Geoff P ) writes:

Rigs, spars and sails from native materials? Bamboo/kokonas?
What else should I ask?
Tenk yu tru... That's Pigin for thanks a lot.

use whatever wood is available cheap locally. light wieght and aloft is
important. bamboo is fine. the surface has silica in it and is quite
strong and abraision resistant. however the inside is soft and will get
softer and weak if wet, and rot if damp. so seal cracks and paint to
keep out water. probably should be cut and left ot dry out before use.

to save money look at native sailing rigs. no metal parts. governments and
the UN publish material on cheap rigs for fishing boats in developing
countries. Check with your local economic developement office.

sail size (power) depends on total weight of boat and contents (called
"displacement"). you can weigh the boat using a long enough lever and an
ordinary bathroom scale, a good exercise for students. Boatbuilder TF
Jones weighs his boats this way. the usual guidelines are 1) sail area
2.25 times the wetted surface area of the hull in light winds, 2) square
root of sail area 1-1.3 times the cube root of displacment in brisk winds.
But usually people compare to other boats of the same shape and weight.

a crab claw sail would be traditional for the area and provide most power
per square foot of cloth, but more work to change tacks. best for long
tacks in steady winds. for easier tacking (short trips, harbour sailing) a
sail with the front edge attached to the mast is best. I favour sprit
sails (cheap, simple, no metal hardware needed) for which there is info on
my web page. They are not very easy to reef. I've tried to describle the
step-by-step design of a small sailboat on my webiste (with lots of
numbers) in an article on a 15ft Solo cruiser. It shows what should be
considered. I'm an amateur, not a marine architecht or professional
designer. I used what I found in books on marine architechture and
sailboat design.

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