Wooden Boat People
By McKenzieDriftBoat.com
Guy's Wooden Drift Boat Project
Hello Everyone,
My name is Guy and this is my first post in this forum. I am here because I want to build a wooden drift boat and, undoubtedly, I will occasionally need advice of the pool of experts and experienced drift boat builders on this forum.
In preparation for this project I have read and studied three books: Drift Boats and River Dories by R. L. Fletcher, Boatbuilding with Plywood by G. L. Witt, and Covering Wooden Boats with Fiberglass by A. H. Vaitses. I have also developed my own set of construction plans based off of the "Original McKenzie Double-Ender with Transom" in Fletcher's book. I used and MS Excel spreadsheet to calculate all of the dimensions, cut angles, compound angles, and bevel angles of all frame components and I used Pilot3D software to calculate the as-cut dimensions of the plywood sides and bottom. At this point I am pretty comfortable with the mechanics of construction and I think that I am just about ready to start purchasing lumber.
Presently, I plan to use Meranti Hydro-Tek plywood; 1/4-in. on the sides and 1/2-in. on the bottom. I found plenty of places to purchase these materials, but they are all far away from Idaho Falls, Idaho, and as a result shipping costs more than the materials. Are any of you aware of a business within a few hundred miles of Idaho Falls that sells this plywood? I have a few requests in to the local lumber companies, but I have yet to talk with someone who has heard of this material before.
I also plan to use Port Orford Cedar (CVG) for the straight frame sections and White Oak (quater sawn) for the bent frame sections (chine logs and sheer rails).
Thank you, Guy
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Replies to This Discussion
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Permalink Reply by Dave Z on
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I have used a piece of lexan. If only by accident! Now I continue to use it. Still put the wax paper down, but the lexan is ultra flat, and smashes any squeeze out real well. Nice work Guy, you are putting the time into this one. Make sure you get it done before the fish start to rise!
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Permalink Reply by Andrew on
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An Tungsten mentioned I used the "peel ply" technique in the first link, I am very pleased with the results.
Here are some pictures, although some of them may not do the finish justice. It is very glass for the most part, although there are some places where the resin cooled off a bit and I was not able to get out all the bubbles. I plan to go back and redo them to fill them in and sand them smooth.
The pictures should give you a bit of an idea of what the finish looks like. I used slow hardener and warmed it up to make if very flowable. The cooler it got the harder it was to get the bubbles out.
Andrew
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Permalink Reply by Guy Fredrickson on
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Thanks Andrew. What type of film did you use and where did you buy it? That's a great tip about using slow cure epoxy and starting with it warm.
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Permalink Reply by tungsten on
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Google Polyethylene Terephthalate, often referred to as PET film but commonly known as Polyester PET. copied from another forum.hope it helps.
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I have used both 0.030" and 0.020" PETg 4'x8' sheets which I cut down to 2' width.
The 0.020" thickness is the easier to work with. It is not as thick so the bubbles work out easier.
I got mine from Sabic Polymer Shapes, and they are about $12 per sheet. There US locations are here.
Sabic Polymer Shapes they also sell UHMW as well.
You may be able to use lexan sheets that you can get at Lowe's or HD, but you may have to do some tests.
I kept my epoxy warm but putting the mixing cup in a bath of hot water, but pretty much anything would work.
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Thanks Andrew and thanks Tungsten.
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I got the side panels cut to size. Now I am going to start on the bottom panels. This picture shows the two panels clamped together ready for the long cut along the sheer line.
And here are the two side panels laid out side-by-side. Shown are the inside surfaces that will be glassed and epoxied before attaching to the frames. The locations of the frames are marked with heavy pencil lines, which will be covered later by the frames. I should receive the fiberglass supplies this week.
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The bottom of my boat is made from four 1/2-in. plywood panels. There are two scarf joints to make two long panels from the four panels. These two long panels will run the length of the boat with a butt-joint down the center (and a cedar backing-board above the butt joint). I got one set of panels epoxied tonight. Here are some pictures. Here is one of the panels in the scarf jig.
As before with the 1/4-in. plywood, some finish sanding is necessary to make a good scarf joint.
Here are the two panels dry fit before epoxying.
Here are the two panels clamped together with the epoxy applied. I'll epoxy the second set tomorrow. Then these will be set to the side until after the side panels are on the frames.
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Here is another series of pictures showing the scarf assembly on the 1/2-in. plywood.
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Lessons Learned: Scarf Joints
I now have 35 scarf joints under my belt (two I had to redo) and this is what I have learned.
I spent a lot of time contemplating how I was going to cut the scarfs. I wound up using the table saw for the narrow oak boards (3/4-in. by 2-in. and ¾-in. by 2-1/2-in.). And I used a router scarf jig for the wider cedar boards (3/4-in. by 3-1/2-in.) and the marine plywood (1/4-in. and ½-in.). Both the table saw and the router jig worked well, but if I had to do it over again, I would use the router jig for everything.
The router jig that I build is probably about as simple as a router jig gets. But it absolutely relied on having a flat and solid work table underneath it. For the work table, I used two saw horses and parts of the packing crate used to deliver the plywood to my house. And I used a sheet of the ½-in. marine plywood as the surface. As you can see in my photos, I had two such tables. These two work table (although temporary) made my life much easier.
When cutting the scarfs on the router jig, it is my opinion that it is best to go back and forth across the entire width of the lumber and work your way from the top (shallow cut) to the bottom (deep cut). And it is good advice to get comfortable (e.g., eye and ear protection) and to take your time. For example, scarfing the ½-in. plywood probably took about 15 minutes.
The one real surprise with cutting the scarfs was that neither the table saw nor the router jig produced, in themselves, adequate joints. Both scarf cuts required additional work to make them true. But this was easy enough to do with a sanding block and a straight edge as I described in earlier posts.
So the bottom line is that it is important to take your time and make sure that your two mating scarf joint surfaces have equal dimensions and are flat and square with the edges of the lumber.
I also noticed that I tended to overlap the mating surfaces a little too much. Once I caught on to this, I would dry fit the scarf joint and then pull them apart about a 1/16th or a 1/8th of an inch and then mark the location lines. This seemed to help.
My plan is to paint the outside of the boat. I will probably leave the inside walls with a wood finish; but I will paint the inside bottom of the boat as well. (Of course, all of the wood is fiberglassed and/or epoxy encapsulated.) If you want to make a scarf joint on plywood that will have a wood finish, then you probably do not want to add the microfibers to the epoxy in the scarf joint. The microfibers give the epoxy a milky white color and this will show itself in the final scarf seem.
For clamping the plywood, I found that putting a wide board (but not too thick) and sandbags above the joint worked well.
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Finally... the "perfect" scarf joint. Of course, it's the last one needed for this boat. But for a brief time, I experienced the Zen of scarf joining...
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Permalink Reply by Phillip Westendorf on
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Guy,
Was a great posting on scarfing plywood sheets. Thanks for doing good documentation and the summary at the end. Thanks also to Andrew and Tungsten for their input too.
Looking forward to more.
phil w.
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