MOST CAPTAINS HAVE AN ACTING CAPTAIN WITHOUT EVER BEING BUMPED UP OR SHIPPED OFF TO PRISON.

Jesus. How many fuckin times do i gotta say it? Sometimes a crew can have more than one. Some times hes not even made, just close to the captain. If there is no one capable of running the crew it gets given to another captain to supervise. It is a very common practice whether or not ivy can find proof of it in the fbi feild manual.