metacentric stability

Metacentric stability is a fundamental concept in naval architecture that ensures a ship remains upright. When a ship inclines, the center of buoyancy (where the buoyant force acts) shifts. If this shift creates a righting moment that counteracts the inclination, the ship will return to its upright position. This stabilizing effect is called metacentric stability, and the point where the vertical lines of buoyancy intersect is known as the metacentre (M).1

The position of the metacentre (M) relative to the ship's center of gravity (G) is crucial. If G is below M, the ship is stable. If G is above M, the ship can become unstable and capsize, especially if weight (like ice) accumulates high on the vessel. The metacentric radius (BM) is calculated using the formula BM = I/V, where I is the moment of inertia of the waterline plane and V is the immersed volume. Naval architects use inclining experiments to verify predicted stability before a ship sails.1234