My
Backyard Boats:
The Weekend Skiff -- Choosing a Sail Plan
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Graph
paper is fun to play with when trying out sail plans.
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Spring
2001: This
page from the notebook I kept while making the Weekend
Skiff gives you an idea of the way I worked out my
sail plan options.
I took the dimensions from various sail plans
in various places and scaled them to match the profile drawing
in plans for the skiff.
By matching the scale, I could draw a plan and hold it up
to the drawing in the boat plans to see if I would encounter
weather helm, lee helm, or balanced helm.
I would match the sail's center of effort on my scale drawing
with the center of effort for the skiff.
The scale that I used is on graph paper with 4 squares per inch.
I'm not that good at math, so I had to use a number of different
rulers until I found one that I could get accurate results with.
My old Pica pole from newspaper work worked best
for me. Dynamite
Payson's book on Instant Boats gives good guidance
for those of you who know your way around scale rulers.
In fact, if you want to make a balanced lug sail
like the one drawn here, you could print the scan from my notebook
and enlarge it in a copier to 8 1/2- by 11-inch size and see
for yourself how well it might work. Then get a PolyTarp
kit and make it. Takes about two hours. Then consult Canoe
Rig or The
Sailmaker's Apprentice to set up the rigging.
That's what I did.
I made a gaff/jib rig that was a total disaster
(we were sitting on all the strings) and a balance lug that
I liked, and a sprit sail that didn't work that well, because
it made things hot for the crew by coming down too low. One
constant was the mast. I used two pieces of 1x4 yellow pine
and one piece of 1x4 fir to make a square blank 11 feet long.
I tapered it with a block plane. Each sail plan I tried was
bound by this mast dimension, though I used fir closet poles
to make booms and sprits and lug stuff such as yards as needed.
I tapered the mast to accommodate the gaff rig, since that
was the first one I tried, so the mast is a bit stiff.
Another limiting factor was the beam of the boat,
which restricted the length of any boom I tried, since I wanted
to avoid pivoting on a dipping boom that was too long.
Bolger
is good on explaining this gotcha. I didn't use any sail plans
with booms more than 9 or 10 feet long. One of the benefits
of the sprit over a traditional boom is that a sprit can be
longer and still not cause the problem that a long boom can.
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