Box Shaped Vessel Centre of Gravity (C of G)
In Fig 1, the C of G is the point at which the entire weight of a body may be considered as concentrated so that if supported at this point the body would be balanced. The location of a body’s centre of gravity may coincide with the geometric centre of the body, especially in a symmetrically shaped object composed of all the same material.
Centre of Buoyancy (B)
The centre of buoyancy is the centre of the underwater volume of a vessel. It is the point through which the upthrust of the water surrounding the vessel may be considered to act. The position of B is dependent on the shape of the underwater portion of the vessel, in the case of a box shaped vessel it is found by drawing diagonals from the water line to the opposite submerged corner of the vessel, as shown in Fig2.