Thursday, December 4, 2014

The Disappearing Fillet Radiused Chine

If you watched the last America's Cup races, you may have noticed that the hull shape has basically been turned upside down; flat on the bottom with a radiused chine and veed on the foredeck.  I'm sure that millions of dollars were spent reaching that design conclusion, so the least I can do is figure out a way for the backyard builder to achieve a close result (minus the carbon fiber). 


Radiused chines have previously been constructed with strip planking in between the plywood panels, but fitting the long tapered strips is very time consuming.  What I am proposing is a method that uses disposable fillets in a stitch and tape hull.


Stitch the panels together by any method that you choose.  In this example 
I'm using 6mm (1/4") plywood.


I'm planning an outside radius of 50mm (2") so the spatula tool must be shaped to the correct radius and width.  Install a fillet using the lightest and easiest to shape filler, like microspheres or Q cells.  Even polyester resin could be used because the fillet is only temporary.  Mix it as dry as possible for easy shaping later.

Lay in heavy double bias fiberglass tape.


Remove the stitching and grind or plane off the chine while checking the radius often with a plywood template.  Use a long sanding board to make it fair.  This is the hard part but it will look great.

Finish off with lighter fiberglass sheathing on the outside. 


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