Monthly: August 2015

13 Aug

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The Cartop Carrier Yacht

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An Inveterate Tinkerer Turns Things Upside Down
by Jim Graves

I stopped at a nearby neighbor’s almost perpetual garage sale, where a Sears cartop luggage carrier about six-feet long caught my eye. I figured that with a bit of work—some judicious cutting and drilling here and there—it’d make a quickly-built and quirky little sailboat.

After a bit of planing and sawing, the hull begain to show promise of a capable, if tiny, sailing craft. Much online research was begun to find the specific ratios and distance dimensions. A lot of small boat comparisons of apparent sail area to hull profile were tallied; the same with lee board size and location. The “quick” project went the same as all the others, taking far longer than expected, but the enjoyment was not diminished. It became obvious that, more than with motorcycles and other builds, a sailboat has to have all its component parts designed at the same time to work properly. As in an engine, everything has to work together, and small dimensions matter. It takes at least as long to research and design as to build and install. But the hope remained that, in the end, maybe it would float.

I also consulted with a few experienced and successful sailboat designers. I learned that the scale of the appendages does not change at the same rate as the hull, when scaling to a different length. So, as always, a bit of “over engineering” in places seemed wise, if specifics are not known. That is, we don’t have to know some of the exact parameters, but should be able to compare and copy closely. Thought was applied to where stress would originate and travel. Also, it was decided the materials used should be conducive to low-cost construction. Pine wood was settled on for its lightweight and finished beauty.

Some extra heft was put in the leeboard swivel surface. The hull was stiffened using 6″ pvc thinwall tubing around the upper inside gunnels. And it provides floatation. The mast step is pvc tube too, held stiff and distributing the loads by lateral tubes to the gunnels, with a stiffening plate under. More pvc space frame may be added later. If it floats. An aluminum extendable tube was attempted as mast, but added unneeded complication; the old proven aluminum tube being resorted to. The experimental  sail is of painters drop cloth. The boom will be changed from the pvc to matching aluminum. L-boards and rudder are foil shaped, and the rudderhead is hand carved, using electric power tools. Stand by in a future issue of Small Craft Advisor, for the results of the sea, I mean, pond, trials…. if it floats.

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The all-self-built assembly.

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Showing lee board swivel mounting.

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Inside. Flotation gap allows enough room for skipper’s nap below.

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