A certificated deck officer responsible for navigation equipment, charts, publications, and often designated ship's safety officer.
In practice
The second mate also serves as the ship's medical officer, maintaining the medical kit in accordance with flag state regulations and ITF/MLC 2006 requirements, and is responsible for administering first aid and maintaining the medical log. They typically manage the ship's safety equipment plan — tracking inspection dates for immersion suits, EPIRB batteries, pyrotechnic expiry dates, and SART performance — and prepare the relevant entries in the SMS record-keeping system. Port state control officers frequently scrutinise the currency of navigational publications and the condition of life-saving appliances, areas directly within the second mate's responsibility.
Regulatory detail & full definition
The second mate holds a Certificate of Competency as Officer of the Watch (OOW) — navigation, at operational or management level under STCW II/1 or II/2 — and serves as a watchkeeping deck officer, typically on the 12–4 watch. In most fleets the second mate is designated the ship's navigating officer, responsible for the accuracy and currency of all navigational charts and publications in paper or electronic form, including ECDIS chart updates, Notices to Mariners corrections, and pilot books.
The second mate also serves as the ship's medical officer, maintaining the medical kit in accordance with flag state regulations and ITF/MLC 2006 requirements, and is responsible for administering first aid and maintaining the medical log. They typically manage the ship's safety equipment plan — tracking inspection dates for immersion suits, EPIRB batteries, pyrotechnic expiry dates, and SART performance — and prepare the relevant entries in the SMS record-keeping system. Port state control officers frequently scrutinise the currency of navigational publications and the condition of life-saving appliances, areas directly within the second mate's responsibility.