Entry & progression
Governing: 46 CFR 10.107, 12.201, 12.401, 12.601, 12.703; USCG-2021-0097, 89 FR 93040 (25 Nov 2024), effective 17 Jan 2025. Builds on: nothing. Start here.
Two ladders, one credential
Every US deck rating lives on the Merchant Mariner Credential (MMC) as an endorsement. There are two families, and you will normally need both.
| Family | What it answers | Deck endorsements |
|---|---|---|
| National | Are you qualified under US law (46 U.S.C. chapter 73; 46 CFR Part 12, subparts D and G)? | Ordinary Seafarer; Able Seafarer (six categories); Lifeboat Operator; Lifeboat Operator-Limited |
| STCW | Do you meet the STCW Convention standard for seagoing ships? | RFPNW (Reg. II/4); Able Seafarer-Deck (Reg. II/5); PSC / PSC-Limited; Basic Training |
46 CFR 12.201(a)(1) and 12.601(a) say the same thing in two places: an applicant for any STCW endorsement "must hold the appropriate national endorsement, unless otherwise specified." The STCW rating sits on top of the national one; it does not replace it.
What changed in January 2025
The Coast Guard's course-completion rule (docket USCG-2021-0097) also replaced gendered titles. It took effect on 17 January 2025.
| Before | Now |
|---|---|
| Ordinary Seaman | Ordinary Seafarer |
| Able Seaman-Unlimited / -Limited / -Special | Able Seafarer-Unlimited / -Limited / -Special |
| Able Seaman OSV, Sail, Fishing Industry | Able Seafarer-OSV, -Sail, -Fishing Industry |
| Lifeboatman | Lifeboat Operator |
| Lifeboatman-Limited | Lifeboat Operator-Limited |
| Apprentice mate (steersman) | Apprentice Mate of Towing Vessels |
Two practical notes. First, the rule is explicit that "mariners do not have to apply to have the endorsement titles changed"; the new wording appears at your next credential transaction. Second, to avoid confusion with the STCW Able Seafarer-Deck, the Coast Guard calls the Part 12 endorsement the national Able Seafarer. The statute, 46 U.S.C. 7306, still says "Able Seaman". Old sea service letters, job adverts and crew agents will use the old names for years.
CAUTION — "AB" means two different things A yacht crew agent asking for "an AB" usually means the national endorsement. A flag-state manning document for a 500 GT seagoing ship means the STCW Able Seafarer-Deck. Check which one before you accept the job.
The regulatory vocabulary
46 CFR 10.107 fixes the terms you will meet on every checklist:
- Entry-level mariner: holds no rating other than Ordinary Seafarer, Wiper, Steward's Department or Steward's Department (F.H.).
- Qualified rating: any Able Seafarer category, QMED, or tank vessel endorsement.
- Deck crew (for 46 U.S.C. 8702): Able Seafarers, Boatswains and Ordinary Seafarers.
- Lifeboat Operator: qualified to take charge of, lower and operate survival craft.
How the pieces stack
- Ordinary Seafarer. Entry-level, no professional exam (12.703). Covered in L1.2.
- Lifeboat Operator. Needed before any Able Seafarer endorsement (12.401(c)(6)). Covered in L2.3.
- National Able Seafarer. Sea service plus an exam or approved course (12.403, 12.405). Covered in module 2.
- RFPNW. STCW II/4 watch rating, assessed on board (12.605). Covered in L3.1.
- Able Seafarer-Deck. STCW II/5, built on RFPNW plus more service and PSC (12.603). Covered in L3.2.
- OICNW / Mate. The bridge, covered in L4.3 and in USCG Deck: Sea Service, Tonnage and the Yacht.
The medical certificate, drug test, TWIC and the CG-719B application are common to all of these. They are covered in USCG The MMC Application and are not repeated here.