Diaphone - Driver
Driver (of a diaphone) (G.B.)
The device which imparts to the moving part of the modulator its reciprocating motion by the action of compressed air.
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