Here are the photos, blurry and small they are my record of history being made.
The official hover height for a stock Scat II is 6 inches. My experience with river rocks tells me its more like 3 inches. Things like ski/skid rails on the bottom take an inch out of the height, that's what a rock ripped off which lead to eventual hull failure.
My new hover height should be 12 inches, I guessing my top speed will be lowered from 45 mph to 35 mph because of increased frontal area and drag.
With the higher cushion height on such a small craft, lowering the operating speed is a good thing, would not want to flip over in a gust.
I won't be racing anymore, it's a crusier now.