TeeGee 15.7 Sport designing and building a stitch and glue version of the Old Town Discovery canoe.
History: we were looking for a small boat for oar and motor. The Erdre river will be the principal boating place - I hope you see why we need a boat =:-D
The local canoe rental had the Old Town Discovery 13 which we tried and liked. Having two growing boys the 13' was too small.
This page will document the building. Eventually if all works as planned the plans will be published here.
Questions will be answered on this forum. Or, if you send a small PayPal donation, by e-mail.
Design: I got the basic dimensions from the Old Town web site and fed them to Carene50 (no longer available) hull design software. After a couple of cardboard models and a little tweaking a design took form.
The cardboard model above is the final cut. The sides are different because I toyed with the idea of cutting the top panel and making a false lapstrake. I was inspired by the Annapolis Wherry (who wouldn't be!) and like the way the shadows of strakes beautify the lines. I have decided to go for the plain top panel for this prototype. Using two panels would have made the boat more rigid - I want to test in the least reinforced possible way.
The lines are modified in that the Old Town Discovery is a symetrical canoë with the back end cut off. I moved the centre of the hull back so I have a fine entry and more volume in the back third of the boat. This is where I will be sitting with a tiller extension when the small outboard motor eventually gets fitted. I was very pleased to see this design decision validated by the Swift Canoe which showed up earlier this year. The difference is that my canoë is narrower and has a round bottom.
The Carene50 models were opened in a free Linux CAD program and printed directly to bristol (light cardboard). It was not so easy to get the full scale plans printed. All the large format print shops want Autocad .dwg format. All I could give them was .dxf... One guy tried and had massive scaling problems.
In the end I printed at 1/10 on my epson inkjet printer, taped the two A3 sheets together and then we enlarged them in an industrial photocopier.
Tracing: The plan was transfered to two sheets of ply (half the boat) by drawing a 10 cm spaced grid of vertical lines on the photocopy. This was very easy because the CAD software prints a tiny point, invisible to the naked eye, every 1 cm on the epson printout. Enlarged the dot is about 2 mm square.
Where the plan lines intersect with the grid a hole was punched into the ply with a tack and small hammer. After the plan was lifted off, the tack holes were joined by tracing a pencil line guided by a flexible wood batten.
Marking and tracing were done on the floor of the office/living room. Just enough room for a sheet of ply between my desk and the couch.
The second half of the boat will be traced to the sheets of ply from the first set of parts. Yes, this means cutting twice but it also means less risk of wasted wood had I made a mistake on tracing the first set of parts (I didn't).
Materials: The boat can be cut from 3 sheets of 6 mm marine ply and one of 9 mm marine ply. A nesting model was made to verify this. The prototype is being cut from 4 sheets of 5 mm exterior grade Oukoume ply and one of 9 mm marine grade.
A 11 kg kit of SP Systems epoxy.
The amount of biaxial glass will be specified later.
I will probably be using pine for the rubrails and various bits and pieces. Mahogany would have been my first choice but I was unable to locate a local supplier.
Cutting: I really want one of these saws for boat building but they are not sold in France!!! The boat was cut with this one - I'm shouting at it for not going straight (in a curved sort of way...).
Yes that is the size of my "back yard". No I won't be building there - we thought about it but even with the back kitchen door off wouldn't have access to the dishwasher... The wood was cut on the picnic table. The sail in bag is the main of my 15' catamaran. The barbeque is out of sight to the left near end of the panels =:-D
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