However, it is possible for conditions to exist which
do not permit B to move far enough in the direction in
which the ship rolls to place the buoyant force outboard
of the force of gravity. The moment produced will tend
to upset the ship, rendering it unstable. Figure 12-21
shows an unstable ship in which the relative positions of
B and G produce an UPSETTING MOMENT. In this
illustration it is obvious that the cause of the upsetting
moment is the high position of G (center of gravity) and
the GEOMETRIC CENTER OF THE UNDERWATER
BODY (B—the center of buoyancy).