Tuesday, 1 January 2013
Cutting Deck Beams and completing the deck frame
The deck beams are formed with tenons cut at 73 degrees to set the gunwales to the correct vertical angle. The length is also marked from the gunwales locked into place with temporary formers to determine the required profile in plan.
Two arched deck beams are formed to provide some clearance for legs inside the kayak. The width of the kayak has again come from 'my measurements' - hip width plus some clearance (so again, a real made to measure fit should be achieved). I finally end up setting the temporary spreaders to give me a 21" wide kayak and some further shape forced into the bow and stern of the kayak. Deck beams are then marked to match the final shape once the tenons are cut. The width of the kayak will be at the wide end of the Greenland design (just like me!) but considerably narrower than most modern recreational kayak designs.
The tenons get locked into place with 3mm oak dowelling which I have cut for the job. They also have a lashing underneath made in artificial sinew and on alternative deck beams to help maintain the 73 degree angle of the gunwales.
A further lashing brings together both the stern and bow ends and in doing so I get to tie my first 'Eskimo knot' of the project!
The bow and the stern are dowelled with 9mm oak dowels turned into trunnels with a softwood wedge driven into both ends. The softwood will swell when it gets wet and the whole joint will tighten up further. The wedge has to be carefully placed at right angles to the grain in the gunwales to prevent them splitting the frame when they swell.
The trunnel and wedges are planed smooth to produce a 'clean' and secure fixing. The whole frame has been formed into a strong and stable shape, exactly matching the shape and dimensions set up from the formers and with the absence of any glue. The frame is designed in these traditional kayaks to be strong but also flex in the sea and absorb the force of waves without straining and breaking up.