33 CFR 183.37: Maximum weight capacity: Boats rated for manual propulsion and boats rated for outboard motors of 2 horsepower or less.

(a) The maximum weight capacity marked on a boat that is rated for manual propulsion or for motors of 2 horsepower or less must not exceed 3/10 of the difference between the boat's maximum displacement and the boat's weight in pounds.

(b) For the purposes of paragraph (a) of this section:

(1) “Maximum displacement” is the weight of the volume of water displaced by the boat at its maximum level immersion in calm water without water coming aboard. For the purpose of this paragraph, a boat is level when it is transversely level and when either of the two following conditions are met:

(i) The forward point where the sheer intersects the vertical centerline plane and the aft point where the sheer intersects the upper boundary of the transom (stern) are equidistant above the water surface or are equidistant below the water surface.

(ii) The most forward point of the boat is level with or above the lowest point of water ingress.

(2) “Boat weight” is the combination of:

(i) Hull weight;

(ii) Deck and superstructure weight; and

(iii) Weight of permanent appurtenances.