46 CFR § 11.497 - Mate (OSV).

(a) The minimum service required to qualify an applicant for an endorsement as mate (OSV) of offshore supply vessels is—

(1) Twenty-four months of total service in the deck department of ocean or near-coastal self-propelled, sail, or auxiliary sail vessels. Service on Great Lakes and inland waters may substitute for up to 1 year of the required service. One year of the required service must have been on vessels of more than 100 GRT; or

(2) One year of total service as part of an approved or accepted mate (OSV) training program.

(b) A person holding an endorsement as mate (OSV) may qualify for an STCW endorsement, according to § 11.309 of this part.

(c) The Coast Guard may exempt an applicant from meeting any requirement under STCW Regulation II/1 (incorporated by reference, see § 11.102 of this part) that the Coast Guard determines to be inappropriate or unnecessary for service on an OSV, or that the applicant meets under the equivalency provisions of Article IX of STCW.