Look at adding the effect to the material of the windows you’re using, if you’re always looking out through the ships windows than this will be sufficient to give the effect to everything “beyond” the window, you could switch between this and the normal underwater methods if you switch to a third person (outside the sub) view at any time.
Hi Antoine!
A lot of time is passed since your post… but I’m going to struggler against the same problem.
Did you managed to create that effect?
I had a strange idea about doing that in post-process but using a custom depth to separate the stuff inside the submarine from the stuff in the water… but I’m not sure if it’s a great idea
Bye!