It depends on how senior you think this person is:

"A helmsman or helm is a person who steers a ship, sailboat, submarine, other type of maritime vessel, or spacecraft. On small vessels, particularly privately owned noncommercial vessels, the functions of skipper and helmsman may be combined in one person. On larger vessels, there is a separate officer of the watch, who is responsible for the safe navigation of the ship and gives orders to the helmsman."

http://en.wikipedia.org/wiki/Helmsman