Ranks and Positions on a Ship: Who Does What in the Crew

A rank belongs to military service. Seaman, petty officer, warrant officer, lieutenant, captain first rank, admiral: these titles belong to a navy, and a rank stays with a person regardless of which ship or unit they serve on.

A merchant vessel runs on a different pair of terms. A position is what a person is hired for on a specific voyage: seaman, bosun, third officer, chief engineer. A certificate of competency is the document proving the right to hold a position at a given level. A certificate is issued by a state authority based on education, sea service and an exam, not by a shipowner or a training centre.

That is where the common phrase "a seafarer holds the rank of captain" goes wrong. He holds a Master Mariner certificate and a Master's position on this particular ship. Change ships, and the position may change; the certificate stays.

The international framework for all these positions is the STCW Convention (STCW 78, with the 2010 Manila Amendments, in force since 1 January 2012). It splits the crew by level of responsibility: support level, meaning ratings, operational level, and management level.

The deck department handles navigation, cargo, mooring operations and hull upkeep.

Ordinary Seaman (OS) is the entry point into the profession: deck work, painting, help with mooring, all under a bosun's direction. Requirements for a rating forming part of a navigational watch are set out in STCW rule II/4. Most people start here, and it is what the seaman second class course trains for.

Able Seafarer Deck (AB) covers the same scope of work, plus the right to stand at the helm, keep lookout watch and handle more complex rigging tasks. That is STCW rule II/5, and it requires documented experience as a seaman.

The bosun is the senior rating on deck: assigns tasks, looks after rigging and deck stores, and reports to the chief officer.

Officer positions follow. The Third Officer (3rd Officer) holds the first officer post: watchkeeping duties, lifesaving and firefighting equipment, and part of the ship's paperwork. The Second Officer (2nd Officer) handles navigation in the narrow sense: chart work, corrections, passage planning, ECDIS. The Chief Officer runs cargo operations and stability, organizes the deck department, and remains second-in-command. The Master answers for the ship as a whole: safety of navigation, crew, cargo, and dealings with port authorities and inspections.

Officer positions fall under STCW rule II/1, for a navigational watch officer at operational level, and rule II/2, for master and chief officer at management level.

For a detailed look at the able seaman’s duties and requirements, see who is an able seaman.

The engine department covers the main engine, auxiliary machinery and the ship's systems.

Wiper is the junior position in the engine room: cleaning spaces and assisting engineers, roughly the engine-room equivalent of an OS on deck.

Motorman (Oiler) is the watchkeeping rating in the engine room: monitoring machinery, lubrication, readings, and helping during repairs. Requirements for an engine-room rating are set out in STCW rule III/4, and the able seafarer engine qualification in rule III/5. Training runs through the motorman (machinist) second class course.

Fitter is the ship's mechanic-welder.

The Fourth and Third Engineer keep watch, service auxiliary machinery and maintain logs, under STCW rule III/1. The Second Engineer runs the engine-room workload: planned maintenance, the main engine, task allocation. The Chief Engineer answers for the ship's entire technical operation and reports directly to the master. Requirements for chief and second engineer split by propulsion power: STCW rule III/2 for ships with a main propulsion of 3,000 kW and above, rule III/3 for 750 to 3,000 kW.

The Electro-Technical Officer (ETO) is a standalone qualification added to STCW after the 2010 Manila Amendments, under rule III/6, covering electrical equipment, automation and control systems. A separate rule, III/7, covers electro-technical ratings. Ships carrying refrigerated cargo also need a reefer engineer.

The Chief Cook and Messman look after crew catering and the living quarters, a role that carries real weight: food directly affects how a crew performs at sea, and the requirements for catering on board sit in the Maritime Labour Convention (MLC 2006).

There is no single international uniform standard for merchant fleets. The practice traces back to a mid-20th-century British tradition and varies by country and by company, as the Marine Insight guide to merchant navy uniform points out.

The general logic holds across most fleets: gold stripes on shoulder boards and sleeves, growing in number with the level of responsibility. A master and a chief engineer carry the most, junior officers fewer. Engineers are traditionally marked by a purple stripe between the gold bars, something the same guide notes for engineering officers.

Reading a position off a photo does not work in practice. Another company runs a different scheme, and working overalls usually carry no stripes at all.

Moving up comes down to four things.

Training, meaning mandatory STCW courses and specialization, is what a training centre provides. Sea service is documented time in a position, recorded in a seafarer's record book. Without sea service the next step stays out of reach, however many certificates are on file. Exam and certificate: a certificate of competency issued by a state authority. And English: Marlins and CES tests are part of the hiring screen at most companies.

Pay moves with rank too. How it differs from a rating to a master is covered separately in officer salaries on ships.

A typical deck trajectory: ordinary seaman, able seafarer, then either bosun or, with a navigational background, third officer, followed by second officer, chief officer and master. In the engine room the path branches less: wiper, motorman, fourth engineer, third engineer, second engineer, chief engineer.

What a training centre covers at each stage is listed in the course catalogue.

For the full path from third officer to master, see how to become a ship captain.

Certificates for every line in this table are issued by the state. A training centre delivers the STCW courses behind them and issues completion certificates for those courses.