High speed craft
High speed craft means a craft that is operable on or above the water and has characteristics so different from those of conventional displacement ships, to which the existing international conventions, particularly SOLAS, apply, that alternative measures should be used to achieve an equivalent level of safety. In order to be considered a high speed craft, the craft must be capable of a maximum speed equal to or exceeding V = 3.7 displ .1667, where V is the maximum speed and displ is the vessel displacement corresponding to the design waterline in cubic meters.
46 CFR § 114.400
Terms used in this subchapter are defined in paragraph (b) of this section. The number in parenthesis after certain terms describing areas on a vessel refers to the applicable column and row number where that area is listed in Tables 116.415 (b) and (c) of part 116 of this subchapter.