46 CFR 90.10-40: -40 Offshore supply vessels.

(a) An offshore supply vessel is a vessel that is propelled by machinery other than steam, that is of 15 gross tons or more, and that regularly carries goods, supplies or equipment in support of exploration, exploitation, or production of offshore mineral or energy resources.

(b) An existing offshore supply vessel is one that is—

(1) Of at least 15 GRT but less than 500 GRT (6,000 GT ITC if GRT is not assigned) as defined in § 125.160 of this chapter, contracted for, or the keel of which was laid, before March 15, 1996; or

(2) Of at least 6,000 GT ITC (500 GRT if GT ITC is not assigned) as defined in § 125.160 of this chapter, contracted for, or the keel of which was laid, before August 18, 2014.

(c) A new offshore supply vessel is one—

(1) That is of at least 15 GRT but less than 500 GRT (6,000 GT ITC if GRT is not assigned) as defined in § 125.160 of this chapter, and was contracted for, or the keel of which was laid, on or after March 15, 1996;

(2) That is of at least 6,000 GT ITC (500 GRT if GT ITC is not assigned) as defined in § 125.160 of this chapter, and was contracted for, or the keel of which was laid, on or after August 18, 2014; or

(3) That underwent a major conversion initiated on or after March 15, 1996.