33 C.F.R. § 183.35
(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 except for water coming through one opening in the motor well with its greatest dimension not over 3 inches for outboard motor controls or fuel lines. 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:
(2) “Boat weight” is the combination of:
[CGD 72-61, 37 FR 15782, Aug. 4, 1972, as amended by CGD 73-250, 40 FR 43857, Sept. 23, 1975; CGD 75-176, 42 FR 2681, Jan. 13, 1977; USCG-1999-5832, 64 FR 34716, June 29, 1999]