How can lifting a heavy fishing net over the side cause a vessel to capsize?

Lifting a heavy fishing net over the side of a vessel can cause it to capsize by creating a significant upsetting moment that compromises the ship's static stability.

In naval architecture, a vessel remains stable as long as its metacentre—the point where the buoyant force intersects the midplane—remains above the centre of gravity. When a heavy load is lifted over the side, it acts as an external weight that induces a heel (sideways inclination). This shift moves the vessel's centre of gravity, potentially causing it to rise toward or above the metacentre.12

If the centre of gravity rises above the metacentre, the vessel loses its righting moment, and the forces of weight and buoyancy instead act to increase the angle of heel, leading to a capsize. This risk is particularly acute for smaller vessels, where the dynamic impact of lifting a load—especially when compounded by heavy seas or wind—can quickly exceed the vessel's capacity to resist rotation, a measure known as dynamic stability.12