Friday, October 28, 2011

Baby Steps

I'm making progress on my prototype skin-on-frame canoe.  The canoe in question is 1/2 scale.  Why 1/2 scale?  Well, marine plywood isn't cheap and this model is as much to establish building methods as the feasibility of the design itself.   When I start a design, I usually take the offsets or whatever design I'm working on at the time and create a CAD model.  I'm fortunate that I have a copy of the CAD software that I use at work on a machine at home.  (The user license allows for this...)  Once my design has been created and checked visually on the computer for smooth curves and regular transitions, I usually create a Adobe Acrobat file of the drawing.  These files can be taken to your local print shop on a thumb drive - in my case, a local office supplies store - and printed in full scale on their large format printers.  It's not that expensive, really.  The other thing is that if you're getting multiple patterns from the same drawing, you may want extra copies - they can do that with either by printing more copies or large scale photocopies.

Once the prints have been made, I usually turn them into templates by bonding them to cardboard sheets (NOT corrugated cardboard...) with some spray adhesive.  In this case, I had a choice.  I could have adhered them directly to the plywood that I'd be cutting out, but opted not to in case I wanted to make changes or notes on the templates.

As you may note from my templates, I've only positively identified the location of the keel and sheer stringers on the canoe and will by seeing where the best location is for additional stringers around the turn of the bilge and on the bottom of the hull frame.  Mostly I'm concerned about how the stringers will bend and twist into place at this point.  Also missing are the concave cuts between stringer notches in the sections to provide clearance for the covering fabric once water pressure is exerted on the covering.

Tonight I managed to get the plywood sections cut out and ready to put on the strongback.  Earlier today, I made a trip to my conveniently located lumberyard and picked up a 2x4 for the strongback and a few pieces of poplar to be stringers, mounting blocks and floor-boards.  On the real boat, this will probably be pine or cedar for rot resistance, but for now, that's not an issue on the model After I got the lumber strapped to the car's roof rack, one wag at work commented on how fast and straight the trees grew on my car roof. 
More to come...

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