The Able Seaman (AB) rating — officially renamed Able Seafarer–Deck in 2024 — is the Coast Guard’s experienced deck-crew credential. One national written exam covers every AB category; drill it with original questions cited to 33/46 CFR and COLREGs.
An Able Seaman (AB) is a U.S. Coast Guard deck rating for an experienced unlicensed deck crew member — standing lookout and helm watches, handling lines and ground tackle, and performing seamanship duties. The 2024 rules renamed the national rating Able Seafarer–Deck, but “Able Seaman” and “AB” remain the common terms.
There are six categories — Unlimited, Limited, Special, Special (OSV), Sail, and Fishing Industry — that differ only in the required deck sea service and the scope of the endorsement (46 CFR 12.401). Because every category takes the same written exam, you can raise a category later on sea time alone, without re-examination.
The required deck service per 46 CFR 12.403. The three most-searched categories link to a dedicated practice page.
| Category | Deck service | Where / on what |
|---|---|---|
| AB-Unlimited | 36 months | 36 months (3 years) of deck service on vessels operating on oceans or the Great Lakes. |
| AB-Limited | 18 months | 18 months of deck service on vessels of 100 GRT or more not exclusively confined to rivers and smaller inland lakes. |
| AB-Special | 12 months | 12 months of deck service on oceans or the navigable waters of the U.S. including the Great Lakes. |
| AB-Special (OSV) | 6 months | 6 months of deck service on offshore supply vessels on oceans or navigable waters including the Great Lakes. |
| AB-Sail | 6 months | 6 months of deck service on sailing school vessels or sail-powered oceanographic research vessels (or equivalent). |
| AB-Fishing Industry | 6 months | 6 months of deck service (not as a processor) on oceans or navigable waters including the Great Lakes. |
Training substitution (46 CFR 12.403(b)): approved school-ship graduates qualify with no further service; other approved programs can substitute up to one-third of the required service.
One identical written exam for every category: two modules, 50 questions each at a 70% pass mark. The Rules of the Road module is closed-book — no references permitted in the exam room.
Q450 · 50 Q · 70%
Q451 · 50 Q · 70%
The lights and sound-signals topic overlaps directly with our Rules of the Road drills, and Deck General/Safety maps onto Deck General and Deck Safety — so AB candidates can start drilling from our live deck bank today.
Every AB credential also requires you to qualify as a Lifeboat Operator (Lifeboatman) or Lifeboat Operator-Limited (46 CFR 12.401) — a separate 50-question module (Q445) at a 70% pass mark. In person at the REC you also complete the AB02 marlinespike-seamanship demonstration (knots, bends, hitches, and splices, against the clock) and a practical survival-craft demonstration.
The Coast Guard fees for an AB qualified-rating endorsement are $280 ($95 evaluation + $140 exam + $45 issuance) under 46 CFR 10.219, plus the CG-719K medical, drug test, and TWIC (46 CFR 10.203).
Document your deck sea service
The months required for your category (46 CFR 12.403) — 12 for Special, 18 for Limited, 36 for Unlimited — on the sea-service form or a company letter.
Pass the medical & drug test
USCG medical certificate (CG-719K, 46 CFR part 10 subpart C) and a chemical test for dangerous drugs (46 CFR 16.220).
Get a TWIC
A Transportation Worker Identification Credential is required before the MMC issues (46 CFR 10.203 / 10.209).
Submit your application to the NMC
File CG-719B (or the NMC online portal) with sea-service, medical, and drug-test evidence and the fees (46 CFR 10.219).
Pass the AB exam and demonstrations at a REC
After the NMC approves the application, pass Q450 and Q451 (50 questions, 70% each), the Lifeboatman module, and the marlinespike and survival-craft demonstrations.
You test at a Regional Examination Center after approval — find yours in the state-by-state guide and REC locations.
An Able Seaman (AB) is a U.S. Coast Guard deck rating for an experienced unlicensed deck crew member who stands lookout and helm watches and performs seamanship duties. The 2024 rules renamed the national rating 'Able Seafarer', but 'Able Seaman' and 'AB' remain in common use. There are six categories — Unlimited, Limited, Special, Special (OSV), Sail, and Fishing Industry — that differ only in required sea service (46 CFR 12.401).
Yes. There is one national AB written exam, AB01, for every category: Q450 Navigation General & Rules of the Road (50 questions) and Q451 Deck General/Safety (50 questions), each with a 70% passing score. The categories differ only in the sea service required and the scope of the endorsement issued, so you can raise a category later without re-examination.
Yes. Every Able Seaman credential requires you to also qualify as a Lifeboat Operator (Lifeboatman) or Lifeboat Operator-Limited (46 CFR 12.401). That is a separate 50-question module (Q445) at a 70% pass mark, plus a practical survival-craft demonstration.
Yes. Beyond the written modules, AB applicants complete the AB02 marlinespike-seamanship demonstration — tying and making knots, bends, hitches, and splices within a time limit — and the practical lifeboat demonstration. CaptainsGround drills the written exam; the practical demonstrations are performed in person at the REC.
The Coast Guard fees for an original qualified-rating endorsement are $95 evaluation + $140 examination + $45 issuance = $280 under 46 CFR 10.219. Add the CG-719K medical exam, drug test, and TWIC on top of that.
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