1) I'd head for home. The damage you've obviously taken has rendered your boat vulnerable. You've learned some valuable lessons and gained much-needed experience . . . none of which will do the Kriegsmarine any good if you don't carry through to another mission because you've been sunk or captured.
2) Write more. I insist. Damn good story!
3) Also, check the compartments for remaining water. I had that happen to me once; the compartment had been repaired and flooding stopped (so all the visual indicators appeared as 'ship-shape and Bristol fashion) but because I'd shifted the crew out to rest I hadn't realized that, although the damage had been repaired and the
flooding had been stopped, not all the water had been pumped out
