IACS History File + TB

Transcription

1 IACS History File + TB Part A UI SC246 Steering gear test with the vessel not at the deepest seagoing draught Part A. Revision History Version no. Approval date Implementation date when applicable New (June 2011) 27 June July 2012 New (June 2011).1 Origin for Change: Based on IMO Regulation (SOLAS II-1 regulation & ).2 Main Reason for Change: To develop a UI in respect of SOLAS Regulations II-1/ and and establish conditions for ships which cannot achieve deepest seagoing draught at the trial to replace the alternative requirement in UR M42.15(i)..3 List of non-iacs Member classification societies contributing through the TC Forum and/or participating in IACS Working Group: None.4 History of Decisions Made: PT agreed that no amendment to SOLAS II-1 regulation 29 would be necessary and that the draft UI to be developed by the team would be sufficient to meet the objectives of the task. Review of DNV proposed method completed and the need for experimental data confirmed as necessary to verify the predicted steering gear loads for steering gear when rudders are partially submerged. Reference to ISO 19019:2005 Sea-going vessels and marine technology Instructions for planning, carrying out and reporting sea trials agreed by the PT as the reference procedure for all ships which are not at deepest seagoing draught. Draft UI and Proposed amendment to URM42 developed to support this reference. Additional conditions were developed by the team to be applied when testing steering gear in accordance with the ISO instructions on all occasions when ships were not at the deepest draught for the trial, in order to establish reliable and consistent test methodology..5 Other Resolutions Changes UR M42 (Rev.4 June 2011) Page 1 of 3

2 Part B.6 Dates: Original proposal: Made by M. Wharton Manager PT PM6801 Panel Approval: 30 April 2011 GPG Approval: 27 June 2011 (Ref: 5031gIGv) Page 2 of 3

3 Part B Part B. Technical Background List of Technical Background (TB) documents for UI SC246: Annex 1. TB for New (June 2011) See separate TB document in Annex 1. Page 3 of 3

4 Part B, Annex 1 Technical Background for UI SC246 New, June Scope and objectives To establish alternative steering gear trial conditions for vessels which cannot be tested at their deepest seagoing draught and to develop a UI in respect of SOLAS Regulations II-1/ and and based on this interpretation consider whether/how UR M42.15(i) is compatible with UI and propose amendments to M42.15(i) as necessary. 2. Engineering background for technical basis and rationale The SOLAS regulations require that the main steering gear and rudder stock shall be: - of adequate strength and capable of steering the ship at maximum ahead service speed which shall be demonstrated; and - capable of putting the rudder over from 35 on one side to 35 on the other side with the ship at its deepest seagoing draught and running ahead at maximum ahead service speed and, under the same conditions, from 35 on either side to 30 on the other side in not more than 28 s Alternative steering gear trial conditions to those where the vessel is at the deepest sea going draught, which is normally equal to the summer load line, are considered necessary for certain ship types in order to provide acceptable testing conditions. In order to establish a sound and uniform practice, the draft UI is suggested to refer to ISO 19019:2005 and through a proposed amendment to UR M42 allow the trial requirements contained in the ISO instructions to replace the requirement for alternative testing provided that the loading condition specified will result in predictable trial conditions in compliance with UR M42.15(i) as proposed for amendment. The extant ISO 19019:2005 Sea-going vessels and marine technology Instructions for planning, carrying out and reporting sea trials contains a procedure to demonstrate the performance requirements of SOLAS regulations for steering gear and refers to the loading condition for the ship to be as close as practical to full load displacement. This procedure is referenced to replace the specially considered clause in M42.15, subject to additional conditions developed by the team to establish consistent and reliable testing for ships not tested at the deepest sea-going draught. 3. Source/derivation of the proposed IACS Resolution For ships not at the deepest sea-going draught for the steering gear trial ISO 19019:2005 Sea-going vessels and marine technology Instructions for planning, carrying out and reporting sea trials is referenced. The following extracts are relevant and applicable: 6.1 Steering gear trials Purpose Steering gear trials are performed to verify the performance of the steering gear and to demonstrate its efficiency.

5 6.1.2 Trials specification If the loading condition is not contractually specified, steering gear trials shall be conducted at a displacement as close as reasonably possible to full-load displacement for merchant ships and warships. and; Ahead-steering-gear trial With the main propulsion engines delivering maximum continuous rating ahead or at the corresponding shaft speed, the following rudder manoeuvres shall be executed. The first direction of rudder movement, i.e. port or starboard, shall be at the discretion of the trial captain, considering the conditions in the area. The following description is for first rudder deflection to port. a) Amidships to 35 port Hold for sufficient duration in order to record time taken, at the steering gear, between rudder amidships and 30 ; b) 35 port to 35 starboard Hold approximately 10 s; record time taken, at the steering gear, between 35 hardover to 30 to the opposite side (as the steering gear is slowing down between 30 and hardover); c) 35 starboard to 35 port Hold approximately 10 s; record time taken between 35 starboard and 30 port; d) 35 port to amidships Record time taken between 35 port and rudder amidships; e) trial completed. This trial shall be repeated for each power unit of the steering gear and, if possible, for both units acting together. For emergency power units, trials shall be performed at reduced speed and reduced rudder angles. Setting of the propulsion plant of a singlescrew main propulsion system shall not be changed during the trial; however, change in throttle adjustment or propeller pitch in the case of a controllable-pitch propeller plant or multi-screw main propulsion systems is permissible during the trial to avoid overload or overspeed. If the maximum rudder angle is less than 35, the maximum possible rudder angle shall be used, with time determined to the maximum angle minus 5, as above. The additional requirements to be satisfied during the trial were developed and agreed by the PT to establish consistent and reliable trial conditions for all occasions when the trial is undertaken with the ship not at the deepest sea-going draught. 4. Summary of Changes intended for the revised Resolution: To replace the alternative trial conditions may be specially considered term in UR M42.15(i) with specific requirements when the loading condition for the ship at the steering gear trial is contractually specified to be other than the deepest seagoing draft or the ship cannot achieve deepest draught to test in accordance with ISO 19019:2005 subject to additional conditions for consistent and reliable testing. Proposed amendment 15. Trials The steering gear should be tried out on the trial trip in order to demonstrate to the Surveyor's satisfaction that the requirements of the Rules have been met. The trial is to include the operation of the following:

6 (i) the steering gear, including demonstration of the performances required by Regulation and For controllable pitch propellers, the propeller pitch is to be at the maximum design pitch approved for the maximum continuous ahead R.P.M. at the main steering gear trial. If the vessel cannot be tested at the deepest draught, alternative trial conditions may be specially considered as stated in Section of ISO 19019:2005 Sea-going vessels and marine technology Instructions for planning, carrying out and reporting sea trials are to be applied. If the loading condition is such that the ship is not at the deepest draught, steering gear trials shall be conducted at a displacement as close as reasonably possible to fullload displacement as required by Section of ISO 19019:2005 on the conditions that either the rudder is fully submerged (zero speed waterline) and the vessel is in an acceptable trim condition, or the rudder load and torque at the specified trial loading condition have been predicted and extrapolated to the full load condition. In this case for the main steering gear trial, the speed of ship corresponding to the number of maximum continuous revolution of main engine could is to apply. 5. Points of discussions or possible discussions SOLAS II-1/ and Reviewed by the PT in order to generate a UI for the performance requirements for the main and auxiliary steering gear UR M42.15(i) Reviewed by the PT in order to establish requirements to replace the alternative trial conditions with specific reference to ISO 19019:2005 Sea-going vessels and marine technology Instructions for planning, carrying out and reporting sea trials subject to additional conditions developed by the PT. From work specification items for the panel task: A review of the DNV proposal Steering gear test with partly submerged rudder was completed and an evaluation of the need for experimental data was completed, it was considered necessary that experimental data would be required to verify the proposed method. 6. Attachments if any None