Water Craft - January/February 2010
Setting up the building frame. Twin fore-and-aft stretchers interlock between each pair of moulds to ensure they are the right distance apart and a triangular arrangement locates the former for the stem. CNC cut-outs help accurate set up of the moulds on the centreline.
that Alec had devised some clever interlocking fore-and-aft beams to hold the moulds at the correct spacing. Triangulated beams located the fore and aft stem profiles with the usual string centreline aligned with a pre-cut indicator in each of the moulds.
I have always seen clinker boatbuilding as an organic process – once the moulds are up I hardly ever use the tape measure as each component derives its shape and size from what has preceded it. It seems to me that the thinking devoted to the kit build process obviates use of the tape for erecting the moulds. Just how simple could this kit-building lark be?
The first task, if it can be called a task, was watching the CNC cutter perform its magic on the 3/8” (9mm) Robbins Elite planking plywood. This was an eye opener: my normal routine of spending hours spiling and jigsawing planks was replaced by a machine cutting millimetre-perfect planking in minutes, complete with alignment holes. There might be benefits in boat kits after all.
Plankingpreparations The next revelation was the plank-scarfing jig, a very simple assembly consisting of lengths of wood on a flat base with the router running on guide rods. Place the plank end firmly against the cut groove in the base, wedge in place and run the router over the plank end a few times, adjusting the depth of cut as you go – a perfect scarf. Do the same on the next plank section, making sure that it’s the right face of the plank which you’re cutting. All much less effort than my usual attack with a block plane.
The length of the boat at 22’ (6.7m) requires all the planks to be made up of three sections with two scarf joints, so gluing the three sections together in perfect alignment needs a foolproof way of setting up. The kit system provides for this. Each dry assembled joint presents three pre-drilled small holes. A temporary pin is placed in each and a fine cord stretched between them. Adjust the angle until the cord just kisses the same side of all three pins and you have perfect alignment.