Sail Skills - Stability Free guide to ship and small vessel stability.  Aimed at small vessel users but suitable for professional mariners.  Diagrams, text and animations explaining stability: from righting lever to movement of liquid in tanks – the free surface effect.  Demonstrates adding weights to a vessel, heel and list.  Especially recommended for RYA examination candidates. Righting moment and lever A small sailing vessel heeled by the wind Diagram:  relating topweight in a sailing vessel to levers and moments Levers & moments Diagram:  a vessel heeled showing righting lever (GZ) A vessel recovering from inversion Inverted Stability Heel & angle of heel Diagram:  a vessel kept afloat by her buoyancy Buoyancy Diagram:  centre ofbuoyancy (CB) of a vessel heeling Centre of buoyancy (CB) Diagram:  a vessel at the angle of vanishing stability (AVS) Angle of vanishing stability (AVS) GZ Curve for a stiff and tender vessel - showing initial steepness of curves GZ Curves Centre of gravity (CG) Diagram: centre of gravity (CG) of a vessel heeling
Every penny helps … Stability Home>Stability Explained>Inverted Stability back to top Negative righting moment RM restores vessel to inverted position After heeling to AVS, RM becomes positive and restores vessel to upright position Vessels with a narrow beam and low centre of gravity tend to quickly develop a positive righting moment (RM) A large water-tight superstructure is used in RNLI lifeboats to make them self-righting Inverted catamaran initially develops powerful negative RM when heeled
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