Part 1—Regulations and Other Information

CODE OF FEDERAL REGULATIONS – TITLE 33 – NAVIGATION AND NAVIGABLE WATERS

PART 183—BOATS AND ASSOCIATED EQUIPMENT

Subpart D—Safe Powering

Sec. 183.51—Applicability

This subpart applies to monohull boats less than 20 feet in length, except sailboats, canoes, kayaks, and inflatable boats, that are designed or intended to use one or more outboard motors for propulsion.

Sec. 183.53—Horsepower capacity

The maximum horsepower capacity marked on a boat must not exceed the horsepower capacity determined by the computation method discussed in paragraph (a) of this section, or for certain qualifying boats, the performance test method discussed in paragraph (b) of this section.

(a) The maximum horsepower capacity must be computed as follows:

(1) Compute a factor by multiplying the boat length in feet by the maximum transom width in feet excluding handles and other similar fittings, attachments, and extensions. If the boat does not have a full transom, the transom width is the broadest beam in the aftermost quarter length of the boat.

(2) Locate horsepower capacity corresponding to the factor in Table 183.53.

(3) For a boat with a factor over 52.5, if the horsepower capacity calculated in Table 183.53 is not an exact multiple of 5, it may be raised to the next exact multiple of 5.

(4) For flat bottom hard chine boats with a factor of 52 or less, the horsepower capacity must be reduced by one horsepower capacity increment in Table 183.53.

Table 183.53—Outboard Boat Horsepower Capacity

[Compute: Factor = Boat Length X Transom Width]

[Note: For flat bottom hard chine boats, with factor of 52 or less, reduce one capacity limit (e.g. 5 to 3)]

(b) For boats qualifying under this paragraph, the performance test method described in this paragraph may be used to determine the horsepower capacity.

(1) Qualifying criteria.

(i) Thirteen feet or less in length;

(ii) Remote wheel steering;

(iii) Transom height

(A) Minimum 19 inch transom height; or,

(B) For boats with at least a 19 inch motorwell height, a minimum 15 inch transom height;

(iv) Maximum persons capacity not over two persons;

(2) Boat preparation.

(i) The boat must be rigged with equipment recommended or provided by the boat and motor manufacturer and tested with the highest horsepower production powerplant for which the boat is to be rated, not to exceed 40 horsepower.

(ii) Standard equipment must be installed in accordance with manufacturers’ instructions.

(iii) The lowest ratio (quickest) steering system offered on the boat model being tested must be installed.

(iv) The outboard motor must be fitted with the manufacturer’s recommended propeller providing maximum speed.

(v) Standard permanently installed fuel tanks must be no more than one-half full. Boats without permanent tanks must be tested with one full portable tank.

(vi) Portable tanks must be in their designated location or placed as far aft as possible.

(vii) The outboard motor must be placed in the lowest vertical position on the transom or, if mounting instructions are provided with the boat, at the height recommended.

(viii) Boat bottom, motor and propeller must be in new or almost new condition.

Note: The use of the following special equipment should be considered because of the potential for exceeding the capabilities of the boat while performing the test: Racing Type Personal Flotation Device, Helmet.

(3) Test conditions. Testing must be conducted on smooth, calm water with the wind speed below 10 knots. The test must be conducted with no load other than a driver who must weigh no more than 200 pounds. The motor trim angle must be adjusted to provide maximum full throttle speed short of excessive porpoising or propeller ventilation or “cavitation”, so that there is no loss of directional control.

Previous  |  Next