Mate (naval officer)
A mate is a deck naval officer aboard a merchant vessel, such as the chief mate, second mate, or third mate. Between 1800 and 1890 "mate" was also the naval rank now known as sub-lieutenant—master.
One of the mates is always the watch keeping officer, unless the master takes that responsibility. Each mate also has other duties, such as making the passage planning, overseeing loading and unloading and personnel management.
