This looked interesting: http://sundog-soft.com/sds/2013/10/triton-ocean-water-torque-3d-released/ small fee involved, but might open up the possibility for drivable boats and I would think water jumps and crashes maybe. I know this is not what devs have in mind, but it would open things up a little for modders.
The reason for no driveable boats so far is simply because JBeam structures don't define bouyancy yet (torque3d does have basic bouyancy already though). The only advantage this would bring would be the waves, which itself is a fair addition to the game I think.
Well BeamNG already has a water system with waves and stuff, this one is better for looks though I must admit
Considering how heavy BeamNG already is, it would be even more taxing on the lesser computers. Plus, it doesn't seem very helpful unless you want a realistic boat simulator(which BeamNG is not)
Re: WE NEED WATER PHYSICS!!! Lets get this straight and admit, there's not a finished game with no water effects/physics