scenario fits well with various well known factual analyses, presented by critics of the official scenario. Due to recent erudition the scenario has later been modified and republished February 2008 [4]. Te suggestion to open the pilot door of
Al Salam Boccaccio 98, if the scuppers did not drain satisfactorily, was brought forth by a Scandinavian naval architect, a long term consultant of the owners [5]. Dismissing the suggestion as a panicky initiative by the ship’s command at time of peril is consequently out of the question. Furthermore, from the Estonia case we know that the rear ramp of the wreck was slightly open. Te experts assisting the shipyard suggest this might have been a measure to drain water from the car deck. Whether or not such acts are an unspoken art of the trade is unknown. However, other means should be available and this one omitted! Though drainage by pilot doors may
reduce heel, it certainly has a destructive effect on the GZ-arm. Furthermore, it seems far from obvious that drainage by such doors might exceed the pulsating inflow by waves if the ship, at time of peril, is turned in bad weather and the open pilot-door faces the weather. Note: Both Al Salam Boccaccio 98 and Estonia were turned in severe but not extreme weather. The freeboards of these ships were
alarmingly low and this explains the dramatic loss of the righting arm. For Al Salam Boccaccio 98, the bulkhead deck would in fact be submerged at mere 7º of list [6]. Tis is why Egypt has recommended that the drainage of the car decks of these ships should be fitted with pumps. Te perils of the low freeboards of these
ships were particularly highlighted by Professor Vassalos at the 9th International Ship Stability Workshop last summer when he strongly warned against the 2009 SOLAS regulations now being discussed. The general survivability of these ships was also strongly criticised by various scholars at the Passenger Ships Conference in London last year. Seemingly they considered that close to zero-tolerance should be adopted for all likely damage scenarios entailing huge loss of life.
Proposed regulations Te Scandinavian proposal to IMO will, if brought into effect, guarantee proper
The Naval Architect April 2008
Figure 1. Possible scupper grating [2].
drainage in port [2]. It is, however, not obvious that the proposed regulations will prevent unacceptable accumulation of water at sea, in as much as the proposal seems to consider static heel, rather than roll. Modern simulators, like the ones now being used for the Estonia analyses, should be able to simulate the dynamics of the drainage systems fairly well. Te use of time-domain simulations of various distress scenarios may consequently be analysed and precautionary measures may be taken. Use of such simulations might as well improve the deterministic/ probabilistic proposals now being analysed by IMO regarding drainage as well as damage stability. The existing rule merely states: ‘In
view of the serious loss of stability which could arise due to large quantities of water accumulating on the deck or decks consequent on the operation of the fixed pressure water-spraying system, scuppers shall be fitted so as to ensure that such water is rapidly discharged directly overboard’. Common to all of the proposals now
being analysed by IMO are that they describe deterministic measures to mend the way this functional rule has been put to use. Although new regulations should be expected to improve the situation, it is not altogether obvious that they will maintain the obligation to design prudently. Taking into account the unwritten grandfather rule of IMO, that alterations
should generally not be expected on existing ships, rapid improvement may not be taken for granted. Nevertheless:
• The scupper systems of ro-ro vessels should be scrupulously analysed
• Drainage procedures for ro-ro vessels should be drawn up
• Use of doors at bulkhead deck for drainage should be avoided
• Dynamic simulations should be carried out to analyse whether these ships will
function as intended, at time of peril, or notNA
References [1] Lloyd’s List, Black box transcript reveals four hours of confusion and fear as ferry sank, 24 July 2006, London [2] IMO, MSC 83/3/2 [3] A N Cockroſt, ‘A Guide to the Collision Avoidance Rules’, Stanford Maritime, $2b [4] Rolf Imstøl, MV Estonia, A Possible Sinking Scenario,
http://home.broadpark. no/~ri_marin/Estonia/possible_scenario. pdf [5] E-mail from Anders Björkman 7/12/2007 [6] The International Technical Committee formed to Investigate and Analyse the causes for the sinking of the FerryAl Salam Boccaccio 98 in the Red Sea in February 2006, Technical Report, Egypt 2006 [7] Rolf Imstøl, List of Publications
www.hib.no/ansatte/RCI/Publications
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