Centre of gravity (of a buoy)
The point about which the net moment of all the gravitational forces acting on the buoy is zero for all positions of the buoy. The total weight of the buoy may be considered as a downward force through this point.
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM