BOATBUILDER'S HANDBOOK

Flotation -  Applicability


Since the regulation is divided according to boat type, the applicability for the various types is discussed in each subpart. The exceptions, however, apply to all subparts and are as follows:

Sailboats, canoes, kayaks, inflatable boats, submersibles, surface effect vessels, amphibious vessels, multi-hull boats and race-boats need not comply.

Following is a summary of the applicability by boat type and subpart.

Subpart Boat types Flotation Required
F Inboards, Inboard/Outdrives And Air Boats Basic Flotation
G Outboard Boats Rated for More Than 2 Horsepower Level Flotation
H Outboard Boats Rated for 2 Horsepower or less and Manually Propelled Boats Modified Level Flotation


NOTE:

Certain catamarans may be considered as mono-hull boats for the purpose of this regulation. For example, the waterline of some catamaran designs will form a single closed curve when the boat is loaded with the maximum rated horsepower engine and the maximum weight capacity. These boats will be considered by the USCG as mono-hulls and must comply with the flotation requirements.


Subpart F - Flotation Requirements for Inboards, Inboard/Outdrive, and Airboats

FEDERAL LAW

183.101 - Applicability

This subpart applies to monohull inboard boats, inboard/outdrive boats, and airboats less than 20 feet in length, except sailboats, canoes, kayaks, inflatable boats, submersibles, surface effect vessels, amphibious vessels, and raceboats.


Discussion:

Monohull inboard, inboard/outboard boats and airboats less than 20 feet in length must comply with a flotation system called Basic Flotation. Basic Flotation contains the requirements and tests. Basic flotation is the simplest type of flotation mode covered in this regulation. It simply requires that the boat be manufactured with sufficient flotation material to keep it afloat in the event of a swamping. It does not, however, require that the boat remain in an upright or indeed any specific position. It may float, and usually does, in a "spar" position, the bow sticking up and the stern sunk. The requirements include some materials tests. Basic Flotation covers this type of flotation.
 

Subpart G - Flotation Requirements for Outboard Boats Rated for Engines of More Than 2 Horsepower

FEDERAL LAW

183.201 - Applicability

(a) This subpart applies to monohull outboard boats that are:

(1) Less than 20 feet in length; and
(2) Rated for outboard engines of more than 2 horsepower.

(b) This subpart does not apply to sailboats, canoes, kayaks, inflatable boats, submersibles, surface effect vessels, amphibious vessels, and raceboats.


Discussion:

Monohull boats under 20 feet in length and rated for more than two horsepower must comply with the more sophisticated flotation system called Level Flotation. The Level Flotation system requires that the swamped boat, loaded with certain weights representing weight capacity, part of 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. The Level Flotation section covers the requirements and tests to perform.

 


Subpart H - Flotation Requirements for Outboard Boats Rated for Engines of 2 Horsepower or Less

FEDERAL LAW

183.301 - Applicability

(a) This subpart applies to monohull outboard boats that are:

(1) Less than 20 feet in length; and
(2) Rated for manual propulsion or outboard engines of 2 horsepower or less.

(b) This subpart does not apply to sailboats, canoes, kayaks, inflatable boats, submersibles, surface effect vessels, amphibious vessels, and raceboats.


Discussion:

Manually propelled boats and boats rated for outboard engines of 2 HP or less must comply with the Modified Level Flotation requirements. As the name suggests, Modified Level Flotation is similar to Level Flotation, but with variations in the persons weight and capacity weight numbers. Section 6.0 discusses the calculations, tests and other requirements.

NOTE:
Level Flotation may also be applied to inboard boats, outboard boats of less than 2 HP, and non-powered boats. Nothing in the regulation says that a boat may not be manufactured to comply with a flotation system superior to the one required. These are only minimum requirements. Many manufacturers choose to install Level Flotation in boats that do not require it.

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RESOURCES

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Photo Library

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