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8 Cards in this Set
- Front
- Back
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State two primary forces that affect boats stability |
Gravity and buoyancy |
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Define center of gravity and state how it changes as wieght is added or subtracted upon the boaat |
The center of gravity of a boat is fixed for stability and does not shift unless weight is added, subtracted, or shifted. When weight is added (e.g., vessel takes on water), the center of gravity moves toward the added weight. When the weight is removed, the center of gravity moves in the opposite direction. |
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Define buoyancy |
The upward force of water displaced by the hull |
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Define equillibrium and state how it changes during rolling heeling and listing |
Equilibrium---When a boat is at rest, the center of buoyancy acting upwards/vertically is below the center of gravity acting downwards. Heeling is a temporary leaning, listing is a permanent leaning, and both are different from rolling which is a side to side motion |
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Two types of stability |
• Longitudinal. • Transverse. |
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Two types of forces that efffect stability |
static and dynamic forces. |
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List the general boat design features that influence stability |
• Size and shape of the hull. • Draft of the boat (the distance from the surface of the water to the keel). • Trim (the angle from horizontal at which a vessel rides). • Displacement. • Freeboard. • Superstructure size, shape, and weight. • Non-watertight openings. |
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State the effects of freezing spray |
Icing can increase the displacement of a boat by adding weight above the center of gravity causing the center of gravity to rise. This can cause a vessel to heel over and greatly reduce stability. Sea swells, sharp turns, or quick changes in speed can capsize a vessel that has accumulated ice on its topside surfaces. |
