design by Gavin Atkin

Gavin Atkin designed this lovely little lapstrake canoe for a friend and has generously offered the plans as a free download. Currently he is even building one for himself. Below are the building notes which come in the zip file, as well as a few samples of the drawings which are in both .gif and .dxf formats.

Building Notes

From building one prototype for this boat and having been involved in another, by a conventional and rather labour intensive method, I became convinced there was a better and simpler way of building this little canoe with such classic lines.

Here's the idea. I don't see how to avoid having to make some sort of strongback and moulds, because a key feature of this design is the hollow at the bows, which can't be achieved by s&g alone. The garboards are made wide to give the boat stability and fixed to each other and to the next strake by stitch and glue - really they have to be because the angle between the two is so acute in the centre section. However, the next strake - the third - is stitched to the second strake such that it laps it by a measured amount, prior to filling the lap with epoxy putty. The same principle is applied to fourth and third strakes. You'll need to plane the outer corners of both the second and third strakes to accept the uppermost strakes to provide good wide glueing (faying) surfaces. Use a Surform for this if your carpentry is as poor as mine, btw.

Now I have introduced the basic principle, the order of building goes like this:

- Set up a strongback and moulds as shown in the drawing. The first three moulds are placed such that the distance from the stem to be is to their aft-most side, so that the material can be tapered using a batten so that it conforms to the curved strakes of the boat. The strong back should be made of fairly rigid material, but the moulds may be of something a little softer - the prototypes were built on chipboard moulds cannibalised from an unwanted wardrobe. A taught sting from one end of the strongback to the other should be used to line up (centre) the moulds - notch or otherwise construct the strongback or frames to allow this. Also, sight along the moulds and from the sides to make sure the moulds line up top and bottom, and do not lean fore and aft. Finally, cover the moulds with polyurethane food wrap, non-stick masking tape or whatever to prevent the hull becoming stuck down.

I have tried to keep the number of moulds down, and you may be grateful to notice that I have limited them to five :-)

- Place an 11ft keelson along the moulds and fix it firmly in place using screws and small wedge-shaped chocks - you will need to be able to reach the screws to remove them when the time comes to liberate the hull from the moulds. Also fabricate and attach the stem and stern. I've found a really good way to do this is to mark out the shape on a piece of flat cheap material, such as more chipboard, and then to cut it out. I then cover it in polythene food wrap using masking tape. The next step is to cut and assemble pieces of my timber such that they covered the shape required with a little of the stem or stern material overlapping the template. Using 1 1/2 by 1 material, I managed to do both stem and stern for my prototype Imp in five pieces: three for the outer edge, one reinforcing piece on the inside, and one more to mate with the keelson. I then glue these together (using epoxy mixed with filler to make the glue) and clamp them. Once the glue has gone off, you can mark round the template and removed the excess on the stem and stern before glueing and screwing the stem and stern pieces to the keelson and to the strongback.

- Now we have the strongback complete with moulds, keelson and stem and stern, it's time to scarf the panels, and to mark out and cut the 3/16in ply material to size and shape. Don't use 1/4in ply, as it's too heavy to make the bends required, and will make your boat heavy besides. The scarfing can be done in a variety of ways according to taste and to ability, but I prefer to do it the dog-simple way by butting the material and taping it first one side and then the other. Naturally you'll need to turn the sheet over very gingerly when only one side has been taped in order to tape the opposite side. Use a good flat surface for supporting the material as the epoxy goes off before applying the second tape, and take care also to fill any slight gap that might have appeared between the butted sheets, for air bubbles are the enemy of this process. Another enemy is poorly mixed epoxy - so mix it really well, using something like two hundred swirls before being satisfied even with a small pot-full. And don't accept anything less than a good job or your boat will have kinks in its planking. If you make a scarf this way and it isn't right, remember that a blow-lamp will enable you to quickly remove a tape and allow you to start again.

I've provided my usual coordinates: x is the distance in inches along the bottom and y is the vertical distance in each case. I find it helpful to rule off the material in ten-inch squares before beginning the plotting process. Once the marking out is completed and checked - always measure twice and cut once except where you measure three times - I recommend cutting out the shapes using an ordinary handsaw partly because your mistakes will be smaller than if you use an electric saw, and partly because the resulting sawcuts will often be neater. Some people prefer a pullsaw for this kind of work, but I don't see the advantage myself.

- The next task is to trim the stem and stern pieces and the keelson so that the panels will lie snug. This can be done by clamping or screwing the panels to the moulds to try the fit, and then trimming the stem or whatever using a plane or a spokeshave or Surform, depending on your level of skill. The stern and stem pieces should trim down virtually to a knife edge, and the garboards (the first strakes) should butt each other for almost the whole length of the boat, though I do not think it is possible to expect them to do this at the turn of either the stem or stern. These areas will eventually be covered with a protective strip, however.

- At this point I think assembly can safely begin. The garboards should be glued and screwed to the keelson, screwed temporarily to the frames and glued and screwed tight over the stem and stern. The second strakes are to be stitched and glued to the garboards. Hopefully, this should be a simple procedure requiring no more fitting! However, when the third strake is attached, small lands will be required to be cut in the second strake and the stem and stern to 'let in' the next strake up so that each strake lies nicely along the stem or stern. These lands are half-inch wide rebates that start 3-4in from the cutwater and increase in depth until at the apex of the cut water the lower strake has been entirely cut away - or nearly so. These rebates take little time to cut: just a few stroked with the saw followed by a few moments' work with a sharp chisel or a rasp.

Once the lands are cut, the edges of the lapped strakes should be trimmed with a plane or Surform to enable the following strake to lie neatly and to create a nice wide gluing surface that will require the minimum of epoxy glue. Then stitch the strakes together using doubled-up cable ties with the aim of pulling the strakes together and achieving a fair curve

- When all the strakes are in place, the garboards and second strakes are stitch and glued, and the third and fourth strakes have been assembled and glued into place, use epoxy putty to fill in the vee-shaped laps as required. Finally, add the gunwales (outwales to you over-the-ponders).

By this point you should have a shapely hull still on its moulds. If you have luck on your side, the hull will come off the moulds easily, and you will be able to place a temporary stretcher in place of the central mould while you take care of the carpentry.

- The rest of the job is down to conventional carpentry of the kind you will find in many boat-building books. The boat needs breasthooks, a gapped inwale, and a stretcher placed a little towards the bows so that the user will be able to carry it on their shoulder, and the crew can paddle the boat unimpeded.