Not a bit suprized about the sled beating the jeep across the water, you actually get better traction on water than snow with a sled. The first rule of snowmobiling on ice is 'when in doubt, throttle out'. I made a bad/dumb call this past winter and end up crossing close to a mile of open water. Went across a lake at night trying to save an 80 mile back track when a trial that was supposed to conect to the one the other side the lake didn't go through, HUGE pucker factor.

Durring the summer up here in the snow belt there are sanctioned water cross races, both drags and ovals. This is a frind of mine.
