As you know view range is limited when under water, with this trick you can see under water as far as usual.
This only works in places where waves are high enough (e.g. near beach or rock around water) you should position your camera inside water (better works in third person view when you click left mouse button and move camera with mouse) and move it up slowly untill view range limit gone. Then hold like this for few seconds while waves go higher than your camera and u will see whats under water.
Point is to place your camera between waves (top of water) and unseen box that activates underwater view.
Dont think this ever get fixed because they have to rebuild game engine to fix this one.