Small Boat Safety
How Boats Float
Boats float because they displace an amount of water equal to their weight. Their shape allows them to float on top of the water even though they may be made of materials that are heavier than the water itself. Stability of any boat is related directly to the below-water hull shape and to the height of the center of gravity. Therefore, all weight, including the crew, should be near the centerline and as low in the boat as possible.
| A typical small craft boat hull is shown from astern, showing the slight V-shape that is most common among recreational craft. Note that the Center of Gravity (CG) and the Center of Buoyancy (CB) forces are equal when the boat is empty and at rest. |
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Here the boat is heeling to the right, submerging more of the hull on that side. This moves the Center of Buoyancy and creates a force on that side that tries to bring the boat back to a level position.
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This diagram shows the same boat loaded with passengers and gear. Note the waterline and how little freeboard (the distance from the top edge of the side of a boat to the water) remains. Adding weight has also caused the Center of Gravity to be higher and further from the Center of Buoyancy. If the elevated Center of Buoyancy gets off-center, such as when a standing person leans to one side of the boat, it is much harder for the boat to right itself because that distance between the Center of Buoyancy and the Center of Gravity. The boat will either heel too far and allow water over the sides of the boat, resulting either in a swamp or a capsize; or, in the case of a light-weight boat, the forces trying to right the boat may "kick" the craft right out from under the passenger, resulting in a fall overboard.
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Avoiding Capsize
Follow these three simple steps to avoid capsizing.
Keep your shoulders inside the gunnels. Center yourself in the boat keeping your center of gravity low in the boat.
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Maintain three points of contact. Keep both hands and at least one foot, or both feet and at least one hand, in contact with the boat at all times.
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Load the boat properly. Check the load capacity plate and keep within its limits. Keep gear weight centered both from side to side and bow to stern.
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SPLASH FACT
Although the law does not require everyone to wear a lifejacket, some boaters should seriously consider wearing lifejackets:
- Windsurfers
- All persons during rough weather
- Persons who cannot swim
- Persons with health conditions such as seizures
- Persons boating at night
- Persons boating alone or in remote areas
- Persons boating in fall, winter, and spring when water temperatures are less than 77 degrees F
- All persons when boating in conditions of risk
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