46 CFR 11.406: Service requirements for Second Mate, unlimited tonnage
Last reviewed: October 14, 2026
This section sets the minimum service needed for a Second Mate endorsement on ocean or near-coastal self-propelled vessels of unlimited tonnage. It gives two service routes for Third Mates and explains how Great Lakes, inland and STCW service is credited. It also covers certain Masters and the path to an STCW endorsement.
Applies toApplicants for an endorsement as Second Mate of ocean or near-coastal self-propelled vessels of unlimited tonnage.
What it says
One way to qualify is one year of service as Officer in Charge of a Navigational Watch (OICNW) on ocean self-propelled vessels while holding an endorsement as Third Mate.
46 CFR 11.406(a)(1)“One year of service as Officer in Charge of a Navigational Watch (OICNW) on ocean self-propelled vessels while holding an endorsement as Third Mate”
The other way is 12 months of service on deck while holding an MMC endorsement as Third Mate of ocean self-propelled vessels of unlimited tonnage, including at least 6 months as officer in charge of a deck watch on ocean self-propelled vessels.
46 CFR 11.406(a)(2)(i)“A minimum of 6 months service as officer in charge of a deck watch on ocean self-propelled vessels.”
Service as Boatswain, Able Seafarer, or quartermaster on ocean self-propelled vessels, while holding an Able Seafarer certificate or MMC endorsement, may be accepted two-for-one, up to a maximum substitution of six months.
46 CFR 11.406(a)(2)(ii)“which may be accepted on a two-for-one basis to a maximum allowable substitution of six months (12 months of experience equals 6 months of creditable service)”
Service on the Great Lakes will be credited day-for-day up to 100 percent of the total required service.
46 CFR 11.406(b)(1)“Service on the Great Lakes will be credited on a day-for-day basis up to 100 percent of the total required service.”
Service on inland waters other than the Great Lakes that are navigable waters of the United States will be credited day-for-day for up to 50 percent of the total required service.
46 CFR 11.406(b)(2)“will be credited on a day-for-day basis for up to 50 percent of the total required service.”
Service on vessels to which STCW applies, whether inland or coastwise, will be credited day-for-day.
46 CFR 11.406(b)(3)“Service on vessels to which STCW applies, whether inland or coastwise, will be credited on a day-for-day basis.”
A holder of an unlimited-tonnage Master of Great Lakes and inland, or Master of inland, endorsement may obtain this Second Mate endorsement by completing the prescribed examination in subpart I of this part.
46 CFR 11.406(c)“they may obtain an endorsement as Second Mate of ocean or near-coastal self-propelled vessels of unlimited tonnage by completing the prescribed examination in subpart I of this part.”
Common questions
How much service do I need for Second Mate of unlimited tonnage?
One route is one year as OICNW on ocean self-propelled vessels while holding a Third Mate endorsement. The other is 12 months of service on deck while holding an MMC endorsement as Third Mate of ocean self-propelled vessels of unlimited tonnage.
“One year of service as Officer in Charge of a Navigational Watch (OICNW) on ocean self-propelled vessels while holding an endorsement as Third Mate”
Does Great Lakes service count toward Second Mate?
Yes. Great Lakes service is credited day-for-day up to 100 percent of the total required service.
“Service on the Great Lakes will be credited on a day-for-day basis up to 100 percent of the total required service.”
Can I qualify for an STCW endorsement with this Second Mate endorsement?
Yes. A person holding this endorsement may qualify for an STCW endorsement according to § 11.309 of this part.
“A person holding this endorsement may qualify for an STCW endorsement, according to § 11.309 of this part.”
The text of 46 CFR 11.406
Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR
Service requirements for Second Mate of ocean or near-coastal self-propelled vessels of unlimited tonnage
(a) The minimum service required to qualify an applicant for an endorsement as Second Mate of ocean or near-coastal self-propelled vessels of unlimited tonnage is—
(1) One year of service as Officer in Charge of a Navigational Watch (OICNW) on ocean self-propelled vessels while holding an endorsement as Third Mate; or
(2) While holding an MMC endorsement as Third Mate of ocean self-propelled vessels of unlimited tonnage, 12 months of service on deck as follows:
(i) A minimum of 6 months service as officer in charge of a deck watch on ocean self-propelled vessels.
(ii) Service on ocean self-propelled vessels as Boatswain, Able Seafarer, or quartermaster while holding a certificate or MMC endorsement as Able Seafarer, which may be accepted on a two-for-one basis to a maximum allowable substitution of six months (12 months of experience equals 6 months of creditable service).
(b) Service towards an oceans, near-coastal or STCW endorsement 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) If an individual holds an endorsement as Master of Great Lakes and inland self-propelled vessels of unlimited tonnage or Master of inland self-propelled vessels of unlimited tonnage, they may obtain an endorsement as Second Mate of ocean or near-coastal self-propelled vessels of unlimited tonnage by completing the prescribed examination in subpart I of this part.
(d) A person holding this endorsement may qualify for an STCW endorsement, according to § 11.309 of this part.
Sections it refers to
The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of April 16, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.