Collision Bulkhead

Forward-most watertight transverse bulkhead, located between 5% and 8% of the load-line length aft of the forward perpendicular under SOLAS II-1 Reg. 9. It must extend at least to the bulkhead deck and be free of openings below the deepest waterline (apart from one or two pipes fitted with screw-down valves operable from above the bulkhead deck). The collision bulkhead is the structure that is meant to localise flooding from a stem impact, preserving residual buoyancy long enough for the crew to assess damage stability and abandon if necessary.