Ok 1st off WOW
2nd I think the Uboat is rocking the same amount whatever the weather, not sure if this is a by-product or not.
3rd, I noticed this:
4th, strange black shadows at the front of the boat in this weather, moved around really quickly, but stayed out in front in a long black reflection
and lastly, about the shimmering, I don't know if you can really see it in this screenshot, but I did investigate and it seems that it only is only really noticeable in the free camera, not so much on the fixed and again I think more so in exceptionally good weather:
Anyway, hope these comments are helpful, I'm off back to the blue sea, got some revenge to take after my last patrol
