The chain locker is a compartment within the bow of a vessel for the storage of the vessels anchor chains. The top of the chain locker will be open to level of the windlass through a pipe known as a spurling pipe. Chain lockers are generally fitted with a perforated flat bottom, the space below known as a mud box and connected to the bilge system. The bottom on the chain locker will also be fitted with a bitter end for the anchor rode, the attachment point for the end of the anchor chain.
Chain lockers are tall, narrow compartments. This promotes an even stacking of incoming chain, and prevents shifting during ship motions. Structure is kept to the outside of the compartment. In the case of the port and starboard chain lockers being adjacent, a longitudinal bulkhead is still fitted; however, for stiffening, half-round profiles are used (which do not snag). The centerine bulkhead that separates the 2 anchor rodes shall be fitted with foothold cutouts to allow for inspection and cleaning of the space.