2.6 Buoyancy, stability and emergency ascent
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC/Circular.981 – Guidelines for the Design, Construction and Operation of Passenger Submersible Craft – (29 January 2001)Amended by MSC/Circ.1125 - Annex - Guidelines for the Design, Construction and Operation of Passenger Submersible Craft - Chapter 2 - Design and Construction - 2.6 Buoyancy, stability and emergency ascent

2.6 Buoyancy, stability and emergency ascent

  2.6.1 Passenger submersible craft should be able to ascend/descend in a safe and controlled manner throughout the craft’s rated depth of operations to the satisfaction of the Administration.

  2.6.2 Passenger submersible craft should be able to maintain an acceptable stability and trim during ascent, descent, while submerged and on the surface.

  2.6.3 Passenger submersible craft should be capable of remaining on the surface with the hatches open during all normal design environmental and operating conditions without downflooding.

  2.6.4 Two independent means, one of which is to be operated with no electric power, should be provided to bring the unit to the surface in a stable and upright condition.

  2.6.5 In addition to the means provided in accordance with paragraph 2.6.4, passenger submersible craft should be provided for emergency surfacing with means to jettison sufficient mass so that if the largest single floodable volume, other than personnel compartments, is flooded, the ascent rate will be equal to the normal ascent rate. The jettisoned mass may consist of a drop weight, appendages subject to entanglement or a combination of both. Alternatively, the passenger compartment may be provided with a means of separating it from all other parts of the system, including appendages, provided the personnel compartment is positively buoyant when released.

  2.6.6 The possibility of entanglement should be considered in the design of the passenger submersible craft. Design features, operational and emergency procedures and/or means of jettisoning may be necessary.

  2.6.7 In accordance with the emergency procedures, it may be necessary to provide means to jettison lifting cables and umbilicals.

  2.6.8 Jettisoning systems, where provided, should require at least two positive manual actions and should be independent of electric power.

  2.6.9 Passenger submersible craft should have adequate stability under any possible combination of dropped jettisoned masses to provide for the safe recovery of passengers in accordance with the emergency response plan.

  2.6.10 Passenger submersible craft should be provided with means of externally bringing the craft to the surface.


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