Ship Construction
Ship construction questions test the structural and subdivision features that matter to an engineer: watertight boundaries, tank and cofferdam arrangements, the collision bulkhead, and how machinery spaces are protected and accessed.
Key rules
- Collision bulkhead: SOLAS II-1/12 places it not less than 0.05L (or 10 m, whichever is less) and not more than 0.08L from the forward perpendicular, often stepped where a bulbous bow is fitted.
- Double bottoms, cofferdams and void spaces separate incompatible fluids. The engine room is bounded by watertight bulkheads and the shaft tunnel.
- Openings: watertight doors operate locally and from the bridge, with alarms and position indication, and are not left open at sea.
- Corrosion control: coatings, sacrificial anodes, and planned inspection of tank boundaries and sea chests.
Worked example
A ship has L = 180 m. The collision bulkhead must lie between 0.05 x 180 = 9.0 m and 0.08 x 180 = 14.4 m from the forward perpendicular. A proposed position at 8.2 m fails, and so does one at 15 m, regardless of how convenient either is for tank arrangement.
Traps
Using length overall instead of length between perpendiculars; assuming a bulkhead is watertight because it is painted; ignoring how a new opening changes subdivision; confusing a cofferdam with a void space.