Traces or Wash There are several methods can be used to analyze the measured data. The first, is based on the wave energy approach i.e the calculation of the energy of the wave system at the measuring position. Secondly, it is based on the maximum and minimum amplitude of the generated wave or to find the highest wave in the measured data. The wave elevation for the model NPL5b series catamaran and monohull fitted with bulb01, bulb02, bulb03 and bulb04 with varying speed are shown in Figure 5.2 and Figure 5.3 respectively. The ship-generated waves or wash height is closely related to wave-making resistance of ship which varies with the length Froude number, Fn. Also the maximum wave height, H max is inversely proportional to a cubic root of a distance from sailing line, x. Considering this, the non-dimensional maximum wave height as shown in Equation (5.1) was introduced in order to investigate their changes with Fn. H nd = ( H max / B)(x/L) 1/3 (5.1) where, L and B represent a ship length and breadth respectively. As shown in Figures 5.4 and 5.5, the non-dimensional wave height for all models with and without bulb increase with Fn until a critical value. At Fn 0.5 they attain the peak values. When Fn>0.5, those values decrease with Fn. The changes of nondimensional maximum wave heights with Fn seem similar to those of wave-making resistance coefficients as expected. Although the data shows some scattering, it is clear that the non-dimensional

90 80 Advances in Marine Technology 2006 wave heights depend mainly upon the length Froude number as well as others parameter perhaps, such as depth Froude number, water depth to draught ratio etc Wave resistance Typical wave resistance results defined in the following equations for monohull and catamaran configurations respectively, are shown in Figures 5.6 and 5.7. C C W W = = C C T T (1 (1 + + k ) C F β k ) C F (5.2) (5.3) Where (1+k) and (1+βk) represent the form factor for monohull and catamaran respectively. Figures 5.8 and 5.9 are plots of the specific resistance against Froude number in monohull and catamaran s/l=0.2 configurations respectively Trim angles versus Froude number Figure 5.10 is a plot of trim angle against Froude number. Generally it shows that, for all four models, as speed increases, the trim angle also increases. It is interesting to note that as Fn>0.5 the hulls fitted with bulbous bow experienced more trim than the original hull without bulbous bow. It can also be noted that this plot indicates that the trim increases with the L PR of the bulbous bow itself.

91 Bulbous Bow for High Speed Displacement Craft Comparison of the numerical results with experimental Data Figures 5.11 and 5.12 show comparison between experimental and theoretical results. The discrepancies between the experimental and theoretical results may be due to inaccuracy in both the experiments and the theoretical method. Overall, it is believed that the phase shift between the theoretical and experimental results is probably caused by the asymmetric flow effect about each demihull which is not taken into account in the theoretical method bulb01 bulb02 bulb03 bulb04 wash height[mm] Catamaran s/l=0.2 x=0.634l, Fn= time[secs] Figure 5.2 Catamaran, s/l=0.2: Experimental wash height from different bulbs

92 82 Advances in Marine Technology monohull x=0.472l, Fn=0.40 bulb01 bulb02 bulb03 bulb04 5 Wash height[mm] time[secs] Figure 5.3 Monohull: Experimental wash height from different bulbs 700 Monohull: Non dimensional Wash Height Lamont tank Non dimensional wash height bulb01 bulb02 bulb03 bulb Froude No. Figure 5.4 Monohull:Non-dimensional maximum wave height

93 Bulbous Bow for High Speed Displacement Craft Catamaran, s/l=0.2: Non dimensional Wash Height Lamont tank Non dimensional wash height Froude No. ori bulb01 bulb02 bulb03 bulb04 Figure 5.5 Catamaran, s/l=0.2 :Non-dimensional maximum wave height 2 monohull bulb01 bulb02 bulb03 bulb04 Cw x Fn Figure 5.6 Monohull: Wave resistance

94 84 Advances in Marine Technology catamaran, s/l= ori bulb01 bulb02 bulb03 bulb Cw x Fn Figure 5.7 Catamaran s/l=0.2: Wave resistance Monohull:NPL5b Rt/Disp bulb01 bulb02 bulb03 bulb Froude No. Figure 5.8 Monohull: Specific resistance

95 Bulbous Bow for High Speed Displacement Craft catamaran, s/l= Rtm/Disp ori bulb01 bulb02 bulb03 bulb Fn Figure 5.9 Catamaran s/l=0.2: Specific resistance 3 Catamaran s/l= trim[deg] ori bulb01 bulb02 bulb03 bulb Fn Figure 5.10 Catamaran s/l=0.2: Running trim

96 86 Advances in Marine Technology 2006 wash height[mm] exp theory x=0.541l Bulb03 x=0.634l Bulb03 Bulb03 x=0.472l time[secs] Figure 5.11 Experimental and theoretical wash height at Fn=0.48 wash height[mm] Bulb03 exp theory x=0.634l Bulb x=0.541l Bulb x=0.472l time[secs] Figure 5.12 Experimental and theoretical wash height at Fn=0.54

97 Bulbous Bow for High Speed Displacement Craft CONCLUSION It should be underlined that, all results mentioned in this paper are based on the preliminary investigation of one NPL5b series high speed displacement hull form in monohull and catamaran (s/l=0.2) configurations. From this study it is seems that the bulbous bow has an important effect on the resistance and wash. The effects of the bulbous bow can easily be seen both on wash height and wave resistance. Also, it can be seen from the waves traces that the theoretically obtained traces is fairly close to those obtained from measurements taken from model tests. It also appears that the trace with the smallest distance from the model centreline is most accurate, and the trace farthest the least accurate. It is also important to note that those with circular cross section bulbous bows offer a significant reduction in wave making resistance coefficient as well as reduction in wash height together with the practical advantage of a simple construction procedure. 5.8 REFERENCES Abdul Ghani, M.P (2003), Design Aspects of Catamaran Operating at High Speed in Shallow Water. PhD thesis, University of Southampton Abdul Ghani, M.P and Wilson, P.A (2002), Wake Wash From High Speed Displacement Craft, Asia Pacific Workshop on Marine Hydrodynamics, Kobe, Japan Couser, P.R et al., (1998), An Improved Method for the Theoretical Prediction of the Wave Resistance using Slender Body Approach, International Shipbuilding Progress, Vol.45, 1998, pp Goodrich, D.(1999), Boat Race, Engineering, Vol. 240, No.11 Hoyle, J.W et. al, (1986), A Bulbous bow Design Methodology for High Speed Ships, SNAME Transactions, Vol. 94, 1986, pp.

98 88 Advances in Marine Technology Insel, M. (1990), An Investigation into the Resistance Components of the High Speed Displacement Catamarans, PhD thesis, University of Southampton Insel, M. and Molland, A.F, (1978), An Investigation into the Resistance Components of the High Speed Displacement Catamarans RINA Transactions, Vol. 134, 1992, pp Kofoed-Hansen, H. et al(1999), Prediction of Wake Wash from High-Speed Craft in Coastal Area, International Conference Hydrodynamics of High Speed Craft Kracht, A.M.(1978), Design of Bulbous bow SNAME Transactions,Vol. 86, 1978, pp Roddan, G. (1999), Bulbous bows for Trawler Yachts and the Long Range Cruiser, Fifth Annual West Marine Trawler Fest, Poulsbo, Washington, USA Wehausen, J.V. (1973), The Wave Resistance of Ships, Advance in Applied Mechanics, Vol. 13, 1973, pp Schneekluth, H and Betram, V.(1987), Ship Design for Efficiency and Economy, Butterworth-Heinemann

99 Ship Handling and Safety in Restricted Water 89 6 SHIP HANDLING AND SAFETY IN RESTRICTED WATER Adi Maimun A. Haris Muhammad 6.1 INTRODUCTION Restricted water may be defined as narrow channels or canals, waterway with vertical or over changing banks, or areas that include piers and breakwater. Obviously, most restricted water includes shallow water, and many include significant current and tide. All ships are required to be directionally controllable in the horizontal plane so that they can proceed on a straight path, turn or take other avoiding actions as may be dictated by the operational situation. They must further be capable of doing this consistently and reliably not only in calm water but also in waves or in conditions of strong wind. When a ship is proceeding in very shallow water or restricted water, its dynamic behavior is much different from that of the same ship proceeding in a wide stretch of deep water, because of changes in magnitude of the hydrodynamic forces and moments acting on it. Furthermore, above phenomenon is important from the viewpoint of manoeuvring safety, because manoeuvring ability becomes of critical importance in shallow water, as in harbors or other restricted waterway.

100 90 Advances in Marine Technology SHALLOW WATER EFFECT ON MANOEUVRING As a vessel moves through shallow water there is more resistance than normal to the inflow of water to replace that displaced by the hull. The propeller and hull are operating in a partial vacuum. The handling of the vessel becomes sluggish; in depths of water of one and a half times the vessel draught or less, the steering can become erratic. Consequently, in shallow water a vessel should only be operated at slow to moderate speeds. Some of the investigations of ship handling operations in shallow water obtained are influenced hydrodynamic force The Effect of Water Depth Relative to Ship Draught Yeh (1964) carried out model tests of seven different hulls in varying depths of water at different current velocities, and oriented at various angles to the axis flow of the current. Figure 6.1 is a plot of the non-dimensional side-force coefficient Y as a function of the ratio of the depth of water to the draught. For a ship lying at right angle to the current, the transverse side force, Y C, may be calculated from the equation: ' C 1 ' YC = YC ρ LHU 2 2 C where, L = Waterline length of ship H = Mean draught of ship U C = Current velocity ρ = Water density (6.1) The data in Figure 6.1 and data for other angles of flow have

101 Ship Handling and Safety in Restricted Water 91 been reduced to a series curve of side force and moment as a function of flow angle and depth to draught ratio (Figures 6.2 and 6.3). This curve will provide a rough estimation of hydrodynamics effects of shallow water. Figure 6.1 Effect of water depth on side force of a ship moored in a broadside (90-deg) current (Yeh, 1964) Figure 6.2 Non-dimensional side force coefficient as a functional of depth ratio and resultant flow angle (Yeh, 1964)

102 92 Advances in Marine Technology 2006 Figure 6.3 Moment coefficient as a functional of resultant flow angle for various depth draught ratios (Yeh, 1964) Effect of Water Depth on Turning Trajectories Currently, there are a number of theoretical and experimental methods for predicting ship manoeuvring in shallow water and also the effect of loading. As shown in Figure 6.4 examples of turning trajectories obtained in computer model simulations for various ships with changes in water depth illustrated how significant the turning trajectory can be influenced by water depth.

103 Ship Handling and Safety in Restricted Water 93 Figure 6.4 Effect of water depth on computer trajectory performance (Eda and Walden, 1979) Effect of Water Depth on Z-Manoeuvres The results of the Z-manoeuvres tests shown in Figure 6.5 indicate significant decrease in overshoot angle in going from deep to shallow water. Figure 6.5 Effect water depth overshoot angle at various ship speed ( Bindel, S., 1960)

104 94 Advances in Marine Technology SAFETY STANDARD IN SHIP MANOEUVRING The standard for ship manoeuvring has been developed by international Maritime Organization (IMO) to ensure safe operation of ships at sea. The standard provided criteria on the ship i.e.: 1. Turning Ability By turning circle with 35 or maximum rudder angle to port & starboard. Criteria: The advance should not exceed 4.5 ship lengths and the tactical diameter should not exceed 5 ship lengths. 2. Yaw checking ability, course keeping ability By zig-zag tests with a known rudder angle alternatively to port and starboard when a known heading deviation from original heading is reached. Criteria: a. The value of the 1 st overshoot angle in the 10 /10 zig-zag test should not exceed 10 if L/V is less than 10 seconds 20 if L/V is 30 second or more: and [ ( L / V )] degree if L/V is 10 s or more but less than 30 second b. The value of the 2 nd overshoot angle in the 10 /10 zig-zag test should not exceed the above criteria value for the 1 st overshoot by more than 15 c. The value of the 1 st overshoot angle in the 20 /20 zig-zag should not exceed 25

105 Ship Handling and Safety in Restricted Water INTERACTION EFFECTS DUE TO CLOSE PROXIMITES OF BOUNDARIES When a ship moves through water of unrestricted depth and width, the lines of flow go not only around the side of the ship but also along the bottom of the ship. In shallow water, the flow under the hull is restricted, causing greater flow along the sides. This change in flow in turn change the side forces and moments acting on the ship and hence the hydrodynamic derivatives of the ship. In addition to being shallow, the channel is also restricted in width, as in a canal, the hydrodynamic derivatives are even more severely altered that they are in shallow water of unrestricted width Bank Effects Bank effects are significant when the vessel sails close to the side of the waterway. These effects are introduced by the different in flow of each side of the vessel as is shown in Figure 6.6. Often the bank effect is described as bank suction. Figure 6.6 Force acting on the ship in a canal (Abkowitz, 1964)

106 96 Advances in Marine Technology 2006 As shown in Figure 6.6, the increase in velocity of flow between side hull and nearest quay wall, creates the side force and moment. Further study by Vantorre (1998) on the effect of lateral restriction with special attention to hydrodynamic phenomena affecting a ship which is moving laterally towards a vertical boundary included interaction with effect due to (low) forward speed and propeller actions. It was concluded that the intensity of the interaction depends on the distance between ship and quay wall Interaction Between Ships Even in deep water, interaction effect can be significant when two ships are in close proximity. The pressure field created by a ship moving ahead in open water is illustrated in Figure 6.7. its actual form depending on the ship form. Figure 6.7 Pressure field for ship in deep water

107 Ship Handling and Safety in Restricted Water 97 The pressure field extends for a considerable area around the ship, and any disturbance created in this field necessarily has its reaction on the forces acting on the ship. If the disturbance takes place to one side of the ship, it is to be expected that the ship will, in general be subject to a lateral force and a yawing moment. Figure 6.8 Measured interaction force and moment (and correction rudder angle) between two ships on parallel courses as larger ship overtakes the smaller (Newton, 1960)

108 98 Advances in Marine Technology 2006 For predicting interactions ship to ship concerned forces and moments (Figure 6.8) have been developed and in reasonable agreement with available model test data. The interaction force and moment in a channel may be assumed to depend only on transverse distance, and the ship s yaw angle. In the case of one ship passing close to another, the interaction forces are functions also of the longitudinal distance, separating the two ships as well as the lateral distance and the yaw angles, plus the relative sizes of the ship. Figure 6.8 summarizes the most significant result reported By Newton (1960), two models were towed without propeller and with β = δ R = 0 on parallel straight courses at different longitudinal position relative to each other over a range of fullscale speed from 10 to 20 knots, and the Y-force and N-moment acting on each model in each position was measured The Sinkage and Trim Effect in Shallow Water In a bulletin entitled Notes on Ship Controllability, (1983) Tuck presented results obtained from theoretical studies on the problem of sinkage and trim of ship in shallow and restricted water. Sinkage is defined here as the downward vertical displacement of ship center of gravity, and positive trim as the bow up angle of rotations of the ship about its center of gravity. Squat is the resultant movement due to sinkage and a bow-up rotation. In many cases, trim can be negative owing to low-speed operation in shallow water. In Figure 6.9, as examples of computation of sinkage and trim, Tuck shown curves of sinkage against Froude number, Fh for values of width/length of infinity, 3.4, 1.0 and 0.5. Froude number here is based on water depth, i.e.,

109 Ship Handling and Safety in Restricted Water 99 Fh = U gdw (6.2) Tuck s theory predicts the points on the curve shown in figure 10 for ships moving along the centerline of a channel that has vertical walls. Since the points calculation cover wide ranges of practical ship forms and ship speeds, the curves may be considered as the universal curves of sinkage and trim. In the figure, _ W is the effective width of the canal relative to ship length, i.e., _ W = 2 ( W / L) 1 Fh (6.3) The figure 6.10 shows that the effect of the finite width is much larger for sinkage that it is for trim. A sufficient amount of bottom clearance is one of the crucial requirements for ship operating in a canal. Figure 6.11 shows contour of speed as limited in canals of various size to enable the ship to clear the bottom of the canal. These curve were obtained by using the following semi-empirical equation which is based on model test result. 2 2 pq( m 1) F l = 2 m 1 (1 ) q + me n where, F l = Limited Froude number, U / gl p = Draught /ship length, H/L q =1/(1+e), where e=0.24 from test result m =water depth/ship draught, Dw/H n =ship beam/canal width, B/W 1 (6.4)

110 100 Advances in Marine Technology 2006 Figure 6.9 Sinkage at various widths (Tuck, 1967) Figure 6.10 Sinkage and trim at finite width relative to infinite width (Tuck s theory)

111 Ship Handling and Safety in Restricted Water 101 Figure 6.11 Limiting speed in canal based on squat (Eda, 1971) 6.5 OTHER EFFECTS Other effects, such as wave, wind and current affect the vessel behavior during manoeuvring in restricted water, anchoring, mooring, docking and etc. Wind, waves, current forces affect the horizontal motion of a vessel. The operator has no control over them. These forces cause the vessel to drift, and also affects the speed and heading angle. The operator must use environmental forces to their advantage and use propulsion and steering to overcome the environmental forces. Usually, a good mix of using and over coming environmental forces results in smooth, safe boat handling Effect of Wind The wind acts on the hull topsides, superstructure, and on smaller boats, crew. The amount of surface upon which the wind acts is

112 102 Advances in Marine Technology 2006 called sail area. The vessel will make leeway (drift downwind) at a speed proportional to the wind velocity and the amount of sail area. The aspect or angle the vessel takes due to the wind will depend on where the sail area is centered compared to the underwater hull s center of lateral resistance. A vessel with a high cabin near the bow and low freeboard aft (Figure 6.12) would tend to ride stern to the wind. If a vessel s draught is shallower forward than aft, the wind would affect the bow more than the stern. A sudden gust of wind from abeam when mooring a vessel like this might quickly set the bow down on a pier. Knowledge of how the wind affects a vessel is very important in all close quarters situations, such as docking, recovery of an object in the water, or manoeuvring close aboard another vessel. If manoeuvring from a downwind or leeward side of a pier, it is best to be within the wind shadow created by the pier in blocking the wind (Figure 6.13). Account for the change in wind by planning manoeuvres with this wind shadow in mind Effect of Waves Waves are a product of the wind acting on the surface of the water. Waves affect boat handling in various ways, depending on their height and direction and the particular vessel s characteristics. Vessels that readily react to wave motion, particularly pitching, will often expose part of the underwater hull to the wind. In situations such as this, the bow or stern may tend to fall off the wind when cresting a wave, as less underwater hull is available to prevent this down wind movement. Relatively large seas have the effect of making a temporary wind shadow for smaller vessels. In the trough between two crests, the wind may be substantially less than the wind at the wave crest. Very small vessels may need to make corrective maneuvers in the trough before approaching the next crest.

113 Ship Handling and Safety in Restricted Water 103 Broaching or broaching-to, described the loss of directional stability in waves induced by large yaw moment exceeding the course keeping ability of the rudders. Orbital motion of water particles in the wave can result in a zero flow past the rudders, which become ineffective. This loss can cause the ship to turn beam on to the waves. The vessel might even capsize due to a large roll moment arising from the forward momentum and the large heading angle. The effect is greater because the ship hydrostatic stability is often reduced by the presence on the waves. Broaching is likely when a ship is running with, or being slowly overtaken by the waves. It may be sudden, due to the action of a single wave, or be cumulative where the yaw angle builds up during a succession of waves. Although known well since man put to sea in boats, broaching is a highly non-linear phenomenon and it is only relatively recently that good mathematical simulations have been possible. When the encounter frequency of the ship with the waves approaches zeros the ship become trapped by the wave. The ship remains in the same position relative to the waves for an appreciable time. It is then said to be surf riding. This is a dangerous position and broaching is likely to follow. The master can get out of this condition by a change of speed or direction, although the latter may temporarily result in large roll angles Effect of Current Current will act on a vessel s underwater hull. Though wind will cause a vessel to make leeway through the water current will cause drift over the ground. A one-knot current may affect a vessel to the same degree as 30 knots of wind. Strong current will easily move a vessel upwind. As with wind, a large, stationary object like a breakwater or jetty will cause major changes in the amount and direction of current (Figure 6.14). Caution should be taken when manoeuvring

114 104 Advances in Marine Technology 2006 in close quarters to buoys and anchored vessels. The effect of current can be observed by looking for current wake or flow patterns around buoys or piers. Environmental conditions can range from perfectly calm and absolutely no current to a howling gale at spring tides. Chances are that even if one does not operate at either extreme, some degree of environmental forces will be in action. The operator should know how his vessel responds to combinations of wind and current and determine which one has the greatest effect on his vessel. It may be up to a certain wind speed, current has more control over a given vessel, but above that certain wind speed, the boat sails like a kite. For example, if a sudden gust of wind is encountered, the boat may immediately veer, or it may take a sustained wind to start it turning. When current goes against the wind, the wave patterns will be steeper closer together. Where current or wind is funneled against the other, tide rips, breaking bars, or gorge conditions frequently occur in these types of areas and may present a challenge even to the most proficient coxswain. Figure 6.12 High cabin near bow, low freeboard aft

115 Ship Handling and Safety in Restricted Water 105 On the other hand, making leeway while drifting downstream (down current) requires a change in approach to prevent overshooting in the boat s landing. Figure 6.13 Wind shadow Figure 6.14 Effects of current

116 106 Advances in Marine Technology 2006 In the case of docking or mooring, wind and current are among the most important forces to consider in manoeuvring. The operator should use them to advantage, if possible, rather than attempting to fight the elements. Spring lines are very useful when mooring with an off dock set or when unmooring with an on-dock set. Use the spring lines to spring either the bow or stern in or out (See Figure 6.15). Figure 6.15 Making use of current Anchoring Two factors which must be considered when anchoring a ship are the distance the ship is fixed objects, such as the shoreline, and the distance the ship is from other moving objects, avoid any fixed objects are: i. The length of ship ii. The length of cable to be let out to allow the anchor to secure itself at the observed water depth iii. The safety factor

117 Ship Handling and Safety in Restricted Water 107 Consequently, the radius distance used to eliminate collision with other anchored ship is twice the distance determined from fixed objects. In restricted water or heavy weather it may helpful to set two anchors. These will reduce the circle through which the boat swings as the wind and the tide change; they will also increase the holding power. In a tidal stream the two anchors are normally in line with the tidal stream the two anchors are normally in line with the tidal flow with the vessel lying between them (Figure 6.16a). In threatening weather anchors should be set ahead of the vessel, one on either bow. The angle between then should be about (Figure 6.16b) Figure 6.16 (a) Single and two anchors

118 108 Advances in Marine Technology 2006 Figure 6.16 (b) Anchors for heavier weather 6.6 RESEARCH AT UTM - UTILISATION OF TIME DOMAIN SOFTWARE FOR THE SAFE DESIGN OF VESSELS In their paper, Maimun. et al. ( 2001 ) showed the use of a time domain simulation program to evaluate the dynamic stability and seakeeping performance for a vessel operating in astern waves. These results help in the design of vessels for safety against dynamic effects of following seas situation. This is crucial for small vessels entering harbour areas with relatively large astern seas situation. The presented results obtained from simulation studies show the effects of hull form parameters such as L/B and C pla /C plf ratios on the ship stability and seakeeping performance. In this evaluation, it is assumed that the wave is the only external force to induce the motion of the vessel.

119 Ship Handling and Safety in Restricted Water 109 To evaluate the influence of hull form variation on the dynamic stability, the hull forms, which have different geometries, are simulated in the computer program. In the parametric study, the vessel is travelling in astern seas at the speed ratio, V S /V W range of 0.2 to 0.8. Wave height is increased or decreased to obtain the most critical condition where the vessel may capsize. Figures 6.17 and 6.18 show the results of changing L/B and C pla /C plf on the dynamic stability respectively. The curves show the boundary of capsize or non-capsize situation for the vessel travelling in astern sea. In this study, roll angle is used to determine the critical situation. If roll angle is more than 100 degree, it is considered that the vessel has capsized. To investigate the effect of hull form variation on the seakeeping performance, the ratios of motion responses: heave, pitch and roll to the wave amplitude are used. For the simulation runs, one meter wave height and the wave length equal to vessel length are selected. The speed ratio is varied to obtain the different motion characteristics. As an example, Figure 6.19 and Figure 6.20 show the results of the roll motion responses due to the change of L/B and C pla /C plf respectively. Wh (m) L/B Speed ratio, Vs/Vw L/B = 3.0 L/B = 3.5 L/B = 3.8 Figure 6.17 Boundary curves of changing L/B.

120 110 Advances in Marine Technology 2006 Based on the simulation results, the outcome of varying hull form on dynamic stability and seakeeping analysis can be given as follow: i. L/B which gave the lowest motion response and comparable dynamic stability could be determined. ii. A certain C pla /C plf gave the best dynamic stability. iii. An L/B and C pla /C plf ratios could be found to define the vessel with the most optimum dynamic stability and seakeeping value. Wh (m) CPLA/CPLF Speed ratio, Vs/Vw CPLA/CPLF = CPLA/CPLF = CPLA/CPLF = Figure 6.18 Boundary curves of changing C pla /C plf. In another paper, Maimun et al. (2002) presented results obtained from theoretical and experimental studies on the effect of heeling in ship manoeuvring. The heeling effect on a ship manoeuvring was conducted using captive model in the UTM towing tank. The manoeuvring

121 Ship Handling and Safety in Restricted Water 111 derivatives were obtained using the PMM (Planar Motion Mechanism) attached to the towing tank. The derivatives were then incorporated into the time domain simulation program developed using MATLAB. It was found from the simulation that the resulting heel angel could significantly impair the manoeuvrability of the vessel during turning. Figure 6.21 Turning circle with fixed heel angle to port side. Results from simulation program given by Figures 6.21 and 6.22 shows the turning circle tactical diameter for a starboard turn will increase with increment of heeling angle to starboard, and vice versa with increment of heeling angle to port. This indicates that the vessel will have a better turning ability with heel angle outwards (portside) to its running path. The advance distance of heeling outwards (portside) decrease remarkably with the increment of heel angle. However the decrease of advance of outwards heeling angles is less significant.

122 112 Advances in Marine Technology 2006 Referring to simulation result of turning circle in Figure 6.23, the speed of the vessel also effect the turning ability of the vessel. The vessel with higher forward speed will have better turning ability. This in mainly because rudder effectiveness will increase with increasing speed. However, the advance for the case of higher speed is relatively big due to limitation of rudder turning rate. Figure 6.22 Turning circle with fixed heel angle to starboard side. In order to study the turning manoeuvre simulation, the vessel was free to roll with different KG heights. The heel angle will be affected by the location of KG. The vessel with KG higher than the center of lateral force will have outwards heel angle. However with KG lower than the center of lateral force (not usual in real situation) the heel angle will be acting in ward the turning circle. Figure 6.24 shows the turning paths for various KG conditions. The advance and tactical diameter for case of higher KG will be smaller.

123 Ship Handling and Safety in Restricted Water 113 However, Figure 6.25 shows that the heeling angle is higher at higher KG. This means that the vessel is more prone to capsizing and thus, there should be a maximum limit for the value of KG for safe turning during manoeuvring. Figure 6.23 Turning circle with various speed conditions Figure 6.24 Turning circle with various KG conditions

124 114 Advances in Marine Technology 2006 Figure 6.25 Heel angles at various KG condition Figures 6.26 and 6.27 illustrate the overshoot angle for various speed and KG conditions in the zig-zag manoeuvre. It is obvious that the overshot angle will decrease with the increase of the speed. This is due to the effectiveness of rudder increase with increase of speed. Meanwhile, for higher value of KG, the overshoot angle will be slightly larger Comparison with IMO criteria The IMO criteria require that the advance of turning circle should not exceed 4.5 ships length. From simulation result in Figure 6.28 most of the lower KG conditions did not satisfy this requirement. Event though the result for higher KG this requirement. Consequently the heel angle would be larger and hence exhibit another serious stability problem, if not considered seriously,

125 Ship Handling and Safety in Restricted Water 115 would lead to the capsize of the vessel. For analysis of the tactical diameter, most of the conditions fulfill the requirement of not exceeding 5 ship s length as shown in Figure Figure 6.26 Zig-zag manoeuvre at various speed conditions. Figure 6.27 Zig-zag manoeuvre at various KG conditions.

126 116 Advances in Marine Technology 2006 Figure 6.28 Advance distance at various KG conditions Meanwhile, Figure 6.30 shows the overshoot angles at different heights of KG. The overshoot angles for all cases exceed the criteria, which is 25. This indicates that the control effectiveness of the vessel is not sufficient.

127 Ship Handling and Safety in Restricted Water 117 Figure 6.29 Tactical diameter at various KG conditions 6.7 CONCLUSIONS i. A description of vessel manoeuvring behavior in restricted water is given. ii. The hydrodynamic effects due to shallow water and boundaries could be well explained from the many research conducted experimentally and theoretically. iii. Wind, current and waves have very significant effect on the behavior of the vessel and should be considered in their operations. iv. The use of time domain simulation could be utilised in improving vessel safety design

128 118 Advances in Marine Technology 2006 Figure 6.30 Overshoot angle of 20/20 at various KG conditions 6.8 REFFERENCES Bindel, S Experiments on the Ship Manoeuvrability in Canals as Carried Out in the Paris Model Basin: First Symposium on Ship Manoeuvrability. David Taylor Model Basin Report 1461 (Oct. 1960). Eda, H Notes On Ship Controllability (Revised). New York: Technical & Research Bulletin SNAME. Maimun, A. Wong, K.S. and Yeak, S.H The Effect Of Hull Form Variation On Dynamic Stability And Seakeeping Performance For Vessels Operating In Astern Seas.

129 Ship Handling and Safety in Restricted Water 119 Universiti Teknologi Malaysia. Johor. Malaysia: Marine Technology 2001, Universiti Teknologi Malaysia, Johor, Malaysia, 30 th 31 st Oct Maimun, A. Loh, S.P. and Lee, R Manoeuvring Assessment of a Fishing Vessel. Hiroshima. Japan: Proceeding of DGHE JSPS. Seminar on Marine Transportation Engineering. Newton, R.N Interaction Effects Between Ships Close Aboard in Deep Water: SNAME Transactions. Vol. 68. Peyton, D.R A Discussion on Ship Movement and Ship Handling. SE University of New Brunswick Canada: Hydrographic Operations. Dept of Surveying Engineering. Tuck, E.O Sinkage and Trim in Shallow Water in Finite Width: Schiffstechnik. Bd. 14. Vantorre, M. and Laforce, E Experimental Investigation of Hydrodynamic Force Acting on a Ship in the Vicinity of a Quay Wall. Val de Reuil. France: Proceeding of DGA. International symposium and Workshop on Force Acting on a Manoeuvring Vessel. Yeh, H NS Savannah Shallow Water Mooring Test: DTRC Report August 1964.

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131 Effect of Double Chine on Planing Hull Vessel Performance EFFECT OF DOUBLE CHINE ON PLANING HULL VESSEL PERFORMANCE Adi Maimun A. Haris Muhammad Ahmad Fitriadhy A. Zulkhairullah S. Vigneshwaran 7.1 INTRODUCTION In recent years, the use of high-speed vessels particularly planing craft for performing various tasks has dramatically increased. Many researches in planing hull seakeeping technology have quantified the relations between hull form, loading, speed/length ratio, sea state and the expected added resistance, motions and wave impact accelerations. The process of optimization of hull form for achieving the best hull shape was studied by Valdenazzi, As noted, the shape with the best performance at sea, are in terms of hydrodynamic behaviors, structural robustness, transport capability, operational and economic merit. Referring to other hull forms of planing craft performance at sea, the planing hull form with hard chine yields more efficient high-speed lift capability and better seakeeping ability, Libby (2003). The Marine Technology Department of Universiti Teknologi Malaysia (UTM) had conducted a research on performance of

132 122 Advances in Marine Technology 2006 planing hull form in order to find the cause of large roll motions and propose ways of reducing them. A study was carried out on a single chine 22 meters long patrol boat to improve the seakeeping capability by incorporating side keel to the vessel, Maimun (2002). With the incorporation of double chine, a larger above water volume would result in higher metacentric height and thus increase in stability as the vessel is heeled. The additional chine would also result in higher damping, resulting in lower roll motions especially near the resonance frequency. 7.2 PLANING HULL FORM Planing hulls are hull forms characterized by relatively flat bottoms and shallow V-sections (especially forward of amidships) that produce partial to nearly full dynamic support for light displacement vessel and small craft at higher speeds. These types of hull form lift and skim the surface of the water causing the stern wake to break clean from the transom. The crafts are generally restricted in size and displacement because of the required power-to-weight ratio and the structural stresses associated with traveling at high speed in wave. Most planing hull crafts are also restricted to operate in reasonably calm water, although some deep-v hull forms are capable operated in rough water. As mentioned by Koelbel (1971), in general there are three types of planing hulls with different characteristics and advantages. They are namely: (i) Deep Vee Bottom, (ii) Inverted Vee Bottom and (iii) Round Bottom. In Deep Vee Bottom type, single hard chine is most frequently used. This form has the advantages of (i) being a substantially good planing surface form, (ii) being simple and economical to produce, and (iii) having excellent accommodation space for machinery, armament, and crew. It has a disadvantage of having a

133 Effect of Double Chine on Planing Hull Vessel Performance 123 greater wetted surface with consequent greater resistance. Its characteristics in a seaway compared to other planning hull forms are only fair. On the contrary, planing hull forms are poor in rough water, Thomas (1971). The double chine hull was formed by incorporating an additional chine located above the present chine. This gives the hull form more rounded than the single chine. The main objective of developing this hull form is to combine the seakeeping qualities of the semi-displacement hull with the dynamic stability and higher speed potential of the chine hull form. Described as evolutionary rather than revolutionary, it offers several important features, Cameron (2001). i. Increased large angle stability levers (GZ) due to the increased hull volume offered by the upper chine. ii. Increased deadrise at fore peak section compared to a single-chine hull, reducing accelerations in head or quartering seas. iii. Twin chines forward help deflect spray and result in drier running in heavier seas. iv. Increased hull volume due to the twin chines offer good directional stability in following seas. Apart from the above features, it also offers more volume for the required accommodation and machinery spaces with higher payload capability. 7.3 THE EXPERIMENT Experiment Work The tests that were conducted in the towing tank of Marine Technology Laboratory of UTM (120m x 4m x 2.5m) are;

134 124 Advances in Marine Technology 2006 resistance, roll decay, and beam seas test The Model The ship model used in the experiment is a 1/10 scale model of a 22.0 m long planing hull- Rajawali. The experiments are conducted on two hull models namely; single and double chine planing hull models. The new double chine hull is designed based on the single chine hull design with similar or almost similar parameters of length, breadth, depth, deadrise angle, and displacement, Zulkhairullah (2004). The dimensions of the two hull forms are shown in Table 7.1. Figures 7.1 and 7.2 show the body plans of the single and double chine models. Table 7.1 Main dimensions of single and double chine Hulls Single Chine Double Chine Dimension Light Full Light ship Full Load ship Load Loa (m) Length of water line (m) Breadth of water line (m) Draft (m) Depth (m) Deadrise Angle (Deg) Block Coefficient Displacement (tonne)

135 Effect of Double Chine on Planing Hull Vessel Performance 125 Figure 7.1 Body plan of single chine planing hull form Figure 7.2 Body plan of double chine planing hull form

136 126 Advances in Marine Technology ASSESSMENT OF VESSEL Stability Assessment The vessel stability is very important particularly in safety assessment. A stiff vessel will return quickly to the upright and may engender motion sickness. Whilst, a tender vessel may not have enough righting moment to prevent capsizing when acted by a large disturbing force. The stability therefore must be just right in the range of condition in which a vessel may find itself during its operation and life, even damaged or mishandled. As a statutory requirement, the stability of the vessel has to be approved by the classification society or marine authority such as International Maritime Organisation (IMO) before construction works. In the assessment of stability of the vessel, both static and dynamic stability are considered. In general, the dynamic stability considers the effect of vessel speed as well the influence of relative speed between the vessel and the wave. In these circumstances, the vessel may encounter unstable characteristics and highly unpredictable behaviour. However, in this study only the upright static stability by using large angle stability (GZ) characteristics is considered. Figure 7.3 and 7.4, show the comparison for GZ curves for single and double chine planing hull at full load and light ship conditions, the results show that the stability curve of the double chine is higher than the single chine in both full load and lightship condition with same trend and range of stability. The results for maximum GZ and stability moment at angle of heel 50 o are summarised in Table 7.2.

137 Effect of Double Chine on Planing Hull Vessel Performance 127 Table 7.2 Summary of static stability results for single and double chine hull at Angle of Heel of 50 deg. Single Chine Double Chine Parameter Full Lighshi Full Lighship Load p Load GZ (m) Displacement (Tonne) Righting Moment (Tonne-m) From Table 7.2 the increase in righting moment due to double chine at lightship and full load conditions are 17.3 and 13.6 percent respectively. Figure 7.3 Comparison of GZ Curves for single and double chine at full load condition

138 128 Advances in Marine Technology 2006 Figure 7.4 Comparison of GZ Curves for single and double chine at lightship condition 4.2. Resistance and Power performance Many towing tank tests are performed to determine the ship s horsepower requirements and performance characteristics. The tests are conducted on two hull designs (single and double chine planing hull model) in order to select the better hull to be constructed. The extrapolation of total resistance of model to full scale is based on Froude s principle and model-ship correlation line, Savitsky (1985). Calculation of frictional resistance is based on the method of International Towing Tank Conference, 1957 (ITTC 1957). Using the method, the predicted resistance of the double chine planing hull at ship speed of 20.0 knots (service speed), R TS = kn with coefficient (C TS ) = x 10-3.

139 Effect of Double Chine on Planing Hull Vessel Performance 129 Figure 7.5 Comparison of resistance from model tests Figure 7.5 shows the comparison of the ship-model resistance experiment test result between a single chine Valdenazzi (2002), and a double chine planing hull. The maximum difference of resistance between these two hulls is about 20% at 10 knots. At the operation speed of 20 knots, the increment was 7.7% while 5.3 % at 30 knots. In the case of Savitsky s method (Full Planing) at 20 knots, the resistance between both hulls differed about 2 percent, Savitsky (1985). Figure 7.6 shows the comparison of resistance for the double chine hull using model test in towing tank and Savitsky s Method (full planing). At the speed of 20 knots, Savistky s Method gave lower resistance as compared to the towing tank test with 9.86 % difference.

140 130 Advances in Marine Technology 2006 Figure 7.6 Comparison of resistance between model tests and theoretical prediction Seakeeping Analysis Roll Decay Test Roll decay test is performed to determine the natural frequency and roll damping coefficient of the vessel. The summarized results of roll decay test for single chine and double chine planing hull are shown in Table 7.3. The average of damping coefficient, b for the double chine planing hull was tonnes m 2 /s. The value is higher than the single chine by 14 percent Beam Seas Analysis The model is subjected to the regular beam waves and zero forward speed. The test conditions include a range of wave periods from 0.95 to 2.44 seconds with 0.05 m standard wave height.

141 Effect of Double Chine on Planing Hull Vessel Performance 131 Figure 7.7 shows the comparison of roll response of single and double chine planing hull. Near the natural frequencies, the maximum RAO for the single and double chines are 4.54 and 4.19 respectively. This shows that the effect of the double chine is to decrease the RAO by 7.8 percent. This is consistent with the higher roll damping from the double chine as observed in roll decay test. Figure 7.8 shows the theoretical prediction of response using the TRIBON software. As shown, the maximum roll RAO of the double chine hull was lower than the single chine. The roll RAO of single chine was 1.68 at wave frequency of 1.56 rad/s while 1.61 at the frequency of 1.6 rad/s for double chine planing hull.the values were compared at the maximum roll response condition. The percentage of reduction in roll response between both hulls was found to be 4.3 percent. Figure 7.7 Comparison of Roll RAO between single and double chine planing hull at zero forward speed in regular beam waves (Model Experiment)

142 132 Advances in Marine Technology 2006 Figure 7.8 Comparison of roll RAO between single and double chine planing hull at zero forward speed in regular beam waves using TRIBON software (Theoretical) 7.5 CONCLUSIONS i. The effect of the double chine is to increase the large angle stability levers (GZ) for a given waterplane area. This increase in stability is due to the increased hull volume offered by the upper chine. At heeling angle of 50 deg., the increase in righting moment due to double chine are 17 percent (at lightship) and 14 percent (at full load). ii. Roll Decay test shows double chine planing hull has higher roll damping coefficient than single chine by 14 percent. iii. Experimental results and theoretical predictions show double chine reduces the roll response by about 8 and 4 percent respectively. iv. Model tests on resistance show the double chine has higher resistance than the single chine by about 12 %.

143 Effect of Double Chine on Planing Hull Vessel Performance 133 Table 7.3 Summary of results for roll decay test Double Single No. Descriptions Unit chine chine 1 Mass Displacement, Δ tonnes 2 Virtual radius of gyration, k xx m 3 Added mass (20%), a n tonnes 4 Virtual mass moment of inertial, I v tonnes.m 2 5 Damped frequency, (ω d )model rad/s 6 Damping ratio, γ Natural frequency, (ωn)model rad/s 8 Natural frequency, (ω n )ship rad/s 9 Critical damping, b c tonnes.m 2 /s 10 Damping moment coefficient, b tonnes.m 2 /s 11 Tuning factor, Λ Decaying constant, v m 2 /s 13 Non-dimensional damping factor, κ Magnification factor, µ φ Restoring moment coefficient, c Nm 16 GMt (from roll decay test) m 17 KMt (from hydrostatic data) m 18 KG ship m 7.6 REFERENCES Cameron, A. 2001, Hull Design for High Speed Working Craft, Work Boat World Asia Koelbel, J.G. 1971, Seakeeping Considerations in Design and Operation of Hard Chine Planing Hulls, Small Craft Engineering Report (120) Performance Prediction, University of Michigan, Michigan, Kumar, M. 2001, Improving Seakeeping Characteristic of a Planing hull Vessel Using Bilge Keels, Undergraduate Thesis, Faculty of Mechanical Engineering, Universiti

144 134 Advances in Marine Technology 2006 Teknologi Malaysia. Lewis E. D. 1989, Principles of Naval Architecture, Volume II: Resistance, Propulsion and Vibration, The Society of Naval Architects and Marine Engineers, New Jersey, Libby, M. S. 2003, Fast Ferry Operations and Issues, Report No. ME 99-5A, Maine Maritime Academy, Castine. Maimun. A., Yeak, S.H., Wong, K.S. and Kumar, M. 2002, Effective Use of Side Keels on Planing Hull Vessel, MARTEC 2002, ITS, Surabaya, Indonesia, 10 th July Savitsky, D., 1985, Planing Craft, Naval Engineering Journal, February 1985, pp Thomas, C.G. and Bruce, J. 1982, Introduction to Naval Architecture, E. & F.N. Spon Ltd, London, Valdenazzi, F., Harries, S., Viviani, U. and Abt, C. 2002, Seakeeping Optimisation of Fast Vessels by Means of Parametric Modeling, HSMV 02, Baia, Napoli, Italy, Sept Zulkhairullah, A. 2004, Performance of a Double Chine Planing Hull Form, Undergraduate Thesis, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia.

145 Ship Detection Through Remote Sensing Satellite SHIP DETECTION THROUGH REMOTE SENSING SATELLITE Omar Yaakob Mohd Halim Abdul Sideek 8.1 INTRODUCTION Malaysia, as a maritime nation is mostly surrounded by sea. Maintaining the country s security and safety of shipping is vital for the interest of this maritime nation. In this regards ship detection and surveillance system will increasingly be required to play a major role. One of the potential threats to shipping is the act of piracy and armed robbery at sea. With the current chaotic world political condition throughout the globe, there is a new threat of terrorism which has the potential to destroy the very fabric of society. At sea, terrorism has the added dimension of vastness of the area of operation which is almost impossible to be patrolled effectively. At present, surveillance is carried out by expensive and manpower-extensive patrols. Radar, aerial and optical surveillance are also used with all their respective limitations. The infrared optical surveillance cameras which are usually available at day and night in a moderate climate region cannot work well because the high-humidity the tropical sea-surface absorbs the infrared and degrades the image quality significantly. There are still other difficulties in terrestrial radar and optical cameras, for example the risk of losing instruments and difficulties

146 136 Advances in Marine Technology 2006 to integrate individual information derived from the many radars distributed across various countries, which are necessary to cover the wide area concerned. On the other hand, although aerial surveillance by manned or unmanned airplane may overcome these difficulties to some extent, and have a capability to fly to the dedicated area anytime if necessary, but to operate the system round the clock is not practical. There is thus a need for a more practical and efficient surveillance systems. 8.2 THE NEED FOR SURVEILLANCE SYSTEM Piracy The menace of piracy at the South East Asian Seas is increasing significantly. The International Maritime Bureau, a unit under International Chamber of Commerce reports weekly statistics of piracy incidents on their website ( The data from the website was used in Higuchi, Figure 8.1 shows that the piracy attacks by location are 567 times in Indonesia, 130 times in Malacca straits, 85 times in South Chine Sea, respectively for periods. The statistics also shows that the attacks by type are 374 times by attempted boarding, 1,435 times by ship boarded and 74 times by hijack in this period. It also shows the attacks by type of violence are 1,848 times by crew taken hostages, 236 times by crew injured, and 286 times by crew/passengers killed or missing.

147 Ship Detection Through Remote Sensing Satellite 137 A ttacks by Location for Indonesia :567 tim es -> (a) Malacca S traits :130 tim es -> (b) South C hina Sea : 85 tim es -> (c) A ttacks by Type for the A ttem pted boarding : 374 times Ship boarded :1,435 times Hijack : 74 tim es Type of violence for C rew taken hostage :1,848 times Crew injured : 236 times C rew /passengers killed : 286 times or m issing 10N Equator (b) 10S (a) (c) Figure 8.1 Piracy incidents in the South East Asian Seas, Higuchi (2000) International Maritime Organization (IMO), through their official website ( also recorded acts of piracy and armed robbery against ship in the Straits of Malacca as shown in Table 8.1. Table 8.1 Acts of piracy and armed robbery against ship in Straits of Malacca. Year Location International water Territorial water In port areas TOTAL The IMO reported that while the number of incidents shown in Table 8.1 has reduced, the usage of dangerous weapon is increasing as well as the use of violence on the crew and

148 138 Advances in Marine Technology 2006 passengers Illegal fishing The fishing industry plays an important role in the Malaysian economy. Department of Fisheries (2004) reported that this industry produced 1.73% of the national Gross Domestic Product (GDP). The percentage has improved by 1.37% compared to The fisheries sector in 2004 produced 1,537,998 tonnes of fish valued at RM 5,505.9 million. Amongst this value, the production from marine capture fisheries sector contributed 1,331,645 tonnes or 87% of the nation s fish production with value of RM4,241.4 million. In recent years, the coastal fisheries still remained the major contributor with a production of 1,060,150 tonnes, which is 69% of the total nation s production and for the deep-sea fisheries sector, it managed 271,495 tonnes therefore contributing 17.6% to the total fish production. However in the past few years, Malaysian waters became a target for illegal fisherman from neighbouring countries for its rich deep water fish resource. Foreign trawlers have been found to be operating in our waters, causing concern about the destruction of our fish stocks. Besides the destruction of fish stocks by trawlers, concern has been raised regarding the decline in shark population, which is prized by foreign fishermen, Malaysian Nature Society (2004). This is because according to the Malaysian Nature Society, the number of consumers who can afford, or had access to shark's fin has risen. This figure alone has become a catalyst for the fishermen from as far as China to come to Malaysian waters. Most of the sharks that are caught are only for their fins and the meat will be thrown back to the seas for other scavengers Oil Pollution

149 Ship Detection Through Remote Sensing Satellite 139 Ocean oil pollution is a major environmental concern that affects many countries in the world. It has been reported that operational tanker oil discharges (i.e. dumping of oil during tanker cleaning operations) form about 45% of the total ocean oil pollution in the world while ship accidents and oil platform accidents contribute only 5% and 2% respectively (Lu & Soo, 2004). Hence, deliberate oil emissions from ships impose a much greater long-term threat to the ocean environment than those from big ship accidents. Monitoring illegal ship discharges is thus an important component in ensuring compliance with the marine protection legislation and the general protection of the coastal environments. Table 8.2 show the Statistics of ocean pollution in Southeast Asian waters from September 1995 to May From this table we can see the seriousness of the problem we are facing. In about 32 months there are 7218 cases in the region and mostly in the Straits of Malacca. The main effects of pollution are that they cause extensive damage not only to the environment such as fisheries and coral, but it also threatens the economic source for the fishermen and others who depend on the seas for a living. It is important for the authorities to detect and identify ships involved in piracy, illegal fishing or pollution. This Chapter proposes the use of satellite images to detect the movement of ships and finally identify the culprits. An important trace left by the ships is its wake or waves pattern generated by the movement of the ship through water. 8.3 SHIP WAKE AND SATELLITE IMAGE A moving ship (or any other object moving at or near the water surface) generates a trace on the water surface which is called a wake. Around and directly behind the ship, the wake is rather complex, with so-called bow and stern waves, eddies and currents, and foam. It depends on the actual shape of the ship, the ship's

150 140 Advances in Marine Technology 2006 screws, and the ship speed, among other factors. Here, the ship wake is a combination of two different phenomena: i. The turbulent wake, i.e., foam, turbulent water and sometimes surface films in the ship's track ii. The Kelvin wake, i.e. a characteristic wave pattern behind the ship. The determination of the ship characteristics such as the breadth, length, speed, orientation can be done from the observation of the wake features such as the wake angle and wake arm from the SAR image. Table 8.2 Statistics of ocean pollution in Southeast Asian waters from September 1995 to May 1998, (Lu & Soo, 2004). Number of Slicks Percentage (%) Total Slicks Linear Slick Type Curve Patch km Slick Size 5-10km km km METHODS OF IMPLEMENTATION Satellite detection system is very dependable system when effectively used in the surveillance work. In order to solve the problems that were earlier discussed in the problem definition section, a different approach for each problem is needed.

151 Ship Detection Through Remote Sensing Satellite 141 The methods for solving the problems are as further described below Piracy One system proposed to overcome the problem of piracy, is given in Higuchi (2000). Figure 8.2 shows an example and process of ship detection by high-resolution Satellite Aperture Radar imagery. In this system ship data, such as ship name, shape, size, etc. is registered in advance to identify the ship by the imagery. The ships are recommended to be equipped by the Automatic Identification System (AIS) for easier detection and conformation of ships. Imaging as well as data processing are totally scheduled by mission coordination, where tasking command to the satellite are programmed and up linked to the satellite via tasking station. Down linked imagery data are received at the receiving station, and processed in order to obtain corrected high quality imagery for ship detection and identification. In context of Malaysia we might use the Malaysian Centre of Remote Sensing situated in Mentakab Pahang. In case of pirate attack or hijacking, satellite sensor resources are concentrated to the spot area concerned, and one can trackdown the identified ship using sequential imageries obtained from satellites orbiting. The example above is based on the high-resolution Synthetic Aperture Radar, which has a strong advantage of both day-andnight and all weather operational availability. An unknown or foreign and unregistered ship which might be a pirate ship can also be detected by the imagery from the satellites. So in order to prevent a hijack or piracy acts to the ship, the processing centre may send a warning in advance for the ship and the authority to despatch help or prepare for any possibilities. From the image we can also acquire the length, direction and speed and hence

152 142 Advances in Marine Technology 2006 determined the elapsed time before the foreign ship arrived. Tasking & Receiving station Down link Imaging Command Imagery of detected ships Unknown ships Down link data Tasking command Front Front end end & Image Image Processing Mission coordination Ship data of Customers Ship nam e Shape Size,etc Customers Ship Ship companies Insurance companies etc. etc. Registered ships (known) Ship Ship detection Identification V esseltrack data Position, speed, direction, etc. Figure 8.2 Ship detection and data processing chain, Higuchi (2000) Illegal fishing In solving the problem of illegal fishing, we must first consider the main spot where usually illegal fishing takes place in order for better and more efficient surveillance. The detection of a foreign fishing vessel is same as for the pirate vessel. Although a ship is imaged only as a simple spot in lowresolution imagery, an intensity profile at higher resolution imagery reveals a pattern reflecting the individual ship structure above the deck. By using this intensity profile one can effectively identify the registered customer s ship with the help of properly registered databases.

153 Ship Detection Through Remote Sensing Satellite Oil Spills In SAR images, the brightness of the sea surface is a measure of the sea surface roughness. Smooth sea surface appears dark while the brightness increases as the sea surface becomes rougher. Oil films are very effective in damping wind-generated gravity capillary short waves on the sea surface and hence they appear dark against a brighter background in a SAR image. The detectability of oil slicks in a SAR image depends on the ocean surface wind speed. If the wind speed is too low (typically below 2 to 3 m/s), the sea surface background does not have sufficient roughness to contrast with that of the oil film. On the other hand, if the wind speed is too high (typically above 15 m/s), the oil can be dispersed by the surface waves and the slick can disappear below the sea surface. Not all dark sea surface areas in SAR images are oil slicks. Sea surface may also appear dark due to natural slicks, low sea surface wind speed, certain atmospheric and oceanic phenomena and other reasons. Contextual information such as the shapes and locations of the suspected oil slicks can help to avoid false detection. 8.5 DETECTION ALGORITHM The basic structure of the detection algorithm is summarised in Figure 8.3.

154 144 Advances in Marine Technology 2006 Input Image Identify individual Ship Determination of Ship Orientation Defined region of Radon transformation Wake Detection by Radon Transform Calculation of Ship Speed and Heading Output Data Figure 8.3 Basic Structure of the detection algorithm In general, ship image in SAR imagery are easily identified by a bright features of the ship in the image. However there are a few different types of ship wakes are observed such as Kelvin wake, turbulent wake and narrow V wake. However turbulent wakes are the most frequently observed wake in the SAR imagery.

155 Ship Detection Through Remote Sensing Satellite CASE STUDY To demonstrate the utility of the method, a case study is now presented. The image shown in Figure 8.4 was taken at the Flemish Cap, East Coast of Canada by using a RADARSAT-1 satellite, taken from Canada Centre for Remote Sensing website, ( Two oil patches can be seen as black patches. Five ships have been detected and it is assumed that one of them might be the one responsible for the oil spill. Figure 8.5 shows an enlarged image of the middle marked ship. Figure 8.4 Image taken by RADARSAT-1

156 146 Advances in Marine Technology 2006 Figure 8.5 Enlarged image of the second marked ship Figure 8.6 show the image of the ship after the removal of false ship pixels as some individual pixels may have greater than the threshold but does not belong to the ship. Figure 8.6 Removal of false pixel

157 Ship Detection Through Remote Sensing Satellite 147 Enlarging the image in Figure 8.6 gives Figure 8.7, which also show numbering of the pixels. In this image the ship is 3 pixeldiagonals long. From the image resolution provided with this image, a single pixel on the image represents a 47meter x 52 meter area on the ground, or 70.1 diagonally. Hence the length of the ship can be calculated by multiplying the number of pixels. For this ship, the approximate length of the ship is: Length = pixels x 70.1m = 3x 70.1m = 210.3m Figure 8.7 Enlargement and pixel numbering However in determining the ship dimension, and error margin of 70.1 m error must be taken into account because the probability of one false pixel that have been taken as the ship after the

158 148 Advances in Marine Technology 2006 elimination of false pixels. However with a better image resolution and quality, this error can be reduced up to a few meters. Next the calculation of the ship orientation is done by using a root mean square method to measure the slope of the image from the scattered pixels. The angle of the ship heading can be determined by using the following formula: φ = where, tan 1 m m = the slope of the overall pixels. φ = angle of ship heading Table 8.3 shows the individual pixel coordinates taken from the image in Figure 8.7. So from the root mean square method the value of the slope m is By using equation 1, the ship heading is found to be degree. Table 8.3 Pixel position Pixel X Y Using the basic equation for the calculation of speed as given by Khoo et. al (2003), the speed of the ship is obtained as follows

159 Ship Detection Through Remote Sensing Satellite 149 m 3pixel x pixel u = 104 cos sin = 1.82 m/s = 3.6 knots Here we have established the speed and direction of one ship. Repeating this process for the other ships seen on the image will ensure provide a clue as to which ship may have caused the oil slick. 8.7 CONCLUSION The method provided in this Chapter will at least solve some of the problems mentioned earlier in this Chapter. We may not only save our resources for our next generation but also secure the safety of our country in the process. 8.8 REFERENCES Department of Fisheries Malaysia (2006). Annual Fisheries Statistics Kuala Lumpur: Ministry of Agriculture Higuchi H., (2000). Combating Piracy by Space-based Ship Surveillance and Tracking. Japan: The Okazaki Institute. Khoo V. et. al (2003). Computer Based Algorithm for Ship Detection from ERS SAR Imagery. Singapore: National University of Singapore

160 150 Advances in Marine Technology 2006 Lu J. & Soo C.L., (2004). Oil Pollution Statistics in the Southeast Asian waters compiled from ERS SAR imagery. Singapore: National University of Singapore. Wahab, (2004). End of the Lines for Malaysian Shark s. Malaysia: Malaysian Nature Society

161 Motion Planning and Control of a Wheeled Mobile Robot MANAGEMENT OF INLAND WATERWAY SYSTEM FOR TRANSPORTATION Ab Saman Abd Kader Kong Kim Fong 9.1 INTRODUCTION Inland waterways transportation system (IWTS) is one of the modes of transportation. Generally, waterways can be categorized into natural and artificial waterways. Rivers and lakes exist naturally as the result of geographically terrain while the artificial canals were constructing by human. The inland waterway as transportation systems comprise some facilities such as locks, inland port, weir, dock, navigation aids and bridges to facilitate navigation of the vessels. Various studies by different parties had shown that IWTS has some advantages compared to other modes of transport. Studies have also shown that IWTS is the cheapest and least demanding on land acquisition, energy, and labour, resources and most environmental beneficial form of all (Doerflinger, 1975). Further discussion on the advantages of IWTS is beyond the scope of this paper. In the other hand, management can be defined as a process of achieving the objective by effective and efficient way through planning, organizing, leading and controlling. At present, the philosophy of management had been changed significantly adapting to the surrounding environment. The management of

162 152 Advances in Marine Technology 2006 water resource for transportation can be defined as a process of planning and controlling the resource such that it can serve the purpose for transportation. Transformation of natural water resource to the IWTS will change the physical characteristic and natural behavior of the rivers. Besides, development of rivers for transportation will also change the economic value of the river as well. A well designed IWTS requires an understanding of the problem, assembly and evaluation of all pertinent facts, and development of a rational plan (McCartney, 1986). The main objective of waterway management is to maintain a safe navigation for IWTS and to protect the waterway environment. Good management practices should be able to provide an efficient and cost effective inland waterway transportation system which is competitive with other modes of transport. In order to manage the inland waterways transportation system effectively, we must consider all aspect of navigation along the channel, inland port and their intermodal connecting points. This paper also discussed the application of TQM practices in some aspects of waterways management for transportation. 9.2 COMPARISON OF PREVIOUS MANAGEMENT PRACTICES AND TQM Today, the new concept in management known as Total Quality Management or TQM, which is different from the previous concept of management (Besterfield, 1995). In TQM, the total quality of one system is controlled by the quality of every single element contributing to that system. TQM also emphasize on prevention and detection. Taking all above into consideration, the new philosophy of waterways management should shift from reactive to proactive. Table 9.1 shows the comparison between old management practices and TQM on some quality elements while table 9.2 shows old management style and TQM in waterway management for transportation.

163 Motion Planning and Control of a Wheeled Mobile Robot 153 Table 9.1 Old style and TQM Quality Elements Previous States TQM Decisions Short-term Long-term Emphasis Detection Prevention Errors Operations System Responsibility Quality control, QC Everyone Problem Solving Manager Teams Procurement Cost Life-cycle costs, partnership Manager s Roles Planning, assign, control and enforce. Delegate, coach, facilitate and mentor. Table 9.2 Old style and TQM in waterway management for transportation Problem Old style New Concept (TQM) Sedimentation Dredging Overall sediment management Water Pollution Treatment process Prevent pollution entering the waterways Integration Responsibility Information Separate, lack of integration Spread over a number of authority Old data/information Intermodal transportation system Coordination of all authority Timely information, up-to-date accurate information, real time

164 154 Advances in Marine Technology RECOMMENDED MANAGEMENT MODEL IN IWTS Every country has different economic structure, level of development, political system, historical background, climate and geographical feature. Thus, the model of waterway management varies from one country to the other. The set up of management model for various waterways must be formulated accordingly to accommodate the special requirement of each waterway in different countries. The model recommended is the generic model for management of waterways system for transportation. Some of the management model in other countries especially in U.S has been successfully implemented till today. Some major aspects in management IWTS had been identified such as environment standard, water quality, navigation requirement, safety standard, operation and maintenance of infrastructure etc. The following sections discuss several basic elements in the management model for IWTS. Table 9.3 shows various model of management for IWTS in other countries and the corresponding government policy. Table 9.3 Model in management of IWTS and the corresponding policy Organization Establish Government Policy British Waterways (UK) 1 January, 1963 Transport Act, 1962 Sarawak Rivers Board (Sarawak, Malaysia) October, 1993 The Sarawak Rivers Ordinance, 1993 Inland Waterways Authority of India (IWAI) Waterways Authority (NSW, Australia) October, 1986 IWAI Act, July, 1995 Port Corporation and Waterways Management Act, 1995

165 Motion Planning and Control of a Wheeled Mobile Robot TRANSPORTATION PARAMETERS The development of a waterway system for transportation require some consideration of the following interrelated elements (Hochstein, 1975): Estimation of potential commodity flows Determination of cargo fleet characteristics Location of inland ports and harbors Determination of dimensions of channels and hydrotechnical construction facilities such as locks, canals, underbridge clearance, etc. The management system for waterway transportation involves some major aspect such as planning, design and development of infrastructure, safety of passenger and freight, management of environment quality and operation of infrastructure. The following part will briefly discuss these aspects of waterways management. Management of river for transportation requires maintaining adequate depth in the rivers for vessels passage. In some waterways with limited water supply, water is stored in upstream reservoir during high runoff and then released whenever required. Usually, navigation dam and lock is built to maintain adequate navigation depths. Water management has to limit the loss of water inherent during the lock operation especially in waterways with limited water supply. Water released from reservoirs for navigation is also used for other purposes, such as hydro-electric power, lowflow augmentation, water quality, enhancement of fish and wildlife and recreation. Seasonal or annual water management plans are prepared which define the used of water for navigation (US Army, 1997). Research and development (R&D) play important role to fulfill the concept of continues improvement in TQM. Through research and study conducted by agency involved in management of rivers

166 156 Advances in Marine Technology 2006 basin, the agency involved will gain more knowledge about the behavior of the rivers and effect of human activities on the ecology along the waterways. It is important to know the characteristics of a river under study so that engineering works can be designed that will help the rivers to do what it would do naturally rather than designed to force it into an unnatural situation which will fail ultimately (Petersen, 1986). Thus, the most appropriate measures or steps can be searched and formulated through study and research Management of Environment Quality At present, the issues of environment are getting great concern all around the world. The development of waterways system for transportation will generate some potential effect on the quality of environment along the waterways. Poorly planned and managed waterways system not only will pose a threat to the safety of waterways user and freight, but also may pose environmental hazards. Thus, in the IWTS management system, water quality is among the major aspects to be managed. The standard of clean water is specific, based on some parameter such as ph (alkalinity and acidity), turbidity, BOD (biochemical oxygen demand), COD (chemical oxygen demand), TOC (total organic carbon) and TOD (total oxygen demand), heavy metals and inorganic solids. Every party has different criteria to determine the standard of water quality. Table 9.4 shows the stream classification for water quality criteria of different user. Although the utilization of waterways for purpose of transportation will not affected so much by the quality of water. But, transportation activities in waterway will give some effect to the quality of water that will be use by other party, such as irrigation and water supply. Besides, vessel discharges, spills and grounding can result in minor catastrophic damage to shellfish fisheries even causing the closure of beaches (Clyde Hart, 1999).

167 Motion Planning and Control of a Wheeled Mobile Robot 157 Table 9.4 Stream Classification for water Quality Criteria Use Quality Criteria Water supply (with Coliform bacteria MPN: 50/100 ml maximum chlorination only), Color: 10 ppm fish life, bathing, recreation Turbidity: 10 ppm Bathing, fish life, recreation, water supply after complete treatment ph : 6.0 to 8.0 range D.O. (dissolved oxygen) not less than 7.5 ppm; no single observation i.e. 6.0 ppm No toxic material, free acid, debris, odor or taste producers; no sludge deposits of any kind Coliform bacteria: MPN (monthly average) between 50 and 500/100 ml Color: 20 ppm maximum desirable ph: 6.0 to day BOD (biochemical oxygen demand): maximum for any sample = 3.0 ppm; average 1.5 ppm D.O.: monthly average 6.5 ppm; no sample 5.0 ppm Water supply after Coliform bacteria: monthly average 500 to 5000/100 ml complete treatment, Color and turbidity: removable by filtration industrial process, navigation ph: 6.0 to 8.5 Navigation, cooling water 5-day BOD: monthly average 2.0 ppm; single sample 4.0 ppm D.O.: monthly average 6.5; single sample 5.0 Not constitute nuisance, ph: 6.0 to 8.5 No toxic substance, free acid, floating debris (Source: McGauhey,1968) To maintain adequate depth in waterways, dredging will cause

168 158 Advances in Marine Technology 2006 degrade or pollute water quality especially dredging with open water discharge will activate dormant organic matter and increase turbidity and BOD. The dredged pollution is best described in term of water quality because it is difficult to isolate or define dredge pollution (Adolf, 1974). The most appropriate measures in water quality control are the elimination of direct sources of pollution. The waste from boat operation and maintenance include pollutants such as gasoline, oil, grease, solid waste, trash, lead, copper and detergents (US Army, 1993). Increased pollutant loadings may result from facility construction, vessel discharges and accidental spills (US Army, 1991). Other wastewater emanate from four primary sources as follow (Eckenfelder, 1980): i. Municipal sewage ii. Industrial wastewaters iii. Agricultural runoff iv. Storm-water and urban runoff Management of boat sanitary waste discharges includes the installation and proper use of equipment onboard the vessels and onshore equipment for collection and disposal (US Army, 1993). Another effective mean of managing boat sanitary waste discharges would be to educate boaters about the potential health risks associated with the discharge of sewage. Table 9.5 shows the processes applicable to wastewater treatment. As TQM is more emphasize on prevention, the management of environmental quality should shift from detection of pollutant to prevention and control of pollution entering into marine environment. Thus, the authority should focus on identifying the every source of pollution entering into the waterways rather than detection after the waterways had been polluted.

169 Motion Planning and Control of a Wheeled Mobile Robot 159 Table 9.5 Processes applicable to wastewater treatment Pollutant Biodegradable organics (BOD) Suspended solids (SS) Refractory organics (COD, TOC) Processes Aerobic biological (activated sludge), aerated lagoons, trickling filters, stabilization basins, anaerobic biological (lagoons, anaerobic contact), deep-well disposal Sedimentation, floatation, screening Carbon adsorption, deep-well disposal Nitrogen Phosphorus Heavy metals Maturation ponds, ammonia stripping, nitrification-denitrification ion exchange Lime precipitation; Al or Fe precipitation, biological coprecipitation ion exchange Ion exchange, chemical precipitation Dissolved inorganic solids Ion exchange, reverse osmosis, electrodialysis (Source: Eckenfelder, 1980) Safety Aspect of IWTS In management of waterways for transportation, safety of waterways user and freight should be achieved before considering the cost or economic factors. The measures to maintain a safe inland waterway system should be started from design, planning, development, operation and maintenance of waterway track etc. The safety of waterways could be upgrade by following aspect: i. Waterways track (design) ii. Navigation aids iii. Personnel (training)

170 160 Advances in Marine Technology 2006 iv. Regulation The goal of design in IWTS is to create a safe, efficient, reliable and cost-effective waterway that is environmentally and socially compatible with the region (McCartney, Nov 1986). Well designed waterway transportation systems not only result in increasing the safety of waterways user and freight, but also increase the efficiency and reliability of IWTS. Navigation aids provide guidance to waterway user travel along the waterways. As technology has advanced, additional systems have been added to the mixture of aids to navigation and shipboard navigational aids available to the mariner (Rick Walker, 1999). Appropriate measures must be taken to determine the type of this new system that is necessary today and in the future to enhance mobility and safety on the waterways. Education and training are vital to ensure that the waterways operators remain well informed regarding recent developments in waterways system. Increase awareness of waterways operator can be view as early prevention of accident in waterways besides, regulations enable the authorities to control the activities in the waterways. The regulation should cover wide range of aspect on the waterways system. In searching new approach to increase marine safety had lead to the introduction of the Prevention Through People (PTP) approach to maritime community particularly in United States. In many cases, implementing and enforcing rules and regulations is not always the most effective way to improve marine safety because regulations only provide for short-term technical solutions and fail to adequately address the larger long-term issues associated with human and organizational factors (Scott Calhoun, 1999). The use of PTP approach, a non-regulatory solution can be a very effective way of getting at the root of a problem parallel with the concept TQM of identifies the root of a problem. Besides, PTP uses an extremely effective and vital approach to safety that can increase the effectiveness of waterways management by continuous improvement through constant feedback.

171 Motion Planning and Control of a Wheeled Mobile Robot Planning, Design and Development of Infrastructure Dimension of the infrastructure are dependent upon the economic factor in the waterways. The vessel speed in restrict canal or waterways are highly dependent upon the dimension of the waterways. Vessels moving in the restrict waterways require more power to achieve corresponding speed of vessel moving in open sea. Also, vessels navigate in waterways might experience some phenomenon such as squat and back suction. In determining the requirement for cross section of the waterways, some of the common criteria used are blockage ratio (ratio of channel area to submerged vessel area), the draft-depth ratio and the maneuverability requirement (ESCAP, 1991). The waterways should have sufficient wide depth to enable safety of vessels passage. The wide of waterways track varies from one part to the other. The width of waterways depends strongly on traffic density, ship maneuverability, surrounding environment (weather, obstruction), aids to navigation. Phenomenon of bank suction, suction phenomena also occur during the interaction of vessels (when the ships meet or encountering) and overtaking. This phenomenon may pose a threat to the safety of inland traffic. Table 9.6 shows the guidance for minimum channel width. The development of IWTS should incorporate engineering design, economic cost benefit and environmental impact evaluation from the beginning of planning stages. Once the IWTS had been developed, maintenance and improvement of waterway system and facilities are the major work for most of the waterways authority. Planning and development of IWTS is base on economic study of potential of the waterways such as cargo flow and volume and future expansion.

172 162 Advances in Marine Technology 2006 Table 9.6 Guidance for Channel Widths Location Maneuvering lane Minimum channel width in percent of beam Vessel controllability Very good Good Poor Channels with yawing forces Straight channel Judgment* (ft) Bend, 26-degree Judgment* turn Bend, 40-degree turn Judgment* Ship clearance (ft) but not less than 100 ft Bank clearance (ft) plus 60 plus 150 Judgment will have to be based on local conditions at each project. (Source: Bruce, 1983) A vessel moving in bend ways require more space compare to vessel moving in straight waterways. This requires a space for bend ways to be determined by some parameter such as length of vessels, width of vessels, deflection angles, maneuverability of vessels and surrounding environment. Figure 9.1 shows the variation in deflection angle and channel widths occupied by tows of different sizes.

173 Motion Planning and Control of a Wheeled Mobile Robot 163 Deflection angle, α = 11.8 Channel width, W = 350 α = 12.0 W = Tow α = 10.7 W = Flow 3000 R α = 10.2 W = α = 9.8 W = α = 7.7 W = Note: Radius of curve 3000ft Degree of curve 90 Current velocities 3fps Figure 9.1 Variation in deflection angle and channel widths occupied by tows of different sizes (Source: US Army, 1980) Operation of Infrastructure Management of the waterway system for transportation usually involved the operation of some infrastructure that use to support the purpose of transportation. Some of the common infrastructures in waterways are lock, navigation dam, inland port, turning basin and bridge. Figure 9.2 shows the principle sketch of weir and

174 164 Advances in Marine Technology 2006 navigation lock. Locks are the common structure especially in canalised waterways. Locks and dams would be required in streams having steep gradient with velocities too high for navigation or where conditions make it impractical to develop the required depths naturally because of rock outcrops, sediment movement, and other factors that could adversely affect navigation and flood-carrying capacity of the stream (US Army, 1980). In canalised waterways and canal with locks and dams, the time required for transit at the locks constitute a significant part of the total trip time for the inland vessels. The schedule of lock operation should be proper coordinate with the traffic flow to avoid delay and reduced waiting times in lockage. Reduce transit time in locks will reduce total trip time and reduce the operation cost of inland vessels. Transit time in locks depend on the following factors (US Army, 1990): i. Design of the lock operating equipment (lock gates, filling and emptying system). ii. Pilot skill. iii. Towboat capacity. iv. Design of the approach channels, guide walls and lock wall appurtenances (line hooks, check posts, floating mooring bits, etc). v. For dual locks, transit time can be reduced by separating the locks a sufficient distance to allow simultaneous arrivals and departures.

175 Motion Planning and Control of a Wheeled Mobile Robot 165 Guiding structure Guard wall Upper lock gate Lock chamber Weir Lower lock gate Guiding structure Guard wall Figure 9.2 Principle sketch of weir and navigation lock (Source: ESCAP, 1994) Control of Traffic The main purpose of traffic control is to maintain smooth traffic condition and safety in waterways especially in busy waterways. Waterways users usually involve wide range of user from commercial transportation purpose to recreational purpose. Thus, in some particular area of waterways, anchorage, mooring and berthing area for commercial vessels and pleasure craft should be clearly defined. For safety purpose and ensure the smooth passage of vessels, waterway authorities will set the speed limit for vessels navigate along the waterways. The set up of speed limit taking into consideration of safety requirement, channel condition, vessels behavior and traffic density. Waterway authorities also responsible

176 166 Advances in Marine Technology 2006 in providing vessel traffic information, navigation aids and directing vessels during accidents. Appropriate and accurate information are extremely useful and important to waterway users particularly vessels for voyage planning. Vessels navigate along the waterways require more caution on narrow waterways, terminal, anchorage area, mooring and berthing terminal, sharp bends and busy waterways. Usually, these locations require more navigation aids to ensure the safety of waterway user. Besides, carriage of dangerous cargo and night navigation in waterways also require more caution and strict regulation Sediment Management Utilisation of water resource for transportation is highly dependent upon the maintenance of adequate navigation depth. Dredging is also the common method to maintain adequate navigation depth. In future, as the ships are likely increase in size and number in waterways, dredging will play vital roles in maintaining adequate depth of waterways. The volume of dredged materials will increase as well. As disposal of dredged material is usually the major dredging problem, waterways management for transportation purpose will meet great challenge in the future. Thus, overall sediment management is the solution that will reduce frequent of dredging work, if not eliminate. One of the main concepts in TQM is to find and solve the root of the problem or upstream prevention. As long as maintain adequate navigation depth is consent, control of sediment in river flow is the long-term solution. Reduction of sediment volume entering the waterway will reduce the frequency of dredging work. Besides carry out the dredging work to maintain adequate depth for passages of vessels, the management of waterways for transportation should also try to control the entering of sediment in the rivers together other authorities involved in river basin management to solve the problem of flooding, water quality and

177 Motion Planning and Control of a Wheeled Mobile Robot 167 drainage. 9.5 APPLICATION The concepts of new management practices have some advantage over the previous management practice. New management practices place emphasised on continues improvement, which parallel with concept of TQM that will lead to research and searching the best practices to be implemented. Besides, new management practices also more emphasised on prevention than detection, which will result in reduction of the possibility of problem to occur, if not eliminated. In management of water system for transportation, prevention of pollutant and sediment from entering the waterways could be regarded as parallel with concept of prevention in TQM. Good management practice should and continuously finding better measures through research and development. The waterways authority should focus on finding the real root causes of problems or identify the potential problems. This practice will ensure that the appropriate corrective actions are taken before the real problems occur. Coordination among various authorities involved and participation of public and private sectors in rivers basin management for various purposes play vital roles. Greater coordination among various authorities will result in increase the sharing ideas, expertise, knowledge and information thus avoid duplication or overlapping of decision-making process. Besides, public involvement can increase public awareness of arising issues in waterways. Good management practices will guarantee longterm benefits and sustainable development of waterways for various interests.

178 168 Advances in Marine Technology CONCLUSIONS Development of waterways system for transportation required wide range of knowledge at early stage of planning to operation. Every development project should be study and impact assessment studies should be produced. The economical benefits derived from development of rivers system for transportation must be balanced against the damage to the marine environment. Besides, successful developments of inland waterways as one mode of transportation require participation of various parties, which include government agency, private corporation and public. All activities carried out along the rivers basin are interrelated to each other. The interests of different parties involved in rivers basin management always clash between one another. Thus, every single agency related or involved in rivers basin management should corporate to address all issues arisen. 9.7 REFERENCES Adolph W. Mohr. (1974) Development and Future of Dredging Paper in Journal of the Waterways, Harbors, and Coastal Engineering Division, Proceedings of the American Society of Civil Engineers, Vol. 100, No. WW2, May Besterfield, D.H., Besterfield-Michna, C., Besterfield, G. H. & Besterfield-Sacre, M. (1995). Total Quality Management. Clyde Hart (1999). MTS Delivers Value. Proceedings of the Marine Safety Council, October December 1999, Volume 56, Number 4. Doerflinger, Frederic. (1975) Inland Waterways A New Environmental Dimension. Environmental Conservation, Vol. 2, No.2, 1975, pp Eckenfelder, W. Wesley. (1980). Principles of water quality management. CBI Publishing Company, Inc. United States.

179 Motion Planning and Control of a Wheeled Mobile Robot 169 ESCAP, Inland Water Transport Infrastructure. Module 1, Seminar on Inland Water Transport, ESCAP Guidelines for the Design of Inland Navigation Canals United Nation, Engineering Division, ASCE, Vol. 101, No. WW4, Nov, Hochstein, A.B (1975). Optimum Dredged Depth in Inland Waterway. Paper in Journal of Waterways, Harbors and Coastal L. M., Bruce. (1983) Deep-draft Navigation Project Design. Paper in Journal of Waterway, Port, Coastal and Ocean Engineering. ASCE, Vol. 111, No. 1. January, L.T., Scott Calhoun (1999). Waterways Management and PTP: Safety in the Marine Transportation System Proceedings of the Marine Safety Council, October December 1999, Volume 56, Number 4. McGauhey, P. H. (1968). Engineering Management of Water Quality. McGraw-Hill. New York. McCartney, B. L. (1986). Deep-Draft Navigation Project Design. McCartney, B. L. (1986). Inland Waterway Navigation Project Design. Paper in Journal of Waterway, Port, Coastal and Ocean Engineering. ASCE, Vol. 112, No. 6. November Office, Chief of Engineers, U.S. Army, Layout and design of shallow-draft waterways Engineer Manual , Washington, D.C., December 31, Office, Chief of Engineers, U.S. Army, Planning and Design of Navigation Locks Engineer Manual , Washington, D.C., September 30, Office, Chief of Engineers, U.S. Army, Tidal Hydraulics. Engineer Manual , Washington, D.C., March 15, Office, Chief of Engineers, U.S. Army, Environmental Engineering for small boat basins. EM , Washington, D.C., October 31, Office, Chief of Engineers, U.S. Army, Hydrologic Engineering Requirements for reservoirs. Engineer Manual ,

180 170 Advances in Marine Technology 2006 Washington, D.C., October 31, Paper in Journal of Waterway, Port, Coastal and Ocean Engineering. ASCE, Vol. 111, No. 1. January Prentice- Hall, Inc. Englewood Cliffs, New Jersey. United States of America. Petersen, M. S. (1986). River Engineering. Prentice-Hall. Englewood Cliffs, New Jersey, United Sates of America. Ric Walker (1999). Waterways Management Research & Development Proceedings of the Marine Safety Council, October December 1999, Volume 56, Number 4.

181 The Development and Use of Inland Waterway System for THE DEVELOPMENT AND USE OF INLAND WATERWAY SYSTEM FOR ECO-TRANSPORTATION Ab Saman Abd Kader Mohd Zamani Ahmad 10.1 INTRODUCTION The growing concern towards the present status of rivers have prompted many authorities around the globe to seek a comprehensive and lasting solution towards reviving the state of these river networks. One of the most highly recommended solutions is to upgrade or improve this river system into a more meaningful use in the form of transportation system. The development of rivers can be fully utilised for certain economic benefits while control and monitoring of river conditions can be easily implemented. Inland water transport (IWT) via rivers and canals have ben long thriving for a number of reasons. Being one of the oldest mode of transport system compared to road and rail, IWT exists in a number of countries, developing and developed alike. Although it is slow in speed and less flexible compared to road transport in particular, the relatively safer and environmentally better of the IWT is very attractive to be ignored. It is not suprising that many European countries, USA and other parts of the world, potential of IWT have been investigated, identified, developed and utilized with complementary with other

182 172 Advances in Marine Technology 2006 modes of transport system. Especially in the countries where road transport have been very congested, polluted with excessive noise and pollution, IWT has been an alternative mode of transport for the movement of cargo, passengers, sport, leisure and tourism activities. The development of IWT will contribute to the enhancement and preseverance of environment namely, congestion and pollution. Similarly a by-product of the environmental advantages of the IWT, facotrs such niose, vibration and visual intrusion are an added advantages that sustain the environmental qualities INLAND WATERWAYS SYSTEM FOR TRANSPORTATION Inland waterways are multifunctional. Well designed waterway track may be multifunctional, providing opportunities for landscape enhancement, wildlife conservation, recreation, pedestrian access, land drainage, flood protection, water transfer, and hydropower generation, some of which may contribute towards offsetting or sharing the costs involved. Water transport uses less fuel, which means less pollution occurs. The greater fuel economy of waterborne freight transport means scarce resources are conserved and pollution is reduced. In the EU, transport accounts for about a quarter of all carbon dioxide (CO 2 ) emissions, about 40% of volatile organic carbons (VOC) emissions Road and up to 90% of carbon monoxide (CO) emissions in some countries. Road transport alone contributes 45% of emissions of nitrogen oxides (NOX). Wider use of waterborne freight transport would contribute to reducing air pollution. For example, CO 2 emissions can be reduced by at least 75% compared with road transport. Table 10.2 shows emission estimates for different type of transport modes (Transportation, 1994) The efforts of utilising inland water transport have been carried

183 The Development and Use of Inland Waterway System for 173 out in many countries in a number of ways. However, many relevant authorities do not aware the maximum potentials from utilising inland water transport. The consideration for developing and utilising inland waterway transport is generally based on factors such as political, economic, technological and environmental issues. At present however, in many parts of the globe, more individuals and authorities begin to recognise inland water transport as a competitive mode of transport system (Kader, 1997). It should be considered, developed and utilised as an integral part of a wider multi-modal concept which treated all modes of transport on a balanced consideration. However, the widespread effect of congestion on road being highly preferred mode of transport is not only an environmental issues, but economics too, as reflected in the concern of the industry and commerce establishments to cope with transport problems of today and the mounting demand for future transport requirements. In general, inland waterway transport has some advantages in terms of the following environmental factors such as: i. Noise and vibration The main sources of transport noise are road, air and rail systems. The relative large carrying capacity of inland waterway craft, couple with the low resistance to movement of water, reduce the engine power required to move a given load compared with other modes, thus reducing the amount of noise generated. Vibration effects are also less, since they are transmitted through water, as opposed to the solid land surface in the case of road and rail transport (Harrison, 1974). ii. Visual intrusion Waterways cause a little in the way of visual intrusion and, moreover, can even enhance the appearance of an area through the clearance of derelict land. Tourism can also be promoted.

184 174 Advances in Marine Technology 2006 iii. Safety The inland water transport, with its slow transit speeds is relatively safe and less vibration levels. Railways are susceptible to accidents and can result in a loss of lives and valuable cargoes. A study on safety of transporting bulk cargo has shown that barge spills occur less often than trucks and rail cars. iv. Capacity In term of capacity, a 1,500-tonne barge carries as much as fifteen 100-tonne rail cars or sixty 25-tonne trailer trucks. This barge is 59 meter long, the fifteen rail cars would be 250 meter long and the sixty trucks would be over 0.8-kilometer long. Similarly, one 200 TEU barge is equivalent to road vehicles or 3 block trains making barge transport up to three times cheaper than road, according to a study by National Transportation Library (1994). v. Energy efficiency Fuel efficiency show that water transport is the most fuelefficient mode of transport for moving freight. One comprehensive study by the Congressional Budget Office (CBO) revealed the advantage of water transport compared to other modes. According to CBO, to move one tonne of cargo by barge would require 5 litres of fuel for a distance of 500km compared to 330km by rail and l00km by road (CBO, 1982). vi. Natural habitats & landscapes Inland waterways are generally perceived as being a positive element in the landscape. They constitute a major recreational resource and will be visited by large numbers of people for boating, angling, walking, sightseeing and other leisure pursuits. The movement of freight traffic has little or no adverse effect on these activities. Indeed viewing the passage of freight craft often increases levels of visitor enjoyment. The movement of boat traffic has an impact on waterway ecology. Moderate amount inland

185 The Development and Use of Inland Waterway System for 175 water traffic is actually beneficial to conservation, since boat keep waterways clear of weeds, thus encouraging a high density of species TRANSPORT AND ENVIRONMENT The environmental impacts of water transportation vary from river to river and project to project, but in many cases, the environment is not noticeably affected by waterway freight transport. Where it does have a negative impact, the effect is usually minimal. Because of the concern over the impacts that the different transportation modes have on the environment, three studies have been done. All three studies compared the same cargo shipped by different modes, and concluded that inland water transport recorded fewer accidents, consume less energy, produce less harmful emissions, and are less disruption to society in general. These finding show that transporting bulk commodities by water for instant, is environmentally compatible, and provides a means of sustainable development. In addition to the many advantages of commercial freight transportation, there are numbers of coincidental benefits related to water transportation can be gained such as recreation and tourism, wildlife habitat, flood control, public water supply, irrigation, industrial use and economic development. One specific benefit of waterways is that they can interact with nature in a very environmentally friendly atmosphere. Transport is a major source of gaseous and particulate pollution. A study done in the Department of Transport (DOT, 1992) found that transport producing 57% of nitrogen oxide, 91% of carbon monoxide, 42% of volatile organic compounds emissions. It also releases 21% of carbon dioxide to the atmosphere. Inland waterway transport results in less atmospheric pollution than other modes for moving a given volume of goods.

186 176 Advances in Marine Technology 2006 Table 10.1 Atmospheric emissions for different modes of transport Emission Levels per Tonne km Pollution Type Inland Road Rail Waterways Carbon monoxide Hydrocarbons Nitric oxide Sulphur dioxide (Source: European Parliament, 1991) Table 10.2 Atmospheric emissions for different modes of transport Pollutants (in pounds) produced in moving one ton of cargo Mode (1,000 mile) Hydrocarbon Carbon monoxide Nitrous oxide Tow boat Train Truck (Source: Transportation, 1994) Since the fuel consumption is relatively lower, it is reasonable to assume that resultant air pollution will also be lower. The result of work carried out by European Parliament in 1991 shows the following levels of air pollution arising from different modes of freight transport is shown in Table Similarly, another study prepared by the Environmental Protection Agency (EPA), the following air emissions reading by mode is also recorded as in Table 10.2.

187 The Development and Use of Inland Waterway System for INLAND WATERWAYS REQUIREMENTS FOR TRANSPORTATION Inland waterways morphology concerned with the structure and form of rivers, including channel configuration (platform), channel geometry (cross sectional shape), bed form, and profile characteristics. Channel morphology changes with time and is affected by water discharge. Including velocities, sediment discharge, including quantity and sediment characteristics, the composition of bed and bank materials and other factors Physical Characteristics of The River Different rivers and different reaches of the same river have different alignments, channel cross-section shape, bed and bank material, slope, and valley characteristics. While a great many factors affect stream channel form directly, others affect it indirectly by their influence on the directly affecting variables. These variables are: i. Stream discharge ii. Longitudinal slope iii. Sediment load iv. Resistance of banks and bed to movement by flowing water v. Vegetation vi. Temperature vii. Geology It was observed that that these factors are not all independent ones, as many depend, to a greater or less extent, on the others. The interrelation between longitudinal slopes, sediment load and resistance of the banks and bed to movement is particularly close

188 178 Advances in Marine Technology 2006 and complex RIVER ALIGNMENT AND CHANNELISATION River alignment can generally be categorized in three basic types and combinations of the three basic types, as follows (Petersen, 1986): i. Straight channels: These are usually relatively short reaches and are transitory because even minor irregularities in channel shape or alignment or a temporary obstruction can create a local disturbance that sets up a transverse flow leading to meandering. ii. Meandering channels: This consist of a series of bends of alternate curvature connected by straight crossing reaches are usually relatively flat. Meandering channels are unstable, with banks caving in the downstream reaches of concave bends. There are deep pools in the bends and high velocities along the outer concave bank. Depths in crossings are relatively shallow compared to depths in bends. iii. Braided channels: There are numerous channels which divide and rejoin in braided reaches. The stream is wide, and the banks are poorly defined and unstable. At low flows there are two or more main channels which cross each other, subsidiary channels, sand bars, and islands. At high flows, most bars are inundated RIVER BANK STRUCTURES There are several type of river banks, such as muddy banks, swamp banks and sand banks. For the riverbanks development, the most important things to prevent is the corrosion of the river

189 The Development and Use of Inland Waterway System for 179 banks that will reduce the water depth and increase the width the river. However it takes long time to effect the depth and the river width. For the construction of an inland port, the banks must be modified with the construction of concrete banks. The water depth and the location of the port must be suitable. The riverbanks that going to construct must be deep enough to allowing the vessel to pass by or to stop. For shallow depth, the banks must be excavated (Petersen, 1986). The development of the riverbanks also improves the flow of the river. Besides that, it will help the river to looks nice. The suitable width of the river must be considered to improve the traffic condition of the river. This is because, when the river becomes the transportation lanes, the traffic of the river will become messy if the width of the river is not improve, unless the width is sufficient to support the traffic River Bank Erosion River bank stability depends on the interrelated stream variables as well as on channel geometry. It is observed that there is no universal low-cost method for solution of field erosion problems and that on major streams and tributaries bank protection will be expensive, but that on smaller streams innovative methods can provide short-term, low-cost protection. River bank erosion and retrogression or retreat occurs in many ways, primarily as a result of one or a combination of the following: i. Removal of soil particles from the bank surface either continuously or intermittently over a period of time. ii. Sequential failures of small segments of bank material. iii. Failure of a single large segment of bank material.

190 180 Advances in Marine Technology 2006 The changing conditions that affect bank stability are as follows: i. At the surface, a. Severe surface deterioration that may result in an unstable bank configuration, such as erosion by stream flow at the toe of the bank; erosion at the water surface due to waves and erosion along the bank surface due to over bank flows. b. Deep tension cracks due to excessive drying of a cohesive soil or similar structural change that may cause the bank to weaken and become unstable. Crumbling may occur if excessive drying is followed by submergence. c. Overburden placed along the top of bank that may cause an otherwise stable bank to become unstable. ii. Moisture content within the bank The slope of a cohesionless bank may be temporarily steeper than the angle of repose of the bank material due to capillarity or other temporary stabilising effect. When the stabilising effect is removed, the bank becomes unstable River Bed and Bank Construction The articulated concrete mattress used on the rivers today is a significantly improved design over the mat first used in It is essentially the only type of revetment constructed on many river beds in recent years. The mattress is formed by connecting the squares to each other transversely and longitudinally (with corrosion-resistant fastenings) and to the launching cables. The mattress sections are mounted on barges and placed on the bank which has been cleared and graded to a 1 V:3H slope. The mattress sections are placed riverward from the water s

191 The Development and Use of Inland Waterway System for 181 edge at low water to just beyond the toe of the underwater bank slope and in an upstream direction, with each section overlapping the downstream mattress a minimum of 5 ft. Since there is no space between each block and each square and connections are flexible, the mattress is flexible and adjusts to irregularities in the bed and bank as shown in Figures 10.1 to Figure 10.1 Channel cross section showing extent of articulated concrete mattress Figure 10.2 Bank protected with articulated concrete mattress

192 182 Advances in Marine Technology 2006 Figure 10.3 Scour on berm above upper bank paving Figure 10.4 Bank protected with articulated concrete mattress 10.7 INLAND WATERWAYS DRAUGHT There is a need for a suitable river depth for the navigation of the passenger ferry of other kind of boat. Study must be made to recognise the potential of the river to become the transportation lane for the use of the tourism. The depth of the river must be

193 The Development and Use of Inland Waterway System for 183 navigable to prevent accident and traffic jam. The draft of the boats that operated in the river must be known to determine the navigable depth. Navigable depth can be obtained in few ways such as the followings (Petersen, 1986): i. Natural stream flow may provide adequate depth, or tidal backwater in the down stream reaches of some streams may provide adequate depth. ii. Upstream storage reservoirs to provide releases for navigation during low-flow periods. iii. Canalisation by a series of locks and dams to provide pools having adequate depth for navigation. Canalisation is used where the stream flow, either natural or modified by upstream water storage. iv. Stabilisation and rectification structures to stop migration of bends, fix the channel in a series of easy bends suitable for navigation, and constrict the channel to increase depth for navigation. Stabilisation and rectification works are widely used, either alone or in conjunction with upstream storage releases or in conjunction with locks and dams BOATYARDS AND MARINAS Most people berth their boats at yards where there is generally a wide range of facilities. The larger inland yards sometimes called marinas whereas the boatyards or small inland ports are very important to give the service to the users. Until a certain density of craft is reached in any given locality, bankside moorings spreading from the slipway, docks and other yard installations are quite adequate. But if this kind of development is allowed to expand unchecked, a degree of linear sprawl becomes evident. This is undesirable on both rivers and canals. Preferable by far is the grouping of moorings and associated facilities off the main navigation channel. Here a

194 184 Advances in Marine Technology 2006 compact arrangement of a well planned mooring jetties in a landscaped and planted environment can improve the look of the location in a way that linear moorings seldom can (Massachusetts, 2001). Worked-out gravel pits are particularly suitable for marina use. Neat rows of floating jetties provide permanent moorings, while on shore there are ample car parking spaces, a chandlery shop, fuelling station, clubhouse and grassed areas. A frequent argument advanced by people opposing creation of new marinas of this kind is that the reach of river concerned will suffer from acute congestion, as will the locks at each end of the pound in question. The canal system was provided with pleasure craft moorings when traditional trading activities ceased, making working-boat yards available. Often these were merely small strips of waterside land, perhaps with a slipway or dry dock and ideal for small-scale operations. When there are many short arms, docks and basins no longer required for goods traffic. These almost always belong to the navigation authority, and a conflict of future use can arise here in town or city centres, where the water represents a highly valuable asset in terms of potential building land. Such locations that remain undeveloped must inevitably become fewer in number, prompting construction of completely new basins especially for marina use. If this can be planned to yield high quality gravel or ballast before being laid out as moorings, the developer has an added incentive. Most of these have so far been created were excavated solely with boats in mind. By increasing the width of the canal considerably, enabling cruisers to moor alongside jetties placed nearly at right angles to the bank. Local authorities working under the various planning acts need to be satisfied over many points ranging from adequate car parking space to social and economic considerations like labour availability and the conservation of attractive landscape. New marinas and boatyards do not cater solely for the private boat owner, but increasingly play an important role in hiring out craft

195 The Development and Use of Inland Waterway System for 185 by the week or fortnight, an activity bringing an influx of tourists to an area and generally welcomed by local government representatives. Priority is being given to marina schemes that will encourage tourism or located near the large centers of population. As a rough method of sitting boat moorings on the canal system, large marinas should be set at km intervals, and smaller bases sometimes offering no more than basic refuse disposal facilities, water and fuelling, 5-10 km apart. The inland marina need not be a center of specific boating alone. The sides of a basin can sometimes provide an ideal smallscale housing schemes, combined with attractions like restaurants or cafes that appeal to non boaters as well as boaters and so help to create life and activity throughout the year. There is surely a lesson here for established boatyards to broaden their scope to include land-based activities. In addition to servicing boats belonging to permanent customers or casual visitors, the good boatyard should be able to deal with repairs or fitting out, whether in glass reinforced plastic, timber or steel. The boating scene retains for the most part a friendly atmosphere. An option open to the private, boat owner is to join a cruising club and take advantage of non-profit-making moorings and other facilities. Communal working parties may be held to construct a new slipway, erect additional jetties, or haul boats from the water for their refit. According to McKnight, (1975), the following are the factors to be considered in relation to these facilities: i. Boat Parking or terminal Dinghies and small keel boats are normally brought ashore after each day's sailing, but larger keelboats, cruisers or commercial boats are generally taken out of the water only at infrequent intervals. Parking areas are required for the onshore accommodation of both categories.

196 186 Advances in Marine Technology 2006 ii. Location The majority of the smaller boats are usually manhandled, during launching and recovery, and because of this and the frequency with which these operations take place the boat park is normally located adjacent to the slipway or other launching facility, for ease and convenience. The site should be reasonably level, preferably firm and well drained and with space for a trailer park, about one third of its size, adjoining. It should also be capable for future extension, where appropriate, to cater for possible further development of the facilities. iii. Capacity and size The size of a boat park is basically dependent upon the number of boats involved and their dimensions. Sufficient spaces should be provided for all the boats normally expected to be kept on site. A boat park for craft, which are normally kept in the water, houses, only trailers for the majority of the time. Because they generally occupy a smaller space than boats, the parking area is underutilised except for the relatively short periods when the boats are ashore. The dimensions of boats vary considerably and, as a result, so do the sizes of the parking spaces necessary and the width of the aisles between them. A space 6 or 7m long by 3m wide will normally be adequate to accommodate the majority of dinghies and small keelboats and their trailers, but a greater area will be required for larger craft. The aisle width is usually slightly greater than the length of the parking bay.

197 The Development and Use of Inland Waterway System for 187 Figure 10.6 Water transport terminal or jetty 10.9 MOORINGS Unlike dinghies and centerboard craft, the larger keelboats and motor cruisers are only removed from the water at infrequent intervals, and suitable moorings are needed for them to tie up to during the intervening periods. Only extensive areas of water or long stretches of navigable river can afford adequate mobility to such craft. Mooring facilities can vary in size from those ac accommodating single vessels to those such as large marinas, catering for hundreds of boats. The capacity of a new development may be influenced by many factors, including the position and characteristics of the particular site, the size of the unsatisfied demand for moorings on the water concerned, and the capacity of the water to accommodate additional craft without becoming overcrowded. As with slipways, mooring, structures situated on river should be designed and constructed so that significantly to obstruct or interfere with the flow of water. All mooring structures should be