| Projects
4M - The Sailboard Thing |
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This craft
was designed and built in the week prior to the Weir Wood May 1999 practice. These pictures show the construction of the planing foils. These were made from marine plywood laminated with epoxy resin and glassfibre on both surfaces. The foils are formed to a parabolic curvature. This was achieved by laminating them onto a smooth surface (kitchen worktop) that had been bolted to the garage floor at each corner but with a 25mm dowel running under the board in the middle. The bolts were tightened such that the board was bent into the desired curvature. The lamination and holding of the foils during curing was greatly aided by the use of 'vacuum bagging'. The second picture shows the vacuum connection to the bag. The white material is the breather fabric. |
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These pictures show the
underside and top surface of the board. As the whole thing was built in a week of evenings
there was no time for any cosmetic enhancement! There is only one footstrap. Mainly because I wasn't certain where I would need to stand. The foils are supported on threaded rods. The angle and distance below the board can thus be varied. A 40cm fin was used. |
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Results were very encouraging. The board accelerated and rose up on to the planing surfaces. The handling whilst different to a conventional sailboard was not unacceptable. The ride was quite firm with a hint of skipping at high speeds between the fore and aft foils. | |
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After being
neglected for too long the old hull was revived in the week running up to Speed Week 2002. I
decided to try different foils. The objective being to see how
wing like surface piercing planing foils may perform. The
foils are simply made from 18 mm marine ply, with a straight chamfer on
the top surface leading edge over 85 mm to produce a knife like leading
edge. The fin is 65 cm in length but only 50 cm is in the water. (It is removed in the first picture). The rear foil is 145 x 35 cm and the forward foil 95 x 35 cm. The under surface is flat although a concave surface is preferred. The forward foil is mounted at 4.5 degrees incidence and the rear at 3 degrees. I am not expecting great speed but would like to find out how easily such a configuration can be made to plane. Especially in low wind speeds. |
Amended 08/04/06
