A mate on a ship operates and maintains a merchant boat. A typical deep-sea ship includes a crew of at least three mates, including the first mate or chief mate, second mate, and third mate. Your duties as a mate can vary depending on the size of the vessel. You supervise the ship during your shift, delegate duties to lower ranking crew members, and manage other sailors on board. You may also charter a course for the boat, steer the vessel, or navigate on open water. Additional responsibilities include conducting bridge watch and maintaining log entries. Mates are responsible for the overall maintenance of the ship as well.