Merchant Navy Rank "Third Mate" or 3rd Officer (3/O) belongs to the deck department of merchant ship and is responsible to the Master and C/O for:
- The maintenance of lifesaving equipment, including vessel lifeboats, to ensure that such equipment is kept at a constant state of readiness according to SOLAS requirements.
- The maintenance of all fire fighting appliances, including hoses, breathing apparatus and extinguishers. The 3/O ensures that such equipment is kept at a constant state of readiness according to SOLAS requirements.
- Reporting any deficiencies in lifesaving or fire fighting equipment which may affect safe vessel operations to the Chief Officer (C/O).
- Maintaining Lights, Shapes, Flags, Halyards and Sound Signalling Apparatus.
- Keeping a safe navigational watch as instructed by the Master.
- Taking charge of a mooring party.
- Keeping a cargo/port watch as instructed by the Chief Officer.
- GMDSS Duties as assigned by Master.
- Any other duties as instructed by the Master.