Rethinking the rig

After a few more launches, I'd had it with the sprit rig. With the sail laced to the mast, the only way to reduce sail is to douse it by brailing, which causes lots of flapping and drag, and the brailing line gets fouled in various ways. Bringing down the sail means striking down the mast. The sprit is hard to tension properly (seems that I hung the snotter too high). But the worst problem is the difficulty of controlling the sail's shape without a boom, which makes tacking difficult, and the traveler I had to rig up for the mainsheet interferes with tiller and outboard. Adding a boom would solve some of these problems but would increase rig complexity.

So I thought about it and decided that a new rig would be a good idea, which suits my tinkerer's heart nicely (this will be the sixth rig for three boats). I had some good experiences with a standing lug rig with a sprit boom, if we discount the disaster involving the flimsy foremast of my cat ketch breaking in a stiff wind. Since the current mast is robust enough at a diameter of 75 mm (3 inches), I can concentrate on the pluses of the rig. Only three control lines (halyard, snotter, sheet), same as the sprit rig. Reefable and easier to deploy, not to mention take down. A sprit boom doesn't hit you on the head, needs no boom vang or gooseneck/jaws. And no fancy sheeting system is needed.

I took to pencil and paper and designed a new sail of roughly the same trapezoidal shape, but will need some cloth removed and some added to the existing one. There will be a small addition of square footage (up to about 112 square feet or 10.4 square meters) and the center of effort (COE) will be almost the same. My inspiration once again is John Welsford's Houdini and David Nichols' book on traditional sails for small boats. Regarding spars, I am simply shortening the existing sprit into the new boom, and making a very plain yard out of stock lumber.

I also decided to follow kind advice from the Wooden Boat Forum about the tiller. Between the sheet and the outboard, the existing tiller gets in the way. So I am replacing it with a Norwegian tiller, which runs at a right angle to the rudder, parallel withe the transom, and is controlled by a long pole with push-pull action. This will allow me to sit wherever I need to in the boat, and to use a simple 2:1 sheet tackle attached to the center of the transom top. The wood was cut to rough size and planed before I left; I will shape it and cut the mortises (one in the top of the rudder, one in the tiller's tenon for a wedge to keep it in place) when I get back to Greece.

I folded the sail into my carry-on bag and brought it back to California. I had plenty of leftover sailcloth but needed more luff tape and grommets. I also bought a sailmaker's palm for hand stitching but have not needed it yet. I was reminded that sewing a sail with a regular sewing machine is doable if a bit of a pain, and it's not worth my while to invest in anything more than heavy duty needles. The reconfigured sail is now (November 11) ready for next spring (the pandemic permitting). I will update readers with photos then.

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,

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