Ranks & ratings

Merchant marine crew are organised into three departments — deck, engine, and catering — with a fourth, hotel, on passenger ships. Each department has officers (licensed, post-STCW Chapter II–IV certificate of competency) and ratings (skilled and unskilled crew, post-STCW Chapter V). The Master is in overall command; the Chief Engineer heads the engine department on near-equal footing.

Certificate references below cite the relevant chapter and regulation of the STCW Convention as amended (the Manila amendments of 2010 introduced the Able Seafarer endorsements and the Electro-Technical Officer certificate).

Deck department

Responsible for navigation, cargo operations, mooring, deck maintenance, and the safety of the vessel and her crew. Headed by the Master.

Master / CaptainCapt.
Cert: STCW II/2 — Master ≥ 3000 GT (or coastal/limited tonnage variants)
Overall command. Final authority on navigation, cargo, safety, security, and discipline. Owner's and flag state's representative on board.
Chief Officer / Chief MateC/O
Cert: STCW II/2 — Chief Mate ≥ 3000 GT
Second in command. Cargo plan and operations, stability, deck crew supervision, GMDSS records, oil record book, safety and maintenance schedule. Stands the 4-8 watch.
Second Officer2/O
Cert: STCW II/1 — OOW ≥ 500 GT
Navigation officer: charts and publications, voyage planning, GPS/ECDIS configuration. Stands the 12-4 watch traditionally.
Third Officer3/O
Cert: STCW II/1 — OOW ≥ 500 GT
Safety officer: lifesaving and firefighting equipment, drills, ISM records. Stands the 8-12 watch.
Deck Cadet
Cert: Pre-sea + sea-time training under approved record book
Trainee officer; rotates through deck tasks under the Chief Mate's supervision.
Bosun (Boatswain)
Cert: AB Deck + experience
Senior deck rating; supervises the unlicensed deck crew, plans and executes daily deck maintenance under the Chief Mate.
Able Seafarer Deck (AB)
Cert: STCW II/5 — Able Seafarer Deck (post-Manila amendments) or earlier AB endorsements
Helmsman, lookout, mooring, lifeboat handling, deck maintenance. Often the on-watch lookout becomes helmsman during pilotage.
Ordinary Seafarer (OS)
Cert: STCW II/4 — Rating Forming Part of a Navigational Watch
Junior deck rating; lookout, helm, deck cleaning. Progresses to AB after sea time and assessment.
Pumpman (tankers)
Cert: AB + tanker familiarisation + advanced cargo endorsement
Operates and maintains cargo pumps, ballast pumps, COW, IGS. Reports to the Chief Officer.

Engine department

Responsible for propulsion, electrical generation, fuel and lubrication, auxiliaries, refrigeration, hydraulics, and engine-room safety. Headed by the Chief Engineer.

Chief EngineerC/E
Cert: STCW III/2 — Chief Engineer ≥ 3000 kW
Department head. Equal in rank with the Master for technical matters. Manages bunkers, lube stocks, spares, planned maintenance, machinery condition reports.
Second Engineer2/E
Cert: STCW III/2 — Second Engineer ≥ 3000 kW
Day-to-day running of the engine room. Plans the work list, supervises engine ratings, leads major overhauls. Stands the 4-8 watch on watchkeeping ships.
Third Engineer3/E
Cert: STCW III/1 — OOW Engineer ≥ 750 kW
Generators, fuel oil purifiers, boiler operation. 12-4 watch traditionally.
Fourth Engineer4/E
Cert: STCW III/1 — OOW Engineer ≥ 750 kW
Auxiliary machinery (compressors, pumps, AC), bilge and ballast systems. 8-12 watch traditionally.
Electro-Technical Officer (ETO)
Cert: STCW III/6 — ETO
Ship's electrical and electronic systems: switchboards, power management, bridge electronics, ECDIS, automation, navigation lights, motors. Reports to the Chief Engineer.
Engine Cadet
Cert: Pre-sea + approved sea-time training record book
Trainee engineer officer; rotates through watches and maintenance under the Second Engineer.
Fitter / Engine Storekeeper
Cert: STCW III/5 + workshop experience
Welding, machining, mechanical repairs in the engine workshop. Maintains spare-parts inventory.
Motorman / Oiler
Cert: STCW III/5 — Able Seafarer Engine, or III/4 RFPEW
Engine room watch and maintenance ratings. Greasing, sounding, taking readings, assisting officers.
Wiper
Cert: STCW III/4 RFPEW
Junior engine rating; cleaning, painting, basic engine room duties.
Electro-Technical Rating (ETR)
Cert: STCW III/7 — ETR
Supports the ETO; cable-laying, motor maintenance, workshop electrical work.

Catering / hotel department

Provides food, accommodation, and (on passenger ships) hospitality services. On cargo ships small but essential; on cruise ships the largest department.

Chief Cook
Cert: MLC Ship's Cook certificate (vessels ≥ 10 crew)
Plans menus within the provision budget, prepares meals, manages provisions inventory, hygiene.
Second Cook / Cook's Assistant
Cert: Catering training
Assists the Chief Cook; bakery, breakfast service.
Steward / Messman
Cert: Catering training
Cabin and accommodation cleaning, mess service, laundry.
Hotel staff (passenger ships)
Cert: STCW V/2 + Crowd / Crisis / Passenger Safety
Bartenders, waiters, housekeeping, entertainers, casino staff, retail, spa, medical. Subordinate to the Hotel Manager / Hotel Director.

Supernumeraries & visitors

Pilot — Compulsory or advisory navigator with local knowledge for harbour or canal transits. Boards by pilot ladder (or helicopter).
Surveyor — Class, flag, P&I, or charterer's representative. Conducts inspections in port.
Riding crew / repair team — Shore-based fitters, painters, technicians on a specific work list while under way or in port.
Supercargo — Charterer's representative onboard for the duration of a voyage; oversees cargo operations.
Doctor / Medic (passenger ships) — Medical officer for crew and passengers; quasi-officer rank.
Security officer (high-risk transits) — PCASP — Privately Contracted Armed Security Personnel — for piracy-risk areas.

Watch organisation

On a typical foreign-going cargo vessel the bridge keeps three 4-hour watches per 24-hour day, repeated: 12-4, 4-8, 8-12 (the "graveyard", "forenoon" and "dog" watches in older usage). Each watch is stood by an OOW (officer of the watch) and a rating lookout. Engine watches mirror the bridge, except on UMS (unattended machinery space) ships where the engine room is monitored from the bridge and the duty engineer is on call. See the watchkeeping page for STCW rest-hour rules.