Sunday, 19 December 2010
Wednesday, 8 December 2010
the stringers we use are all sitka spruce from robbins timber in bristol. they come in a lenght of ca. 5500mm ready machined to a thickness of 35x25mm and in good quality with very few defects and nice straight grain. we only have to thickness them down to 35x22mm and scarph them to the required length. before scarphing the lengths together we coat them in epoxy and round off the corners that are going to be facing inwards. doing this before scarphing makes handling much easier.
we find the quickest way to coat a lot of stringers at once is to clamp them flat together, apply resin with a roller or brush and take them apart once the epoxy is gelled so they do not get bonded together. don’t wait too long… we coat on face side (35mm) first, coat the opposite 35mm side, then round of the corners and do the rounded side at last. the second narrow side is left bare and gets a quick saturation coat before the planking sheets get glued on with spabond.
routering the corners where easy on a simple router table set up but even easier freehanded with this priceless little fella :
for the scarph joints we used a 1:12 ratio which were easily cut on the radial arm saw with a little jig.
shame that none of that wood will be seen in the finished boat…
Tuesday, 7 December 2010
when we first set up the bulkheads we just located them on their correct position, in the right height and perpendicular to the centreline at the base. they were still able to lean for or backwards and to twist between sheer and keel line.
on the picture above you can see the temporary keel in the middle and the sitka spruce keel stringers before they are glued in.
some of the bulkheads, specially the ones with a quite big cut out in the middle and therefore narrow at some places, were not stiff enough to remain straight under the load of the keelstringers. some bulkheads were slightly bowed because the flocoat cured whilst they were leaning against a wall and the epoxy fixed their slight bow. with the help of additional stringers on each side we straightened them up again.
we clamped the stringers in position and used laser, plum bob and tape measure to do fine adjustments until all bulkheads were straight and plum. in order not having to do all that again we marked the bulkhead locations on the stringers. when it came to glueing the stringers in place all we had to do was to get everything to the marked position.
to keep accessibility into the hull easy for a long time, we only glued in the stringers on one side of the hull and left the other side more or less open. you are going to see more of that in the next posts.
this is this weird guy who seems to be on a lot of the photographs i take of the building process. one of the rare pictures where he is wearing more than just the headphones and the glasses…
if you need some nice pottery, he is the man!