[Probex]

FFT cranked up visual fog factor to 0.5 from stock 1. This means that you can visually detect the enemies at 14km or more! However, with the umodded game range limitations you (yourself, live person) can only see them when they are around 8km away.
(This is for YOUR sub though, not for the enemies)

9km mod, gives you an extra 1km (actually a bit more because of stock fog gradation).


For the enemies, FFT increased (in sim.cfg)

[Visual]
Light factor=1.75 from 1
Enemy surface factor=150 from 400
Enemy speed factor=9 from 15 knots

This may mean:
a) Perhaps enemies can see you better in poorer lighting conditions
b) Enemy distance is not as much of a factor in detecting you visually
c) Enemy ship's speed plays less of a role in their visual spotting.



So basically, you would have been detected by the Destroyer anyway with FFT, but perhaps you would not have been able to see him turn towards you until he was a bit closer steaming at full speed, without the 9km mod.

I have altered Sensors.cfg in order to decrease your crew's ability to see inside the fog.
FFT has it at 0.5, I put it to 0.95 (to match the new extra visibility), and the stock was at 1.



For testing, create a local Lan game and load the LAST of the coop missions (Convoy in Surigao Strait). Weather is clear. You will start seeing merchant ships coming into view out of the fog at 9km (almost immediately after being rendered by the game engine).