Now I tested with your test mission and it seem to work as purpoused. I put value to -15 again (GetContactDepth() >= -13) Felt weird that they could spot me with peri barly touching surface like they did when I put it to -17.
But what do they see actually? just periscope, or do they spot me like if I was surfaced when above this value?

Can I cruise around at 15.5 meters and all is safe since I m to deep for shooting and too shallow for depthcharge? Anyways its a big step in the right directon

thx