Centerboard, rudder and spars

Since the boat is right side up, I had to lift it off the ground by at least 45 cm (18") to fit the CB and put it in place when it was fully finished. I did it with the help of two people and several bricks (first photo). The CB pivots around a 6 mm (1/4 inch) bolt. The rudder needed a pivot bolt of its own so it can be lifted with a line. Gudgeons and pintles attach it to the transom. The tiller I made from pine lumber, and its jaws from two 12 mm pieces of plywood. There is a pivot bolt attaching the tiller to the rudder top, so the tiller can move up and down as needed, especially with the outboard I plan  to use.

Sandwiching lead shot inside the centerboard without mixing it with glue proved very ill-advised. The shot was small, and the gluing of the plywood layers was not tight enough, so the shot was swishing around inside.  I was force to prize the layers apart, not an easy thing given how strong epoxy is. Then I mixed the lead with latex caulk and reglued the CB. The result was an imperfect lamination that made the CB too thick to fit in the CB trunk without getting stuck. The next inevitable step was to use an electric planer to remove a couple of millimeters from one side of the CB. Not something I would recommend except in extremis. In any case, it was done with a lot of flying shavings and some gouging, but after sanding, a little puttying and more sanding the CB was ready for more work.

The work in question was fitting a block to a corner of the CB for raising and lowering it. It involved cutting a semi-circular piece off the top forward corner and chiseling channels for the two stainless steel straps that are bolted to the CB on one end and the sheave at the free end (photo). Both bolts had to be cut very short to fit inside the 24 mm-wide CB trunk. Another sheave is fitted on the corresponding corner of the CB trunk for the lifting/dropping line. Because of the extra 4.5 kg of ballast and its leverage, the fittings needed to be sturdy. The 2:1 purchase from the blocks helps. The CB was coated with epoxy but no paint or varnish, since it will be invisible and protected from UV rays. Fitting the CB into its trunk and putting in the pivot bolt were tough: imagine being on your back with a lead-weighted CB on your chest, under a boat on bricks that could come tumbling down on you, trying to thread a quarter-inch bolt through three holes that need to be precisely aligned. My wife watched over me just in case. I'm happy to say that the CB and its raising and dropping bock and tackle system were fitted well and work fine (third photo).

Before I finished assembling the CB block system, I made the spars. The mast I made from a 4 m long (13' 1") piece of fir, 75 mm (3 inches) square. As in previous times, I cut the corners off at 45 degrees (this time with a hand-operated rotary saw since I don't have a table saw) to make an octagon. I went surprisingly well. Then I used an electric planer and a palm sander to make the mast round. The sprit I made by laminating two 4 m long boards. I had to extend it to 4.3 m, which I did by gluing a lumber extension between two plywood jaws. The latter form a shallow slot for the snotter, the improbably named line that holds the sprit up and adjusts its tension. Planing and sanding turned the sprit approximately round too. Both spars are visible in the next photo.

Cutting the hull pieces, building the skeleton

One set of four long pieces (garboard, two middle strakes and sheer strake) marked and cut, with an extra 17 mm added to the width for the laspstrake overlap. The scarf joints definitely need smoothing, and some need strengthening too. The second set was easier because the pieces can just be copied, avoiding the arduous process of measuring, marking the reference points given by the software, hammering nails into the points, bending a piece of wood to the nails and marking the cut line, for each of the eight long edges. I helps that the curves are long and smooth, because gross errors in measurement show up easily by spoiling the curve. It only happened twice out of dozens of points I marked.

Then I built the skeleton of the boat. I cut a piece of 4x6 cm board to the right length, which comprises a strongback stretching between the transom and the fore bulkhead. This was secured on top of three sawhorses, flanked by boards on either side. The mid bulkhead and the rowing thwart bulkhead were nailed and glued on either side of the CB trunk. The transom is nailed and glued to the back of the keel/skeg. The aft and mid bulkhead and the frame at the middle of the side benches are supported by the sawhorses. One frame that will support the benches has two halves that are joined with boards. The transom and fore bulkhead are temporarily screwed to the ends of the strongback. One temporary frame attached to the strongback completed the skeleton. All frames are notched for the keel and the garboard cleats. The seat and sheer cleat notches will be cut as the side pieces are put on.

The next step will be to nail and glue the garboard to the skeleton. I tried it on for fit and it seems all right, but I will need to cut 6 mm off the edge where it abuts the CB trunk, which is 12 mm thicker than the keel. I am hoping to have the hull completed but not epoxied, primed or painted before I go away. The rest, including flipping the boat right side up and putting in benches and decking, will have to wait until next year.

Frame assembly

This past week was very productive.  The entire skeleton of the boat is basically ready.  There it is on the right.  I started with a lot of cutting and joining.  I ripped inwales and seat stringers (tricky angles) and scarfed them together to a full sixteen feet.  I also scarfed together the keelson.  I cut a seat stringer for the transom (extra tricky, since the transom is not vertical).  Then I butt-joined the seat risers that serve as a vertical frame.  I cut round holes for inspection ports in the middle of what will be buoyancy chambers.  I glued cleats along three of their sides, and cut notches in the fourth for the transverse frames.  All this gluing went well.  I test fit everything many times.  Then I nailed the risers to the sawhorses to make sure everything stayed square and level. 

Then came the time for more gluing.  The day was very hot, and the behavior of the epoxy took me by surprise, although I should have known better.  While I was trying to attach the transom (it was messy, fighting gravity the whole time), the first batch of mixed epoxy turned very hot and solidified in no time.  You see, epoxy resin and hardener mix in an exothermic reaction, the heat of which needs to dissipate.  On a hot day it doesn't happen.  So with the next batch I put the measuring cup in a bowl of ice-water and it worked a charm.  Anyway, the fore-end assembly and the transom are on, the centerboard case is attached, and some of the frames (first and third forward of the transom) have cleats glued on that strengthen their joint with the seat risers.

All this time I was working with a respirator on, because my daughter the sculptor kept insisting (she has worked with all kinds of toxic stuff) and I kept getting throat irritation every time I used epoxy anyway.  That was fine, but on a hot day it gets sweaty, the glasses get in the way, etc.  The final ignominy was that I got some epoxy in my hair, and it was very hard to remove.

Another problem came from working alone.  Attaching the centerboard case (which is pretty heavy) to two frames was very difficult.  Trying to put screws into oak requires pilot holes of perfect length and diameter, or the screws break or strip.  Got it done, though.  

The next step is to strengthen the frame-riser joints with epoxy fillets and short cleats, and put on the keelson, which I have test-fitted already.  Then, once I bevel the keelson, I will be ready to start putting on the boat's "skin".  More fun and games, starting with scarfing together plywood sheets into 16x4 foot pieces, measuring and cutting etc.

Till next time,
boatbuilder