Appendix - Model test method
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - International Conferences - SOLAS/CONF.3 - Resolutions of the Conference of Contracting Governments to the International Convention for the Safety of Life at Sea, 1974 – (November 1995) - Resolution 14 - Regional agreements on specific stability requirements for ro-ro passenger ships – (Adopted on 29 November 1995) - Annex - Stability requirements pertaining to the agreement - Appendix - Model test method

Appendix - Model test method

Parent topic: Annex - Stability requirements pertaining to the agreement

1 Objectives

 In the tests provided for in paragraph 1.4 of the stability requirements pertaining to the agreement, the ship should prove capability to withstand a seaway defined in paragraph 3 hereunder in the worst damage case scenario.

2 Ship model

  2.1 The model should copy the actual ship for both outer configuration and internal arrangement - in particular of all damaged spaces, having an effect on the process of flooding and shipping of water. The damage should represent the worst damage case defined for compliance with paragraph 2.3.2 of SOLAS regulation II-1/8 (SOLAS 90). An additional test is required at a level keel midship damage, if the worst damage location according to SOLAS 90 is outside the range ± 10% Lpp from the midship. This additional test is only required when the ro-ro spaces are assumed to be damaged.

  2.2 The model should comply with the following:

  • .1 Lpp is to be at least 3 m;

  • .2 hull is to be thin enough in areas where this feature has influence on the results;

  • .3 characteristics of motion should be modelled properly to the actual ship, paying particular attention to scaling of radii of gyration in roll and pitch motions. Draught, trim, heel and centre of gravity should represent the worst damage case;

  • .4 main design features such as watertight bulkheads, air escapes etc., above and below the bulkhead deck that can result in asymmetric flooding should be modelled properly as far as practicable, to represent the real situation;

  • .5 the shape of the damage opening shall be as follows:

    • .5.1 rectangular side profile with a width according to SOLAS regulation II-1/8.4.1 and unlimited vertical extent;

    • .5.2 isosceles triangular profile in the horizontal plane with a height equal to B/5 according to SOLAS regulation II-1/8.4.2.

3 Procedure for experiments

  3.1 The model should be subjected to a long-crested irregular seaway defined by the JONSWAP spectrum with a significant wave height Hs, defined in paragraph 1.3 of the stability requirements, and having peak enhancement factor γ and peak period Tp as follows:

  • .1 with γ = 3.3; and

  • .2 equal to the roll resonant period for the damaged ship without water on deck at the specified loading condition but not higher than and with γ = 1.

  3.2 The model should be free to drift and placed in beam seas (90° heading) with the damage hole facing the oncoming waves. The model should not be restrained in a manner to resist capsize. If the ship is upright in flooded condition, 1° of heel towards the damage should be given.

  3.3 At least five experiments for each peak period should be carried out. The test period for each run shall be of a duration such that a stationary state has been reached but should be run for not less than 30 min in full-scale time. A different wave realization train should be used for each test.

  3.4 If none of the experiments result in final inclination towards the damage, the experiments should be repeated with five runs at each of the two specified wave conditions or, alternatively, the model should be given an additional 1° angle of heel towards the damage and the experiment repeated with two runs at each of the two specified wave conditions. The purpose of these additional experiments is to demonstrate, in the best possible way, survival capability against capsize in both directions.

  3.5 The tests are to be carried out for the following damage cases:

  • .1 the worst damage case with regard to the area under the GZ curve according to SOLAS; and

  • .2 the worst midship damage case with regard to residual freeboard in the midship area if required by 2.1.

4 Survival criteria

  4.1 The ship should be considered as surviving if a stationary state is reached for the successive test runs as required in 3.3 but subject to 4.2.

  4.2 Angles of roll of more than 30° against the vertical axis, occurring more frequently than in 20% of the rolling cycles or steady heel greater than 20° should be taken as capsizing events even if a stationary state is reached.

5 Test approval

  5.1 It is the responsibility of the Administration to approve the model test programme in advance. It should also be born in mind that lesser damages may provide a worst case scenario.

  5.2 Test should be documented by means of a report and a video or other visual record containing all relevant information of the ship and test results. A copy of the video and report should be submitted to the Organization, together with the Administration's acceptance of the test.

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