Alternative term: Lamp Exchanger (G.B.)
A mechanism, usually operated automatically, which replaces one lamp by another in service in a light.
Most usually this is done when the first lamp has failed in service.
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
centre of gravity
Centre of buoyancy
International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM