it is the only setting that getting reset on game start. All the other settings remain.
Generic Mod Enabler - v2.6.0.157
[H:\Silent Hunter 4\Silent Hunter 4 Gold Edition\MODS]
1 Game Fixes Only Mod v1.1
2 MaxOptics IV for GFO 1.1
3 Real Environment mod install
4 GFO Patch for Real Env
6 Bigger Better Protractors
7 Extra Allied naval bases for Stock SH4 + UBM v3.0
9 Webster's New sonar view for v1.5
Easy AOB
Metric Nomograph for GFO MaxOptics
CEPEGA Clock
CEPEGA Controls
CEPEGA Maps_cfg
CEPEGA clean Binocular
red marked mods are my own modified versions of files from other mods wich i changed to my likings.
i will try it out now without any mod enabled, and see if this change the situation.
[edit] disabling the mods does not solve the problem. Will try to delete the "SH4" folder in "My Documents" folder and reinstall the game again and see if the problem remains in vanilla version (never checked this).
[edit 2] made a fresh install on E: drive after uninstalling the game and deleting "SH4" folder in "My Documents". Still no luck

One thing is suspicious - there is no option for Imperial/Metric/Authentic in my GameplaySetting.cfg
[Current]
LimitedBatteries=true
LimitedCompressedAir=true
LimitedO2=true
LimitedFuel=true
RealisticRepairTime=true
ManualTargetingSystem=true
NoMapUpdate=false
RealisticSensors=true
DudTorpedoes=true
RealisticReload=true
NoEventCamera=true
NoExternalView=false
NoStabilizeView=false
MPShowPlayerNames=true
MPShowTorpedoes=true