In naval architecture the metacentre shows the relationship
between the Centre of gravity of a vessel and her Centre of buoyancy when
heeled. By relating those two centres it provides an index of her righting or
restoring tendency. By plotting the positions of the heeled metacentres for
sections along the length of the hull, the designer traces a curve called the Metacentric shelf. This curve is considered to give a
good guide to the fore-and-aft Balance of a boat under sail.