Usually, that damage does not show on your boat's damage screen either. Think of it as the outer doors are damaged and not able to keep the sea out of the tube. Therefore, you cannot open the inner doors and put a torp back on the rack... But, there is no way to do that in the game anyway, and in real life, while they could pull a torpedo, such as the Type 18 to recharge the batteries, it would most likely have been impossible to change the rack to be able to change the tube used anyway. One thing about the game though, your torpedoes will continue to reload into the other tubes, while in real life, it would have been very difficult, if not impossible to move the torpedoes off the racks behind the damaged tube to other racks for use... I could be wrong, but I do know that I would not want to be on the boat if they were trying to do that... maybe while on the surface, they could use the loading crane to help, but that would take a good while to accomplish.
