[DSII] Sinking hover tanks

Some time ago we had a discussion about heavy hover tanks over water.
The 
conclusion was 
that if the tank massed enough that the pressure/area (PSI in US terms)
was 
too great the tank
would sink while furiously blowing bubbles from under its' skirt.
Basicly a 
Hammer's Slammer 
hover-tank would probably sink.

The thing we didn't discuss was how movement would affect this. If the
tank 
were moving at
100KPH would this affectively give it a greater area under the skirts?

Any ideas?

Roger Books (offlist for some time)