Paul Gartside 18' Racing Gaff Cutter • Cabinversion designed by Dominik Gschwind

2012-10-31

Week 15 - Coachroofbeams / Spars

Actually we are since quite a while working on the spars parallel to the work on the boat.
The process to get nice rounded wood is pretty much comparable to the way of fashioning the looms of the oars about which I've been reporting earlier.
So we started by glueing the boards with mirrored grain as on the photo.
In the case of mast and spars we only use epoxy and for those parts which have to get extended we use spar scarf ratios of 1 : 12 (Lloyd's rule).
All mast and spars are made of douglas fyr which is heavier but more rigid than sitka spruce that we used on the oars and indeed also could have been used for the rigging. However because of Glóeys in general very solid construction as a seaworthy pocketcruiser I decided for douglas fyr.
There are a lot of bronze fittings on the rigging which have to be trimmed and fitted to the mast, spars and stem. On the picture below we see to the left the mainboomendcap with an eye for the toppinglift, in the middle the boomendfitting towards the gooseneck and on the right side the custommade gammoniron which will be sitting on the stem and support the bowsprit.

On the boat we started making templates for the coachroofbeams. The plan was to create them as laminates of 1/8" sapele veneers bent over individual formers. And to fashion these formers we used the 9mm templateplywood as a corematerial to which we glued cheeks in 18mm ply.
The role of the 2" holes along the formercurves is to allow centric clamping. It looks like a lavish effort to build separate formers for each beam but it isn't at all. We just used a copy routerbit with a bearing and that makes the job very effective.
But before beeing able to fit the laminated beams to the coachroof we had to glue the beamshelfs in.
They are made of three 1/4 " sapele mahogani veneers on each side which made it easy to bend them to the endposition.
The tight clampingspacing secured a nice even contact and finally after the epoxy had cured we trimmed the overhight coamings and the beamshelf to their correct bevels (changing bevel along the roofedge) and fitted the laminated beams.

2012-10-27

Week 14 - Deckcovering / Coamings

With the following tasks Glóey changed her look quite a lot. She has no visible filigrane skeletonstructure anymore because we've covered the deck with marine plywood (Robbins Elite Ply).
But let's have a look step by step:
Before glueing the formshaped plyelements to the deckframing we did some painting- and varnishingwork. The reason for this is that it is just so much easier to do that now than later when the boat is covered.
The framingcompartments on the plywoodunderside got 2 coats of primer and 2 coats of EPIFANES traditionel 1-pack paint. The douglasfyr of beams, beamshelf and carling got 3 coats of EPIFANES Rapid Clear and thereafter 2 coats of EPIFANES clear varnish (1-pack), sanded between the coats with 320 grit sandpaper. In the buoyncetank at the bow we've painted 2 coats of SEATEK Epoxyprimer.

Beside that we also fittet the 2" GRP tube for the rudderstock through the sternpost and the kingblocking. It is a fiberglasstube with nylonbushes at either end and with rubber o-rings inside the bushes.

And this is how the boat looked like with a covered deck (underdeck).
After glueing the ply on a little overlapping we trimmed the edges with a blockplane on the convex outside and with a good old Stanley Nr. 79 side rebateplane along the concave inside.
The inside had to get accurately plomb to become the future jointsurface of the vertical coamings.
Coamings are the structural elements on the side of the cockpit and the cabin (coach) which are joint to the carling. On the photo to the left you can see how we were scribing the complicated shape of the coamings to a piece of flexible 3mm hardboard. For the coachroofoutline we've built a jig which could now be used for the template as well as finally to screw the overhight plywood-coamings on.
Materialwise we used 2 sheets of 9mm marineplywood (Robbins Super Elite) which hat to be scarfed to manage the necessary length. So the coamings got 18mm strong!
Normally Lloyds recommends a 1:8 ratio on plywoodscarfs but we decided to use 1:10 just because of the stresses in the material caused by the bending.This quality of plywood is an absolute pleasure to plane and the veneers help to get the scarffaces really flat. Because of the limited possibilities in the workshop we had to glue the scarfs of those long elements on the floor which was covered with the loftingboards. That methode doesn't allow real clamping and therefore we used heavy pieces of lead to create the necessary pressure.
Some improvised helpingconstructions gave us the possibility to clamp the coamings when glueing them on to the boat. On the inside we also used silicon bronze screws in to the carling to support the joint. These screws have such a nice look with that slightly red bronzealloy that they also will be a decorativ part of the interior.
In my design of the triangleshaped coachroof I wanted to have an elegant frontpost which unfortunately is a bit tricky to fashion. Simply because of the fact that there is so much bendingpressure on the coamings while glueing them. As visible on the photo we solved the problem by trimming the "first" nose off with a chisel and blockplane and glue another piece of straightgrained sapele mahogani on which finally could be trimmed to it's endshape. The sectionlike photo also shows that the shape of the frontpost was choosen in a way to get max. gluesurface inside the coamings.
Along the cockpit it was a straight forward process to fix the coamings because of the existing possibilities to use conventional G-clamps.
The topside of the doubleplywood will here be covered by a bendable strip of sapele after shaping it later to it's final lines.
And this is how she looks with coamings...


2012-10-10

Week 12/13 - Benchbridge / Bulkheads / Deckframing

it's time to get more life into the hull...
After fitting the centreboardcase we went on working on the fullbeams, bulkheads and the benchbridge. As visible on the photo beside there is a strongbeam in the aft end of the cockpit which both got the deckcamber on top and a convex curved shape for the coaming on the front side.
Beams are chiseled into the beamshelf and glued with epoxy. A very nice job and once one has got the trick with the marking it's pretty much a straight forward process.
Time to spile for the first bulkheads. It's a bulkhead below the benchbridge which is split in 2 pieces by the centreboardcase.
Spiling is a technique to mark curved shapes on a template with a dummystick. Nowadays we also use the selflevelling laser to make alignments.
And this is the view from the cabinside. The benchbridge is indeed a bridge athwartships which both gives more stiffness to the boat as well as creates an extended cabinspace for baggage etc..
Benchbridge and bulkheadparts are connected by very strong epoxyglued tongue and groove joints. The two pieces of lead on the photo are used to but weight on the structure while glueing because there are no direct possibilities for clamping.
After fashioning all the fullbeams the carling was put in place. A laminate out of 7 strips to be able to bend all in to it's curved shape. That method worked surprisingly well thank's to 4 extra positioningpoints to the 3 existing ones on each side (with assistingbeams). The carling is the fore and aft member of the deckframing which supports the halfbeams.
Now after having glued and skrewed all halfbeams in the deckshape has become more and more imaginable. All deckframingwork is done in douglas fir, a very easy to plane timber and with a beautiful slightly redbrown color. This is even bettre visible on the last picture which shows the varnished framing.
As a preparation before laying the underdeck we fashioned all the reinforcement pads (1" plywood) for all the later through bolted deckfittings like sheetleads, running backstays etc.. Their function is to spread the loads on the structure. To get them flush with the topsides into the framing we rebated them in (see photo).



After sanding we varnished the whole deckframing with 3 coats of EPIFANES Rapid Clear and 2 topcoats of EPIFANES traditional 1-pack Clear Varnish...