Anybody out there water ski? Technical question: How fast does the boat need to be going to pull one 175# person on a slalom ski? I've got a 20' Kenner Ski Barge with an 85hp Mercury on it that I'm trying to get fixed up, and I'm curious as to what the top speed will be on it. A friend of mine back in the late 60s had a 19' Ski Barge with a 60hp Mercury on it, and it would pull one of us on a slalom ski; it wouldn't pull two. It had no speedometer, so I don't have a clue as to how fast we were going, but if I could find out, I could use that info to estimate how fast the slightly larger Ski Barge with 1/3 more horsepower should be.