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STABILITY

Slides from ROM2

Only available direct from RYA training

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Stability Righting lever

Boats return to the upright because of an interaction between their weight and buoyancy

centre of gravitycentre of buoyancy

As a boat heels, B moves away from G creating a righting lever called GZA heavy boat takes more energy to heel because......energy = boat weight (force) x GZ (distance) = RM (righting moment)

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AVS for a vessel without roller furling gear

AVS for a vessel with roller furling gear

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Lifeboat Curve

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Testing underway

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IMS 33 Racer

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IMS 41 Racer

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MALO 41

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IMS 33 – Righting Arm (GZ) Curve

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IMS 41 – Righting Arm (GZ) Curve

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MALO41 – Righting Arm (GZ) Curve

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IMS 33 – Righting Lever (kN) Curve

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IMS 41 – Righting Lever (kN) Curve

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MALO41 – Righting Lever (kN) Curve

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Contessa 32 – Righting Lever (GZ)

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Different Hull Designs

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Water Ballast

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Finding the Centre of Gravity

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GZ

GZ (Righting arm) vs. kN (Righting moment)

IMS 33AVS 127⁰

Area above curve = energy required to capsize yacht

IMS 41

GZ (Righting arm) vs. kN (Righting moment)

AVS 135⁰

Area above curve = energy required to capsize yacht

MALO 41AVS 132⁰

Area above curve = energy required to capsize yacht

GZ (Righting arm) vs. kN (Righting moment)

Different STIX…and different capacity to resist capsize

IMS 33 IMS 41 MALO 41ISO STIX 33.3 ISO STIX 47.8 ISO STIX 55.4

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