Length when used in terms of the vessel's length (excluding bow sprits, bumpkins, rudders, outboard motor brackets, handles, and other similar fittings, attachments, and extensions), means:
(1) The length listed on the vessel's Certificate of Documentation issued under the provisions of Part 67 (Documentation of Vessels) of this chapter or Certificate of Number issued under the provisions of 33 CFR Part 173, Subpart B (Numbering); or
(2) For a vessel that does not have a Certificate of Documentation or a Certificate of Number, the “registered length” as defined in § 69.53 in subchapter G of this chapter or, for a vessel that is less than 24 meters (79 feet) in overall length and is measured using simplified measurement, the registered length as defined in § 69.203 in subchapter G of this chapter.
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.