Flipped again

It took some more rework to get the centerboard to work smoothly: it was getting stuck on the way down. I had to remove the pivot bolt, to which I had foolishly added dabs of epoxy compound at the head and nut ends to seal the holes. It was a devil to remove, with the head getting badly stripped. A lot of sweat equity later, acquired while lying under the boat, I removed the CB and found that the forward end was rubbing against the CB trunk. After rasping a couple of millimeters off the right place and refinishing the  edge, I drilled out the pivot hole, filled it with epoxy, drilled through again, fitted a new bolt and problem solved finally.

The last touches involved leathering the oars and tying loops of line to fit over the thole pins (visible in the photo). Meanwhile my attempt to acquire a boat cover failed, like everything else involving people and purchases off the island in August: first the supplier was closed, then they called it was coming, then called again to say the warehouse was closed until the end of August, which will be too late. So I decided that storing a fully finished boat upside down should be safe, and I got three strong guys to help me lift the boat, remove the bricks and cradles, flip it and lay it on four bricks with styrofoam on top (photo, after touching up puttied holes with paint). This is where it will await my return in the spring. The registration paperwork I hope to complete before I leave, so I will have to get a trailer and hitch and finish the rigging, which is mercifully simple. With any luck I will launch it before next summer. Thanks for reading!

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.

Paint, centerboard and rudder

Once again, nail setting, puttying and sanding was followed by two epoxy coats on the decking. Three coats of white topside enamel later, the boat is gleaming and bright. I used a little paintable caulk to fill the edges of the decking purely for cosmetic reasons (the joints are solidly glued withe epoxy compound so no leaks are possible). I will need to sand the puttied holes and touch up the sheer strake paint on the outside.

For the centerboard and the rudder I calculated I needed about 6 kg (13.2 lbs) of lead weighting. I opted for lead shot which will be sandwiched between the two outer layers of each, placed in voids cut in the middle layer: a square of 30 cm a side for the CB (for 4.5 kg) and a 8.5 cm radius circle for the rudder (for 1.5 kg). The third photo shows the CB void packed with lead. In calculating the sizes I reckoned on a specific gravity of 11 for lead and a packing ratio of 78% for the little spheres (i.e. the voids between the little balls of lead will be about 22% of the space). I was a bit off and I had a little lead left over.

The fourth photo shows the top layer of the CB laid on with nails  and epoxy and weighed down with stones and a bag of cement. Nothing but the latest technology!

The last photo shows the two main parts of the rudder laminated from three layers. One of them is the pivoting bottom with its own lead ballast inside. I will need to put on the jaws and make a tiller. Both rudder and CB will be shaped hydrodynamically and finished with epoxy and varnish. More in the next post,

Backbone and frames

Well, the backbone is ready and it evokes the boat that will be. A small problem arose while I was joining the CB trunk to the the fore keel/stem: a measuring error meant that the tip of the stem is 20 mm lower than it should be. Given the strength of epoxy, taking the joint apart would destroy a lot of wood, so I could either do  a bodge and adjust things as I put on the sides, or rerun the design. I chose the latter, running the software with a small adjustment and coming up with new measurements for the long side pieces.  Fortunately I hadn't marked the pieces on the plywood, let alone cut them. By now I have transferred the dimensions and drawn the cut lines for two of the four pieces. Once all are cut it will be time to build the skeleton of the boat on a strongback, using the backbone and the frames. 

Speaking of frames, I have finished cutting them out of 12 mm and 8 mm plywood, as seen in the second photo. Only the fore and rear bulkheads and the transom are single pieces. The rest are attached to the CB trunk, or are parts of the seat framing, or in the case of the flimsiest pair, will be a temporary frame.

Slow progress

Last weekend I sanded the masts smooth and tried them on again.  They really look good, but it's clear if you look closely that they were not precision-cut on a lathe.  I prefer the hand-hewn look anyway, it has my handiwork all over it.  I will need to sand them with fine grit and epoxy them, but I will do that as part of a big coating push later.  I also cut the hole for the inspection port in the foredeck (next to the mast hole) and began sanding the decking. 

In preparation for further work on the insides of the boat, and for selling the old trailer, I moved the boat to a cradle I built out of the original building frame long boards and some more lumber.  I won't have to stand on a stepladder and lean over a precariously balanced trailer to do what I need to do any more.  Now that the weather is warmer (although not as warm as we had in the middle of March) I have moved all the tools and supplies back into the garage.

This weekend I cut the lumber pieces for the ballast box, drilled a hole in the centerboard for the pivot bolt, tried it in (it fits perfectly as per plan) and test-fitted all the ballast box pieces and the mizzen mast step, which sits at the aft end of the ballast box against frame 5.  I measured the size of the box and estimated how much lead shot it could take.  Turns out it's under 75 pounds.  Given the weight of the boat without the ballast, I decided that 50 pounds of lead shot is a good amount: it will help make the boat more stable without adding unnecessary weight.  And lead is not cheap anyway.

I also gave every part of the boat on the top and insides a good sanding, vacuumed up all the dust and shavings, and started putting in the epoxy fillets along the inside bottom seams and where the splashguards meet the fore and side decks.  In the coming week I hope to finish all that, build the ballast box, and perhaps carve the boat's name on the rubrails.  Then, after a final light sanding, I will be ready to put on the epoxy coats, and finally the paint and varnish.  It's good to be able to see the light at the end of the tunnel!

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Control surfaces

In the past four weeks I worked on the plans for spars and sails, but I also took advantage of the few and rare mild and dry days to work on building and finishing the control surfaces (rudder, tiller and centerboard—CB).  I call them control surfaces, even though I don't know if anyone else does, because of the aviation analogy: that's what rudder, ailerons, elevons, etc. are called in planes, and I used to build model planes years ago (as if more evidence of being a nerd and an "anorak" were needed).

Anyway, I designed and cut the tiller, which is made of cedar sandwiched between two layers of 6mm (1/4 inch) plywood.  The plywood extends beyond the cedar core to create the jaws that will enclose the top of the rudder, and the jaws themselves are reinforced with a layer of 9mm (3/8 inch) plywood on each side.  You can see the nice, curved shape that I cut: it brings the tip of the tiller down from the high transom top to a comfortable hand position, but high enough to clear the boat’s sides if necessary.  I will find out if I need a tiller extension after the launch.  And BTW, if you look carefully at the rudder you'll see a couple of holes drilled in error (pathetic, I know, but easily fixed with filleting compound).

 I also glued together the two layers that make up the rudder top and bottom and the centerboard.  Finally I did a lot of sanding on all the pieces, including putting rounded leading edges and tapered trailing edges on the CB (last photo) and rudder bottom, to reduce the drag they create as they flow through the water.

Then, as planned, I moved most of the tools and materials into the basement—the garage has got too cold for epoxy to cure, not to mention uncomfortable for the person doing the work.  The basement has no real ventilation in the winter (too cold to open the windows) and it lies under the dining room and kitchen of the house, so I have to be careful about fumes and dust.  I duct-taped a furnace filter to a box fan, which takes care of most of the dust, and I do whatever epoxy work I need in small batches with a respirator on and the fan at full blast.  So far things have worked out OK, and I will leave the coating of the spar surfaces until the spring.  Anyway, I am pleased to say that I am basically done with the rudder, tiller and centerboard.  They have been sanded and given two coats of epoxy; the rudder jaws were nailed and glued on, and the pivoting and fixed parts of the rudder drilled and bolted together.  The fit is pretty tight and some extra sanding was necessary: I will need to use some waterproof lubricant to make the pivoting smoother.  The tiller will be connected to the rudder top with a bolt (a clevis pin is standing in for now) that allows the tiller to pivot up when needed, and pintles and gudgeons were bolted and screwed in place.  

So the rudder is almost ready to use.  In the spring I will give it a couple of coats of spar varnish as well.  At that time I will attach the centerboard to its case with another bolt so it can pivot into the water—this will need to happen before I fill the ballast box with lead and lay down the floorboards.  Both rudder and CB will need bungee cords to keep them in the down position and cleated lines to pull them up.

Next I will be laminating and shaping the yards, working on the sails and starting on the masts.  All this will probably be after the holidays, and I’ll have about three months to do it before the weather allows me to go back to the garage to finish the boat.  With a lot of luck the boat will be launched on the first sunny, warm day of the season!

So merry Christmas, happy holidays and a great new year to all.  Check 176inches after the new year!

boatbuilder