Building a flat bottomed canoe

[troy2000]

I'm building a canoe with my younger son as a summer project, before he goes into the Army this fall.

Warning: following the steps and procedures in this thread is no guarantee of success, and your experience and results may vary markedly from those shown below.

Step 1: go get some wood.

You don't need much; 32 feet of 1 x 12 will do the sides, and 1 sheet of 3/8" plywood will do the bottom. For the frames, stem, transom and miscellaneous, we're using stuff we have laying around. Of course, we probably have more stuff laying around than the average city dweller would....

The sides will be pine. It would be nice to do the Cajun thing and use cypress, but this is California. For what it would cost me to run down cypress boards, I could probably migrate to Louisiana, buy a house, and have enought left over for the cypress. Since the canoe will spend most of its life upside down on a pair of sawhorses anyway, I think the pine will do fine as long it's kept painted.

We bought two 12-footers and an 8-footer, because no one in this area stocks 16-foot 1 x 12's. That means we'll be scarphing 4 feet onto the stern end of each side. For the bottom we picked up a sheet of 3/8" BC pine; it was only about twenty bucks.

Step 2: prepare the worksite, and collect your tools.

All my tools were behind the rental on the opposite corner of our place, where my parents and nephew used to live. Unfortunately, there's no power there right now. So the new workshop became a shade tree we could reach with power cords from our house.

Why there? Because that's about where the two of us ran out of steam, while moving my 400-lb thickness planer. In the middle of taking a breather we looked around and said, 'you know what? There's shade here....'

Step 3: make sure you have a reliable power source.

Step 4: plane the side planks to make the boat lighter, and make them easier to bend. We took them down from 3/4" to 9/16", and decided not to push our luck any farther.

The plank leaning to the left is an old piece of red oak. We ran it through a few times to make sure the planer still worked, and to shake some dust and rust off the blades. I was also thinking of using it to make the transom, but it turned out some bugs were already using it for a home. Ah well, it would've added weight anyway.

Step 5: well, there really hasn't been one yet. We moved a work table, table saw, jointer, power miter saw and some miscellaneous tools under the trees. I started making a jig so we could cut the scarfs with a router, but ran out of daylight and ambition at about the same time.

 

[troy2000]

OK, step 5: build a simple scarphing jig, with sides tapered from a 2 x 4 and a plywood bottom; screw it to the table; make some sort of slide for the router. Taper the ends of the 1 x 12's.

A lot of people route the wood a little at a time--either by readjusting the depth of the router, or by moving the wood a step at a time. But I'm not that ambitious. Since we had a good carbide bit and we were routing soft wood, we set the wood, set the router depth, and did it. Of course, I did a pass along the end and the sides first, to reduce splintering, and took small bites. On the first one we started at the top and worked towards the bottom, and it made a mess of shavings. On the rest we got smart and started at the end first, and all the shavings went under the slide and off the table.

Sep 6: glue the scarphs. We used Gorilla Glue per the instructions: a thin layer on one side and let it set for a few minutes; dampen the other side with water. For clamping pressure we used wood screws and blocks of wood. And we used plastic bags to keep the glue off the table and the blocks. Then we let everything set overnight.

 

[lewisboats]

Hey...! Where's the hair?

Like that jig though but NOT a fan of Gorilla Glue. Too many reports of failure and my my...the cost!

 

[hoytedow]

I would not use Gorilla glue, but epoxy, for the scarf joint, though Gorilla glue has its uses. This is not one of them. I prefer the pine over cypress as well, having used both. Although cypress has some very good qualities, such as screw-holding. But cypress weighs 45# vs 25# for spruce or white pine(per cubic foot). I admire the craftsmanship.

 

[troy2000]

Hey...! Where's the hair?

Like that jig though but NOT a fan of Gorilla Glue. Too many reports of failure and my my...the cost!

The hair comes and goes, depending on when I get around to a barber shop. Sometimes it's a year or two, sometimes sooner....

Believe it or not, neither Grove Lumber, Lowes or Ace Hardware had any usable epoxy. Home Depot did, but it was a 50/50 mix, in pairs of little boutique-sized jars for $14.99.

I would not use Gorilla glue for that either, though it has its uses. This is not one of them. I like the pine over cypress as well, having used both. Although cypress has some very good qualities, such as screw-holding. But cypress weighs 45# vs 25# for spruce or white pine.

We'll see how the Gorilla Glue does. I've used it for this and that, including rifle stocks and furniture, and I've never had anything fall apart yet. Of course there can always be a first time, and I've never used it on a boat.

I think a lot of people put it on too heavy. And/or they smear it on both parts of the joint, instead of smearing it on one and dampening the other half.

You're right about the pine being a lot lighter. And that's a good thing, because the boat's going to be a car topper. But the pine is so soft it'll need some sort of gunwales for protection.

 

[hoytedow]

A little oak(or other hardwood) trim along the impact points would finish it off nicely.

 

[troy2000]

Step 7: unwrap and admire your glue joints, then plane them down smooth.

That brings the thickness of these planks down to a hair under 1/2", which is pushing our luck a little for strength. But this boat won't be seeing heavy use, so I imagine it'll be OK. I took some pictures of the glue lines, but they didn't come out well in the sunshine. They're nice and tight, though.

Step 8: clamp the boards together, and cut an angle off each end. We took off only about three inches, so the bow and transom aren't going to have much of a rake to them. Then plane the boards until the edges match. Trying to use the jointer didn't turn out to be very practical with 16' planks because we had no roller stands, so I turned them up and did them with an old door planer.

Step 9: insert a temporary stem at one end and loosely screw the planks to it. Then tack in a temporary center mold, and start bending the boards. I was pleased at how easily and smoothly they bent. There were some spike knots in one that didn't really show up until it was planed, and they had me a little worried. But the boards didn't kink or crack at any of them. They'll be inside and at the chine when the boat is done.

Step 10. Pull the stern together and tweak it until you're happy with the shape of the boat, then rough out a transom and tack it in place. When I dug this piece out of the pile I thought it was meranti under the dust and cobwebs, but it turned out to be a very nice piece of lighter-than-usual oak when we brushed it off and planed it smooth.

Step 11. turn the boat over and admire the lines, because that's it for the week. Father's day will be spent with the whole family, instead of hanging out in sawdust and shavings with number two son. To be continued next weekend....

And by the way, the little reverse curve at the bow was from the screws being a scosh too tight against the thin temporary stem. It came out when I slacked them a little.

My family is celebrating Father's Day by letting me smoke a nice pork roast for them. They're so good to me....

One final picture: Dwaine zoning out in the middle of the project, watching a bug on the ground. "Hey--it was an interesting bug, dad."

 

[hoytedow]

It looks good.

I take that back. It looks great.

 

[troy2000]

Can't work on the canoe right now, so I'll settle for talking about it.

A few details: after scarphing, planing and cutting off some knots, the side plank dimensions finished out at 1/2" x 11-1/8" x 183-1/2" (15' 3-1/2"). Each end was cut back 2-3/4", to provide a modest rake at bow and stern.

The temporary center mold is 35-1/4" at the gunwales, and 27 -1/4" at the chines. The transom (again, inside the planking) is 16-3/4" at the gunwales, and 9-1/2" at the chines. Remember, those are the face dimensions. The transom had to be cut larger than that, because of the bevels.

There will be a frame amidships to take the place of the temporary mold, and frames at 4' 0" fore and aft of it.

There are generally no thwarts in this sort of boat; people sit or kneel directly on the bottom (yes, foam pads are nice). We may temporarily install a breasthook and stern sheets so we can throw the canoe in the water, but the eventual plan is to have a watertight compartment at each end--both for storage and for flotation. Nothing fancy; basically hinged lids with gaskets.

There's nothing magic or necessary about any of the above numbers, by the way. Between dealing with the wood we had and eyeballing 'til things looked right, they're just the dimensions we wound up with.

For those who aren't used to thinking in feet and inches: the length overall will be a little more than four and a half meters, the extreme beam about 92 centimeters at the gunwales and 72 centimeters at the chines (plus rub strips at the gunwales and a thin external chine log to cover the edge of the plywood), and the plank sides about 1.25 centimeters thick by 28 centimeters wide.

 

[missinginaction]

Troy, best photo of a scarfing jig I've ever seen. Thanks!

MIA

Oh, boat looks good too!

 

[apex1]

Troy, best photo of a scarfing jig I've ever seen. Thanks!

MIA

...and the right advice to start at the bottom....

Richard

 

[troy2000]

Troy, best photo of a scarfing jig I've ever seen. Thanks!

MIA

Oh, boat looks good too!

Thanks.

If you ever route out the slide like I did instead of just putting rails around it, be sure to leave a strip down the center until you get to depth, so your router has something to ride on. Then you can take it out when you route the channel for the bit.

I thought about making a hold-down of some sort for the planks, but settled for screwing them down while I routed them. I had already killed enough time just making the jig....

 

[dskira]

That is my kind of operation, I love it
The 15" planer is quite something, I am jalous !
I will copy your scarfing system it is too cool.
Congratulation for you boat building, and very nice pictures.
Best wishes for you son.
Daniel

 

[troy2000]

That is my kind of operation, I love it
The 15" planer is quite something, I am jalous !
I will copy your scarfing system it is too cool.
Congratulation for you boat building, and very nice pictures.
Best wishes for you son.
Daniel

That planer is one of my favorite toys.

I bought it for a fraction of the retail price years ago, back when portable Japanese thickness planers first flooded the market. Those were flying out the door of my local tool store as fast as it could stock them, while this big ugly thing just sat on the showroom floor gathering dust. I kept admiring it until the store owner sold it to me cheap, just to be rid of it.

 

[hoytedow]

The shut-in Romany dogs heard them [the Dalmatians] and shook the caravans in their efforts to get out. ‥‘The caravans bark but the dogs move on,’ remarked Pongo, when he felt they were out of danger.
[1956 D. Smith Hundred & One Dalmatians xiv.]