Fog for 1 of the 2 players

I am making a multiplayer game where player 1 is a jetski and player 2 is a submarine. to make it seem that the submarine is under water I want to add a fog, but if I do this the jetski will also see a fog.
is there a way to show the fog only at the submarine and not at the jetski?

You dont tell us either (a) how you are accomplish two view or (b) how the fog is rendered BUT assuming

(a) You are using 2 cameras and

(b) The fog is some kind of game object

THEN you would use Layers.