Basically the “walls” within a vessel. They can be simple partitions or strong watertight bulkheads. A square compartment would have 4 bulkheads, and they would be described, depending on their position, as fore bulkhead, aft bulkhead, port bulkhead and starboard bulkhead.

Partitions within a boat's hull or superstructure forming separate compartments.

Sealed compartments in the front and back of a kayak.

The walls of the submarine.

Rigid structures with vertical walls built parallel to the shoreline to prevent storm surge flooding of upland areas; constructed out of treated wood, corrugated steel, PVC, or other materials.

The vertical surfaces or walls within a vessel for structural as well as space planning purposes.