Deck Department
The deck department is the navigational, cargo-handling and safety arm of the ship. The Master commands it; the Chief Officer runs it; the Officers in Charge of a Navigational Watch stand it; the ratings work it.
Officers hold Certificates of Competency under STCW Chapter II. Ratings hold Certificates of Proficiency. These are distinct instruments — this page maps both tracks.
The officer ranks
Two STCW competence levels: Management (Master, Chief Officer) and Operational (the watchkeeping officers). The Deck Cadet is a training berth working toward the first Certificate of Competency.
Management level · STCW Regulation II/2
Master
Commands the vessel and holds overriding authority on all safety matters. Does not stand a routine watch — takes the bridge personally during pilotage, restricted visibility, port approaches, heavy weather and emergencies. Signatory on the ship's official documents. Also known as Captain or Master Mariner.
Certificate: Certificate of Competency — Deck, Management Level, capacity "Master" (STCW Regulation II/2; Table A-II/2)
Management level · STCW Regulation II/2
Chief Officer
Second in command. Primary responsibility for cargo operations, stowage, stability and the maintenance of cargo gear. Manages the deck officers and ratings. On tankers, stands cargo watch during loading and discharge. Does not usually stand a routine bridge watch in the three-watch system; may stand one in the four-watch. Acts as Master when the Master is unavailable.
Certificate: Certificate of Competency — Deck, Management Level, capacity "Chief Mate" (STCW Regulation II/2; Table A-II/2)
Operational level · STCW Regulation II/1
Second Officer
Officer in Charge of a Navigational Watch. Typically the ship's navigation officer — chart correction, voyage planning and ECDIS. Typically stands the 00:00–04:00 and 12:00–16:00 watch in the three-watch system; exact rotation varies by ship.
Certificate: Certificate of Competency — Deck, Operational Level (STCW Regulation II/1; Table A-II/1)
Operational level · STCW Regulation II/1
Third Officer
Officer in Charge of a Navigational Watch. Typically the ship's safety officer — lifesaving appliances and fire-fighting equipment. Typically stands the 04:00–08:00 and 16:00–20:00 watch; exact rotation varies by ship. The first watchkeeping rank.
Certificate: Certificate of Competency — Deck, Operational Level (STCW Regulation II/1; Table A-II/1)
Training berth · Support level
Deck Cadet
Trainee officer accumulating STCW-approved sea service toward the first Certificate of Competency. Works under the supervision of certificated officers. Required to maintain an approved training record book. Not a watchkeeping officer.
Documentation: Approved training record book and STCW-approved seagoing service (Regulation II/1 requirements)
The deck ratings
Deck ratings hold Certificates of Proficiency — not Certificates of Competency. The Bosun leads the deck ratings; the Able Seafarer Deck is the qualified watchkeeper and deck worker; the Ordinary Seaman is the entry grade.
Bosun
Senior deck rating. Leads the deck crew in maintenance, mooring, anchoring and cargo gear operations. Acts as intermediary between the deck officers and the ratings, working directly under the Chief Officer. The Bosun is an experienced Able Seafarer Deck in a supervisory role — not a separate STCW certification class.
Certificate: Certificate of Proficiency — Able Seafarer Deck (STCW Regulation II/5)
Able Seafarer Deck
Qualified deck rating. Stands bridge lookout watch under the Officer in Charge of a Navigational Watch. Carries out deck maintenance, mooring operations and cargo handling assistance. The standard working grade between Ordinary Seaman and Bosun.
Certificate: Certificate of Proficiency — Able Seafarer Deck (STCW Regulation II/5; Table A-II/5)
Ordinary Seaman
Entry deck rating. Assists with deck maintenance, mooring, cargo operations and watchkeeping duties under supervision.
Certificate: Certificate of Proficiency — Rating Forming Part of a Navigational Watch (STCW Regulation II/4; Table A-II/4)
Pumpman
Tanker onlyTanker-specific senior deck rating. Operates and maintains cargo pumps, ballast systems, pipelines, valves and the inert gas system. Found on oil and chemical tankers — not a universal deck department rank.
Certificates: Certificate of Proficiency — Able Seafarer Deck (STCW Regulation II/5); plus tanker cargo operations endorsements (STCW Regulation V/1-1)
How the bridge watch works.
Three-Watch System
4 on · 8 off · 3 officers
Standard on most cargo vessels. Three watchkeeping officers rotate through 4-hour watches with 8 hours off between. Rotation: 00:00–04:00 / 12:00–16:00, 04:00–08:00 / 16:00–20:00, 08:00–12:00 / 20:00–00:00. Compliant with MLC 2006 minimum rest requirements.
Four-Watch System
6 on · 6 off · 4 officers
Used where four watchkeeping officers are carried — common on tankers and large bulk carriers. Four officers each stand 6-hour watches. Requires careful scheduling for MLC 2006 hours-of-rest compliance.
The Master does not stand a routine watch in either system. In the three-watch arrangement, the Chief Officer typically does not stand a routine bridge watch.
How the ranks connect.
The officer track: Deck Cadet → Third or Fourth Officer → Second Officer → Chief Officer → Master. Each step requires documented sea service at the current rank, assessed against STCW competence tables.
The ratings track runs in parallel: Ordinary Seaman → Able Seafarer Deck → Bosun. Some seafarers cross from ratings to the officer track through approved bridging programmes — the route depends on the flag state.
Exam requirements, sea time thresholds and approved programmes are on the pathways pages.
Talk to working deck officers.
The Career & Recruitment category on the Marine One forum covers deck department questions — from first steps to chief mate exams. Read what others have been through, or ask your own question.