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My Attempt to Build a Sport C Class Racing Powerboat

See also my Sport C page.

Sport C is a tunnel boat class using boats about twelve feet long which achieve speeds approaching 60 mph with stock motors up to 35 cubic inches. At these speeds, a tunnel boat can literally fly.

Motors approved for this class are made by Nissan/Tohatsu, Suzuki, Yamaha and US Marine. The Nissans and Tohatsus, however, dominate the class.

Hydraulic trim is used in Sport C, and a reinforced cockpit or capsule is required. The minumum weight for boat, motor and driver is 675 lbs. Speeds top out at 58-59 mph.

The Dillon Sport C is 12'8" long by 76" wide. The reinforced cockpit is foam-core construction using fiberglass, carbon fiber and Kevlar fabric set in epoxy. The remainder of the boat is marine plywood.

Unfortunately, in its original configuration, the Sport C turned out to be 50 - 60 lbs. overweight. I was only able to attain 50 mph with borrowed props availble to me. Not at all confident that I could make this into a competitive boat, I made the decision to convert the Sport C to GT Pro.

In that process, I reduced the weight by about 30 lbs., and also moved the seat aft 22 inches. This changed the boat considerably, and as soon as I started testing the GT Pro setup, I became anxious to try the Sport C motor again. Later in the summer I had the chance.

Using the same props I had tested two years earlier, I squeaked out 55 mph. This, I feel, puts me in the ballpark. So the plan for 2011 is to go back to Sport C with this boat.

You can see the construction of the original Sport C boat on the following pages.

Page One -- Page Two -- Page Three -- Page Four -- Page Five

You can see how I converted the boat to GT Pro HERE.

And then went back to Sport C.

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