Query re Svere hull damage
 

I have just returned from a mission in which my UBoat's hull was damaged down to 40% . I returned to Heligoland for refit but realised that hull damage would not be repaired .
I need to continue this campaign--do I return to my home base and request a new mission and will I receive a new boat to continue or will I need to wait for repairs to my current boat.
Thanks for any help and info ....

you need to dock in kiel, later in game in wilhelmshaven near bremen. just look for the big blue submarine emblem. refitting will only repair your subsystems.

you will get the VII-C class vessel later on in game though, if that is what you want to know.

The only way to heal hull damage is to end patrol. While your ship is in dock it will repair. If some time has passed you may be offered command of a new type of U-Boat or they will send you out on patrol in your uboat but fully repaired of hull damage.