I don't think it's necessarily that the ship is out of control, but the ropes have basically gone over the side and out of reach - it will make it very difficult to catch them again to alter the sail - normally, even though the sheets are slack, and not 'doing anything', they are still tied off to something on the deck, so that when you need to haul in, you've got it easily to hand.

Could be wrong, of course.....