Lieutenants were commonly put in command of smaller vessels not warranting a commander or captain. ... The USN settled on "lieutenant commander" in 1862 and made it a distinct rank.

What rank do you have to be to command a ship?

On the sea a captain is usually the commander of a large warship—a cruiser, battleship, or aircraft carrier in the navy and any sizable ship in the mercantile marine service. In the British and U.S. navies the rank corresponds to the army rank of colonel, as does group captain in the Royal Air Force.

Can a lieutenant be a commanding officer?

In the United States Army, Marine Corps and United States Navy the position of Company Commander is usually held by a Captain or Lieutenant with three to six years of service as an officer.