Able Seaman Exam Prep

USCG MMC — Able Seaman (Unlimited, Limited, Special)

The USCG Merchant Mariner Credential Able Seaman (AB) endorsement is the deck rating that bridges Ordinary Seaman to officer candidacy. An AB stands lookout, helms the vessel, serves on the rescue boat crew, and performs skilled seamanship work — splicing, rigging, cargo gear, deck maintenance. There are several sub-ratings, each gated by sea service: AB-Unlimited (3 years), AB-Limited (18 months on vessels 100+ GT in ocean/near-coastal), AB-Special (12 months any waters), AB-OSV (6 months on offshore supply vessels), AB-Sail (6 months on sail vessels), and AB-Fishing Industry. The credential is issued under 46 CFR Part 12 Subpart B and STCW Code Table A-II/4 (Rating Forming Part of a Navigational Watch) / A-II/5 (Rating as AB Deck).

Exam structure

The USCG AB exam is a single module assembly with three sections drawn from the NMC rating question pool:

• Q200 – Deck General (deck-gen) — 50 questions, 2 hours. Marlinspike seamanship, knots and splices, cargo gear, anchor handling, line handling, helm and lookout duties, deck maintenance, ship construction vocabulary.
• Q210 – Deck Safety (deck-safe) — 30 questions, 1.5 hours. Firefighting, lifesaving, survival craft, pollution prevention (MARPOL Annex V garbage management), medical response, PPE, enclosed space entry.
• Q100 – Rules of the Road (rules) — 30 questions, 1.5 hours. International + Inland. Pass threshold 90% — maximum 3 wrong.

Deck General and Deck Safety pass at 70%; Rules at 90%. AB-Special candidates take a slightly shorter Rules module (Inland only). STCW-endorsed ABs also complete a short Proficiency in Survival Craft (PSC) assessment if they'll serve on vessels with lifeboats.

Eligibility & prerequisites

• Sea service on CG-719S: varies by sub-rating (see above).
• Medical certificate CG-719K (STCW-compliant if sailing internationally).
• TWIC from TSA.
• STCW Basic Training (BT) — Personal Survival, Fire Prevention & Firefighting, Elementary First Aid, Personal Safety & Social Responsibilities. Required for international voyages.
• Lifeboatman or PSC for vessels carrying lifeboats; Proficiency in Survival Craft and Rescue Boats other than Fast Rescue Boats (PSC) under STCW A-VI/2-1.
• Drug test (DOT 5-panel) within 185 days.
• Age 18 minimum.
• Practical demonstrations per NVIC 14-14 Ch. 1 — knots, splices, heaving line, rescue boat operation — signed off in the Able Seaman Record of Assessment.

Study timeline

Most OS candidates prep 6–10 weeks for the AB exam alongside shipboard duties. First-time test-takers studying at home (waiting for sea service to complete) should plan 8–12 weeks, 8–10 hours per week, with an emphasis on Rules memorization.

What examiners look for

The AB exam rewards practical seamanship vocabulary and reg recall. Expect:

• Exact knot names — bowline on a bight, double sheet bend, rolling hitch, Flemish eye splice.
• Block-and-tackle mechanical advantage problems (1:1 through 5:1).
• Rescue boat launch sequence on gravity davits.
• Chafe gear and mooring line handling.
• Lights, shapes, and sound signals — AB candidates are expected to identify a vessel from its running lights at a distance, not just recall the rule text.

Work the NMC sample AB exam PDFs (Q200, Q210, Q100) until you can complete each section inside the time limit with 15 minutes to spare.

Common pitfalls

• The Rules of the Road 90% cutoff catches candidates who over-studied knots and skimped on COLREGS. Three wrong out of 30 is the margin.
• Confusing MARPOL Annex V garbage categories — Plastics, Food, Domestic, Cooking Oil, Incinerator Ash, Operational, Cargo Residues (non-harmful), Cargo Residues (harmful), Animal Carcasses.
• Breeches buoy and line-throwing appliance questions trip candidates who never handled one aboard.
• Forgetting that AB-Special is limited to vessels <200 miles from shore unless upgraded.

Study strategy using MMCE.app

Choose the Deck → Rating track during onboarding and set AB as your target. MMCE.app's 2,754-item AB bank is large enough for eight weeks of daily adaptive drills without meaningful repetition:

1. Daily 15-question adaptive drill across all three modules.
2. Dedicated Rules of the Road block every session — rotate International and Inland nights.
3. Knot & splice flashcards (SM-2) with photo prompts.
4. Weekly timed mock exam — 110 items, 5 hours — to build test stamina.
5. AI tutor explains each miss in plain language with the 46 CFR or Rule citation.

Relevant publications

• The Boatswain's Manual (Morrison/Nelson) — canonical AB reference.
• Chapman Piloting & Seamanship — knots, rigging, watchstanding.
• Navigation Rules, International–Inland (COMDTINST M16672.2D).
• 33 CFR Parts 83–90 (Inland Rules).
• 46 CFR Part 12 (Requirements for Merchant Mariner Credentials) — especially 12.401–12.411 on AB ratings.
• 46 CFR Subchapter W (Lifesaving Appliances and Arrangements) and Subchapter Q (Specifications).
• NVIC 14-14 Ch. 1 — AB endorsement assessment.
• STCW Code Tables A-II/4 and A-II/5.
• MARPOL Annex V and 33 CFR 151 Subpart A.
• Knight's Modern Seamanship (18th ed.).

After you pass

The AB MMC is valid five years. Renew with CG-719B, medical CG-719K, current TWIC, and one year of sea service in the last five years OR a USCG-approved refresher. STCW Basic Training requires five-year revalidation.

Upgrade path: OS → AB-Special → AB-Limited → AB-Unlimited → Third Mate (with appropriate sea service and the Deck Officer exam battery). Many ABs also stack Lifeboatman/PSC, Tankerman-Assistant, Rigger (Fast Rescue Boat), and Basic Training Revalidation. MMCE.app's upgrade flow preserves your AB question history and layers the new Third Mate modules — Q115 Navigation General, Q120 Navigation Problems, Q145 Deck General (officer) — so you never re-study what you already mastered.