Monday, March 28, 2011

Building 'Sharpy' Part 50

Continuing with the keel, I made the leading edge from hardwood - in fact, a piece of skirting board from Homebase. The tricky bit was cutting a semicircular groove along the front where the sides converge to form a ‘v’ section. The piece of wood was thinner than shown on the plans, but I shall fill the gaps either side with epoxy putty. Instead of screwing this piece of wood to the plywood between the aluminium pieces, I nailed it with bronze nails. Before doing so, I epoxied both surfaces and protected the outside of the aluminium pieces from epoxy dribbles with Sellotape.

Make a note that I first cut the groove with a small chisel and shaped it into a semicircular section with a small half-round file and a piece of sandpaper rolled around a drill bit. After I had made the groove I fashioned the ‘v’ section with a hand plane.

Shaping and fixing the aft edge of the keel piece should be easier than the forward one, because it does not have a groove. The semicircular groove on the leading edge is to accommodate a 2 millimetre Bowden cable which takes the weight of the keel and runs over a pulley housed in a bracket at the front of the coaming. The lower end of the cable is attached about 2 inches from the bottom of the keel on the aft side and it runs through a groove under the bottom of the keel and up the leading edge. The upper end of the cable is clipped to a double fiddle block operated with a 6 millimetre rope that passes through a jam cleat on the deck. The crew can hoist of lower the keel by pulling or easing the keel haul rope. For safety reasons the keel is tied down with a line that is threaded through three small holes that pass through the keel near the upper edge.

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