Hi Stiebler,
Ok after more extensive testing (tests were done with only NYGM up to 3.4 installed) I am almost certain there is a conflict between H.sei's "realistic repair patch for NYGM" and something in NYGM's NSS_Uboat7c.zon file. In base screen, the word "unlimited" appears next to the sonar and radar equipment upgrade options, and then the weird geometry issue will appear in game. Perhaps you guys already know about this (H.Sies's thread is 50 pages long and I tried to locate this issue in there), but hope this helps in your development
regards