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Cheatography

12: Boat stability Cheat Sheet (DRAFT) by

12: Boat stability 12: Boat stability 12: Boat stability

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Stability theory

Center of Buoyancy
The force generated by a vessel displacing water. It changes position depending on heel angle, trim and loading.
Center of Gravity
It is determined by structure and weight distri­bution of a vessel. Ideally the centre of gravity should be as low as possible.
The Angle of Heel
As the boat heels more the righting moment becomes greater.
The Point of Vanishing Stability
When the righting moment becomes zero the vessel inverts. This is called the angle of vanishing stability (AVS).

Righting moment curves - sailing vessel

 

Recrea­tional craft directive

Category
Type
Wind Force
Wave Height
A
Ocean
F8
4m
B
Offshore
F8
4m
C
Inshore
F6
2m
D
Sheltered waters
F4
0.5m
New yachts in Europe are built to the Recrea­tional Craft Directive (RCD). Minimum standards laid down for constr­uction and stability. It gives an indication of the operating limits of a vessel with the category A, B, C or D displayed on the builders plate.

Righting moment curves - motor vessel