During the 3rd November to 27th December 1917 repairs, weren't the forward torpedo tube rooms stripped of its equipment and the torpedo ports sealed and then turned into an additional watertight compartment?
@ Tempus Fugit: I was under the impression the torpedo ports were simply welded shut, not plated over; I have not found photographic evidence for either variant. Of course I will change the pic if you have evidence!
Hmmm,
More likely welded-shut