Building Allie Kat
A Somes Sound 12 1/2
Planking
Sheer Clamps
The sheer clamps are constructed before the planking goes on and set aside for installation after the hull is turned right side up. They're made of Douglas Fir 5/8 x 1-7/8 x 18' long, two pieces on each side, laminated together. You just bend them around the molds and frames and tight against the stem and the transom, all at the sheer. When I did the dry fit with the first pair I heard a snap as I was bending them to the stem. Sure enough, I had a small crack in one of the boards near the bow end. I repaired the crack with TiteBond and swapped ends so that the crack was at the transom end which has a less demanding bend. But I also decided to try to soften the wood with steam before trying again.
I found a video posted by Master Shipwright Louis Sauzedde where he describes a technique for steaming wood in a plastic bag instead of in a steam box. I gave his technique a try and it worked great! After steaming for about an hour I bent the wood around the sheer and let it cool in place overnight. Then I took the boards outside to dry in the sun for a couple of days. There was a lot of spring back when it came off the boat, but I still felt confident that I would be able to get them bent tight to the stem for laminating without breaking. There's a link to Sauzedde's YouTube channel on my Tools and References page.
After the boards were dry I did another dry fit and had no problem pulling the sheer clamp tight. I used clamps at each station and a "Paddler's Hitch", which acts like a pulley system for creating a mechanical advantage, at the stem and the transom.
Note:
When you order lumber for the sheer clamps, consider ordering enough extra to make 2 or 4 faring battens (to be used while cutting out the planks). I managed with just two, but always worried about breaking one while prying them loose from the planking stock.
Remembering the cleanup chore with the laminated floors, I decided to forgo the plastic wrap method and put a plastic sheet under to catch the epoxy squeeze out. And I used packing tape to prevent sticking wherever the sheer clamp touched at the stations and the transom and the stem. There was still a lot of cleaning up, but I prefer wiping up the wet epoxy to scraping and planing after it hardens.
After the glue set, the new sheer clamps came off the boat and were stored in a long stairway that goes up to the loft over my garage/workshop.
Paddler's Hitch
More commonly known as a Trucker's Hitch. Use nylon cord with a smooth surface, such as paracord.
Start with the piece you're going to move. Tie a bowline, then loop it over itself to cinch tight on the moving piece.
Next, tie a knot making a loop in the cord – this loop is sometimes called the "pulley loop." An overhand knot here will work fine but I think a figure eight knot is easier to untie when done (there will be a lot of tension and the knot will cinch tight).
Continue the cord to a stationary anchor point and lead the cord so that it can move or run around the anchor.
Bring the cord back and thru the pulley loop.
Pull the cord tight and away from the piece you want to move. You will have a three-to-one mechanical advantage as you pull.
A simple half hitch at the pulley loop will hold tension securely.
Planking
It was fun watching the shape of the hull develop.
The planks are cut in pairs (port and starboard) from the three pairs of scarfed sapele plywood panels (approximately 2 feet by 16 feet) that I described in the "Getting Started" section – the plans specify which planks come from which panels.
The process of making a pattern in-place on a boat is called "spiling." There are a lot of ways of doing it – I used the compass and batten method. It is important to get the spilling batten draped over the molds and frames at the exact angle that the plank will lay. With a lapstrake boat, the spiling batten must extend up the bevel of the adjoining (preceding) plank and down near the touch point on the mold – in other words, it has to be almost as wide as a plank. Simply tacking a narrow spiling batten to the molds won't work.
I added an additional step of cutting out a full-size pattern made out of pattern plywood for each plank pair.
I used a spiling batten and a large compass to start, giving me a close but not yet perfect shape in my pattern plank. With the pattern plank cut out and on the boat I was able to mark for small adjustments to ensure a perfect fit with the actual plank – errors/changes were mostly at the ends.
I used the circular-saw jig described in Brooks' book for cutting the planks and followed with the router and a pattern bit to get a smoothly finished edge. It is a noisy and very dusty process. I built a tent of plastic sheets over the work bench to try to contain the dust.
After the plank pairs are finally cut, each one (port and starboard) goes on the boat for three fits. The first dry-fit to mark the dory gains at the stem and some planks need gains or shaping at the transom. Second, after the gains are cut another dry fit check; and holes are drilled for all of the screws. Then the plank goes back to the bench for tape and glue. I found that I only needed tape on the inside face of the plank, and also the inside and outside of the stem and transom. Then finally, on the third fit the plank is epoxied and screwed in place.
Tape is removed immediately after the squeezed out glue is cleaned up, before it hardens. The cleanup and tape removal can be done with the clamps in place.
Planks:
The garboard plank went on easily. Too easily it turned out (more on that later). There is a lot of twist in the garboard at the ends, but bronze screws hold the twist and the plank joined tight to the stem and the transom. The bronze screws are countersunk and they stay in the boat. Screws are also required to hold the garboards tight to the keelson – these screws will be removed after the epoxy sets because the garboards get planed flat before the keel is installed and the screws would be in the way. In an email question about something else, I mentioned to Brooks that I used steel screws here and he pointed out that sometimes screws break. And if a steel screw breaks you will have to perform surgery on your boat to remove it. If a stainless or bronze screw breaks it can be abandoned in the boat and epoxied over. He makes an excellent point – no more cheap screws in my boat.
Fitting the second plank gave me my first hint that something was wrong. The plank lay on the boat in a nice fair sweeping curve from stem to stern, but the plank was wide of the station 2 webframe by about a half inch. I could have forced it to close the gap, but that would have wrecked the fair curve and produced a knuckle in the board. I had no idea what was wrong. I left it floating above the frame planning to fill the gap next to the #2 webframe after the boat is turned right-side up.
The third plank was also wide of the station 2 webframe. I determined that the problem was that I didn't put enough taper on the plank landing spots on the stem (not sharp enough). The garboard should have had more twist and a sharper approach to the stem. The number 2 plank followed the garboard and that made it go wide at station 2. Once I cut a more aggressive taper at the stem, I was able to start closing the gap on the third plank, and the following planks all went on easily. The curve of the hull flattens out a little on the third and fourth plank because of the correction, but I don't think anyone will see it except for me.
There are three sets of scarfed plywood planking stock, two straight and one scarfed at an angle. Planks #3 and #4 come out of the angled board. I found there was just enough material left to get plank #5 out of the angled board too (it is scheduled for a straight board), which I did. It felt good to have some extra planking stock in case a do-over became necessary later. It turned out that I immediately needed the extra because I totally screwed up plank #6.
Up to #5, all of the planks had sweeping curves that eased or straightened a little at the ends. Then my pattern for plank #6 came out in a very subtle 'S' shape – the curve reversed itself. I refused to believe it. I moved the fairing battens until I had a sweeping curve with straight ends, just like all the previous planks. Big surprise; the plank didn't fit. I did it over, faithfully following my pattern, and it went on the boat nicely. Once on the boat you can't see the 'S' shape at all. All of the following planks had a little bit of the 'S' shape in them.
Dory Gains:
Dory gains were done by hand with a rabbeting plane. It went quickly and easily. In his book, Brooks offers plans to build a router jig for the job but I don't see how it would be worth the time or effort. Each gain takes only a few minutes to cut.
Plank Lap Bevels:
I built and used a magnetic lap-planing guide as described by Harry Bryan in his Wooden Boat article (there's a link to it on my Tools and References page). I added some double-sided sticky tape to keep the guide from slipping. It works.
Sheer Plank (A special case)
The Sheer Plank must fit to the sheer clamps which have already been made. And it controls or defines the sheer of the boat. There can't be rolling hills. When I laid out the fairing battens for the Sheer Plank I found the familiar "S" shape. This has to be wrong. Right? I took a long look at my sheer clamps - they are stiff and dead straight. There's no way I'm going to be able to bend them laterally first one way and then another to follow the "S". Plus, a look at the profile plans shows a nice fair sheer line. Also there is no twist in the sheer plank to add an unknown variable to how the plank will look and where it will go as it is bent around the curved hull.
This prompted me to remove the "S" shape from the sheer plank.
I started by putting a fairing batten on the boat at the sheer. I assigned the Stem, Transom, and Station 8 (halfway) as controlling (unmovable points). Then I ensured a smooth curve in the batten that looked right to me. I looked from every angle I could - then I nailed it in place. The only sheer point that moved more than a 1/8th inch was at station 2 - it moved about 1 inch away from the sheer. With the sheer edge of the sheer plank defined, I did the same process for the other edge producing a fair curve in the plank and a very gradual and small change in width.
I probably should have done this for each plank. My station 2 was problematic for almost every plank.
Plank Cutting and Installation Videos:
Notes:
The circular saw had no problem negotiating the gentle curves in the planks. It leaves a smooth edge and if the fairing battens were positioned properly, you could skip the router step and consider the planks finished. Fairing battens were held in place with brads - I pre-drilled the very hard sapele for the nails so that I would be able to pull them out.
For wetting-out, two pumps of epoxy is enough to wet both mating surfaces - leaves a little left over.
Six pumps makes just enough thickened epoxy - I mix two pumps at a time. Two scoops of wood flour and one of silica per pump of epoxy. I made my own scoop so can't give an exact volume, but it's easy to figure out.
I spread the thickened epoxy with a stir stick with one end clipped off, square. It was slow - I always thought there must be a better way, but couldn't think of one. My technique was to spread epoxy on the lower half of the preceding plank (boat upside-down) and the upper half of the new plank. This ensured good coverage to both edges, and overlap or double amount in the middle of the joint. I always had uniform squeeze out and never had a spot that seemed starved for epoxy. I think about half the epoxy I puttied onto the boat ended up in squeeze out. That's a big waste, but worth it because I'm confident in my joints.
Before doing any of the above, during the last dry-fit, I nailed brads into the frames and molds at the plank lower edge. I also made sure that frames 8 and 10 were clearly marked on both the new plank and the proceeding one. All of this was to ensure proper lineup on the first try - I didn't want to smear epoxy out the joint while struggling to get screws into pre-drilled holes that are covered in epoxy and impossible to see.
I cleaned squeeze out with a stir stick clipped square and sanded to a feather edge - like a small putty knife. Inside the boat I took a second sharpened stir stick to help left edges of the masking tape. Masking tape must come off before the glue hardens!
The process (without help) from mixing the first batch to the final clamp is about 40 minutes. It takes 7 minutes to clean squeeze out up on the outside and 15 minutes to clean squeeze out and remove tape on the inside.
Salad Tongs (Lapstrake Clamps)
Years ago while still only thinking about this project, I built special purpose lap clamps from a description I found on the internet. I can't find the article now so I can't give credit to whoever thought of it first. But these things work great!
In his book, Brooks recommends clamping the planks together for gluing by driving numerous screws through a batten that overlays and follows the plank lap. Since I already had these clamps made, I tried them instead. If you have enough of them you will get even clamping pressure and no holes to fill when you're done!
Consider making short, medium and long ones. For hardware you need a carriage bolt, a washer, and a plastic knob with an imbedded nut threaded for the carriage bolt. Most of these knobs come with a piece of plastic in the nut to add friction to keep the nut from backing off (such as on a lawnmower handle) – you don't want that! Being able to spin the knob and close the clamp quickly and easily is key to its usefulness.
Plastic tape on the working end will prevent the clamp from becoming a permanent part of the boat.
I built mine with rubber pads on the business ends to keep from marring the clamped planks, but the sapele is so hard the rubber pads weren't necessary. The 1/4th inch thick pads on my tongs didn't give quite enough clearance to completely clean squeezed out epoxy from under the clamp on the inside of the boat (I could get most, but not all). I think 3/8th inch would be better.
