I know this would be a big ask for anyone to undertake but you were talking about the Startrekky look of the damage control scheme and it just got me thinking that even the Cutaway image of Silent Hunter III is a little bit to futuristic.
Would it be possible to instead replace the 2D cutaway with blueprints instead like these ?
I think it would add to the atmosphere of the damage control a bit, felling like your actually at damage control desperately studying the plans to find a way to plug an inaccesible leak or re-wire the batteries to give yourself just a couple more minutes of power like Das Boot.
Edit found the blue prints at
http://www.seajunk.com/nautical-antiques.htm listed there as being about $35 if anyone is interested in buying.
Also found some blueprints for a type XXI at
http://centroeu.com/uboote/typexxi.html