Penalties of mutiny

The Pequod is not a military ship.Their voyage is a purely mercantile venture. So what would be the penalties if Mr Starbuck and the crew did mutiny against Captain Ahab? What if the three mates said they arrested him and put him in the brig because of his pottiness? Presumably, they can't be keelhauled or flogged because they are not a naval crew. So what would happen?

Actually, the penalty could be very severe. Read Billy Budd, another Melville work, that deals with the theme.