20' pontoon (aluminum) with '70 model 60hp Johnson. I took the motor off my old 16' tri-hull that was about gone, but the motor runs really well, and put it on the pontoon. The speedometer on the 16' foot didn't work, but it scooted over the water pretty good, I'm guessing 30-35 mph or so, and would pull 2 skiers. Now on the pontoon, 15-18 mph is the best it will do, and with my 9 YO granson on a tube, much less, maybe 10-12 mph. Would changing props help?
