Working on skeg pattern

I only had about an hour available today, so not much boatbuilding got done. The weather wouldn't permit me to work outside, so I brought a skeg-sized panel of plywood on the floor inside and began to draw the outline for the skeg. Not much of a photo op, but anyway...

The skeg will be made like a sandwich, with 3/4" thick wood between two layers of 6mm plywood. That will give it a hefty 1 1/4" thickness, and I'll be able to screw into the solid 3/4" layer edgewise to make a secure fastening to the hull, besides the epoxy adhesive. Like the rest of the hull exterior, it will be fiberglassed.

Tomorrow promises to be good weather, but most of the skeg assembly will be inside work anyway.

Normative boatbuilding

Monday, Mar. 1: Not much time to work on the boat today, but a couple of things did get done.

I trimmed off the gripe where it had overlapped the bow. I was sorry to see that I had installed it just a little off center, so when it was trimmed even with the sides of the boat and the stem, it makes a wedge shape which is a little lopsided. Nothing to do about it, it won’t have any functional effect, and no one will see it unless they get under the boat. But I still don’t like it.

I also made a pattern for the top edge of the skeg, where it meets the boat’s bottom. As I mentioned yesterday, that pattern had to be made normatively, rather than positively: (Sorry, I couldn’t resist saying that. I had an economics professor who taught me that expression, and have never before had a chance to use it). I’ll make the skeg match up with the shape of the bottom as it should be, instead of how it is right now, under strain from some but not all of the structural pieces are already installed. The rest of the pattern for the skeg should be easy: the bottom edge is a straight line to where it intersects with the sternpost.

A tour boat came by about the time I was cleaning up the work site, and I could hear the guide on his loudspeaker. "That guy has been working on building a boat for a long while now. He's always out there." Hmm. I'm a tourist attraction, now?

First piece of the backbone made and attached

Sunday, Feb. 28: A beautiful Florida winter day. In the 40's at dawn, but 60 degrees by 10 o'clock, and I spent the afternoon working in a T-shirt for the first time since December.

Today's project was the first "keel" piece, the gripe which extends from the bow to about 9" past the aft end of the centerboard slot. The skeg will overlap it by those 9", and end right at the centerboard slot.

I made the gripe from a 1x6 nominal (really 3/4 x 5 7/16) piece of fir. I tapered it to 4" at the bow end, as the plans specify. Then I rounded off the outside edges with a router. The bottom does not have a whole lot of "rocker", curvature fore and aft, but the gripe starts at the place on the bottom where the curve is greatest. The bottom itself is only 6mm (scant 1/4") thick. So I was concerned how to bend the gripe along the bottom without screws ripping through at the aft end. My solution was to use 2 1/2" deck screws at the aft end, and screwed throuth the gripe, the bottom, and a temporary piece of 2x4 inside. That held the aft end secure. The long screws will be removed after the epoxy cures. I left the forward end of the gripe long, and pulled it down to the bottom with a piece of line lashed to the strongback, which you can just see in the picture. Once I was satisfied with the dry fit, I took the assembly apart, aplied epoxy and replaced the screws and lashings. When I install the keelson inside the boat, I will screw the gripe and keelson together . But for now I wanted the gripe to get a good epoxy bond to the bottom. So I climbed underneath and drove about a dozen small bronze screws up through the bottom into the gripe, to draw it up tight so epoxy started to squeeze out the sides. Wiping off the excess epoxy into a nice fillet completed the job. The only thing remaining will be to trim off the bow overhang.

I don't plan to cut the centerboard slot until the keelson is installed inside. Then I can cut the hole in all the pieces at the same time.

Several forces are trying to distort the hull at this stage. The chines are bent to follow the curve of the bottom, and the bottom itself is bent to its required shape, as is the gripe. Bent pieces like that will eventually get used to their shape, at least somewhat. Meanwhile they try to straighten out. The keelson inside will add to that effect. The net result is the hull is trying to flatten itself out fore and aft, which would pull the sides inward. The sides resist that pull now because of the molds the hull is resting on. But even now I can see the center of the bottom is down a little compared with the sides. When I take the hull off the molds, I will have to put in temporary cross braces to maintain the right hull width until the permanent thwarts, which will hold the sides out, are installed. But the other thing I can do to strengthen the boat fore and aft is to make the bottom of the centerboard trunk follow the design's curve, instead of following the stressed shape of the bottom. And I will also make a pattern for the designed curve for the skeg, for the same reason. Cutting the slot for the centerboard will itself help ease the stress, since that will allow the gripe and keelson to bend more easily.

OK, I realize this is more on the subject than anyone wants to read about, but bear with me: it helps me think through the next steps.

The very next step: the skeg.

Hull shell complete

Friday, Feb. 26: Another chilly morning. What happened to global warming?

I trimmed the bottom panel excess where it overlapped the sides, using a jigsaw, then an electric plane, and then a belt sander. I dinged the sides in just a couple of places with the power tools, but those spots will easily be filled and sanded later.
Finally, I hand sanded to ease the sharp edge at the chine.

So the shell of the hull is complete. Just for fun, I measured the length. I say just for fun, because it is what it is. Anyway, it measures just 1/8” longer than the plan. Plenty close enough.

I also trimmed the centerboard to its final shape and rounded the corners. And I was delighted to finally catch the designer in a mistake. He shows the forward lower corner of the centerboard, by the pivot pin, with a curve of about 2” radius. If I built it that way, when the board is lowered that corner would surely swing forward enough to bind against the front of the centerboard trunk. And it would be the devil’s own job to fix after the boat is built. So I rounded that corner using the pivot pin point as the center of the radius. I still need to taper the edges of the board and cover it with fiberglass. I have not figured out yet what gear, if any, will be required to pull the board back up from a full down position. The plans don’t show anything for that. A rope lanyard would do the trick; the only difficulty might be the rope jamming in the centerboard trunk.

I carefully drew a centerline on the bottom, and marked off where the centerboard slot will be. I also marked the six design cross section stations on the bottom and sides. I will need those reference points when working inside the boat.

Next up: build and install the gripe (plank along the bottom) and skeg. And may lightning strike me if I make any jokes about the word gripe.

Bottom on and centerboard progress

Thursday, Feb. 25: Today was sunny, but windy and cold. No good for cycling, but OK for boatbuilding.

I epoxied the bottom panel in place, and screwed it down permanently. That was the easy part. Then I climbed underneath and cleaned off excess epoxy inside. That was messy and awkward, but also necessary. Sanding off the excess after the boat is turned right side up would be time consuming.

Epoxy makes an extremely strong adhesive, and it fills any gaps between the pieces being glued. The technique is to wet out both surfaces with unthickened epoxy, then coat one surface with a paste made with epoxy and a thickening powder, mixed to about the consistency of peanut butter. The two pieces are screwed or lightly clamped together, and left until the epoxy cures. In cold weather epoxy sets up slowly. That allows me time to get a job done, but it also means that I can not do more than one step a day on an epoxied piece. Other epoxy mixtures can be made for sealing bare wood, filling holes, mounting hardware, and fairing surfaces. Every problem in life can be solved with epoxy. Well, almost every problem.

I also worked on the centerboard today. Using the pattern I made yesterday, I cut out two pieces of 12mm plywood to the shape of the centerboard, epoxied the two pieces together, and left them weighted down for the epoxy to cure.

Tomorrow I plan to trim off the excess of the bottom panel. Then the shell of the hull will be complete. If I put it in the water, it would float, but there is a long way to go before I would call it a boat, or put it in the water.

From this point, the project can take several paths. Before the exterior is done, I need to make and install the outer stem, the sternpost, the skeg, and the “gripe”, a keel plank along the centerline from the bow back to behind the centerboard trunk. And the slot for the centerboard needs to be cut. And the whole exterior needs to be covered with fabric and epoxy. After that I can turn the boat over and work on the inside. I need to review the boat’s plans and work out the best sequence of tasks.

I have sent inquiries to a number of sailmakers, and have already received back a wide range of suggestions and quotes. I won’t make a decision on a sail right away. I will be travelling from late April until July or August. There is no deadline on finishing the boat; Of course I would like to have her as far along as possible before leaving, but I won’t be sailing her by then; that’s for sure.

Starting on the centerboard

I now have the bronze screws needed, but I couldn't epoxy and screw down the bottom panel today because of rain.

Once the bottom is on, the next step will be to cut the slot for the centerboard. I will make the board by laminating two sheets of 12mm plywood. but it will also be fiberglassed, so I don't really know how thick it will be, and how wide the slot in the bottom should be. So I spent the afternoon drawing the centerboard trunk and centerboard full scale, and making a pattern for the centerboard. If weather permits tomorrow, I'll attach the bottom and cut out the centerboard.

Bottom's Up

Monday, February 22: Work was held up by a short trip out of town, but I have made the bottom panel and have it ready to permanently install.

The bottom is just under four feet wide, so one plywood sheet reaches across, but the bottom is 13’ long, so I had planned to make it out of two lengths of plywood. But looking at the plans carefully I realized that the joint between two bottom pieces would be in the middle of the centerboard trunk. It would be hard to fit the centerboard trunk parts around the butt strap on the inside of the bottom, so in the end I decided to make the bottom of three pieces. One eight-footer in the middle and shorter pieces at the bow and the stern.

Last Thursday I cut out the three bottom pieces. Friday morning I laid out the pieces indoors, made 4 ½” butt straps to join the pieces, and glued them up with epoxy. After a couple of hours the epoxy was set up enough that I could clean up what squeezed out the sides, but I left weights on the butt joints while we went away for a three day weekend.

On our return home this afternoon I took the assembled bottom panel outside, put it in place, and secured it with a handful of screws. I have ordered a resupply of screws, and must wait for their delivery before I can epoxy and screw the bottom in place.