Certificate of Competency (Deck) Below are links to our Mariner Course Application Details: II/1 Officers in Charge of a Navigational Watch On Ships Of 500 Gross Tonnage or More II/2 1-2 Master/ Chief Mate on ships 3000 gross tonnage or more, Near Coastal & Oceans II/2 3-4 Master/ Chief Mate on ships between 500 & 3000 gross tonnage, Near Coastal & Oceans II/3 Masters on ships less than 500 gross tonnage, Near Coastal ll/4 Rating Forming Part of a Navigational Watch ll/5 Able Seafarer Deck