Cutting out the planks
This is the stage in canoe construction where you turn four sheets of expensive marine plywood into 20 well formed half planks of a canoe or, perhaps, just a small pile of sawdust and a stack of “off-cuts”. So much depends upon the accuracy of the preceding lofting process as well as the 'saw action'.
The half planks are cut from four sheets of marine ply sandwiched together. The idea is to ensure that both ends of the canoe are identical and (more importantly) that both sides of the canoe are identical. The alternative would be to end up with a canoe that did not fit together or only paddled in circles. It is important to ensure that the four sheets stay “in register” while each half plank set is cut out. The best approach is to nail or screw the sheets together at various points between the marked out planks – avoiding the cutting lines and larger waste areas that might come in useful at some later date.
Then, as each plank is cut from the sheet, the section hanging over the edge of the working surface can be clamped to keep everything tightly controlled as it is cut away.
My plan was to cut the planks out by hand. I had modified a Stanley 1-15-215 floorboard saw by grinding off the teeth on the upper/front curved face of the blade to stop these wider teeth jamming in the kerf when I was sawing at a low angle through the boards. I had also been reading that many expert woodworkers favour a Japanese ‘pull’ saw (in particular a ‘ryoba noko giri’) as they cut on the pull rather than push stroke and this allows the blade to be very thin with a very narrow kerf – ideal for this sort of project. Quality Japanese woodworking tools might be expensive but Irwin do a very reasonably priced version with two cutting edges. So a “head to head” between these two saws was in the offing.
Irwin version of ‘ryoba nook giri’ pull saw and the less exotic Stanley floorboard saw – prior to my modification
I elected to screw the four sheets of plywood together at intervals along the waste areas. I decided that screws would be easier than nails to remove if they proved to be in the way. After one last look to check that my plank outlines matched the curves and lines of the sketch in the book I set to.
The Stanley saw was first up. I am a frequent enough saw user to have some confidence in what I am doing and this saw was spot on for accuracy – it followed the plank curves well and effortlessly held a pretty constant distance of less than a millimetre from the pencil lines. The snag was that progress was slow. At 13 teeth to the inch (now there is a non-metric standard measure) I suppose I should have expected this but progress was frustrating.
The Irwin “pull” saw made much faster progress – but – you knew there was a but – this was my first attempt to work with this new style of saw. I found it difficult to keep my saw cut close enough to the lines on a long cut – thus increasing the amount of work required to complete the cutting and shaping of each set of planks. Having said that, the advantages of this style of saw were becoming apparent – I just needed more practice. I suspect that I am going to become a frequent user of this saw and I can’t wait to use it on some jobs where it’s fine cut is going to be a real benefit.
So which saw is the best for this task then? Remember that I am cutting roughly twenty five linear metres through 2.4 centimetres of African mahogany. The winner is – “save up and buy a decent jig saw!”.
No seriously, (homespun philosophy moment) – once you have achieved proficiency with a hand tool then you will find the equivalent power tool finished the job faster – but no more easily. Power tools are not always better. This is just a longish job that is worth taking time over. I had far more fun ripping a couple of oak planks on the table saw to extract some lengths 2.5 centimetres wide to scarf together to form the inwales and outwales of the canoe. Given that I ended up buying two metre planks then I will have to cut 16 scarf joints to achieve the (roughly) five linear metres required – so one of the next tasks will be to make a simple jig to cut the scarfs as the time will be repaid in accuracy and efficiency.
Why were my planks only two metres long when this part of France is virtually a continuous oak forest? Well, most consumers of oak timber are artisan carpenters. They all have planer/thicknesers and band saws and can buy the pretty crude pieces of timber available from the saw mills. I could have easily purchased a slice through a tree trunk but would have had extreme difficulty in getting the required lengths out of that. So it was buy what was available at the DIY level or involve a local artisan to prepare the lengths of oak for me.
More from me when I have finished sawing – which might be a while as a combination of family commitments and entertaining look like “taking out” the coming weekend one way and another.
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