Thursday, Sept. 30
Yesterday and today were spent moving along two unrelated projects.
I sanded all the filled holes yesterday, and refilled about a dozen places which I either missed or filled unsatisfactorily. Today I found that these refilled spots had failed to cure overnight. I think the catalyst I used was too old. I had no reason to think waiting longer would help the bad epoxy mixture to cure, so I scraped off the excess, sanded, and wiped the spots with acetone. Those will be potentially weaker spots, even when covered with fabric and epoxy, but there's nothing more I can do about it, and I don't think they will be much of an issue anyway.
Also today I rolled out the polyester fabric and cut pieces to cover the bottom and topsides. As if I wasn't already feeling stupid, it turns out I ordered one yard of fabric too little, so it won't reach the stern on the starboard side. I have enough offcut pieces to make up the difference, but I will have an overlap bump near the stern on the bottom and topside. I'll have to smooth that bump with filler and sanding. Extra work which would have been avoided if I had just ordered enough fabric. Even so I don't have enough to cover the rudder, so I'll have to order more.
I am ready to take the plunge and cover the bottom and sides with fabric set in epoxy. I want to do that whole job in one day because as long as epoxy is tacky I can add more and it will bond chemically. If I let it harden I would have to let it cure and sand it before adding any additional epoxy.
The other project is the sprit. Yesterday I marked and cut the taper, using the method I described in my last post, leaving it a tapered 4-sided stick. Today I marked it for 8-siding and planed it down to those marks. Then I 16-sided it by eye with a plane, continued to plane off any perceptible edges, and sanded it round. The job went more quickly than the mast did. The sprit is a smaller spar, and I had the comfort of having made the mast using the same method and skills, which I have not forgotten yet. All three spars are now ready to finish.
Finally, as I was cleaning up at the end of the day, the sailmaker called to let me know the sail is finished, so I'll try to also fit in a visit to the sail loft tomorrow.
Thursday, September 30, 2010
Tuesday, September 28, 2010
342 Holes Filled, and a Challenge for Readers
Tuesday, September 28
Two projects today: one mindless, the other definitely not.
I filled 342 screw holes, bolt holes, dings, joints and mistakes with epoxy putty. Yes, I counted. I had nothing better to do at the time. That was the mindless job. Tomorrow, when the filler is cured, I'll put on my respirator and sand them all down.
The other job was to calculate and mark the taper for the sprit. I did not have to invent a method; Howard Chapelle's Boatbuilding spells out how to do it. I enjoyed the challenge, and if you care to give it a try, see if you can follow his instructions and determine what the diameter of the sprit should be at intervals along its length. All you need is a piece of paper, a ruler, pencil and compass. Here are the plan specificatons, and Chapelle's instructions, reproduced here without permission, of course:
Sprit length 10'5"
Sprit diameter:
3/4" at sheet (aft) end
1 3/4" at 1/3 aft of mast
7/8" at fore end
(Fore end extends 10" forward of mast)
Two projects today: one mindless, the other definitely not.
I filled 342 screw holes, bolt holes, dings, joints and mistakes with epoxy putty. Yes, I counted. I had nothing better to do at the time. That was the mindless job. Tomorrow, when the filler is cured, I'll put on my respirator and sand them all down.
The other job was to calculate and mark the taper for the sprit. I did not have to invent a method; Howard Chapelle's Boatbuilding spells out how to do it. I enjoyed the challenge, and if you care to give it a try, see if you can follow his instructions and determine what the diameter of the sprit should be at intervals along its length. All you need is a piece of paper, a ruler, pencil and compass. Here are the plan specificatons, and Chapelle's instructions, reproduced here without permission, of course:
Sprit length 10'5"
Sprit diameter:
3/4" at sheet (aft) end
1 3/4" at 1/3 aft of mast
7/8" at fore end
(Fore end extends 10" forward of mast)
Monday, September 27, 2010
Last Thwart In, Starting on Exterior
Yesterday I permanently installed what I call 'thwart 3", to the aft of the centerboard trunk. I epoxied and screwed it in place, and although that thwart is hard to get in place past the frame against which it butts, the epoxy made it a little slippery, and the fit went smoothly. I screwed it down to the risers, and added screws through the frames and through the sides. That thwart, which is just about midship, provides almost all the lateral support for the boat's sides, holding it in its shape. All those screws will help make it a strong assembly, and I filled all gaps with epoxy to make it stronger yet.
The two thwarts sagged just a little when I put my weight on them, so I made wood blocks to screw under the thwarts and also screw into the ends of the centerboard trunk. I epoxied and screwed them into place, and now the thwarts are solidly rigid.
The only remaining installation inside the boat is the stern sheets (the seat at the stern), which doesn't support anything except the sailor, so the boat is now structurally complete. Rather than do the finish work inside, I decided to turn the boat over and finish the sides and bottom. Preparing to turn it over was a good occasion to clean up the work site, pulling out all the scrap pieces of wood which have accumulated under the boat and sweeping up a lot of sawdust and planer shavings. Also before turning her over, I trimmed the outer stem and the sternpost to their final heights. Here the boat is ready to turn over:
I turned her over with the help of Mrs. Strongback, whose dedicated work at the gym qualifies her for that name, though she'd deny it.
I braced the boat up high enough to work on, and sanded the entire exterior hull in preparation for filling, sanding, fairing and sanding before covering the exterior in fabric and epoxy. Here, she's ready for that next step, which I plan to tackle tomorrow:
After turning the boat over, I weighed it by weighing myself holding up each end. It's 184 pounds now. The centerboard will add 30 pounds, the rudder nd tiller probably a little less, and the rig probably 40 pounds. So around 300 pounds is what I'll end up with.
I 8-sided the little club spar, then sanded it round, or rather roundish, and notched the ends. It is ready to varnish, unless I decided to sand it more first. Finally today, I ran the sprit timber through the thickness planer repeatedly to get it to a smooth, square 1 3/4" thickness. tapering and rounding it will be a significant job, more than the club, but less than the mast.
The two thwarts sagged just a little when I put my weight on them, so I made wood blocks to screw under the thwarts and also screw into the ends of the centerboard trunk. I epoxied and screwed them into place, and now the thwarts are solidly rigid.
The only remaining installation inside the boat is the stern sheets (the seat at the stern), which doesn't support anything except the sailor, so the boat is now structurally complete. Rather than do the finish work inside, I decided to turn the boat over and finish the sides and bottom. Preparing to turn it over was a good occasion to clean up the work site, pulling out all the scrap pieces of wood which have accumulated under the boat and sweeping up a lot of sawdust and planer shavings. Also before turning her over, I trimmed the outer stem and the sternpost to their final heights. Here the boat is ready to turn over:
I braced the boat up high enough to work on, and sanded the entire exterior hull in preparation for filling, sanding, fairing and sanding before covering the exterior in fabric and epoxy. Here, she's ready for that next step, which I plan to tackle tomorrow:
After turning the boat over, I weighed it by weighing myself holding up each end. It's 184 pounds now. The centerboard will add 30 pounds, the rudder nd tiller probably a little less, and the rig probably 40 pounds. So around 300 pounds is what I'll end up with.
I 8-sided the little club spar, then sanded it round, or rather roundish, and notched the ends. It is ready to varnish, unless I decided to sand it more first. Finally today, I ran the sprit timber through the thickness planer repeatedly to get it to a smooth, square 1 3/4" thickness. tapering and rounding it will be a significant job, more than the club, but less than the mast.
Saturday, September 25, 2010
Centerboard Trunk Done/Complete/Installed/Finished
I started the day putting a third coat of paint on the centerboard trunk cap, in the darkened green color I finally settled on yesterday. Also, since this is the last chance to paint the undersides of the thwarts and see what I'm doing, I gave the undersides a coat of the same trim color paint.
Moving on to the boat itself, I painted the sides and frames adjoining the thwart locations, because they will be hard to reach after the thwarts are in.
While that paint dried, I started work on the small spars, the sprit and the club. The sprit is to be 10 1/2 feet long, with a maximum thickness of 1 3/4". That is an inconvenient thickness to find. I decided to laminate it of two nominal 2x spruce boards. At the fore end it should taper down to 7/8". and at the sheet end it is only to be 3/4" thick. Anyway, there was was quite a pile of rejected lumber at Home Depot before I had selected a 2x6 12' spruce board with straight grain and only small sound knots- an oversight on their part. I ripped two pieces 2" wide on the table saw, and glued them together with epoxy, clamping them to the still-extant strongback with all my clamps. Tomorrow or whenever, I will run the glued piece through the thickness planer to make one 1 3/4" square piece before marking and planing the tapers. With the offcut of the 2x6, I chose the best 4' section to make the club. The plans just say make it 4' long, with no details. I planed the piece to 15/16" square, then tapered it to a shy 3/4" square at the ends. I don't know if that is the right size. I just want it to be strong enough, but light weight in case it hits someone (i.e. me) in the head.
When these minor spars are made I need to set about finishing them as well as the mast. There will be several coats of varnish to apply. The weather pattern at this time of year is not good for varnishing: hot and sunny early, thunderstorms late, and humid all the time. I ought to try to find space indoors for it. I can always carry the spars outside for sanding between coats.
By the time I'd rough-cut the sprit and club, the paint was long since dried. I went ahead with final installation of the forward rowing thwart, gluing and screwing it in place. Then I could install the centerboard trunk. I applied a thick coat of epoxy to the keelson in the way of the centerboard trunk, and laid the trunk in place, sliding it forward into the notch in the thwart. I dropped two bolts into place to align the trunk, then climbed underneath and drove the other six bolts up through the bottom and the trunk logs. Then I pulled the first two bolts, drove them up from underneath, put washers and nuts on them all, and tightened the bolts down until there was epoxy squeezing out, both outside and in the slot. Cleaning up that excess, a good day's work was done. Tomorrow the after thwart can go in.
Moving on to the boat itself, I painted the sides and frames adjoining the thwart locations, because they will be hard to reach after the thwarts are in.
While that paint dried, I started work on the small spars, the sprit and the club. The sprit is to be 10 1/2 feet long, with a maximum thickness of 1 3/4". That is an inconvenient thickness to find. I decided to laminate it of two nominal 2x spruce boards. At the fore end it should taper down to 7/8". and at the sheet end it is only to be 3/4" thick. Anyway, there was was quite a pile of rejected lumber at Home Depot before I had selected a 2x6 12' spruce board with straight grain and only small sound knots- an oversight on their part. I ripped two pieces 2" wide on the table saw, and glued them together with epoxy, clamping them to the still-extant strongback with all my clamps. Tomorrow or whenever, I will run the glued piece through the thickness planer to make one 1 3/4" square piece before marking and planing the tapers. With the offcut of the 2x6, I chose the best 4' section to make the club. The plans just say make it 4' long, with no details. I planed the piece to 15/16" square, then tapered it to a shy 3/4" square at the ends. I don't know if that is the right size. I just want it to be strong enough, but light weight in case it hits someone (i.e. me) in the head.
When these minor spars are made I need to set about finishing them as well as the mast. There will be several coats of varnish to apply. The weather pattern at this time of year is not good for varnishing: hot and sunny early, thunderstorms late, and humid all the time. I ought to try to find space indoors for it. I can always carry the spars outside for sanding between coats.
By the time I'd rough-cut the sprit and club, the paint was long since dried. I went ahead with final installation of the forward rowing thwart, gluing and screwing it in place. Then I could install the centerboard trunk. I applied a thick coat of epoxy to the keelson in the way of the centerboard trunk, and laid the trunk in place, sliding it forward into the notch in the thwart. I dropped two bolts into place to align the trunk, then climbed underneath and drove the other six bolts up through the bottom and the trunk logs. Then I pulled the first two bolts, drove them up from underneath, put washers and nuts on them all, and tightened the bolts down until there was epoxy squeezing out, both outside and in the slot. Cleaning up that excess, a good day's work was done. Tomorrow the after thwart can go in.
Friday, September 24, 2010
Green Paint
From what I've been able to learn, phasing out and ultimately banning oil-based paint is on the EPA's agenda. The idea is that prolonged exposure to solvents can cause brain damage, which certainly gives me a Mulligan. The paint makers are working to develop acrylic paints which hold up as well as oil based paints and can be applied over old oil based paint. Anyway, for this boat I decided to get ahead of the curve and use the best acrylic (water-based, hence "green") paint I could.
There is a good Dyco paint store in my town, with knowledgeable people, and they tell me that acrylic paints dry fast but cure slowly, as long as a month. Their paints are not specifically for marine use, but they encouraged me to give them a try.
I bought a white semi gloss paint for the topsides, a light gray green for most of the inside, and a darker gray green for concrast color on the trim. I'll use red antifouling paint, which I already have, for the bottom, the centerboard and trunk inside, and the rudder below the waterline. When I first applied the light color to the risers, I was surprised that it looked almost white. Today I sanded and painted the centerboard trunk, and used the darker color on the cap. I decided that both colors are too light and that there is not enough contrast between them. So I took the paint back to the Dyco store today and had both colors darkened. After putting a second coat on the c.b. trunk (really does dry fast) I liked the lighter of the two colors but still wasn't satisfied with the amount of contrast. So I took the trim paint back to the store again. They started all over with a dark base, and insisted on not charging me for the new trim paint. Impressive: that will keep me going back to them. While I was out I also picked up a piece of spruce for the sprit and club spars.
So here is the centerboard trunk, with a swatch of the darker trim color just visible on the cap. I like the colors, which is important because I will to be looking at them a lot. Even more important, Mrs. Strongback likes them.
There is a good Dyco paint store in my town, with knowledgeable people, and they tell me that acrylic paints dry fast but cure slowly, as long as a month. Their paints are not specifically for marine use, but they encouraged me to give them a try.
I bought a white semi gloss paint for the topsides, a light gray green for most of the inside, and a darker gray green for concrast color on the trim. I'll use red antifouling paint, which I already have, for the bottom, the centerboard and trunk inside, and the rudder below the waterline. When I first applied the light color to the risers, I was surprised that it looked almost white. Today I sanded and painted the centerboard trunk, and used the darker color on the cap. I decided that both colors are too light and that there is not enough contrast between them. So I took the paint back to the Dyco store today and had both colors darkened. After putting a second coat on the c.b. trunk (really does dry fast) I liked the lighter of the two colors but still wasn't satisfied with the amount of contrast. So I took the trim paint back to the store again. They started all over with a dark base, and insisted on not charging me for the new trim paint. Impressive: that will keep me going back to them. While I was out I also picked up a piece of spruce for the sprit and club spars.
So here is the centerboard trunk, with a swatch of the darker trim color just visible on the cap. I like the colors, which is important because I will to be looking at them a lot. Even more important, Mrs. Strongback likes them.
Thursday, September 23, 2010
Fitting the Centerboard Trunk and Thwarts
Thursday, Sept. 23
After putting the trunk in place on the keelson this morning, I located the first bolt hole by tapping a bolt down through the log and rapping it to make a mark on the keelson. I drilled through the keelson, bottom and gripe, using a level to keep the drill straight up. After the first bolt was seated, I marked and drilled a second hole at the other end of the trunk. Since I was drilling 1/4" holes for 1/4" bolts, the holes (after the first one) needed to be in just the right place or they wouldn't fit. I was worried how that would go, needlessly. I put a rat tail file in the electric drill and reamed the hole out just a little, and the bolt dropped right in. The other six bolt holes went just as well. I'm using carriage bolts, which for final installation will be driven up from underneath, so I went under the boat and countersunk the bolt holes so the head of the bolts will seat below the gripe's surface level, and can be filled and faired later. To give myself a fore and aft reference for fitting the trunk when the thwarts are in, I marked the side of the trunk at the bottom, perpendicular to one bolt hole, and marked on the keelson at the same place.
When all the centerboard bolts were drilled, and the board was in place, it was finally time to cut the centerboard slot in the bottom. I have been putting that off on any pretext, because cutting a hole in the bottom of the boat is a thought which should make anyone uncomfortable. And any mistake would be hard to fix. To mark where to cut the slot, I could think of two approaches. I could mark where the outside of the centerboard trunk lies, and measure how far the slot is from the ends and sides; or I could go low-tech and tape a pencil to a long stick and reach down in the centerboard trunk and mark the slot outline. I did both. The measured marks lined up pretty well with the stick/pencil marks. Where they were off a little, I gave greater weight to the stick/pencil marks. But I was out of excuses: it was time to cut. Using the circular saw, I lined up the blade and the saw's reference mark with the cut line and gradually lowered the saw until it was flush with the keelson. Success: the saw blade was on the cut line. After cutting the fore and aft lines, I cut the ends with the jigsaw, and checked the hole by replacing the centerboard trunk. Not only looks OK, the saws had made clean cuts which will need very little trimming or sanding. A hole has never looked so good to me:
With the centerboard bolt hole reference marked, I could start to fit the trunk with the thwarts. I moved the trunk out of the way and screwed the forward thwart in place.
Using the refernce marks, I measured for the notch to cut in the thwart for the trunk, and made the cut with the jigsaw.
When the trunk was moved into the notch in the forward thwart and the bolt locations checked, I removed the thwart and the trunk and repeated the process with the thwart at the after end of the trunk. When the notch was cut in that thwart, I replaced the forward thwart and the trunk, and negotiated the after thwart into place. When the after thwart dropped into place, it was a happy moment. I had been worried that this assembly would be an impossible Chinese puzzle, like screwing three pieces together in both directions from the inside. In the event, the trunk and the thwarts fit together very well with little complaint.
For good measure, I hung the centerboard, just to see how it would look in place.
Although I'd already accomplished a lot today, there was still time left to take it all apart and sand and fair the outside of the centerboard trunk, in preparation for painting it. That will be easier before it is bolted in place and the thwarts are screwed down, putting some parts out of sight. For the same reason, I'll paint the underside of the thwarts before permanently attaching them, and the inside sides and frames before any of it.
After putting the trunk in place on the keelson this morning, I located the first bolt hole by tapping a bolt down through the log and rapping it to make a mark on the keelson. I drilled through the keelson, bottom and gripe, using a level to keep the drill straight up. After the first bolt was seated, I marked and drilled a second hole at the other end of the trunk. Since I was drilling 1/4" holes for 1/4" bolts, the holes (after the first one) needed to be in just the right place or they wouldn't fit. I was worried how that would go, needlessly. I put a rat tail file in the electric drill and reamed the hole out just a little, and the bolt dropped right in. The other six bolt holes went just as well. I'm using carriage bolts, which for final installation will be driven up from underneath, so I went under the boat and countersunk the bolt holes so the head of the bolts will seat below the gripe's surface level, and can be filled and faired later. To give myself a fore and aft reference for fitting the trunk when the thwarts are in, I marked the side of the trunk at the bottom, perpendicular to one bolt hole, and marked on the keelson at the same place.
When all the centerboard bolts were drilled, and the board was in place, it was finally time to cut the centerboard slot in the bottom. I have been putting that off on any pretext, because cutting a hole in the bottom of the boat is a thought which should make anyone uncomfortable. And any mistake would be hard to fix. To mark where to cut the slot, I could think of two approaches. I could mark where the outside of the centerboard trunk lies, and measure how far the slot is from the ends and sides; or I could go low-tech and tape a pencil to a long stick and reach down in the centerboard trunk and mark the slot outline. I did both. The measured marks lined up pretty well with the stick/pencil marks. Where they were off a little, I gave greater weight to the stick/pencil marks. But I was out of excuses: it was time to cut. Using the circular saw, I lined up the blade and the saw's reference mark with the cut line and gradually lowered the saw until it was flush with the keelson. Success: the saw blade was on the cut line. After cutting the fore and aft lines, I cut the ends with the jigsaw, and checked the hole by replacing the centerboard trunk. Not only looks OK, the saws had made clean cuts which will need very little trimming or sanding. A hole has never looked so good to me:
With the centerboard bolt hole reference marked, I could start to fit the trunk with the thwarts. I moved the trunk out of the way and screwed the forward thwart in place.
Using the refernce marks, I measured for the notch to cut in the thwart for the trunk, and made the cut with the jigsaw.
When the trunk was moved into the notch in the forward thwart and the bolt locations checked, I removed the thwart and the trunk and repeated the process with the thwart at the after end of the trunk. When the notch was cut in that thwart, I replaced the forward thwart and the trunk, and negotiated the after thwart into place. When the after thwart dropped into place, it was a happy moment. I had been worried that this assembly would be an impossible Chinese puzzle, like screwing three pieces together in both directions from the inside. In the event, the trunk and the thwarts fit together very well with little complaint.
For good measure, I hung the centerboard, just to see how it would look in place.
Although I'd already accomplished a lot today, there was still time left to take it all apart and sand and fair the outside of the centerboard trunk, in preparation for painting it. That will be easier before it is bolted in place and the thwarts are screwed down, putting some parts out of sight. For the same reason, I'll paint the underside of the thwarts before permanently attaching them, and the inside sides and frames before any of it.
Wednesday, September 22, 2010
How Will I Raise and Lower the Centerboard?
I received an anonymous comment asking how I will raise and lower the centerboard; a perceptive question. I've been asking myself the same thing, with no final solution. I'm open to suggestions.
The board weighs 19 pounds. It has a specific gravity something less than 1. In other words, it floats. I'm just guessing it will float on its own about halfway down, and will be no problem to raise and lower by hand, with no tackle required.
Two problems occur to me. The easy one is how to keep the board in place when I want it all the way up, or partly up? I drilled a hole near the top of the board, and will insert a wooden peg to hold the board all the way up. I'll hold the board partly up the traditional way, with a wedge.
The trickier problem comes from the fact that the board disappears completely below the top of the trunk by several inches when it is all the way down. Whether I will ever want the board down to its extreme limit depends on how the boat balances under sail. but if I do want it all the way down, how will I get it there, and how will I retrieve it once it is? I will have a stainless steel tang attached to the top of the board. I plan to attach a narrow shackle to the tang, holding a thimble with a spliced length of light line, making a pennant for the centerboard. When the board is up, giving the pennant a good pull back may give the board enough swinging momentum to drop all the way down. If not, I would need a push-stick. I will raise the board by pulling up on the pennant. I'm a little concerned whether the pennant might possibly get jammed in the trunk, but I don't think it will unless the tang can drop below the bottom of the boat.
Once the boat is built, if the board tends to float too high, I can experiment by clamping various weights to it, and then drill an appropriate sized hole in the board and fill it with lead.
If Anonymous or anyone else better ideas, this is a good time to speak up. Thanks for the question, Anonymous, and I'll report the results.
The board weighs 19 pounds. It has a specific gravity something less than 1. In other words, it floats. I'm just guessing it will float on its own about halfway down, and will be no problem to raise and lower by hand, with no tackle required.
Two problems occur to me. The easy one is how to keep the board in place when I want it all the way up, or partly up? I drilled a hole near the top of the board, and will insert a wooden peg to hold the board all the way up. I'll hold the board partly up the traditional way, with a wedge.
The trickier problem comes from the fact that the board disappears completely below the top of the trunk by several inches when it is all the way down. Whether I will ever want the board down to its extreme limit depends on how the boat balances under sail. but if I do want it all the way down, how will I get it there, and how will I retrieve it once it is? I will have a stainless steel tang attached to the top of the board. I plan to attach a narrow shackle to the tang, holding a thimble with a spliced length of light line, making a pennant for the centerboard. When the board is up, giving the pennant a good pull back may give the board enough swinging momentum to drop all the way down. If not, I would need a push-stick. I will raise the board by pulling up on the pennant. I'm a little concerned whether the pennant might possibly get jammed in the trunk, but I don't think it will unless the tang can drop below the bottom of the boat.
Once the boat is built, if the board tends to float too high, I can experiment by clamping various weights to it, and then drill an appropriate sized hole in the board and fill it with lead.
If Anonymous or anyone else better ideas, this is a good time to speak up. Thanks for the question, Anonymous, and I'll report the results.
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