Maritime Training & STCW Courses › AB, RFPNW & Able Seafarer-Deck
Checked against 46 CFR Part 12, 46 U.S.C. 7307 and NMC checklists · October 2026
The short answer
- AB is the national U.S. rating. Since January 2025 its official name is Able Seafarer (formerly Able Seaman), in categories such as Able Seafarer-Unlimited and Able Seafarer-Limited. Most mariners still just say "AB."
- RFPNW (Rating Forming Part of a Navigational Watch) is an STCW qualification for standing lookout and steering as part of the bridge watch on a seagoing ship.
- Able Seafarer-Deck is a higher STCW qualification. You need RFPNW first, then more sea service, survival-craft training, and the national AB.
- They are printed in different places on your Merchant Mariner Credential (MMC): national on one page, STCW on another. Holding one doesn't give you the others.
What is each one?
| National AB (Able Seafarer) | RFPNW | Able Seafarer-Deck | |
|---|---|---|---|
| Type | National endorsement (U.S.) | STCW endorsement | STCW endorsement |
| What it's for | Serving as an able seaman on U.S. vessels, in the category your endorsement covers | Lookout and helm as part of a navigational watch on a seagoing ship | The senior deck rating on a seagoing ship |
| Minimum age | 18 | 16 | 18 |
| Must already have | Lifeboat Operator (or -Limited) | A national rating; STCW Basic Training | RFPNW; national AB; Basic Training; Proficiency in Survival Craft |
| Regulation | 46 CFR 12.401–12.403; 46 U.S.C. 7307 | 46 CFR 12.605 | 46 CFR 12.603 |
Need help with "national" versus "STCW"? National vs. STCW → · Course vs. endorsement →
Who needs it?
- National AB: mariners hired as ABs on U.S. vessels that are required to carry them. It's the national foundation for most deck careers.
- RFPNW: ratings who stand bridge watch (lookout and helm) on seagoing vessels covered by STCW.
- Able Seafarer-Deck: AB-level deck ratings on seagoing STCW vessels. Many deep-sea employers expect it.
Who may not need it?
If you work only on vessels the STCW rules don't cover, such as inland and Great Lakes vessels, many small domestic vessels, and fishing vessels, you may need the national AB but not RFPNW or Able Seafarer-Deck. Which vessels STCW covers → A deckhand job on a vessel that isn't required to carry ABs may not need an AB endorsement at all. Ask the employer what the job requires before you pay for STCW courses.
Where it fits in your career
Inland mariners often go straight from entry level to national AB. Seagoing mariners usually add RFPNW early, because the watchkeeping sea service for Able Seafarer-Deck only counts once you're qualified as RFPNW. AB to Third Mate →
Requirements
National AB (Able Seafarer)
| Category | Deck sea service | Where |
|---|---|---|
| Able Seafarer-Unlimited | 540 days (18 months) | Oceans or Great Lakes |
| Able Seafarer-Limited | 360 days (12 months) | Vessels of 100 GRT or more, not only on rivers or small inland lakes |
| Able Seafarer-Special | 180 days (6 months) | Oceans or navigable waters |
| Able Seafarer-OSV | 180 days | Offshore supply vessels |
| Able Seafarer-Sail | 180 days | Sailing school vessels or sail-powered research vessels |
| Able Seafarer-Fishing Industry | 180 days | Deck service on fishing vessels (not as a processor) |
Sea service figures from the current NMC National Able Seafarer checklist.
All categories also require: age 18, the Coast Guard medical and drug test, English proficiency, a Lifeboat Operator (or Lifeboat Operator-Limited) endorsement, and passing the Coast Guard AB examination. An approved course can stand in for the exam where its approval says so. 46 CFR 12.401 Lifeboat Operator →
RFPNW
- At least 16 years old, with STCW Basic Training. Basic Training →
- Six months of seagoing service that includes navigational watchkeeping duties under supervision, or Coast Guard-approved training that includes at least two months of approved seagoing service.
- Practical assessments showing the competencies in the STCW Code (Table A-II/4), such as steering, lookout and watch relief. 46 CFR 12.605
Able Seafarer-Deck
- At least 18; meet the RFPNW requirements; hold or qualify for the national AB; current Basic Training.
- While qualified as RFPNW: 18 months of deck service, or 12 months plus approved training.
- Proficiency in Survival Craft (PSC or PSC-Limited). PSC →
- Practical assessments to the STCW Code (Table A-II/5). 46 CFR 12.603 NMC checklist
The course or training
- AB: approved AB courses prepare you for the exam and can, where approved, take the place of the Coast Guard exam. Approved training can also substitute for up to one-third of the required sea service, at no more than 3 days of credit for each day of instruction. 46 CFR 12.403
- RFPNW and Able Seafarer-Deck: the core is practical assessment, showing you can do the job, signed off by a Coast Guard-approved Qualified Assessor, on board or at a school. Some schools offer approved programs that reduce the sea service.
Mariners Online's free study guide covers the AB exam topics, knots, Rules of the Road for ABs, and Lifeboat Operator prep. It's study material, not a Coast Guard-approved course. Open the AB study guide →
What happens after the course?
- Gather your course certificates, signed assessment records, and sea-service letters showing deck and watchkeeping duties. Documenting Sea Time →
- Apply to the National Maritime Center (NMC). You can apply for several endorsements together.
- The national AB is printed with your national endorsements; RFPNW and Able Seafarer-Deck are printed on the STCW page. You hold them only once they're on your MMC.
Common mistakes
- Treating AB and Able Seafarer-Deck as the same thing. One is national, one is STCW. A seagoing employer may want both.
- Building sea time before you're RFPNW-qualified. The Able Seafarer-Deck service counts while you're qualified as RFPNW.
- Using the old 1,080-day figure and waiting longer than you need to.
- Forgetting Lifeboat Operator. You can't get the national AB without it.
- Assessments signed by the wrong person. STCW assessments need a Qualified Assessor.
- Sea-service letters that don't mention watchkeeping. If it isn't written down, the evaluator can't count it.
Know which ship you're sailing on. Inland, the national AB may be all you need. Going deep sea, get RFPNW early, so every watch you stand counts toward Able Seafarer-Deck.
Official sources
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