7/28/2019 Making the Tyvek Sail
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depth should be one inch for each five feet ofluff(or foot). By
the way, for now let's call that pointD for now. More about it
later.Now you need a gym or a dance floor, or something like that.
You can guarantee the owner that you
will not harm it. And you and your helper, ifyou have one, will
for sure need a set ofknee pads, like
volleyball players and flooring people use, or you will come
away with sore knees.
Be sure the floor is really clean, and not dusty. Lay out the
material, and cut it roughly to shape,
leaving maybe a foot ofexcess along the luffand foot. Now lay it
down again and use bits ofmasking
tape to hold it stretched out. Ifyour sail is to have a seam,
stick down only the large panel. Do not, by
the way, use a lot offorce; you don't want to stretch the
material. Now apply the tape to the edge
where the seam is to be. This requires a lot ofconcentration,
and is high precision work; take your
time. The tape is really sticky; mistakes are hard to correct.
Do not stretch the tape; ifyou do you will
get a puckered seam.
Now get the next panel handy, peel the backing offthe tape you
have already laid on the other panel,
and attach it. Also tricky.
Tape down what you have on the floor. Remember, minimum tension,
just enough to hold it smooth.
I hope you were able to find a long, flexible batten, and also a
long straightedge. With a little ingenuity
and much cussing I was able to make do with an eight foot by one
inch strip ofaluminum that you
can find in any hardware store, but maybe you do better than
that. Draw straight lines for the foot and
the leach, and also straight lines parallel to them and outside
them by the width ofthe tape.
Locate Point D and mark it.
For bending the batten and holding it in place so that you can
draw
the curve ofthe luff, you can use. bricks, cans ofpaint, heavy
booksor lots oflight ones. But be wary ofthis: the batten will tend
to bend
much more at Point D than elsewhere ifyou just pin it down at
head,
tack, and Point D, giving you a curve the is not fair. The
batten
wants to be bent outward just a little bit more, halfway between
Point
D and the corner. Do it.
To do a perhaps better job than you can do by eye, you might
want
to mark a couple ofmore points on the curve. Try this.
Halfway
from Point D to each corner, measure out from the straight line
a
distance equal to 3/4 of(or .75 times) the distance you measured
outto find Point D. This will give us a really good approximation
ofan
arc ofa circle, in curves ofthe dimensions we are using.
Draw the curve. Draw also a line, like before, outside it a
distance
from it equal to the width ofthe tape.
Now you have the choice ofattaching the tape to the edge and
then cutting offthe excess Tyvek, or
cutting along the pencil line followed by taping. I say cut
first. This can be done best with good, big,
sharp scissors.
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Now you have a sail, and it is stronger and will set better than
you think, by a lot.
And now be sure that you haven't left anything sticky on the
floor ofthe ballroom- you will want to
use it again. Masking tape leaves little goo behind it, but be
sure.
Take pictures ofyour boat sailing under your creation, and give
one to the guy who gave you the
material, and also one to the guy who runs the ballroom.
A Few Cautions
You will hate the sound ofthe sail luffing- it sorts ofmakes a
rattling sound, it doesn't sound like a sai
at all. But you will grow accustomed to it, especially as you
check your bank balance.
Don't attempt to strengthen this sail by running the seams and
edges through a sewing machine. The
stickum on the tape will gum up the needle immediately. Ifyou
really want to sew the seams, make
them a lot wider than the tape and sew through the Tyvek, but
not through the tape. Any batten
pockets you may want should probably be stitched.
The material is rather stretchy. It isn't as bad as the light
nylon they use to make sails for boats like aSunfish, but it is
nowhere nearly as inelastic as Dacron. When it is blowing hard the
sail will get
slightly more full.
It turned out that the mast I made was a lot bendier than I had
expected, and in any breeze at all the
sail looks lousy- although it sure does drive the boat. On my
next sail I am going to move Point D
farther up the luffand make the curve deeper. Likely you will do
something like that, too.
From making the first sail you will learn a lot about making the
next sails better and faster and more
easily. And you will probably want to start by calling up DuPont
and asking for sample materials and
prices. They make the material in a lot ofdifferent weights and
textures, and different widths. Butyou'll have to buy a lot of it,
probably a roll ofat least a hundred. feet; it is still very cheap,
however.
I have no idea how big a sail can be made in this way and still
not blow apart. Bernie Wolfard writes
ofa 40+ foot schooner with Tyvek sails as big as 300+ square
feet. Reinforcements could be bigger,
seams could be made oftwo widths oftape, etc. And it is a truly
minor disaster to have such a sail
blow apart, most ofthe time. Have oars or a motor.... This is
going to be cheap and fun and
interesting. Set about it.
Bill Wallace
3430 Miramar Drive
Shoreacres, Texas 77571Copyright 1998 by Author
