For the last week, my Twitter feed (@sfriedscientist) has been overrun with pictures of half built canoes. Well, we finally finished the boat, so here is Bluegrass Blue Crab and the Southern Fried Scientist’s guide to building a plywood canoe on a graduate student budget.
If you live near the water, or want to live near the water, or just want people to think you live near the water, you need a boat. It doesn’t have to be much of a boat, just enough to get you, your beverage cooler, a few fishing poles, and a healthy disregard for personal safety out far enough that you can’t get twitter on your smart phone (about 4 miles offshore for Droid users, 600 yards for the iPhone). So why not build a canoe?
You need surprisingly few materials to build this boat. The entire body is made of two sheets of good, flexible exterior plywood (I used 1/4 inch Lauan plywood). A 2 by 4 and some nice scrap wood is fine for the fittings. This is a stitch and glue style boat, so you need zip ties, fiberglass tape, epoxy resin and hardener, wood flour or a putty system, and plenty of tarps, paintbrushes, and throwaway cups for mixing. You’ll also want spar varnish and a good exterior enamel paint. If you’re going to use screws or nails for anything, get them in brass, not steel. This method is simple, but not as easy as brewing beer.
Some fun terms you should know:
- Bow – the front of the boat
- Stern – the back of the boat
- Port – the left side of the boat, when facing the bow
- Starboard – the right side of the boat, when facing the bow
- Centerline – the middle of the boat, running bow to stern
- Athwart – perpendicular to the centerline
- Rubrail – a thin piece of wood that runs bow to stern along both sides of the boat to add strength
- Thwart – a thick piece of wood that runs athwart the middle of the boat to add strength
- Bresthook – a small piece of decking at the bow or stern
- Butt block – a piece of wood used to join two parts of the boat together
- Seat – it’s what you sit on
- Hull – it’s what does the floating
You need a few tools for this project, but nothing fancy. A jigsaw, drill, and orbital sander, plus paintbrushes for the resin and spreaders for the putty should be enough.
Start by measuring and cutting your panels. Stitch and glue is fairly forgiving, so minor variations won’t affect the final product. The important thing is to make sure all the pieces are symmetric.
Line the panels up and glue then down with epoxy and butt blocks. Let this cure the full amount of time recommended by your epoxy mix, usually at least over night. Put some weights (dive weights work great) down to keep pressure on the joints. Once they harden, it’ll feel like one piece of wood.
Now we get to the stitch part. Drill small holes in the panels near the edges and zip tie your panels together. Once you have it stitched together, cover the outside seams in duck tape to prevent the resin from dripping out.
Inside the canoe paint epoxy at every seam. Then spread the putty into the seams, making sure to keep it clean and smooth. Lay fiberglass tape along the seams and paint epoxy over it, throughly filling the fiberglass webbing.
Once the fiberglass is laid down, paint the entire interior with epoxy to seal the hull. Once that hardens, flip the boat over and lay down fiberglass and epoxy on the exterior seams as well.
Now is the time to add any fittings you’d like. I built a thwart and a seat, but you can leave the whole boat empty, too. After the epoxy cures, sand it. Then sand it some more. Then sand it again foor good measure.
Epoxy glue the rubrails on, carefully clamping as you go. I used homemade PVC clamps for two reasons. One, they’re cheap and numerous, and two, epoxy doesn’t stick to plastic, so they come off easily.
Remove the clamps, install the bresthooks, and you’re ready to paint.
The final product. The interior is coated with semi-gloss spar varnish, the exterior is painted with Duke Blue enamel paint. Rubrails are oak, bresthooks are birch. The thwart and seat are old 2 by 4’s and some left over plywood panels.
- Final cost of materials: $198
- Total Time: 21 hours
Does it float? Maiden voyage this afternoon. WhySharksMatter will be taking bets.
~Southern Fried Scientist