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Converting The Dillon Sport C to GT Pro

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The first step was to remove the reinforced cockpit from the hull. This cockpit is not required for GT Pro, plus is was too far forward for the lighter engine and slower speeds in GTP.

The process got started by cutting open the deck.

Once the cockpit was separated from the bulkheads and the coaming it could be lifted out. Describing it, however, is easier than doing it. There were some places where it just didn't want to come away. But I kept working at it, and eventually it came free.

Once stripped of steering gear, instruments, wiring harness, etc., the cockpit weighed 60 lbs. Also, the GT Pro motor is 10 lbs. lighter than the Sport C motor. I'm guessing that ~30 pounds of plywood, lumber and epoxy will be added back onto the boat, for a net reduction of 40 lbs. That still leaves me 10 to 15 lbs. overweight for GT Pro, but GTP boats are less sensitive to excess weight.

Let the rebuilding begin.

The original carlins were cut away when I opened up the deck, so the first step is to replace them. I also added some glue blocks to the ends of the bulkheads for the new coaming to attach to.

Next I extended the coaming all the way up to the bow, establishing a whole new profile.

A patch allowed me to extend the height of the original coaming. There will be a double thickness of plywood here. There will also be an additional layer of plywood where the new and original coaming sections join, strengthening that joint and providing a bit of protection for the driver.

The dashboard and a cowling bulkhead give the new structure some shape.

The weather has been horrible this month (October 2009), and unfortunately this is an outdoor project. Progress has been slow.

Before permanently installing the new coaming, it's time to patch the deck. I got the pieces cut, then waited for one last good day to install them. That's as far as the project went in 2009. See you in the spring....

* * * * *

March 14, 2010: The sun came out and the temperature soared to 55 degrees. I mixed some microballoon sanding filler and filled screw holes and seams in the above mentioned patch work. But it's not spring just yet.

April 17, 2010

I was without a camera for a while, so no pictures of the steps it took to get here.

BUT I'M HERE!

The painting is done. Now on to the setup. Most of the systems are basically in place, there having been a Nissan Sport C motor on here in its original configuration. It's just a matter of getting everything hooked up again, but to a GT Pro motor this time.

April 27, 2010

All set up and about to be taken down to the lake for its first test run. The test went really well. Right out of the box, 48.3 mph, fastest speed yet in GT Pro as far as I know.

I've got room to jack up the motor, more props to try, and a new prop on the way from Ron Hill. Hoping to reach that 50 mph plateau.

These are the props tried so far: an OMC 10x17 (at right) with sharpened edges and trailing-edge cup; and a Hill round-eared cleaver, one of the props that Ron donated to the class last year. Same top speed from both, all in the 6300 to 6600 rpm range. And excellent holeshot.

One duty that remained was to provide a name for the new boat, a name that incorporates my original aspirations for Sport C, and its eventual home in GT Pro.

Presenting, the
"Dillon Sport GT."

The boat now carries a basic set of graphics and is just about ready to race. But first there's more testing to do.

The new Ron Hill prop arrived. It's 9.75" x 17", a little small on the diameter, but hopefully not too much so.

May 12: Results are questionable so far. This one is very slow to get on plane, and my initial test ran it up to 7200 rpm and 48+ mph. Tapping in a little cup brought the rpm down to 6900 or so, but didn't change the speed or the poor holeshot. And now it's very sluggish, slow to get up to speed.

Right now I'm starting to really like Ron's round-ear prop, shown above.

May 14: A little work on the prop took some of the sluggishness out of it, but did little for the holeshot. By holding the throttle down until there was no more lake left, I hit 49 mph on three different passes.

Finally on the racecourse! However, technical problems plagued me at almost every race -- and the season was shortened due to the ailing economy -- so I don't have great race results to brag about.

With time to play in August, 2010, I put the Sport C motor back on. Results were so promising that I decided to return the boat to Sport C for 2011.

First, I had to reinforce the cockpit per Sport C rules. You can see how I did that HERE.


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