The internationally recognised Certificate of Competency authorising a seafarer to keep a navigational watch on the bridge of a seagoing merchant vessel.
The Officer of the Watch (OOW) Deck Certificate of Competency (CoC) is the foundational officer-level qualification in the merchant navy deck career pathway. Issued under the STCW Convention — specifically Regulation II/1 for unlimited vessels of any size on any route — it is a mandatory legal requirement for any seafarer performing certificated bridge watchkeeping duties on vessels above the applicable thresholds. In the UK, the CoC is issued by the Maritime and Coastguard Agency (MCA); in Ireland, by the Irish Maritime Administration under the same STCW II/1 framework.
UK programmes lead to an HNC in Nautical Science (or equivalent CertHE) alongside the STCW Officer in Charge of a Navigational Watch (OICNW) endorsement. Written examinations are set by the Scottish Qualifications Authority (SQA); the oral examination is conducted by the MCA. Since August 2025, UK candidates follow the MCA's Modernised Officer Qualifications (MOQ) syllabus. Training providers include Warsash Maritime (Solent University), East Coast College, and Fleetwood Nautical Campus, amongst others.
The curriculum spans all core areas of professional navigation and bridge operations: celestial and terrestrial navigation, passage planning, Electronic Chart Display and Information Systems (ECDIS), radar and ARPA, bridge watchkeeping procedures, stability and naval architecture, cargo operations, COLREGS, meteorology, maritime law, GMDSS, and human element and leadership skills. Successful candidates hold a qualification recognised in all STCW signatory states worldwide.
Holding an OOW Deck CoC opens the door to employment as a watchkeeping officer on merchant vessels, ferries, offshore support vessels, and commercial superyachts worldwide. It is the essential first rung of the commissioned deck officer ladder, enabling progression through Chief Mate to Master — the most senior deck officer on any vessel. The qualification is recognised in all STCW signatory states, making it globally transferable across fleets and flag states.
Cost note: Published course fees range from approximately £7,288 (Fleetwood Nautical Campus CertHE route) to £9,442.50 (Warsash Maritime HNC/exam route, including HNC, ECDIS, NAEST(O), and EDH but excluding MCA/SQA exam fees). Ancillary short courses required before the MCA oral examination — Advanced Fire Fighting, PSSR, Medical First Aid, GMDSS GOC — carry separate fees and must be factored into the total cost. Overall programme costs including ancillaries typically range from approximately £8,000 to £12,000 or more, depending on provider and which courses are already held.
Revalidation: The OOW CoC is valid for 5 years and must be revalidated before expiry. Revalidation requires demonstrating continued competence through either approved sea service (on vessels of 80 GT / 24 metres or more, typically a minimum of 12 months within the 5-year validity period) or completion of approved refresher and updating training where sea service has not been maintained. Applications may be submitted up to 6 months before expiry and will retain the original anniversary expiry date. The underlying STCW ancillary certificates — including Basic Safety Training, PSSR, Advanced Fire Fighting, and Medical First Aid — each carry their own separate 5-year revalidation requirements.