Building the Bouchie Dory Part 11 – Setting up the building jig
Finally we get to shift from making parts to actual assembly of the boat. In this episode we’ll build a strongback and set up our moulds creating what some refer to as the building jig.
Now we have already built our frames but we also need a couple of temporary moulds. These moulds are important because without them we have nothing to support our stem and transom until the bottom is on.
I’ll show you the method commonly used to create these from common 1×6 lumber. Now most beginning builders gravitate toward using plywood for moulds. I did too but trust me on this. Solid wood moulds are cheaper and easier. They employ very little waste. They are much easier to fair with edge tools and hold fasteners better for lining-off or assisting in the planking process. It’s easier to clamp things to them and lastly, when you’re done with them they can survive sitting around outside better. can be disassembled to use for other projects or can be fed into the wood stove. All things you wouldn’t do with plywood moulds.
Strongbacks come in a variety of styles. Strip builders seem to gravitate to the torsion box type, popularized by Ted Moores in his book Canoe Craft. Europeans often employ a simple plank on edge staked into a dirt floor. It is most often used when a boat is built right side up. Here in North America I believe the ladder strongback is most common and the one that I use. The traditional method for dory construction is actually quite different that what we’ll be doing. Usually the bottom is constructed out of longitudinal planks joined together athwart-ships by cleats. Then the stem and transom are then attached. Then the whole thing is set up on some blocking and shores push the bottom into shape creating what we call rocker. That just means the bottom gets a sweep in it fore and aft. Once that is done, the sawn frames are fastened on and the planking commences. There were moments in this build in which I kind of wish I had gone the traditional route and in fact I had originally intended to. Why did I stick with my old ways? Habit and predictability I suppose. I’ll have to work on changing that in the future because it could only lead to efficiency and heaven forbid, profitability. We can’t have that nonsense in a boatbuilding concern.
The use of sleepers bolted to my very uneven concrete floor and adding legs to the strongback makes the setup so much easier that screwing around with sawhorses. When I’m done, the whole jig is rock solid and you’ll appreciate that throughout the building process.
The method I’ve employed to level up the strongback works well but you could change up the order of operations slightly. for instance, levelling the strongback laterally at the midships point first would be a more productive choice resulting in a little less tweaking later on. Still the basic methodology works well.
Setting up the moulds is straight forward. Align them to your string-line. plumb them up and brace them in some way. Don’t overdue it with the bracing. I often find reasons to crawl up into the building jig to get at the inside of the planking for various reasons and too much bracing can be a problem. Once you have a plank or two on you probably won’t need it at all.
What’s most important is that your boat moulds fair out. before shaving any wood off of offending moulds, make sure you didn’t misplace them. This is one occasion in this build in which I wish I had lofted the entire boat full sized. if I had done that, I would have laid out my station spacing using a tick stick taken from the lofting. In fact I screwed up with one of the station spacings and did’t discover that fact until much much later when the boat was off the mould. It wasn’t a deal killer obviously and in fact proves my point that the boat fairing to itself is the most important factor in your setup. But I should have been tipped off when one of my frames wasn’t fairing in quite like the others. You’ll probably see that in a future episode.
This is one of the most exciting moments in building a boat because for the first time you get to see that actual mass of the boat, or at least get a realistic impression of it. This is one workday that always feels very productive at the end of it.