So called stitch and tape construction is now widely used in all sorts of boats from those that are built from plywood as I have shown here to those that may be built of more exotic materials. As it's name implies the ply panels are at first joined together with temporary wire stitches the inside, joints are then made with epoxy then after the epoxy has set the stitches are removed before the exterior joints are made with epoxy and glass cloth.
Below is the sequence of events for those that are interested in constructing a boat using the stitch and tape method. The picture show a small boat that I was building for my son but the technique will be similar in all cases except that the plywood may be thicker and the epoxy joint will be larger to thus spread the load across a larger area more effectively. I have personally built a number of boats using the stitch and tape method which produces a boat which is both very stiff and strong. One word of caution would not go amiss here and that is to check the boat dimensions carefully before applying epoxy to any joint. If a boat is wired up out of square or in other words with a twist in it once the epoxy sets up the twist will be there for evermore and the boat could be useless.
1 Mark up the planks to be joined. Clamp them both back to back so that you can drill through both of them at the same time. I was using 6mm ply so I measured in about half an inch from the edge to prevent the stitches from tearing out.
2. Spacings will depend on the amount of bend and tension that the plank will be subjected to. I set mine at 6 inch centers and this will be good for most applications, you can always add more if you find that you need them once you start the actual wiring together of the panels.
3. Drill for the wire stitches. The drill diameter should be just slightly larger than the wire gauge that you are using which in my case was a sixteenth.
4. With all the holes drilled open out the panels. Precut some lengths of copper wire and prebend them into a large u shape, then feed them through from what will be the inside surface of the boat.
5. Twist them loosely together on the outside with the pliers. Leave them fairly loose, you can always snug them up a little later. Drill a few more holes and add extra wires if you feel that what you have is insufficient to hold the panels to the correct shape.
6. Continue wiring all the panels together. This was small dinghy so I was able to wire the entire boat together before I even thought about breaking out the epoxy. This is a fun part too as the boat starts to take shape very swiftly. As the boat was small I was able to hold each panel myself as I wired the boat together. Had the boat been any larger then a helper would have been useful; one to hold and adjust the panel up or down as required and another person to do the actual wiring up.
7. The wiring up almost complete. Note the temporary spacer to hold the beam of the boat to the correct dimension.
8 With the wiring complete it is time to mix up some thickened epoxy, I used wood flour, and spread it into the inside joints. Neatness pays here and will save hours of final sanding if you are careful. After spreading on the thickened epoxy smooth it out with a shaped stick like a tongue depressor or the back of a plastic spoon. Larger craft will have fillets that are much larger than these shown here and for that you will need to make a consequently larger spreader and smoothing tool.
9 This is how the finished joint should look, neat and well executed.
10 After leaving the epoxy to set up overnight you can remove all the staples. Most if not all should pull out with a set of pliers but if they are at all reluctant to come out then heat them with a soldering iron. This has the effect of softening the epoxy a tiny bit and allows the wire to be withdrawn.
The boat is now essentially a one piece monocoque structure but there is still a lot of work to do, the outside joints have to be made and the fiberglass reinforcement added. I'll be covering these steps in part two.
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