have found the reason!
using SH3Cmdr, which has the file de_menu as well under !BACKUP/...
This changed and everything worked wonderfully. Almost, only the tubes close themselves when cycling throufh them. before, they remained open after i openend them in the conning tower. Still a great

mod, thx to Nicolas and U-jagd team. My computer is unfortunately "just so" capable of running SH3 with GWX, so OLC with it's 16km athmosphere is not an option...
Cheers!