metacentre

• metacenter (US)

From French métacentre or meta- +‎ centre.

• (UK) IPA^(key): /ˈmɛtəsɛntə/
• Rhymes: -ɛntə(ɹ)

Ship Stability diagram showing centre of gravity (G), centre of buoyancy (B), and metacentre (M) with ship upright and heeled over to one side.

metacentre (plural metacentres)

1. (physics, nautical) The point where a vertical line through a tilted vessel's center of buoyancy intersects the originally-vertical (but-now-tilted) line that passed through the center of buoyancy when the vessel was upright; it must be above the vessel's center of gravity for the vessel to have positive static stability (to tend to return to an upright orientation if rolled to one side, rather than to continue rolling to an inverted orientation).
   • 2017 December 12, National Transportation Safety Board, “1.12 Stability Information - 1.12.1 Concepts”, in Marine Accident Report: Sinking of US Cargo Vessel SS El Faro, Atlantic Ocean, Northeast of Acklins and Crooked Island, Bahamas, October 1, 2015‎, archived from the original on 15 May 2022, page 132:

     A ship's metacenter (M) is the virtual intersection of two successive lines of action of the force of buoyancy when the ship heels through a very small angle. The initial position of the metacenter is used as a reference in stability calculations. The distance from a ship's center of gravity (G) to its metacenter is known as the metacentric height (GM). GM is a measure of the vessel's ability to right itself when experiencing an overturning moment. For the same vessel, a higher GM value indicates a greater initial static stability.

• metacentral / metacentric

• metacenter