Wooden Boat People
By McKenzieDriftBoat.com
Caulk no gue
All wood Boats
I built my first framed oat in 1979. I built a half a dozen or so more framed boats before plunging into wood/fiberglass composite construction, as per an article about Dynamite Payson's work in Wooden Boat magazine.
After that I spent close to 35 years building all fiberglass and wood/fiberglass boats. I'm retired now and I find myself interested in ail wood boats again. Before I jump into what I am doing now a few background, big-picture words about framed boat building might help.
My good friend A.J. DeRosa of http://woodboattours.com keeps a remuda of a dozen or more framed boats going at all times, including a few 20' foot six passenger big boys designed by Cyrus Happy of Ray's River Dories. Aj's greatest contribution, for me, was all about trading oil for paints and varnishes. Perpetually cracking paint and varnish jobs were what drove me away from framed boats in the first place. Boat painting is arduous and exacting work requiring hours of preparation. Oil is easy. A mop attached to a long handle and a bucket of oil (there are recipes) is all it takes. It's easy to oil a boat twice or more every year. If you live in a dry Rocky Mountain climate it's the only way to go. Oregon might be a slightly different story.
Oil instead of paint helps make the framed boater's life easier to manage but there are other problems. Wooden boats do get broken. Bottom panels do get water-logged, fractured and rotten. Framed boats are traditionally glued together as they are built, in conjunction with wood screws and/or ring-shanked nails. When it comes time to remove and replace a bottom panel it's almost impossible without damaging the ribs that panel was glued to. Side panels are even worse, especially so if the gunwales were glued in place, which they often are.
Worn out bottom panels on framed boats have been a problem for a long time. Builders have tried to solve that problem with skid shoes, which are plastic or sacrificial plywood panels screwed on over the glued-in-place bottom panel. All those screws inevitably cause more trouble than they are worth however. 50 screw holes poking into the bottom panel dramatically accelerates the overall deterioration process.
There is a better way. I have been experimenting with a new idea. I am close to finishing a big decked white water dory now using almost no glue at all.
DIY all wood and plywood drift boats can be put together without glue. When everything goes together with Torx screws and marine grade silicone caulk, any major or minor part of the boat can be removed or swapped out at any time. You can build a traditional framed boat the old way, changing nothing other than the bonding material. Instead of glue use hot-rod caulk instead. Traditional kitchen and bathroom silicone caulk is pretty good stuff. It is acetic acid based, which gives it a characteristic nose tingling smell. Marine silicone has no smell, and for reasons I do not in any way chemically understand it makes a substantially stronger bond as well. Marine silicone also has a long ope time which is just what the DIY boat builder ordered. Marine silicone bonds are almost as strong as the wood itself. Almost but not quite. Epoxies and Tightbond glues do make a bond as strong as the wood itself, and therein lies the problem. With Tightbond or epoxy you cannot take two wooden components apart without major collateral damage. Prying wooden parts apart that have been bonded with marine silicone is not easy. But it is possible, without collateral damage of any kind.
All of a sudden worn out bottom panels are no longer a big problem. Back out a bunch of screws and pry that bottom panel off. Then replace it. Wooden boat parts joined with marine silicone are not easy to get apart. Pry bars, chisels and magic cuss words are part of the process. But it can be done, without damaging the parts that were originally joined. In that sense you can think of marine silicone as moderately strong glue--almost as strong as the surrounding wood. But not quite as strong.
If you want to build all wood consider giving up glue and use caulk instead. I use Dowsil 795. There are other brands. Dowsil is good stuff. I buy it by the case now. The following boat does have a molded fiberglass bottom but everything else is wood above that. And caulked instead of glued. The molded bottom was a waste of time. Now that I see how easy it is to swap out major components, I think I'm done with fiberglass forever.
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Replies to This Discussion
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Permalink Reply by Sandy Pittendrigh on
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The only glue (above the bottom shoe) is in the gluelaminated gunwales, which are made from 7 layers of random length 1/4" thick ash, 2-1/2 inches tall. I wish I'd made them 3" tall. Glue-lam gunwales sure are stiff.
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I posted the above photo on Facebook group where members talk about white water dories. One guy complained my rower's foot well didn't look wide enough. He may well be right. I doubt it. This is my second decked boat and the first one is fine, with the same sized foot well.
But even if he is or was right, this aptly demonstrates the value of medium-strength glue construction. If it turned out I needed to make a wider foot well it's no big deal. My deck fastens down with wire clamps, over a 2" thick foam gasket. So would pop the deck off, turn it over and back out all the Torx screws that hold the foot well tight to the bottom of the deck. Take if off and build a new one.
If, on the other hand, the deck had been glued in place, semi-permanently, as most Grand Canyon dories are made, making any modifications below deck becomes a nightmare. Now it's easy.
So that guy's criticisms don't hold water.
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Permalink Reply by Bennett Yarbrough on
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Sandy, I love seeing your ideas on the various websites come to life. Is this the boat with a glass floor/tub with ply bolted on for sides? As far as not too sticky glue, is there any concern of it removing itself in a bad wreck or is that where the screws come in? Please keep the photos coming, I enjoy your ideas!
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Yes to all those questions. I started this boat in 2019 and then got hit by a pallet of bricks falling off a crane. Otherwise known as Covid 19. It's three years later and I am finally back to where I can work again. I"m about a month from rowing, but still 2000 miles from my shop. Enjoying ideal snow conditions in South Texas. Chasing redfish.
This boat does have a molded fiberglass bottom, bolted to 3/8" Hydrotek sides. I thought it was a good idea and indeed maybe it is. But it is tits on a bull too. I got started on this boat before I realized the implications. If a wooden bottom panel can be made easy to remove and replace, then the molded fiberglass bottom was a complete waste of time. It was a of work.
And yes. Dowsil 795 is very good caulk making a strong bond. But by itself it is not enough. Mechanical fasteners and marine silicone together make it all work. I have made a few mistakes in this build. Everything about it is new. To me anyway. I've had to remove a few parts and rework them. And I can tell it is not easy. Marine silicone bonds and grips like a starving monkey. But it is also just barely weak enough to let go BEFORE any surrounding wood breaks too. That's what makes it work.
Most white water boats have a fixed deck. This one has a clamp down deck, clamping down over a thick foam gasket. This is the second boat I've built with a removable deck. That is one idea that panned out. A removable deck makes getting camping gear out of the boat a lot easier. And hull maintenance easier too.
I'm starting to think all boats should be decked. Decked fishing boats could be lower, which makes them easier to get onto and off of. And not wind sails. And yet still capable of big water. Low but decked makes a better white water boat than any open boat. I'm looking forward to Yankee Jim Canyon on the Yellowstone, and the Beartrap on the Madison.
This will be an epic runoff year on the Green too. I hope a cancellation gives me yet one more trip in Desolation Canyon. Especially this year. Oh boy it is going to be big.
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