The first mate is the officer second in command. Ask the first mate, the first mate has the watch, promoted to first mate.
The job is running the ship day to day while the master carries the responsibility. On a merchant vessel the first mate is usually in charge of the cargo as well.
1nounfirst mateThe officer second in command.
“The first mate took the ship out while the master slept.”
first mate is an officer.
Practised in Sea & Sailing