Hello,
i guess it cannot be repaired when they are showing zero percent ? But i am not sure ..
However it is unlikely they would get you so early in the war, few planes had bombs so early, and depth charges carried by some planes were switched to the wrong depth.
While it may be that one Diesel engine was knocked out or became lose of its engine mounts due to nearby detonation it could usually be repaired in a way the boat could at least limp home. Bent prop shafts were a real problem though, noisy and only able to make few revs per minute then.
There are no reports of boats with completely destroyed Diesel engines, certainly if anything managed to destroy the engines completely, the boat's pressure hull itself would be in much worse shape = sunk.
"Room for improvement"
Greetings,
Catfish