MATTHEWSDANIEL SURVEY & ENGINEERING GUIDELINES SECTION I GUIDELINES FOR BARGE TRANSPORTATION

Transcription

1 SECTION I - BARGE TRANSPORTATION MATTHEWSDANIEL SECTION I GUIDELINES FOR BARGE TRANSPORTATION AUGUST 2004

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3 SECTION I - BARGE TRANSPORTATION TABLE OF CONTENTS TABLE OF CONTENTS 1. INTRODUCTION Purpose of Document Principles for Approvability Certificates of Approval Procedures and Contingency Plans Reference Documents PLANNING OF MARINE OPERATIONS General Transportation Manual Considerations During The Preparation Process ENVIRONMENTAL CRITERIA FOR TOWING AND DEPARTURE Environmental Return Period Wind Waves Other Metocean Conditions Departure Criteria and Weather Forecasting Weather-Restricted Operations Point of No Return DETERMINATION OF MOTIONS AND STABILITY General Motion Response Standard Criteria Intact Stability Dynamic Stability Damaged Stability GRILLAGE, SEAFASTENINGS AND CARGO LOADS General Loads During Transportation Grillage and Seafastening Strength Barge Strength Internal Seafastenings Fatigue... 17

4 SECTION I - BARGE TRANSPORTATION TABLE OF CONTENTS 5.7 Cargo Protection OPERATIONAL ASPECTS General Draft and Trim Pre-Sailaway Checks Towing Routes Communication and Reporting REQUIREMENTS FOR BARGES General Documentation Technical Information Ballast and Pumping Systems Pumping System Watertight Manholes Top Hats/Sounding Vents Watertight Integrity Barge Deck Openings Anchoring and Mooring System Size of Anchor Strength of Cable Length of Anchor Line Arrangements Mooring System Navigation Lights and Shapes Manning Crew Duties Requirements if Manned Access... 32

5 SECTION I - BARGE TRANSPORTATION TABLE OF CONTENTS 8. TOWING ARRANGEMENTS General Tow Connections Fairleads Towing Bridle Intermediate Tow Pendant Retrieving Arrangements Emergency Towing Arrangements REQUIREMENTS FOR TOWING VESSELS (TUGS) General and Documentation Manning Bollard Pull Requirements Towing Winches Towing Wire Synthetic Ropes Shackles Tailgates/Stern Rails and Towing Pods Additional Equipment Bunkers Damage Control REQUIREMENTS FOR LAND TRANSPORT Securing of Cargo For Land Transport... 42

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7 SECTION I - BARGE TRANSPORTATION Page 1 1. INTRODUCTION 1. INTRODUCTION 1.1 Purpose of Document This document is intended for use only and has been prepared by (MD) for use when MD acts as Marine Warranty Surveyor. It addresses likely main concerns based on experience. This document does not deal comprehensively with all concerns which will need to be addressed or even, where a particular matter is addressed, does this document attempt to set out the definitive view of MD for all situations. This document gives guidelines which should be reviewed in each particular case by the owner and MD engineer/surveyor to ensure that the particular circumstances of the towage are addressed in a way which is considered to mitigate identified hazards. These guidelines cover the marine aspects of jackets or deck sections or likeequipment, tie-down, seafastening, and towage onboard towed barges or vessels. Marine surveying is an activity involving experienced personnel identifying possible risks to a transportation or towage, and consulting on mitigating the risks to a level which is as low as reasonably practical (for which MD shall be deemed the approving authority) to approve the venture to proceed, on behalf of underwriters. The term "Marine Surveying" as used herein is an activity, which covers: Review of plans, drawings, documents and procedures to verify compliance with final MD acceptance criteria Survey of vessels, structures and equipment as deemed appropriate Confirmation of approval of the activity or venture by issue of a MD Certificate of Approval All the above activities will be based on an acceptance criteria for which MD shall be deemed the approving authority. All reports and certificates are issued solely for the use of MD, its clients and other authorized entities agreed by MD and the client. The review and approval by MD is not meant as a substitute for the independent judgment of professional designers, naval architects, marine engineers, owners, operators, masters and crew, nor as a substitute for the quality control procedures of fabricators, builders, suppliers, materials, machinery or equipment. MD acts through its engineers and marine surveyors or others who are believed by MD to be skilled and competent.

8 SECTION I - BARGE TRANSPORTATION Page 2 1. INTRODUCTION The user of MD services is responsible for ensuring compliance with all applicable laws, regulations and other government directives and orders related to a unit, its machinery and equipment, or their operation. Nothing contained in any guideline or approval certificate issued by the MD shall be deemed to relieve any other entity of its duty or responsibility to comply with all applicable laws, including those related to the environment. MD approval represents that a transportation or towage adheres to a minimal standard satisfactory to MD for purposes of fulfilling the marine warranty survey role. The validity, applicability and interpretation of any approval to meet a minimal standard remains in the sole judgment of MD. MD is not responsible for the consequences arising from the use by other parties. MD will conduct both an engineering and operational review on the proposed seafastening, towage and/or transport, which will include, but not be limited to, the vessel/barge, tug selection, towing arrangements, and seafastening acceptance. Timely completion of engineering and operational review is dependent on quality and completeness of information supplied. Normal practice is for the time period to be not less than a 2-4 week turnaround prior to loadout. Early submission is a prudent practice in order to avoid delay. 1.2 Principles for Approvability The purpose of this Section is to provide general guidance on the principles of approvability. Generally, MD looks for the following characteristics in developing acceptance criteria for a particular seafastening, towage or transportation: The equipment and vessels are suitable for their intended use. There is redundancy in the equipment provided, to cover likely contingencies. The operation is designed taking into account the statistical weather extremes for the area and season, or the operating weather conditions, chosen at values smaller than the specified design criteria, and the weather is forecast for a period long enough to complete the operation. The operations are planned, in nature and duration, such that accidental situations, breakdowns or delays have a very low probability of occurrence and are all covered by contingency actions. Adequate plans have been developed for a safe step-by-step execution of the operation, with clear indications of the chain of command. Suitably experienced and qualified personnel conduct the operations.

9 SECTION I - BARGE TRANSPORTATION Page 3 1. INTRODUCTION 1.3 Certificates of Approval A Certificate of Approval will be issued onsite, immediately prior to the operation, by the Surveyor in attendance when he is satisfied that the preparations for towage are complete, that the operation scheduled is approved or the towed unit/vessel is fit to be towed in the opinion of MD acting through its surveyor and that the weather forecast is satisfactory for the purposes for which the approval is intended. 1.4 Procedures and Contingency Plans Procedures shall be developed and included in the seafastening and towage (transportation) manual. This manual shall also address any possible need to deviate from the established procedures and shall describe appropriate contingency plans. 1.5 Reference Documents 1. ISO "Offshore structures for petroleum and natural gas industries" Marine Operations (in preparation). 2. CSA Standard S475, Sea Operations, IMO Guidelines for Safe Ocean Towing MSC Circ. 884, December API RP 2A "Recommended Practice for Designing, Planning and Construction Fixed Platforms" December ABS Guide for Building and Classing Mobile Offshore Drilling Units, May Sharples, B.P.M., "Transportation and Emplacement of Arctic Structures," FIP Symposium, Calgary, August Sharples, B.P.M., "Loss Prevention of Mobile and Fixed Offshore Platforms During Tow, Installations and Operations," First International Congress on the Physical Protection of Petroleum Installations, Mexico City, February Sharples, B.P.M. & Tait, S., "The Role of the Marine Surveyor," Proceedings of Conference on Concrete Ships and Floating Structures, The Concrete Society, London US NAVY TOWING MANUAL SL740-AA-MAN-010, September Devoy, S.D. & van Hoorn, F. "The Dry Transport of the Green Canyon "Tension Leg Wellhead Platform" by a Semi-Submersible Heavylift Ship," OTC Paper No. 6471, 1990.

10 SECTION I - BARGE TRANSPORTATION Page 4 2. PLANNING OF MARINE OPERATIONS 2. PLANNING OF MARINE OPERATIONS 2.1 General Marine operations shall be planned so as to develop procedures, which are both conservative and practical. The planning shall be based on the use of well-proven principles, techniques, systems and equipment to ensure against major economic losses. The possible impact of the tow on the environment shall also be considered. For projects in which new techniques are applied or existing technology is extended, the documentation shall justify the prudence of the operation. The feasibility of extending existing technology and applying new techniques shall be documented. All planning shall be based where possible on the assumption that it may be necessary to interrupt or reverse the operation. Ports, which may be used as ports of refuge during the tow, shall be identified and surveyed for suitability prior to the operation, if possible. Planning should be based on reasonable timing. A delay in timing of a severe part of the route can change the risk equation significantly. 2.2 Transportation Manual A Transportation Manual covering all normal, contingency and emergency aspects of the operation shall be prepared for review and approval by MD. This may include loadout information which would be subject to the Guideline for Marine Loadouts. The manual shall include details of the following: Description of planned operation. Organization and communication. Site information for loading and port of departure and arrival location. Description and drawings of the structure to be towed. Environmental criteria for tow from appropriate sources. Grillage and seafastenings review results of structural analysis. Barge strength analysis, global and local. Temporary mooring arrangement. Towing vessel(s) information and towing suitability survey. Ballast plan, intact and damaged stability calculations. Summary of the loading and motion analysis. Transportation route and possible ports of refuge.

11 SECTION I - BARGE TRANSPORTATION Page 5 2. PLANNING OF MARINE OPERATIONS Towing procedure and configuration. Weather forecast or weather routing services and schedule. Recording and reporting procedure. Contingency and emergency action plans including contact numbers. The MD Warranty Surveyor, who will require all component parts of the towing equipment to be in satisfactory condition, must attend to survey primary towage connections, in satisfactory condition and where applicable in MD Surveyor's opinion, associated certificates valid. Documentation to confirm that visual examination and/or non-destructive examination (NDE) of the welds on the grillage and seafastenings has been satisfactorily carried out shall be prepared. A competent person shall carry out these tests and the necessary records shall be made available for review. 2.3 Considerations During The Preparation Process Seafastening work shall be started as soon as possible after positioning the structure on the barge and installation of temporary seafastenings should begin immediately after final positioning of cargo. Movement of the barge shall be limited, until sufficient seafastening is completed, to withstand either: an inclination of 5º, or the inclination caused by damage to any one compartment of the barge, whichever is the greater. Final seafastening connections should be made with the barge in ballast condition as close as practical to the transport condition. If manhole covers have been removed, all manhole covers shall be replaced as soon as practical after loadout. Any holes cut for ballasting purposes shall be closed as soon as practical and the barge certification reinstated before sailaway. Unless a contingency plan is in effect with sufficient moorings (whose sufficiency is supported by calculations) or the barge can be sufficiently grounded to withstand a maximum storm event, approved tug(s) shall be available or in attendance, as required, for barge movements, removal of the barge from the loadout berth in the event of deteriorating weather, or tug back-up to the moorings.

12 SECTION I - BARGE TRANSPORTATION Page 6 3. ENVIRONMENTAL CRITERIA FOR TOWING AND DEPARTURE 3. ENVIRONMENTAL CRITERIA FOR TOWING AND DEPARTURE 3.1 Environmental Return Period A set of limiting metocean criteria should be established dependent on the duration of the towage operation. The design storm design environment is not used for calculating bollard pull requirements, which are covered in Section 9.3. Where design environmental criteria are selected on a seasonal basis, due consideration should be given to the possibility of acceleration or slippage to the project schedule, and the consequence of a worse weather condition for limiting the selected environmental criteria. For all operations taking longer than forecastable conditions, extreme data analysis should be used for appropriate return periods or acceptable probability of exceedance, to set design criteria. Such operations are termed "unrestricted" operations. When operations are within forecastable periods, specific limiting operational criteria should be determined with the operation duration dictated by the weather forecastable window. An iteration process is normally needed at the design stage to arrive at an acceptance criteria for the whole operation. Early participation with the MD Marine Surveyor is helpful to this process. Unrestricted tows shall be designed to withstand the seasonal 10-year return period extreme environmental conditions or appropriate probability of exceedance standard, for the most exposed part of the route. It is recommended that the seasonal analysis of extreme conditions take into account tropical revolving storm characteristics. For example, Northern hemisphere operations can be divided into periods May to October for summer operations and November to April for winter operations. Southern Hemisphere and Tropical operations should take due account of the possibility of periods of extreme weather and monsoon conditions respectively. For long duration tows passing through areas having different characteristic seastates, the worst seastate for the route shall be identified and used in the design of the cargo, grillage and seafastenings. For limited distance towing operations with a short planned duration, reduced environmental criteria may be proposed for approval by MD. Environmental data shall be referred to by the following nomenclature: V 1MIN maximum 1-minute mean wind speed at 10 m above sea level. H S Significant wave height. H MAX Maximum wave height. T Z Zero crossing wave period.

13 SECTION I - BARGE TRANSPORTATION Page 7 3. ENVIRONMENTAL CRITERIA FOR TOWING AND DEPARTURE T P Wave period of peak spectral density. The return conditions to be considered should be related to the duration of the marine operation. As a general guidance, the following criteria may be applied: Duration of use Up to 3 days Environmental criteria Specific weather window 3 days to 1 week 1 year return, seasonal 1 week to 3 month 10 year return, seasonal 3 month to 1 year 50 year return, seasonal More than 1 year 100 year return, all year 3.2 Wind While the above can be used as a general guide, marine operations generally cannot be subjected to precise predictions. Thus in deriving the specific metocean conditions for the design, it is recommended that a wider view be taken of generally expected conditions in the area, particularly in areas such as tropical revolving storms where statistical analysis often provides anomalies for specific routes in the data where in reality the anomaly may not be relevant in predicting future operations. Excluding tropical revolving storms from the data base and yet adhering to the above recommendation criteria is only permitted if weather forecasting facilities can sufficiently predict storm conditions on route or at site allowing the unit to be diverted to a safe harbour or safe anchorage. The design wind speed shall be based on the 1 minute sustained wind speed at a height of 10 meters above still water level. The seasonal variation of wind speeds can be taken into account in determining extreme values. 3.3 Waves The design wave height shall be based on the significant height (H S ) associated with wind speeds referred to in Section 3.1. A range of wave periods should be investigated for any sensitivity in the operation based on T P listed below. It is recommended that motions shall be investigated for a range of values of peak period (T P ), particularly if resonant conditions are possible. The range of values, defined in terms of significant wave height, as recommended by ISSC (International Ships Structures Congress), is as follows: (13 H S ) < T P < (30 H S )

14 SECTION I - BARGE TRANSPORTATION Page 8 3. ENVIRONMENTAL CRITERIA FOR TOWING AND DEPARTURE where T P = peak period In the maximum seastate under consideration, the natural period of motion of the unit may be below the above range. In this case, motions shall also be determined in the highest seastate, which may, according to the formula above, have a peak period which is equal to the unit's natural period of motion. For units that have a natural period of motion greater than (30 H S ) and which may pass through areas prone to long period swells, then motions due to swell shall also be determined and considered. In open waters, waves will usually be considered as being long crested. However, in some areas it may be demonstrated that it is appropriate to consider the waves to be short crested and to apply a spreading factor to the wave energy. This is particularly appropriate for fatigue sensitive tows. If a detailed analysis of the joint probability distribution of significant wave height versus peak wave period is carried out, the following criteria may be applied: a) Analyse the tow for the design storm wave height for the most probable value of peak period: (T p ) +/- 1 sec and b) Analyse the tow for combinations of significant wave height and peak period having the same joint probability of occurrence as the design storm wave height and the most probable peak period. The effect of swell shall be considered in the above criteria. 3.4 Other Metocean Conditions Other factors and combinations may be critical and these may include: Combinations of wind, wave, current, Bad visibility, Sea icing, icing on superstructure, exceptional low temperature, Water density and salinity Tidal currents Where the presence of ice may affect the operation, ice movement records, forecasts and monitoring shall be used to assist planning of the operation.

15 SECTION I - BARGE TRANSPORTATION Page 9 3. ENVIRONMENTAL CRITERIA FOR TOWING AND DEPARTURE 3.5 Departure Criteria and Weather Forecasting The departure of a tow will only be approved after receipt of a favorable 72-hour weather forecast covering the intended initial route. During the tow, a weather forecast shall be obtained from a recognized meteorological agency which has detailed knowledge of the area covered by the forecast and which customarily provides services for offshore transportation or weather routing. Weather forecasts shall be provided at 12-hour intervals, and shall contain forecasts for the next 24, 48 and 72 hours, with the weather outlook for the coming 3 to 5 days period. The Towmaster should receive weather forecasts and weather maps, in written form, which is generally done by having an onboard weather facsimile machine or continuous capability. The forecast should be in writing and include relevant parameters such as: Synopsis, barometric pressure, temperature. Wind direction and velocity. Waves and swell - significant and maximum height, direction and period. Visibility, rain, snow, sleet etc. If forecasts are received of weather which is likely to endanger the tow, the Towmaster may then be alerted in good time and can divert the tow to a safe holding area or port of refuge, if appropriate. For certain tows it may be recommended to employ an experienced meteorologist for the duration of the tow, to provide specific forecasts for the tow route Weather-Restricted Operations For weather-restricted operations, the "operation limiting criteria" shall be less than the "design limiting criteria", but the margin is a matter of judgment, dependent on numerous factors such as: Quality of statistical data Quality of forecast Quality of wave and current monitoring A weather-restricted marine operation is generally one, which can be completed within the limits of a favorable weather forecast (generally less than 72 hours), taking into account contingencies. The design weather conditions need not reflect the statistical extremes for the area and season. A suitable reduction may be applied based on the following comments:

16 SECTION I - BARGE TRANSPORTATION Page ENVIRONMENTAL CRITERIA FOR TOWING AND DEPARTURE For weather-restricted operations, the maximum forecast operational criteria can be based on the ability of weather forecasting to predict an allowable weather envelope. In order to utilize this philosophy one must be able to demobilize the marine equipment and run for shelter, within the weather forecasting limitations. However, for a design sea state, one must use an approved meteorological firm and base the design weather to engineering accepted probability levels. For guidance the table under section 3.1 should be used Point of No Return Weather restricted operations may be divided into sequences where the operation may be aborted and brought to a safe condition within the remainder of the existing weather window. The Point of No Return (PNR) should be defined as the last point in time (or a geographical point along a route) at which an operation could be aborted or returned to a safe condition. For the critical operation period between any PNR and the structure reaching a safe condition, the reliability of weather window is crucial. The window duration shall have necessary margins for: Inaccuracy in operation schedule Technical/operational delays Inaccuracy in the timing of the metocean forecast Generally, the forecast window duration shall be in excess of the total critical operation schedule. This, however, needs to be evaluated on background and consequences as given in the guidelines below. As a guideline the following points are made: Operations with vulnerable/critical equipment need extra allowance. Operations with time schedule based on previous similar operations need less allowance. Operations in areas/time of the year where conditions are difficult to predict need extra allowance.

17 SECTION I - BARGE TRANSPORTATION Page DETERMINATION OF MOTIONS AND STABILITY 4. DETERMINATION OF MOTIONS AND STABILITY 4.1 General The cargo, seafastenings and barge shall be shown to be able to withstand the motions and forces resulting from the design transportation conditions including: Loads resulting from vessel motions Loads resulting from design wind Loads resulting from slamming, water on deck and other effects of immersion Effects of barge or vessel flexibility It is recommended that either a motion response analysis is made or that model tests are performed for each transportation case. In the case of benign tows, a minimum seafastening of the forces resulting from an inclination of 5º, or the inclination caused by damage to any one compartment of the barge, whichever is the greater shall be used. 4.2 Motion Response The motion response of the barge or transport vessel with cargo may be predicted by model tests. Alternatively, a computer analysis incorporating proven software and techniques may be used. It shall be shown that, for similar units and environmental conditions, the results from the program correlate well with model test results. The motion response analysis shall use the design environmental criteria for transportation. Motion response calculations shall be carried out by computer programs, which have been validated against a suitable range of model test results in irregular seas. A 3-hour period exposure to the extreme design condition shall be used to determine the maximum response. Under no circumstances will a design acceleration be approved if less than the 1/100 th design motion response or acceleration. If the environmental extremes are near the resonant period of the barge, the results of the motion analysis shall be treated conservatively. Wave directions representing bow, quartering and beam sea conditions shall be used for the motion response analysis. Additional load cases may be required if the windage is such that the vessel cannot control its heading to the waves in the case of a towline break. 4.3 Standard Criteria Standard motion criteria may be applied in lieu of a motion response analysis or model testing for the following conditions. For all other conditions a motion response analysis or model testing of the barge/cargo combination shall be performed:

18 SECTION I - BARGE TRANSPORTATION Page DETERMINATION OF MOTIONS AND STABILITY A large barge is defined by the following parameters, Beam > 72 ft. Length > 240 ft. For a small barge, in which any single dimension is less than the dimensions shown in the table above: The forces to be used for the design of the cargo, seafastening and grillages may be derived using the following table: OCEAN TOW Single Amplitude in 10 Seconds ROLL PITCH HEAVE Large Barges 20 º 12.5 º 0.20g Small Barges 25 º 15 º 0.20g INLAND TOW All Barges 5 º 5 º 0.10g OFFSHORE TRANSPORATION Large Vessels L>76m LOA and B> 23m 20 º 12.5 º 0.20g Small Vessels L<76m LOA and B< 23m 30 º 15 º 0.20g In the above table the following criteria are applicable: The center of motion shall be assumed to be at the still waterline. Heave motions shall act parallel to the global vertical axis. Roll motion shall be combined with + heave. Pitch motion shall be combined with + heave. No allowance shall be made for friction to reduce seafastening forces except as allowed in section 5.3. A minimum seafastening criteria is required, resulting from an inclination of 5º, or the inclination caused by damage to any one compartment of the barge, whichever is the greater.

19 SECTION I - BARGE TRANSPORTATION Page DETERMINATION OF MOTIONS AND STABILITY Where slamming is considered to be a problem 20% shall be added to the loadings resulting from pitch motions to cover this effect. 4.4 Intact Stability The transverse metacentric height (GM) must be positive, at zero angle of heel. The range of transverse statical stability is given in the table. Correction to values of GM to allow for free surface effects should be included in this computation. TYPE INTACT RANGE Large Barges 40 º Small Barges 40 º The acceptability of barges with a range less than 40 degrees will be dependent on motion response predictions. When maximum amplitudes of motion for any specific towage are derived from model tests or motion response calculations, the minimum range of static stability shall be not less than 20+ ( ) degrees, where: = the maximum amplitude of motion in degrees about the axis concerned caused by the design seastate, plus the static angle of inclination from the design wind. Cargo buoyancy may be considered in computation of stability characteristics provided that the cargo is watertight and can be shown to be effective in terms of tie-down and hydrodynamic loading. Cargo overhangs should not immerse as a result of heeling in a 15 m/sec wind in still water conditions. 4.5 Dynamic Stability The area under the righting moment curve to the second intercept of the righting and wind overturning moment curves, or the downflooding angle, whichever is less, shall not be less than 40% in excess of the area under the wind overturning moment curve to the same limiting angle.

20 SECTION I - BARGE TRANSPORTATION Page DETERMINATION OF MOTIONS AND STABILITY Figure 3.1 Wind Heeling Moment Diagram The wind velocity taken for overturning moment calculations shall be the lesser of the design wind speed or 100 knot. For this purpose, a 1-minute mean wind for the 10- year return extreme condition shall be used for the design wind speed. 4.6 Damaged Stability It shall be demonstrated that the barge with cargo will have sufficient reserve buoyancy to remain stable and afloat when any one watertight compartment is flooded. Minimum penetration shall be considered to be 1.5 meters. Two adjacent compartments on the periphery should be considered as one compartment if separated by a horizontal watertight flat. The emptying of a full compartment to the waterline should be considered if it gives a more severe result than flooding of an empty compartment. The ability to compensate for damage incurred, by pumping out or by ballasting other compartments, etc., is not to be considered as alleviating the specified requirements. The unit is to possess sufficient reserve stability in the damaged condition to withstand the overturning moment of a 50 knot sustained wind superimposed from any direction and meet the following criteria: The angle of equilibrium must not exceed 15 degrees after equalization. The deck edge may not be submerged at any point. The vessel's metacentric height (GM) must be at least 2 inches when the vessel is in the upright position.

21 SECTION I - BARGE TRANSPORTATION Page GRILLAGE, SEAFASTENINGS AND CARGO LOADS 5. GRILLAGE, SEAFASTENINGS AND CARGO LOADS 5.1 General The purpose of the grillage and seafastenings is to secure the cargo during the tow so that neither the cargo nor barge suffers damage as a result of severe environmental conditions or other accidental events. The grillage design and layout should take account of any limitations imposed by the load-out method. The basis for the design of the grillage, seafastenings and cargo shall be the loads resulting from the methods defined in Section 4 above. Seafastenings shall be designed to be removed easily without damage to the cargo. During removal of the seafastenings, the cargo shall remain supported and restrained horizontally by the grillage. 5.2 Loads During Transportation The components of load to be considered when analyzing the total forces between the barge and cargo are those due to: Static weight of the cargo and ballast Static heel and trim. Dynamic loads which result surge/sway, roll/pitch and heave Wind load Wave induced bending loads Slamming loads. Loads resulting from immersion of any part of the cargo. The combination of motions, which give the highest loading in any direction, shall be considered using the following combinations. Roll, heave and sway Pitch, heave and surge Alternatively, results of a motion analysis taking account of phase relationships between motions to compute acceleration vectors may be used. The benefits of free surface should not be taken into account in the calculation of motions unless this has been specifically model tested.

22 SECTION I - BARGE TRANSPORTATION Page GRILLAGE, SEAFASTENINGS AND CARGO LOADS Account shall also be taken of any significant loads in the grillage and seafastenings resulting from the relative deflections of barge or transport vessel and cargo, resulting from ballast changes or due to environmental effects. 5.3 Grillage and Seafastening Strength The grillage and seafastenings shall be designed such that the static stresses in all members do not exceed the allowable stresses. Seafastenings shall be designed to accept anticipated deflections of the barge in a seaway. For cargoes that will be delivered offshore, the seafastenings should be designed to be released in stages. The final stage of seafastening should be determined for the particular project, however, the ability of the cargo to resist a 10 degree static angle is a good rule-of-thumb. If seafastening design stresses are high, non-destructive examination may be recommended in an agreed manner particularly in critical areas where the allowable stresses are high using the 1/3 increase in allowable stresses. The amount of NDE should be agreed with the MD Surveyor on site but may typically amount from 20-50% of the critical welds. A maximum friction coefficient may be used when the cargo is stowed on cribbing wood of 15% of the weight (taking the maximum vertical acceleration into account). The formula to determine maximum cribbing friction is: Friction = 0.15 x cargo weight x (1.0 max.acc. vertical ) Where: cargo weight in [metric tonnes] max.acc vertical in [g] The minimum seafastening capacity should be: 5.0 % of cargo weight in longitudinal direction 10.0 % of cargo weight in transverse direction When uplift is calculated due to overturning moments caused by motions and/or wind loads and/or buoyancy loads by submerged water, effective countermeasures are required either in ensuring avoidance of such loads, or applying uplift lashing in the seafastening concept. 5.4 Barge Strength The overall strength of a classed barge, operating within its classification limitations, will normally be accepted. Calculations shall be submitted where necessary to demonstrate that static and dynamic loadings from the cargo and seafastenings are

23 SECTION I - BARGE TRANSPORTATION Page GRILLAGE, SEAFASTENINGS AND CARGO LOADS suitably distributed into the barge structure and that the ballast distribution is satisfactory. If the calculated maximum loads imposed on the barge are planned to exceed the specified permissible loads, then the Classification Society shall be informed. Any subsequent acceptance of the calculated loads by the Classification Society will need to be verified by MD as being based on justified rational analysis. The calculated still water bending moment and shear force shall be checked against the allowable values approved by the Classification Society. 5.5 Internal Seafastenings Internal seafastenings shall be provided where necessary to prevent damage to equipment or loose items forming part of the cargo. Protection against wave slam or spray should also be provided as appropriate. For major items of equipment, calculations may be required. In other cases the requirements for and suitability of internal seafastening may be agreed with the attending MD Warranty Surveyor. 5.6 Fatigue The requirement for fatigue analysis of seafastenings, barge and cargo shall be agreed with MD. In general fatigue analyses will be required where the duration of tow, nature of towing route or season of tow indicate fatigue is possible. Prior to a fatigue analysis being performed the following shall be agreed with MD: Seastate criteria Type of analysis, deterministic or spectral S-N curve(s) applicable Stress concentration factors The minimum allowable calculated fatigue life shall not be less than 4 times the expected duration of tow. Whether or not fatigue analyses are performed, all seafastenings shall be designed for good fatigue characteristics 5.7 Cargo Protection All cargo shall be protected from wave slam and wetting damage as appropriate. This may require provision of breakwaters or waterproofing sensitive areas.

24 SECTION I - BARGE TRANSPORTATION Page OPERATIONAL ASPECTS 6. OPERATIONAL ASPECTS 6.1 General Marine transportation shall be performed by an experienced Contractor with qualified personnel, using suitable systems and equipment. 6.2 Draft and Trim The barge should be trimmed by the stern to give good directional stability. The trim should normally be 1% of the barge length between perpendiculars. The barge shall be ballasted for zero list. Tanks used for ballast shall, where possible, be pressed full. Other tanks shall be empty. The mean tow draft should normally be between 40% and 55% of the barge depth. Where barges with faired sterns are fitted with directional stabilizing skegs, it may be preferable to have no trim. However, allowance should be made for trim caused by the towline force. 6.3 Pre-Sailaway Checks Prior to the issue of the Certificate of Approval for the sailaway, all parties shall be satisfied that the tow (tug, barge and cargo) is ready for departure. Particular attention shall be paid to the following: Tug survey and approval Barge documentation External and internal seafastenings - completion and satisfactory NDE checks in accordance with Marine Warranty Surveyor approved drawings Load spreading devices (grillages) in place Barge approved navigation lights, shapes and power supply Barge draft, heel and trim Watertight integrity of barge including manhole covers checked Ballast pumps operable and tied down; fuel supplies sufficient Condition and preparation of main and emergency towing equipment Anchor; anchor winch and wire Loose gear tied down Mooring gear stowed

25 SECTION I - BARGE TRANSPORTATION Page OPERATIONAL ASPECTS Particular attention to be paid to the main towage hookup The attending MD warranty surveyor may make further recommendations. 6.4 Towing Routes The tow route shall be proposed by the Contractor for acceptance by all parties. In selecting the route, the following items shall be taken into consideration: Requirements for additional tugs to assist with the passage to open sea. Navigation through restricted passages. Emergency shelter areas/ports of refuge. Likely weather and seastate enroute. The route selected shall have adequate bottom and side clearance for the tows, the parameters being dependent on the accuracy of navigation and the size and draft of the tow. 6.5 Communication and Reporting The Towmaster should be fully briefed on all aspects of the tow and be aware of any operational limitations and the contingency plan. The Towmaster shall report each 24 hours the following information to the MODU owner and acting as Marine Warranty Surveyors: Position, time and date (GMT) Situation report, including weather, seastate and speed through water. Anticipated situation for the next 24 hours Sailed distance during the previous 24 hours Any observations with respect to the barge How the barge is riding Damage observed Boarding parties check Tank sounding information Changes in list trim or draft Estimated time of arrival (ETA)

26 SECTION I - BARGE TRANSPORTATION Page OPERATIONAL ASPECTS If any emergency situation occurs, the MD warranty surveyor and MD local office shall be informed immediately.

27 SECTION I - BARGE TRANSPORTATION Page REQUIRMENTS FOR BARGES 7. REQUIREMENTS FOR BARGES 7.1 General The proposed barge shall be inspected by an MD surveyor and approval given subject to its condition and the condition and suitability of the towing equipment and machinery. Documentation required by the flag state and international convention shall be in order and the barge Classed by a major Classification Society. 7.2 Documentation Most transportations are subject to approval from national and local regulatory bodies in particular with regard to the safety of personnel, and the environment. Various barges and vessels will additionally come under the jurisdiction of a flag state. So far as practicable, MD surveyors will check the validity of the appropriate documentation and highlight any areas which come to the attention of the surveyors, accepting the fact that this is a specialist activity and not the general role of the marine warranty surveyor. The following documentation should be available on the barge, vessel or (lead) tug for any towage: a) Certificate of Class issued by a recognized Classification Society. b) Certificate of Registry. c) Tonnage Certificate (if not incorporated in other certification) (determines port dues). d) Certificate/Approval of navigation lights and shapes issued by a recognized authority. e) International Load Line Certificate. f) Documents required for the outward clearance at the port of departure and for inward clearance at the port of arrival to be made available for sighting by the attending surveyor. These include clearance by customs, agriculture, health and other regulatory bodies. Troublesome points, on occasion are the importing of cribbing wood, and seafastening steel, which may need special arrangements. g) Deratization Certificate, or exemption if applicable (some Health Authorities require). h) Oversized tow certificate (sometimes required by large tows on restricted inland waterways). i) Stability Letter (as appropriate to prove-up the stability to regulatory authorities). j) Test certificates covering all components for the main and emergency towing equipment.

28 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR BARGES MD Certificate of Approval for a particular towage/transportation (issued on sailing). For manned tows the following additionally should also be carried when appropriate: a) Life Saving Apparatus (LSA) and Fire Fighting Apparatus (FFA) Certificates. b) Crew List. c) Radio licenses (as required). d) Permission from Certifying Authority to man barge. An operations logbook shall be kept, and any deviations from the agreed procedures shall be recorded. Note: The Marine Warranty Surveyor in conducting a warranty survey does not cover items in the charterer's interest such as suitability inspection and on-hire survey of the barge, both of which should be carried out prior to acceptance by contracting parties. MD can carry out these types of surveys if so instructed. 7.3 Technical Information The Contractor should supply the following particulars of the barge(s) proposed for transportation: General Arrangement drawings. Deck load capacity plans for point loads and uniformly distributed loads. Typical midship and longitudinal sections if required for evaluation of structural strength. Ballast capacity plan. Stability data. Copies of classification and certification documents. If a compressed air ballasting system is fitted, full details shall be provided. 7.4 Ballast and Pumping Systems Ballast pumps of suitable design and capacity shall be provided on the barge for the following: General ballasting and deballasting operations including during and after loadouts.

29 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR BARGES Correction of draft or trim in normal operations and after discharge (especially at sea). Damage control and counter flooding purposes in event of hull damage, grounding etc. Deballasting to reduce draft to enter port Trimming to allow inspection and repair below normal waterline Access to a flooded compartment The use of a compressed air system will not be practicable for all these cases, especially if the barge is holed above the waterline. A compressed air system should have a compressor on board, working into the permanent lines. It should be possible to sound and pump into or out from critical compartments in severe weather. Details of pumping systems and of ballast status shall be retained onboard the lead tug during the tow Pumping System It is recommended that consideration be given to the pump room(s) being protected from flooding, either by cofferdams or by a double skin to the hull. To be considered protected, a pumproom and any compartment required for access, should be separated from the bottom plating by watertight double bottom plating, not less than 65 cm high, and from the outer shell by other compartments or cofferdams not less than 1.5 meters wide. If the pump room is not protected as above, the following alternative arrangements may be acceptable: Two independent pump rooms from either of which any of the compartments can be ballasted or deballasted including simultaneously ballasting operations. At least two portable pumps, with adequate capacity and power source, which can be manhandled into position to serve any of the compartments. Submersible pumps, if used, shall be of such a size that they can be lowered through the manhole. The total capacity of the pumps should be sufficient to deballast, completely, one barge wing tank within a 4-hour period. It may be necessary to have top hats available on board to protect open manholes during a pumping process. The portable pumps may be carried on the tug provided a suitable means of manhandling them onto the barge is provided. Each portable

30 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR BARGES pump should be capable of pumping out from the deepest tank (with top hat installed). Sufficient fuel should be onboard to allow operation of the pumps for at least a 48-hour continuous use at the maximum rating with the possibility of re-supply from the tug Watertight Manholes If manholes to critical compartments are covered up by cargo then either alternative manholes should be fitted or cutting gear should be installed and positions marked for making access, and welding gear and materials carried for re-making watertight. Where a barge is classed, the owner should inform the classification society in good time of any holes to be cut or any structural alternations to be made. Access shall always be available to pump rooms and other work areas Safe ladders, which extend from the manhole opening to the compartment bottom, shall be provided in each compartment. Such ladders should comply with good safety practice having backing cages, for example, where appropriate. Suitable tools shall be provided for removal and refastening of manhole covers and sounding plugs. All manhole covers should be properly secured with bolts and gaskets, renewed as necessary Top Hats/Sounding Each compartment shall be provided with sounding facilities independent of the manhole, unless a sounding plug is fitted in the manhole cover to avoid removing the manhole cover. It is recommended that those compartments, which are commonly ballasted, should be provided with sounding pipes and striker plates. On all tows where the deck may be covered with water, the following shall be provided: a) A portable top hat of 60 cm minimum height that can be bolted in place. The top hat should be constructed to avoid damage to hoses and cables. b) At least one sounding tube extension of 60 cm in height, threaded so that it can be screwed into all sounding plug holes, shall be provided on all tows where the sounding plugs can be covered by water.

31 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR BARGES Vents Vents should be fitted with appropriate closing devices to prevent the ingress of seawater and the valves should be checked to be fully operational.

32 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR BARGES 7.5 Watertight Integrity All weather deck openings shall have adequate securing arrangements to ensure watertight integrity. Door openings on weather decks shall be fitted with sills in accordance with International Load Line Regulations. Compartment manholes shall be properly secured with bolts and gaskets, which must be maintained in good condition. A set of tools shall be provided onboard for releasing and refastening the manhole covers. If manholes to critical compartments are covered by cargo, grillage or seafastenings, care shall be taken to ensure they are properly secured before being covered. Adequate spare parts should be carried onboard to assist the Towmaster in the event of breach of watertight integrity. 7.6 Barge Deck Openings Barges having low freeboards during tow or loadout should be provided with at least one top hat of 60 cm height, with suitable means of fixing to the barge deck, which can be used in an emergency to gain access through a manhole, which may be awash. At least one standpipe of 60 cm height shall be provided with suitable fittings, such that it can be screwed into cap holes, which may be awash. 7.7 Anchoring and Mooring System In all cases, the barge shall be provided with an anchor which has sufficient holding power to hold the barge and cargo in a fully developed gale conditions. (Class Society rules are generally not appropriate for this application since they are sized based on barge alone, and not generally derived using modern calculation methodology) Size of Anchor If calculation methods are not used, the weight of one anchor should be at least 1/10 th of the towline pull required for the tow. A 10-ton anchor is considered as a maximum size provided it can be deployed in such a way as it can penetrate the soil (i.e. not trip out). A high holding power anchor with anti-roll stabilization is preferred. Where no permanent anchoring system is installed, an emergency anchor shall be fitted at the stern on a slanted billboard, with a quick release connection. The cable shall be arranged such that it will payout unobstructed when the anchor is let go.

33 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR BARGES Strength of Cable An adequate length of cable shall be provided having a minimum-breaking load (MBL) of: At least 15 times the anchor weight if the cable is stowed on a winch or capstan, or 1.5 times the holding power of the anchor, if greater Or 30 times the anchor weight if it is flaked on deck or 2 times the holding power of the anchor, if greater. If the anchor is let go, the last few flakes of cable on deck should have lashings that will break and slow down the cable before it is fully paid out Length of Anchor Line The normal minimum standard length of anchor cable required is 180 meters, preferably mounted on a winch. If the cable runs through to storage below decks then the access should be capable of being made watertight. If there is no winch or space is inadequate to flake out a cable properly, a minimum length of 90 meters may be acceptable. Such a reduction will only considered appropriate after a hazard analysis review of the routing Arrangements The inboard end of the cable should be led through a capped fairlead near the barge centerline and be securely fixed to the barge. Precautions should be taken to minimize chafe of the cable. The breaking load of the connections of the cable to padeye or winch and the padeye or winch to the barge structure should be greater than that of the cable. Anchor mounting and release If there is no suitable permanent anchor housing the anchor should be mounted on a billboard at about 60 degrees to the horizontal. The anchor should be held on a billboard in stops to prevent lateral and upward movement. Wire rope and/or chain strops that can be easily released manually without endangering the operator should secure it. The billboard should normally be mounted on the stern. It should be positioned such that on release the anchor will drop clear of the barge and the cable will pay out without fouling. If the anchor is mounted and secured at the stern, this will become the bow when anchored. Anchor lights and shapes must be positioned accordingly.

34 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR BARGES For any system, it shall be possible to release the anchor safely, without the use of power to release pawls or dog securing devices. If the anchor is held only on a brake, an additional manual quick release fastening should be fitted. The strength of the cable connection point on board shall exceed the break load of the cable by at least 10% Mooring System The barge should be provided with at least four mooring positions (bollards/stag horns, etc.) on each side of the barge. If fairleads to the bollards are not installed then the bollards should preferably be provided with capping bars, to retain the mooring lines at high angles of pull. Suitable chafe protection should be fitted to the deck edge for low angles of pull. At least 4 mooring ropes in good condition of adequate strength and length, typically about mm diameter polypropelene or nylon, and each meters long, should be provided for a sea passage. These ropes may be carried on the tug if they cannot be stored and secured on the barge. 7.8 Navigation Lights and Shapes Lights and shapes shall be provided that comply with International Regulations for Prevention of Collision at Sea, and any local regulations. Such local regulations may include aircraft warning lights if airports are nearby. The lights shall have sufficient power from an independent source to last for a period for the duration of the voyage plus 25% reserved. A full set of spare navigation lights and shapes shall be carried on the barge. Alternatively, sufficient spare parts for the navigation lights shall be carried. It is important to note that the lights and shapes must be of "certified" type, i.e. certified by a recognized marine regulatory agency such as a Coast Guard agency. The reader should refer to the specific documents for appropriate definitions however, the following general summary may be helpful: a) Normal lights and shapes (underway) The following shall be onboard at all times, and lit or displayed when appropriate: One (1) port side light. One (1) starboard sidelight. One (1) stern light.

35 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR BARGES One (1) black (towing) diamond shape (when length of tow exceeds 200 meters). b) Difficult tow and Not Under Command (NUC) The following shall be carried at all times and lit or displayed vertically on the signal mast of the towage vessel at the Towmaster's discretion: Two (2) red lights (all round NUC). Two (2) black ball shapes (NUC). Note: The current collision regulations imply that the Red-White-Red/Black Ball Black Diamond-Black Ball "difficult towing" signal should be displayed by the tug only. c) Anchor lights Two (2) white (all round) anchor lights (1 only if barge is under 100 meters in length). If the anchor is mounted and secured at the stern, this will become the bow when anchored. Anchor lights and shapes must be positioned accordingly. d) Fog signals (if barge manned): 7.9 Manning One (1) bell (for use forward when barge is at anchor) One (1) Norwegian horn or other suitable sound signal One (1) gong (only for barges over 100 meters in length, for use aft when barge is at anchor) Navigation lights shall be independently operated (e.g. from gas containers, batteries with solar re-charging panels, or from independent electrical power sources). Spare mantles/bulbs should be carried, and fuel and power sources should be adequate for maximum anticipated duration of the voyage plus a reserve of 25%. On high value, difficult tows, where feasible and where safe, continuous manning or temporary daily man-visits can be a prudent measure to decrease the physical damage risk for the following reasons: Inspection of barge, cargo and seafastenings, giving early warning of problems Maintenance, damage control and repair effected earlier

36 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR BARGES Reconnection of towlines or dropping of anchor when necessary Maintenance of barge lights and shapes.

37 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR BARGES Crew The riding crew should number at least four people including an officer or boatswain. Between them they should have knowledge of seamanship and engineering including electrics. They should be familiar with the use of burning, welding and pumping equipment provided Duties The crew should be organized into a watchkeeping system to ensure a continuous monitoring of conditions on board. They should be familiar with the barge, equipment and cargo and make frequent inspections. All compartments should be sounded daily, where possible. The barge position should be marked periodically on a chart onboard. A barge log should be kept giving: Wind and sea conditions Barge motion Soundings of compartments an conditions of barge, cargo, seafastenings, equipment lights and shapes, Anything unusual, which should be reported. The results of all inspections and reports of barge motion or events should be radioed to the tug at least twice daily Requirements if Manned Suitable accommodation shall be provided with facilities for watch keeping, communications, and cooking, sleeping and sanitary requirements. These may be subject to national and local regulations. At least 2 portable VHF radios should be on the barge. They should have spare batteries or means of recharging and have frequencies on which they can communicate with the tug. Lifesaving and firefighting equipment shall be carried in accordance with international and national regulations for the safety of the number of people carried. The lifesaving and firefighting equipment shall be documented. Safety lines should be rigged for use of the riding crew at all times

38 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR BARGES 7.10 Access Inclinometers shall be fitted for the monitoring of barge motions The decks and access ways should be adequately lit but such lighting should not interfere with or be liable to be confused with navigation lights. Whether the barge is manned or unmanned, there must be suitable access. This may include at least one (1) permanent steel ladder on each side or stern, from the main deck to below waterline level to permit access for a boarding party. They should be clear of overhanging cargo and well positioned to permit access by inflatable dinghies. A pilot ladder on each side of the barge or over the stern, secured to prevent the ladder being washed up on deck may be accepted as a short-term alternative. Handrails to be welded on deck in line with the pilot ladder for access. Consideration should be given to providing a clear space, with access ladders if necessary, so that personnel may be landed or recovered by helicopter.

39 SECTION I - BARGE TRANSPORTATION Page TOWING ARRANGEMENTS 8. TOWING ARRANGEMENTS 8.1 General The barge shall be towed from the forward end using a bridle of suitable construction to give the tow directional stability. If two (2) tugs are used, the bridle may be split and each tug connected to a single leg of the bridle. The tugs should be equal in towing capability. When assessing the strength of tow connections and fairleads on the barge and bridle, the effect of the tug pulling at its maximum bollard pull in any direction shall be considered. Documentation, including bollard pull certificate, and test certificates for all the tow gear shall be valid and available for inspection. 8.2 Tow Connections Towline connections to the barge shall be of the quick release type where possible. For strength purposes, they shall be located over the intersections of transverse and longitudinal bulkheads. They shall also be secured against premature release. The breaking (ultimate) strength of the tow connections shall conform to the following: At least three times the static bollard pull of the tug Designed to be greater than the break load of the bridle with a suitable safety factor Consideration should always be given for the towing connection to be designed to allow for the use of tugs larger than the minimum required. Please refer to Attachment A. 8.3 Fairleads Capped fairleads shall be fitted forward of and in line with the tow connection points. Anti-chafe protection shall be provided along the deck edge. The breaking strength of the fairleads and their connections to the barge deck shall be greater than that of the bridle. If the bridle can rest on the deck edge, during tow, the deck edge should be suitably faired to prevent chafe to the bridle.

40 SECTION I - BARGE TRANSPORTATION Page TOWING ARRANGEMENTS 8.4 Towing Bridle The towing bridle shall consist of two legs having an included angle at the apex in the region of 45º to 60º. If the bridle is a chain bridle it shall be composed of stud link chain with enlarged open links at each end to facilitate connections. If a composite bridle is used it shall comprise two (2) lengths of studded link chain, extending beyond the deck edge, connected to wire pendants fitted with hard eye thimbles. The bridle legs shall terminate in a shackled connection at a towing ring, triangular plate or other approved device. The breaking strength of each bridle leg and bridle terminator shall generally be at least three times the static bollard pull of the tug. Under no circumstances should the breaking strength of each leg of the towing bridle be less than the MBL of the towing wire. 8.5 Intermediate Tow Pendant An intermediate wire tow pendant shall be included between the towing bridle and the tug's main towline for ease of connection. The pendant shall be fitted with hard eye thimbles, and shall be at least 10 meters in length. The breaking strength of the wire pendant shall not be less than the breaking strength of the main towline of the tug, and shall be of the same lay as the main towline except as provided for in the configuration where a "fuse" or "weak link" is used. For a configuration with a "weak link" pendant, this may be approved provided that the strength reduction not more than 10% of the main towline strength, the resulting strength of the pendant is at least 95% of that required for the towline and it forms part of a "customary towing configuration" of the towing company. 8.6 Retrieving Arrangements A retrieval system shall be provided to recover the bridle in the event of a towline or pendant breaking. A retrieving wire shall be connected at the bridle apex either to the triangular plate or to an end link of the bridle leg. The wire shall be led back to a retrieving winch, suitably fairleaded via an "A" frame or block arrangement. The retrieving winch shall be adequately secured where it can best serve its purpose, and shall be capable of being manually operated (even if it has its own power source). In the manual operation mode it should be geared so that the tow bridle apex can be recovered by two men operating the equipment in bad weather and should be fitted with

41 SECTION I - BARGE TRANSPORTATION Page TOWING ARRANGEMENTS ratchet gear and brake. The capacity of the winch shall be sufficient to take the load of the bridle, apex connection, pendant and connections with some reserve. The winch drum capacity shall be such that the required length of wire can be spooled. The breaking load of the recovery wire, shackles, leads etc shall be at least three times the weight of the bridle, apex and intermediate pendant. The wire shall be at least 25 mm diameter. Alternative arrangements may be accepted for retrieving the tow wire. For example, one method may use an additional pendant of not less than 45 meters in length, of the same strength as an intermediate pendant, connected at the fore end of the bridle apex. This pendant is led back to the barge being soft lashed to one of the bridle legs. It should be secured outside all obstructions alongside the deck edge with soft lashings every 3 meters or metal clips opening outward. The terminal eye should be located close to the barge side to enable it to be passed to the tug. A messenger line should be available to assist in this operation. Thus the tug to reconnect comes alongside and the messenger line is passed and subsequently the spare intermediate pendant. 8.7 Emergency Towing Arrangements Emergency towing arrangements shall be provided for use in the event of unsuccessful bridle recovery or other unforeseen failures. The examples below provide guidance on acceptable solutions: Example 1: A single spare towing connection fitted on or near the barge centerline (over a strong point), which could be fore or aft on the barge. Such connection may need a capped fairlead. A pendant of a minimum length 80 meters with hard eyes is connected and led aft to a floating line of length meters; with a connection to a conspicuous plastic buoy trailing system for pickup. If the connection is fitted aft, the towing pendant shall be coiled on deck with the floating line connected to it with the conspicuous plastic buoy trailing system trailing astern. Example 2: Two (2) spare towing connections fitted forward (over strong points), located inboard of the main connections. A wire or chain bridle, towing ring at the apex, all secured with lashings to the barge. A pendant, with hard eye thimbles, is shackled to the towing ring and lashed along the barge side, outboard of all obstructions a connection to a conspicuous plastic buoy trailing system for pickup trailing astern. The pendants and tow connections shall, in either of the above alternatives, be sized similarly to the main towing equipment and have certificates indicating their breaking strength.

42 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR TOWING VESSELS (TUGS) 9. REQUIREMENTS FOR TOWING VESSELS (TUGS) 9.1 General and Documentation The proposed towing vessel will be inspected by a MD surveyor and principal approval given upon satisfactory completion of survey. Documentation required by the flag state shall be in order and the vessel shall be in Class. The following documents could include the following on the tug: a) Certificate of Registry b) Load Line Certificate c) Tonnage Certificate d) Certificate of Class (Hull and Machinery) e) Cargo Ship Safety Certificate f) Certificates for Life Saving Appliances g) Radio Certificate h) Deratization Certificate (if required) i) Certificates for all tow wires, pendants, nylons, shackles, etc. j) Stability Booklet k) Bollard Pull Certificate Towing vessels should be ocean-going tugs with a raised forecastle deck or wellfounded tug/supply or tug/anchor-handling supply vessels. Each vessel will be considered on its merits and its condition at the time of survey, account being taken of the nature of the proposed tow. The towing vessel shall have a spare towline, which shall be similar in all respects to the main towline. 9.2 Manning Sufficient crew is required to operate the vessel and if the tow is unmanned to make periodic inspections of the towed vessel. For offshore towages, the recommended minimum manning is ten (10) men, comprising: One (1) Master (Ocean-going not coast-wise restricted and towing experienced)

43 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR TOWING VESSELS (TUGS) Two (2) Watchkeeping mates (Certificated) One (1) Boatswain Three (3) Seaman Two (2) Engineers One (1) Cook The crewing will be governed by flag state requirements, which may be more stringent; the vessel requirements may dictate a larger or different makeup to the crew. 9.3 Bollard Pull Requirements The total environmental load acting on the barge and cargo are generally sized to ensure the vessel can sustain itself in 40 knot winds without loosing ground. The recommended bollard pull is calculated based upon the combined effects of the following conditions: Significant wave height of 5 meters Wind 40 knots Current 1.0 knots For short duration tows, or benign weather tows the environmental conditions may be reduced. The effective tug bollard pull, taking account of the conditions of the seaway, shall be commensurate with the load calculated as above. Any tug considered for the towing operation should be fully certified for the area of operation including certificates for all tow wires, pendants, stretchers etc. and bollard pull certificate except where there is clearly sufficient horsepower for the intended tow. The bollard pull certificate should not be older than two years. Certain considerations in towing may require additional tugs, increases in bollard pull requirements, or specialized towing equipment. Examples include where the tow is expected to pass through restricted areas, inland tows in restricted passage, areas of continuous adverse currents or weather. 9.4 Towing Winches Winches, winch wires and control lines should have sufficient capacity to hold or maneuver the transport vessel and structure in the design environmental conditions. Towing from a tow hook will generally not be accepted for open sea towage. Towing hooks may be accepted in some special cases where towline recovery and shortening

44 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR TOWING VESSELS (TUGS) up can be achieved in a similar time to a winch and where there are adequate antichafe precautions.

45 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR TOWING VESSELS (TUGS) It is recommended that two towing drums be provided. In the event that only one drum is fitted, the second towing wire shall be stowed on a reel or spooling device so that it can be readily available and easily transferred to the tow winch in an emergency in all weather conditions. The tow winch shall have a minimum holding power of three times the static bollard pull of the tug at the inner layer on the drum. The winch shall be adequately secured to its foundation. All towing winches shall be fitted with an emergency release brake mechanism. 9.5 Towing Wire For ocean towage the towline length can be derived using the following formula: Length = ((Bollard Pull/Min. Breaking Load) x 1,800) meters but not less than 1,000 meters. For benign areas the minimum length may be reduced to: Length = ((Bollard Pull/ Min. Breaking Load) x 1,200) meters. A spare towline will be carried in such a way as it can be hooked up should the main towline break as stated in Section 9.4. The wire shall be in good condition, free from kinks, snags and with no opening of strands. Hard eye thimbles or towing sockets shall be fitted. The tugs tow wire should have a minimum-breaking load of 2.2 times the static bollard pull although a greater safety factor is recommended, especially for tugs with a bollard pull of less than 100 tons. In no case should the tugs tow wire minimum breaking load exceed the minimum breaking load of the connection point. All connections to the structure should have a minimum capacity of 1.3 times the required breaking load of the winch wire or tow wire connected to it. A retrieval system should be available to retrieve the part of the towing arrangement directly connected to the barge or vessel, in case any other part of the tow arrangement fails as noted in Section 8.6. When underway, the tug and tow should be "in step"; that is, meeting and riding over the crests of waves at the same time. Otherwise, the towline is alternately slack and taut, causing heavier than normal stresses. The scope or length of the towline can be adjusted with the winch. The scope of a towline should be long enough to provide a good catenary,

46 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR TOWING VESSELS (TUGS) but not to the extent of having the towline drag on the bottom if in shallow water. A catenary absorbs shocks. Reducing the tug's speed can increase the catenary. 9.6 Synthetic Ropes Stretchers or synthetic springs shall only be connected between the tug's wire and the intermediate pendant and not to the bridle apex connection, if twisting problems can occur. In general, a stretcher made up as a continuous loop is preferable to a single line. The breakload shall be at least 1.5 times that of the main towline, and hard eye thimbles are to be fitted. These ropes are to be in good condition and protected from wear. 9.7 Shackles The breaking load of any shackle in the towline shall be at least 10% greater than the breaking load of the segment of towline or bridle which it is a part of. Where the breaking load of the shackle is not known, the certified safe working load (SWL) of all shackles included in the towing arrangement shall be greater than the static bollard pull of the largest tug to be used. Some reduction in this requirement may be allowed for a tug with a bollard pull in excess of 100 tons, but in any event their breaking load shall be greater than three times the bollard pull. Spare shackles of sufficient size shall be carried in case of breakage or loss. 9.8 Tailgates/Stern Rails and Towing Pods The tailgate or stern rail, if fitted, shall have an upper rail of radius not less than ten times the diameter of the main tow line. Anti-chafe gear shall be carried on the tug and fitted as necessary. The stern rail shall be well faired to prevent snagging. Towing pods, where fitted, shall be of adequate strength, and well faired to prevent snagging; the inside and ends should have a radius of ten times the towline diameter. Alternative arrangements for towline control may be accepted. If gog ropes are used, they shall be able to be adjusted from a remote station if possible. A spare gog rope shall be carried. Mechanical or hydraulically operated stops to control the towline shall, if fitted, be well maintained, and capable of being withdrawn or removed when not in use. 9.9 Additional Equipment The following additional equipment shall be carried onboard: A powered workboat for inspection and communication with the barge while under tow. The tug shall be fitted with adequate means of launching the work

47 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR TOWING VESSELS (TUGS) boat in open sea conditions. An inflatable boat powered by an outboard may be acceptable provided it has flooring suitable for carriage of emergency equipment to the barge. A searchlight to illuminate the tow during nighttime operations. Portable transmitter/receivers for communication should a party have to be placed on board the tow for any reason. Suitable spare batteries or means of recharging them should be provided. An adequate supply of shackles, which are suitable for inclusion within the towing arrangement Bunkers Adequate reserves of fuel and consumables shall be on board for the proposed tow. The tug should have a reserve of fuel and other consumables of at least five (5) days supply or 25% reserve fuel capacity, whichever is greater, for any proposed towage. If refueling enroute is proposed then suitable arrangements must be made before the tow commences Damage Control When the length and area of the tow demand it, the following equipment should be carried on the barge in suitable packages or in a waterproof container secured to the deck. a) Burning gear b) Welding equipment c) Steel plate d) Caulking material e) Sand f) Cement g) Nails h) Wooden plugs, various sizes i) Wooden wedges various sizes j) Hammers and other tools.

48 SECTION I - BARGE TRANSPORTATION Page REQUIREMENTS FOR LAND TRANSPORT 10. REQUIREMENTS FOR LAND TRANSPORT 10.1 Securing of Cargo For Land Transport The securing for land transportation of containers, buildings, subsea components or other cargo items from a fabrication yard, to another land facility or to a port for loadout onto a marine vessel for inland or offshore transport shall be designed in accordance with applicable land transportation standards. Design of land transport securing of loads shall be based on the following criteria: Direction of force relative to longitudinal axis of vehicle Acceleration in G's Downward 1.70 Upward 0.50 Lateral 0.50 Longitudinal 1.80 All securings to be in compliance with the Federal Register, Department of Transporation, Federal Motor Carrier Safety Administration 49 CFR Securing Systems. recommends lashings of Crosby Spectrum 7 type chain (or equivalent), or nylon straps for securing of land transported cargo items. Securing equipment must be arranged to fasten the load from both lateral and overturning loads in all directions. All transport lashings are subject to inspection and approval by. Manufacturer s specifications for all lashing equipment utilized for the land transport will be required. Maintenance and inspection records of previously used lashing equipment will be required. Lashings will be derated for turns around sharp corners and where hooks or load binders engage chains. Any damaged lashing gear will be rejected out of hand.

49 SECTION I - BARGE TRANSPORTATION Page 43 ATTACHMENT A ATTACHMENT A

50 SECTION I - BARGE TRANSPORTATION Page 44 ATTACHMENT A