Basics of Naval Architecture: Stability Principles

Stability is one of the most fundamental concepts in naval architecture. A vessel must be able to return to its upright position after being displaced by waves, wind, or shifts in loading — and understanding the principles that govern this behaviour is essential for safe and compliant ship design.

Static Stability

Static stability describes a vessel's initial resistance to inclination. Key concepts include the centre of gravity (G), the centre of buoyancy (B), the metacentre (M), and the metacentric height (GM). A positive GM indicates that the vessel will return to upright after a small inclination — a basic requirement for all vessels.

Dynamic Stability

Dynamic stability extends the analysis to larger angles of inclination and to the energy required to capsize a vessel. The stability curve (GZ curve) provides a more complete picture of how a vessel behaves across a range of heel angles, and is a central tool in stability assessment under international maritime regulations.

This technical note is currently in preparation and will be available for download soon. Contact our naval architecture team with specific enquiries.