(a) The minimum service required to qualify an applicant for an endorsement as master of ocean or near-coastal self-propelled vessels of unlimited tonnage is—

(1) One year of service as chief mate on ocean self-propelled vessels; or

(2) While holding a license or MMC endorsement as chief mate of ocean self-propelled vessels of unlimited tonnage, 12 months of service on deck as follows:

(i) A minimum of 6 months of service as chief mate.

(ii) Service as second mate, third mate, or officer in charge of a navigational watch accepted on a two-for-one basis (12 months as officer in charge of a navigational watch equals 6 months of creditable service).

(b) An individual holding an endorsement or license as master of Great Lakes and inland, self-propelled vessels of unlimited tonnage, or master of inland, self-propelled vessels of unlimited tonnage, may obtain an endorsement as master of oceans or near-coastal self-propelled vessels of unlimited tonnage by providing evidence of sea service of not less than 24 months under the authority of the credential and by completing the prescribed examination in subpart I of this part. Service will be credited as follows:

(1) Service on the Great Lakes will be credited on a day-for-day basis up to 100 percent of the total required service.

(2) Service on inland waters, other than Great Lakes, that are navigable waters of the United States, will be credited on a day-for-day basis for up to 50 percent of the total required service.

(3) Service on vessels to which STCW applies, whether inland or coastwise, will be credited on a day-for-day basis.

(c) A person holding this endorsement may qualify for an STCW endorsement, according to §11.305 of this part.