Johncanoe - construction


Materials and tools

I used the designer-specified epoxy (System 3) and the highest quality plywood I could find (Lloyd's-certified BS1088 marine okoume from Chesapeake Light Craft). After all, that 1/4-inch thick piece of wood would be the only thing between Davey Jones' locker and me. I think it's much better to be in a boat with a broke wallet than in the water with a broke boat. Not that the difference in price between exterior ACX and BS1088 plywood will actually make one go broke. When the extra epoxy and fillers and sandpaper required to finished the C side is acounted for, there's not that much difference in actual price per sheet. And the Cheap Canoe uses only 2 sheets.

Instead of cutting the wood by hand with my Japanese razor saw, as I did for Krakenbait, I used an electric jig saw. The reasons were purely pragmatic. First, I was on a tight schedule - I had 4 days to have the boat assembled. And second, the beautifully smooth cut made by the razor saw made no difference. The cut edges were going to be embedded in the joints and, with any luck at all, never seen again by the eyes of any human now alive. The only smooth edges needed were for the sheer. Again, since I was using BS1088 plywood, these edges were being supplied by the shop edge of the plywood sheet.

The actual building

The construction went pretty much as described in the plans and the bateau.com website. Layout was very easy because BS1088 plywood is required to have square edges. I did not have to mark off and measure parallel and right angle lines before I could start layout. Nor did I have to worry about which side of the wood to use since BS1088 results in both sides being "A" faces. The only complication was a self-induced one of not leaving any pencil lines on the final-cut pieces. This was to give me the option of finishing the boat bright.

Gluing the butt joints was straightforward, exactly as described in the plans. Stitching the hull was another story. Although the Cheap Canoe (which is neither) is nominally a stitch and glue boat, according to the plans it never gets stitched (a boat of many contradictions). You're supposed to use duct tape to hold the pieces together until the glue sets. This is possible because of the low weight and lack of extreme bending angles and framing. It's supposed to make construction easier because no stitch holes need to be drilled.

However, there's duct tape and there's duct tape. Real duct tape is fabric-based, non-stretchy and relatively unaffected by heat that won't burn your hand. The "duct" tape sold in most home improvement, hardware and DIY stores is a stretchy plastic with a weak adhesive and will soften, stretch and release with only modest amounts of heat. But it is cheaper.

The first use for the duct tape is to hold the sides to the bottom in a sort of triptych, where the tape is the hinge that holds the three sections together. The sides are then folded up and connected to each other at the sheer with a batten (see below).
Bottom and sides flat, ready to fold Sides folded up, attached to batten
However, every time I got the side close enough to connect to the batten, that lousy "duct" tape would pull free and the side would separate from the bottom. The process of folding the side and connecting it to the batten was just too abrupt, and the sudden stress on the tape too extreme for it to handle. Finally, I had enough, grabbed a few cable ties and a drill and just put a couple of stitches in at the center of the panels. I also put a 6-inch screw through the hull at the sheer line into the batten, leaving 4 inches or so sticking out. A cable tie was used to secure the hull to the batten. This gave me a loose, adjustable connection to the batten which didn't require everything to be a perfect fit immediately.


Close-up view of screw holding side to batten showing cable-tie fastener

I was able to fold the sides up (with the cable tie stitches/hinges holding the centers together) and then gently adjust the spacing so that the cheap "duct" tape wouldn't stretch out and pull off. Once everything was together I removed the stitches and let the "duct" tape to hold it all in place. If I had it to do all over again, I'd be sure to find the good, original duct tape to avoid these problems. If it was unavailable, I'd just stitch the boat from the start. Six stitches per side (including the bow and stern) would easily take care of holding everything together.

My next deviation from the assembly sequence in the plans was to make a vertical support for the batten. This was because once the hull was assembled, the sides sat straight on the workbench. This was a problem because it reduced the freeboard by 1/4 inch (something not to be scorned in such a shallow boat) and more importantly, there was no gap between the bottom and the side. Jacques Mertens is very clear that his joints are designed to be loose with a gap that is to be filled with epoxy putty to transmit the loads between the pieces of wood. By making a vertical support for the batten, I was able to raise the sides to get the necessary gap. It also made the sheer and bottom lines look taut instead of droopy.

Batten with vertical brace in place Gap at joint

Now I was ready to start epoxying in earnest. The weather was cooperating. Daytime temperatures were in the 90's, which made the medium speed hardener cure very quickly. The taping of the seams went well, right up until the epoxy went exothermic. Then the combination of the 90 degree air temperature and the heat of the reaction softened that rotten "duct" tape and its adhesive. The boat began to pull apart. After a vain attempt to fix it by adding more tape, I drilled though the seams in the worst places and put in stitches. Maledictions on and a trip to perdition to the people ruined duct tape. May they make lots of money off their cheap substitute and need every penny of it for their health care.

Once the tape follies were over, construction became routine again. I only deviated from the plans a couple more times. First, the rub rail. Since I was unable to find the specified 1x2 pine in long enough lengths of good quality, I used 2 layers of 2 x 3/8 pine. This was available in 15 foot lengths of sufficient quality. The double lamination gave me a slight thicker rub rail than specified in the plans. In the interests of speed, as soon as I had clamped the first layer on, I undid the middle clamps and slipped the second layer on top. I worked my way along the front and back loosening each clamp and slipping the next layer under. It was incredibly messy, epoxy glue everywhere, but I got both laminations on in one long step. While everything was covered with glue anyway, I laminated the stock for the breasthooks and let everything cure overnight.

The breasthooks went in the next morning. I just put them in place and ran a bead of putty across the top edges to hold them in place. After another day of curing, I got out the sander and shaped the rubrail on the bow and stern to a nice point. I also removed the tape ridges and smoothed down the worst globs. Finally, I coated the entire inside with epoxy and let it cure overnight. The next day I coated the outside.

It was now time for the final deviation from the plans. I wanted to have a strong attachment point for the anchor rode, the car tie-down and something I could pick up the boat by. The breasthooks weren't shaped right and I didn't really want to fool around with cleats. It occurred to me that if I put a 1 inch hardwood dowel through both sides at the rub rail just behind the breasthook, it'd be anchored in the thickest wood at the structurally strongest point in the boat. It'd be easy to tie to, and if properly spaced, easy to get a grip on. It also meant that I wouldn't have to glass the breasthooks in since they would not be the gripping strong point for carrying. So I did.

Bow breasthook, rubrail and dowel

The boat was now structurally complete. The penultimate question was the finish - paint or varnish? How about - neither.

OK, we've all known since Noah's Ark that epoxy is degraded by solar UV so it must be painted or varnished with a UV-blocking varnish. But what would happen if it was left uncovered? Well, in the tropics, after about 6 months in the sunlight, the epoxy would begin to break down and get chalky. OK, 6 months of daily tropical solar exposure is almost 1900 hours. I'll be lucky to put in 10 hours a week on the water, with another 4 hours of transportation. Assuming 14 hours of exposure per week, that's about 2 1/2 years before chalking starts. And that's in the tropics. Here in Maryland, the average solar intensity is less. The boating season is shorter. And the boat will be in the garage between uses. So let's be really conservative and say 5 years before chalking starts. Long before that 5 years, the rocks and gravel and branches and carrying racks and cement launch ramps and portages and especially the oyster shells are going to have destroyed an untended epoxy finish. So since the epoxy will need annual maintenance anyway, there's no reason to worry about the 5-year UV bogeyman. Slap on another coat of epoxy and head for the water. And thanks again to that lovely BS1088 okoume, a coat of epoxy without sanding is a perfectly good 10-foot finish (looks great 10 feet away).

Completed boat ready for water

Then came the final step - what to name the boat. After years without a boat, I was ready to go out on the water again. I felt like a kid at Christmas. And what happens at Christmas? The jonkonnu, of course. So, keeping in the spirit of the Cheap Canoe's contradictions, my pirouge became Johncanoe.

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Copyright © 2002, 2003 László I. Mórocz. All Rights Reserved. Cheap Canoe plans excerpts copyright © eboat.net, used by permission.