Building a Northumbrian Coble in Clinker Ply
In which the end approaches...
At this point I was getting sick of looking at the gap in the gunwales above the top edge of the plywood. My plan for this was to cut a long strip with a slight taper that, when tapped into the gap, would create a nice tight fit and would allow for any variance in the width of the slot and (more likely) the roughness of my tablesaw. This ended up working perfectly! I gooped a bunch of thickened epoxy into the gap and then hammered the strip home with a block of wood. When everything cured the new strip was about 5mm proud of the rest of the gunwale and of course everything was covered in dried epoxy. I used a spokeshave to cut everything flush and was amazed at the improvement. The slight unfair lumps where the inner gunwales were scarfed disappeared and the gluelines of the new piece were as good as the gunwales which had been heavily clamped up.
As a short break from the rest of the boat I decided to make the mast. To start with I glued up two 14' long yellow cedar 2x4s. They were both quite warped but luckily they apeared to have come from the same tree and matched perfectly. To start with the taper of the mast is layed out on one side and then this is cut. The taper is again layed out on the newly exposed side and this is cut again resulting in a tapered square cross section with the side length equal to the desired diameter of the mast at each point. In laying out the tapers it is possible to correct for some bend in the wood and I managed to get a nice straight mast out of my warped wood. From the square form the mast must be planed to a octagonal cross section. To lay this out I used a bit of wood with 2 nails and 2 pencils in a 1:1.41:1 spacing ratio and the distance between the nails slightly more than the maximum width of the mast. By holding the nails against the side of the mast theoretically one can easily mark out the lines to which the corners of the square cross section should be removed. This was much more fiddly in practice and it would have been just as easy to measure the ratios and use a batten to draw the lines (this is what I later did for the boom).
Shaping the mast was otherwise uneventful. Once 8 sided I went to 16 sided by eye, and 32 sided was pretty much round. After a little bit of sanding it was looking excellent. I left the mast octagonal below the partners (thwart that supports the mast), but I've since moved the partners much lower in the boat so I'll have to make a bit more of the mast round.
Making the boom was a bit more of an undertaking. I'd grabbed a couple douglas fir windfalls with the idea that I could use them for spars. Before they could be used I had to remove the sapwood (the outer layers of "living" wood which are weak and have poor rot resistance) and get them into some kind of square shape where the taper could be drawn in. I began by making one side flat with a broadaxe (broadhatchet, actually) which is a type of axe where one side is flat and the other side has the bevel ground into it. I started by flattening a small piece at one end of the log and then flattened additional small pieces along the log. To check the relative flatness I placed a straight 2' long piece of wood across the log at my reference end and at the area to be checked and by sighting along these could tell easily how close they were. Once all the areas were flat I flattened the space between them by eye. The process was repeated for the other side so that I could lay out the taper and run the whole thing through the bandsaw. If I were doing it again I think I'd probably just flatten one side and then cut the perpendicular edges on the bandsaw, then saw one taper and then saw the other taper. That would save me having to flatten the extra side by hand which is a lot of work. This whole process was significantly more work than the mast and if I had to do it again I would just buy a fir 2x4 which would be nicely seasoned, straight, clear and would cost about $30 (and that would be enough for both the boom and yard).
To hold the floorboards down I made some little wooden toggles. Getting them to fit was a bit fiddly but they seem to work quite well. I got around to plugging all the screw holes in the gunwales, floors, transom, knees, and whatnot - over 100 plugs in total. I found that the trick to cutting plugs freehand (without a drill press) is just to go at it firmly and, most importantly, at full power. After I'd cut a lot of good plugs I came back the next day to find that my plug cutter suddenly really didn't want to start the plugs without jumping around and when it did the plugs were all ragged on the edges. Close inspection revealed that the tips of the cutter were bent slightly. I think I must have bashed it against my vice when it jumped out of the wood. After some cleanup with a file and a little bit of honing on my waterstone (I used the side of them so as to keep the face nice and flat) it was as good as new. I also made some little triangular plugs to fill the gaps between the breasthook and the inner stem. After a good scraping, some sanding and rounding the edges of the thwarts I screwed them into place.
I decided that having the mast partners at gunwale height was ugly and would get in the way during use, since it effectively blocked off access ahead of the mast which could be troublesome during anchoring or such. My solution was to notch the partners into cleats mounted 2 planks down from the gunwale. I chose to notch the partners into the cleats to provide a direct bearing surface for any horizontal forces rather than relying on screws. The knees add further strength and look good too. I later realized that the mast partners are not actually structurally necessary (which I was wondering about a bit) due to the shrouds, but having them does make everythign a lot more solid looking and provides a good place to belay halyards. I wanted to drive screws for the knees up from underneath but because of the direction of the grain I couldn't do this in place. I had to carefully trace out where the knee would be and then drill the holes at the workbench. I'll probably have to use a ratchet to get them in since there is not a lot of clearance.
After lots of sanding I finally decided that the time had come to oil the inside of the boat. For this I used Deks Olja which is really easy to apply and easy to touch up. I ended up using an entire litre for the interior and had to buy another for the thwarts (and used that whole can too). I'm quite pleased with how the floorboards and hull look but I'm going to varnish the thwarts since they look a bit dull. I did, however, varnish the gunwales, transom and breasthook. After 4 coats they are starting to look really good and by the time they're done will be even nicer (they're supposed to have at least 7 coats). I think the paint I got for the exterior will look really good. I decided to go to cloverdale paint and got some dark green for the hull with a deep red for the shear strake. They didnt have the usual kind of base for the red so I got it custom tinted from a red base which apparently will cover much better. Turns out that BCAA members get really good discounts at cloverdale. I got over 30% off.
The rudder has a kick-up blade so that the rudder doesn't need to be unshipped when beaching the boat. The rudder is made up of many layers of plywood laminated together. The blade is 2 layers and the cheeks of the rudder head are also 2 layers so, along with the 2 layer spacer for the blade, the rudder head is 6 layers thick (about 40mm total). The tiller is attached to the rudder in such a way that by pivoting it upwards it can be slipped right off, yet while it is in position it has pretty much no play in any direction (other that upwards, obviously). To do this there is a big pin at the after end of the rudder which fits into a slot in the rudder head. The tiller then pivots downward on this pin and fits snugly against the foreward side of the rudder head. Finding pintles and gudgeons was rather challenging. I wanted to find some bronze ones since stainless steel doesn't really fit with the look of the boat. I stopped by west marine one day on the way home and they only had a limited selection of incredibly expensive stainless ones. I decided to check out The Bosun's Locker and was very impressed with their selection. They had stainless ones, aluminum ones and, amazingly, bronze ones! The biggest pintles they had were to fit a 1 inch thick rudder but since that appeared to be all that was available in town, I decided they would be quite adequate. To get them to fit I had to cut a dado into the rudder. Overall I don't think that that the narrower detract at all from the look and there is definitely still adequate strength (an inch of plywood...). Also, apparently silicon bronze bolts are not widely available at all. Bosun's locker had a small selection but not quite what I was looking for, so I went to capital iron where they had no bronze bolts at all (although they had a good selection of brass ones). Finally I went to Trotac thinking that no matter what they'd have them, but amazingly they had very little. I ended up finding an opened box of bolts that would work with some redrilling of the holes in the pintles, and they gave them to me for an incredibly cheap price.