Bulkhead Deck

The bulkhead deck is the uppermost continuous deck to which the transverse watertight bulkheads and the shell are carried watertight, defining the upper limit of subdivision for damage-stability calculation. SOLAS II-1 uses it as the datum for the margin line and floodable length in the older deterministic subdivision method, and as a reference plane in the probabilistic framework of regulations II-1/4 to II-1/8 introduced by resolution MSC.216(82) and applied to ships built on or after 1 January 2009. Above this deck, watertight integrity is not assumed in the flooded condition. On passenger ships it governs the extent of the watertight subdivision protecting reserve buoyancy.