Basic Flotation
A basic flotation rule requires that the boat be manufactured with sufficient flotation material to keep it afloat in the event of a swamping. It does not require that the boat remain in an upright or any specific position. It may float, and usually does, in a "spar" position, the bow sticking up and the stern sunk. Applies To: Monohull inboards, inboard/outboard boats and airboats less than 20 feet in length must comply with a basic flotation system. Exceptions: Sailboats, canoes, kayaks, inflatable boats, submersibles, surface-effect vessels, amphibious vessels and race boats. Level Flotation
A level flotation system requires that the swamped boat, loaded with certain weights representing weight capacity (part of the persons capacity and some equipment), must float in an approximately level position and not heel past a certain angle, even when part of the passengers' weight is on one side of the passenger carrying area. Applies To: Monohull boats under 20 feet in length and rated for more than 2 horsepower must comply with this more sophisticated flotation system. Exceptions: Sailboats, canoes, kayaks, inflatable boats, submersibles, surface-effect vessels, amphibious vessels and race boats. Modified Level Flotation
Modified level flotation is similar to level flotation, but with variations in the persons weight and capacity weight numbers. Applies To: Manually propelled boats and boats rated for outboard engines of 2 horsepower or less must comply with the modified level flotation requirements.