Improve prevention of water reaching Ro-Ro ferry vehicle decks during damage

There is a fourth area which is apparently missing namely:- Improvement in the prevention of water reaching the vehicle deck in the event of damage occurring in realistic seagoing conditions. The latter area is as important as the other three and logically should precede them. This point carries over to Task 4, namely survival capability. The tank test programme should cover a wide spectrum of possibilities such as the systematic testing of survivability in waves, with varying distances from the margin line to the bulkhead deck and the provision of external add-on buoyancy. In particular the validity of the present survival criteria should be checked experimentally, in a range of irregular significant sea heights with the enclosed superstructure opened by side damage. It should be emphasised that this Formal Investigation is into the disaster to the HERALD and into possible means of improving the safety and survivability of Ro-Ro passenger ferries. In this context Task 1 should concentrate on Ro-Ro passenger ferries. It is essential that all calculations, including those for residual stability and freeboard, should be in the context of a range of initial trims. The casualty analysis and relative safety proposals appear to have been covered largely by the Norwegian submission to I.M.O. submitted in evidence during the HERALD Investigation (November 1983 Paper SLF/20). Between the evidence based upon Lloyd’s Register’s work and the Norwegian paper, this section would appear to be largely unnecessary. It is difficult to see how the relative safety of new Ro-Ro ships can be compared statistically with existing ships. Risk assessment is also likely to be upon an inadequate statistical basis. This study does not appear to cover actual tank testing but finishes by preparing specifications for a programme of tests. Thus it seems unlikely that there will be any tank test information available for the September 1987 meeting of the SLF Sub-committee of I.M.O. It is considered that the tests should impose statutory damage through portable side plates in the superstructure located at, say, midships and near the quarter points. The model should then be ballasted so that (a) the waterline is at the margin in way of the ‘damage’ location for any given distance between margin line and bulkhead deck. (b) that the metacentric height is adjusted to be alternatively 0.05 m or 0.10 m; and (c) finally, that the vessel be tested statically on a number of headings in irregular sea conditions using a suitable spectrum with a range of significant waveheights. Finally, no target date for the completion of a model test programme is given. It is of considerable importance that this be as soon as physically possible in view of the need to consider the effects of the results upon ferry design. It is essential that the research programme convince Government and the Public that its conclusions are objective and at arm’s length from purely commercial considerations. In particular, the merit rating mentioned in 2.4.4. and 2.5.3 of the programme, requires clarification as to its nature. Is it, for example, to be an operator’s assessment of least possible inconvenience or is it to apply strictly to the safety of the vessel or will it be based upon an objective combination of these and other aspects?