The final step was to draw the true shape of the hairpin or shelf that runs along the sheerline much like an inwale. Because the sheer is curved in the vertical plane its length is greater than it appears in a simple plan view. This hairpin is a substantial piece of timber that has to be sawn to shape so we have to have its true shape. The process of drawing it isn't complicated but is hard to describe and, because it is 6 metres long, I can't take photos of it all. You will just have to read the books or wait for photos showing the hairpin as I make it and fit it into the boat, these will make its name obvious.
With the lofting complete (I think) I have started making the moulds or frames that define the shape of the hull. This is fairly straight forward; the only tricky part is transferring the curved edge of the frame from the floor to the piece of timber. This photo shows the timber laying on top of the drawing - 2 pieces about 200 mm wide but jointed with a screwed on strap.
The blank is laying on top of the drawing and obscuring the line that needs to be marked and cut so how to transfer it? It is simple and very accurate. A number of substantial (ie double diameter) flat head nails are laid on their sidesm head s on the line, and tapped into the floor. the blank is laid on top and either walked on or tapped with a hammer. Here is a photo of the nails on the line.
The marks on the back of the blank are faired with a batten, the line cut, cleaned up with a plane and tried against the drawing. The ends and notches are marked and cut. When on ehalf is done it is used to make a mirror image of itself. the two halves are joined with another butt strap and the frame is complete.
There are 11 frames to make and over the last couple of days I have made 5 of them.
No comments:
Post a Comment