eric, let me explain in more detail - these deep mountain rainforest lakes out here hold almost pure water by the end of winter. pure water does not conduct electricity, and when tested it's the lowest reading i've seen by a huge margin. eg. 40 v.s 200-500++. but conductivity can be taken as an indication of viscosity - which is what affects the ski most. surface tension - don't think that is a big factor on a ski. the drag from the wing base is a real strain on the arms, just as the ski itself is moving through the water. Couple more things to add - the surface tension of water increases as it gets cold, decreases as it heats up, which is what you'd expect. But i think you just made a typo there. ..and the bottom effect that skier bandy about i am very suspicious of. might be just the changes in water texture between two lakes, the shallower being softer. unless there is a good viscosity test done on the water this can't be confirmed. in industry the above is no big deal. tests like this are done by instruments in real time or by the lab. it's how quality control is maintained.it takes time for the lake to bloom, so by june or july just as a garden grows it softens up a bit and yeah the wing goes back on and we start skiing the course again, pumping up the boat speed. most skiers gain 1-2 passes heading south- serious canadian slalomers have to relocate because the water is so different. the closed /man made shallow lakes are better and are good training sites. but on a big canadian lake, it's gorgeous, clean but very difficult in terms of scores. skiing a cold ocean might be close, but even that feels softer to me.