I do all my slalom in open water and probably 5 times a year we go to private lake which is between 4 to 6 feet deep. It is much easier, first the water is not as hard, second we have a shorline very close and we have almost glassy conditions compare to the open water. When I ski well at 32mph on open water, I am at ease at 34mph (15off) on this private lake. And third the water temperature is warmer too...so big differences. Not to mention the psychologique effectof feeling much safer skiing on a not deep lake.