Above: the finished hull and deck wait to meet Jean Genie’s unusual keel with its generous fin area and a large trim tab plus delta-shaped ballasted endplate. The fat section also allows all the boat’s lead (bar trimming ballast) to be contained in the keel – other 5.5 Metres carry up to one-third of their lead as internal ballast (no wonder GBR 42 flies upwind – ed). The twin openings for self-bailers are aft; with a raised double floor plus big self-bailers the modern 5.5 is a drier beast to sail than even its recent predecessors were, where as in the 6 Metres continually pumping out was a specialist and demanding skill in itself. Note too the way the soft chine sharpens up dramatically aft, a trick that Star sailors have known about for many years as they pursue maximum planing area along with optimum spray dispersal. Left: dry-fitting the keel before fitting out


cooking process. To minimise this our moulds were constructed in glass fibre, so we had the same potential expansion rates as the parts being built inside. The deck mould included many ‘implants’


to create rebates for hatches as well as cleat wells, electrical system box, traveller recess and spinnaker storage area. This was again moulded in one shot. The internal structures were also all built in pre-preg using our long vacuum table and oven. Another rule of the 5.5 Metre class is


that the area in way of the keel, longitudi- nally not less than 1/3 of the length overall, 200mm wide and 20mm thick, must be of solid or monolithic construction. This makes for what is in practice a solid glass


44 SEAHORSE


plank, which was constructed off a CNC tool while we were waiting for the hull moulds to arrive. It was subsequently treated as a core material which replaced the foam in the appropriate position. The bulkheads were built with return


flanges which increased the stiffness of the panel. The longitudinals got the same treatment, as they were practically the length of the boat and would have proved hard to handle otherwise. The multiple keel floors that the rule prescribes were built in two long sections and then cut to shape, again from CNC templates. In the end the join of the hull and deck


parts was simple, the glass taping on the outside to reinforce the join being laid


down in a shallow rebate so that the true shape could be realised. The ‘apex’ of the chine was then reconstructed with a very small amount of lightweight epoxy filler utilising templates. We relied heavily throughout on our


CNC router and CAD proficiency to cut all of the numerous moulds, plants, jigs and tools we required to build and check parts. Being able to go straight from draw- ing to mould/tool in-house is a blessing. Wherever possible we prefer to build


from female tools, keeping fairing to a minimum, and the vast majority of these were machined from PET foam which is a recycled product. All in all a very enjoyable build. And the


results speak for themselves. Gavin Tappenden, Composite Craft, Cowes


q


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