This is actually done while on the Butte. I was crusiing in open water with nobody around for at least a mile. I was doing about 24-24 and 3800rpm not to shabby. Topped out at 4600 and 32 mph. Even though boat speedo's are not very acurate it gotta be close as the slip calc all say 9%=32 mph and 15% =30 mph.

Very close to readings.