Builders' Forum Archives
with a stripper it's easy
Posted by Charlie Jones on Apr 6, 2006
you just move the stations apart or together slightly and that increases length uniformly over the length of the boat- you don't get flat or hard spots. You can only use this over a small length change, say 10 % or maybe a small biit more, because you aren't changing beam. I've decreased the length of a strip canoe by omitting a center station which DID make the boat both shorter and narrower and proportionally so.
On a flat panel boat done stitch and glue, it isn't so simple. The shape of the panels determine so much about the boat- the rocker, the curves of the sheers, the beam, every thing. So by JUST lenghtening or shortening a panel, you would most likely distort the shape of the boat more than you'd like.
Iain Oughtred , the designer of many small boats, has designs in glued lapstrake that he shows changes of length by changing the station spacing also, but the panel shapes on those boats are derived from the stations themselves so they automaticaly change in widths as needed. Makes small changes possible. Again - he only changes about 10%.
In the book about stitch and glue boat building by Sam Devlin ( forget the name- it's out in the shop) he goes into some detail about how the panel shapes are derived. Might be really worthwhile finding the book and reading up. There are also design programs on the 'net that you can use to design your own stitch and glue boat. THAT would be your best bet if you just HAVE to experiment.
Or do what Lazlo suggests and find a design that is the size you want- there are literally thousands of canoe and kayak designs around- For example, Duckworks.com lists several dozen.
You are depending on the designer of the boat to give you a well thought out, safe, boat that has certain performance characteristics. Use his design or just keep searching til you find the right one.
In Response to: Extending length of canoe by John Short on Apr 5, 2006