I just bought the material to make the sail for our still unfinished
10' nesting sailboat. I took another look at the material (thin
nylon) at Walmart and did find that you could readily blow air through
it and quickly decided against it. Then I found material that looks
suspiciously like real dacron sailcloth. The clerks had no idea what
it was. It's strong (I can't tear a thin sample of the cloth), it
melts with a match...and it's much thicker than the nylon material AND
you can't blow through it at all. At $1/yd, I couldn't resist it. At
that price, I figured it's worth playing with (even if it is bright,
BRIGHT yellow).

Now I'm trying to figure out how to design the sail. Hubby finally
decided that he didn't want the sprit sail and opted for a cat rig
instead. This material is 56" wide and I'm wondering if I should just
sew the panels together (using the full width of the material) or
what??? It looks like most sails use narrower panels but it seems
silly to cut the material only to resew it. Also not sure how to go
about shaping the sails. I'm thinking of keeping it simple and just
sewing the panels flat and shaping the sail somewhat by curving the
edges of the sail.

Appreciate any suggestions. Not looking for a professional
sail...just trying to do the best I can without knowing what I'm
doing.

Thanks!

Sandy

Sandy, you need to get hold of a copy of The Sail Makers Apprentice, by
Emiliano Marino..

This book will take some of the mystery out of the sail making task..

There is no doubt that you can make your sail without this book but if you
want this to be a good learning experience, with a sail that will look and
perform good and you can be proud of, then find a copy..

One of the most important factors in selecting a material for a sail that
will hold it's shape, is whether it will stretch when you set it and when
you get some wind pressure on it.. The Nylon would have been a mistake and I
hope this other material will resist the tendency to stretch.

There are two methods to getting shape in a sail. The most common with
todays low stretch sail cloth is accomplished by "broad seaming". This is a
method of controling the amount of sail cloth in each sail panel by varing
either the width of the panel or sewing a wider seam in the areas where you
want to reduce the area..

In the old days (when I sewed my first canvas sail), the sail was sewn up
flat with uniform panel and seam widths, and then you cut a curve in the
luff and foot. That was fine for canvas because the material could "set" to
the shape under pressure. Modern sail fabrics can cope with this slight bias
stretching and with wrinkle.

If you were to order a sail kit from Sail Rite, they would computer cut each
sail cloth panel to the width required, the computer would put match marks
on each panel so you would be sewing everything exactly as the computer
calculated. But then "What would you have learned"? How to measure for your
sail and how to operate your sewing machine (which I suspect you already
know).

Ask around for a copy of the book in your area or ask you public library to
get a copy.. (they often have budgets for special book orders and never know
what to the public needs)

If you in the Puget Sound area, I could loan you my copy..

Steve
s/v Good Intentions

"Steve" wrote in message the shape under pressure.

Modern sail fabrics can cope with this slight bias
stretching and with wrinkle.


Correction:

This line should read " Modern sail fabrics CAN'T cope with this slight bias
stretching and with wrinkle. "

Steve
s/v Good Intentions

On 14 Feb 2004 13:29:07 -0800, (sandy) wrote:

I just bought the material to make the sail for our still unfinished
10' nesting sailboat. I took another look at the material (thin
nylon) at Walmart and did find that you could readily blow air through
it and quickly decided against it. Then I found material that looks
suspiciously like real dacron sailcloth. The clerks had no idea what
it was. It's strong (I can't tear a thin sample of the cloth), it
melts with a match...and it's much thicker than the nylon material AND
you can't blow through it at all. At $1/yd, I couldn't resist it. At
that price, I figured it's worth playing with (even if it is bright,
BRIGHT yellow).

Now I'm trying to figure out how to design the sail. Hubby finally
decided that he didn't want the sprit sail and opted for a cat rig
instead. This material is 56" wide and I'm wondering if I should just
sew the panels together (using the full width of the material) or
what??? It looks like most sails use narrower panels but it seems
silly to cut the material only to resew it. Also not sure how to go
about shaping the sails. I'm thinking of keeping it simple and just
sewing the panels flat and shaping the sail somewhat by curving the
edges of the sail.

Appreciate any suggestions. Not looking for a professional
sail...just trying to do the best I can without knowing what I'm
doing.

Thanks!

Sandy


Sail panels are cut into lens-shaped pieces before sewing together.
This builds in the camber (belly) of the sail. It's more complicated
than that but it's all I know about making sails. )
I'm sure someone will be along soon to help.
Mark E. Williams

sail size: look at boats of similar size, shape, and displacement. there
are two guidelines and one caution. first, in light winds you need 2 to
2.25 times the wetted surface of the hull. second, in stronger winds you
need 1 to 1.3 times the square root of the sail area divided by the cube
root of the displacement. make it closer to 1.3 for small boats. the
caution is not to put so much sail on that a nice breeze will blow the
boat over. there's no good way of calculating that. you have to look at
other boats. some people put reef points in their sails to make them
smaller when the wind blows stronger but small dingys usually don't have
them because nobody's supposed to sail boats that small in strong winds.
OTOH I've seen lots of racing dingys get blown over in strong winds. the
sail on my 11 ft one person skiff is 42 sq ft. I put reef points in it but
never use them.

shape: the aspect ratio of a triangular sail is the square of the height
divided by the sail area and should be about 4. I don't think you will
have to cut your 5 ft bolt into panels. you can put a curve in the edges.
use the calculations for the sprit sail on my website. they are good for
trianglular sails too.

reinforcing: add triangles up to 1 ft of cloth at all 3 corners to make
the sail double thick there. you can sew rope along the forward and bottom
edges of the sail.

mast attachment: I like a mast sleeve (like on a Laser) but you can sew
loops of sail cloth or light line to the front of the sail instead, one
every 12" or so. the air escaping around the mast on these sails reduces
power a bit. you don't see loops on boat used for racing. for pleasure
sailing it doesn't matter.

boom: not needed on a really small boat. if the bottom of the sail is more
than 5 ft consider a loose footed boom where the sail is only attached at
the front and back ends of the boom. the boom will hold the sail out
better when the sail is out ot the side.

that's the basics. you sould be able to find info in books at the public
library.

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William R. Watt ) writes:

shape: ..... I don't think you will
have to cut your 5 ft bolt into panels.

woops. I was thinking sprit sail here. You will have to make your sail
wider than 5 ft. The aspect ratio simplifies to twice the height divided
by the width. A 5 ft wide sail with and aspect ratio of 4 gives a 10 ft
high sail and only 25 sq ft, much too small. Increase the aspect ratio to
5 and the sail is 12.5 ft high and still only 31 sq ft. Looks like you'll
have to make the sail wider than the 5 ft bolt of cloth by cutting into
panels. You might want to include a boom in the rig.

--
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try looking up a freeware program called sailcut. it is a perfect
program for projects like this.

William R. Watt wrote:

William R. Watt ) writes:



shape: ..... I don't think you will
have to cut your 5 ft bolt into panels.



woops. I was thinking sprit sail here. You will have to make your sail
wider than 5 ft. The aspect ratio simplifies to twice the height divided
by the width. A 5 ft wide sail with and aspect ratio of 4 gives a 10 ft
high sail and only 25 sq ft, much too small. Increase the aspect ratio to
5 and the sail is 12.5 ft high and still only 31 sq ft. Looks like you'll
have to make the sail wider than the 5 ft bolt of cloth by cutting into
panels. You might want to include a boom in the rig.

--
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William R Watt National Capital FreeNet Ottawa's free community network
homepage: www.ncf.ca/~ag384/top.htm
warning: non-freenet email must have "notspam" in subject or it's returned



--
remove "abcde" from e-mail address to reply

"I think it would be a good idea."
Mahatma Gandhi
http://www.quotationspage.com/quotes/Mahatma_Gandhi/ (1869 -
1948), when asked what he thought of Western civilization

Sandy,
I am curious- did you find this material at Wal-Mart also?
Thanks, Carl McCarty

sandy wrote:

I just bought the material to make the sail for our still unfinished
10' nesting sailboat. I took another look at the material (thin
nylon) at Walmart and did find that you could readily blow air through
it and quickly decided against it. Then I found material that looks
suspiciously like real dacron sailcloth. The clerks had no idea what
it was. It's strong (I can't tear a thin sample of the cloth), it
melts with a match...and it's much thicker than the nylon material AND
you can't blow through it at all. At $1/yd, I couldn't resist it. At
that price, I figured it's worth playing with (even if it is bright,
BRIGHT yellow).

Now I'm trying to figure out how to design the sail. Hubby finally
decided that he didn't want the sprit sail and opted for a cat rig
instead. This material is 56" wide and I'm wondering if I should just
sew the panels together (using the full width of the material) or
what??? It looks like most sails use narrower panels but it seems
silly to cut the material only to resew it. Also not sure how to go
about shaping the sails. I'm thinking of keeping it simple and just
sewing the panels flat and shaping the sail somewhat by curving the
edges of the sail.

Appreciate any suggestions. Not looking for a professional
sail...just trying to do the best I can without knowing what I'm
doing.

Thanks!

Sandy

Carl McCarty wrote in message

I am curious- did you find this material at Wal-Mart also?
Thanks, Carl McCarty


Yep....Walmart! I'd really just about decided to buy some
dacron...but when I wandered through the fabric section of Walmart, I
found this stuff. At $1/yd it's worth it just for the practice....but
it looks good. Really curious to see how it all works out. It's
really strong (one edge of the fabric was imperfect and "ribboned". I
couldn't tear these small ribbons), you can't blow through it, I've
tried stretching it and can't notice stretch, and you can melt it with
a match. Clerk had no idea what kind of fabric it was. I gathered
that they get all sorts of seconds, rejects, etc. Looking forward to
raising our bright yellow sail.

By the way....Any suggestions for "rings" to connect it to mast &
boom? Hubby wants to just use some twine. I'm looking at some
plastic shower rings that we've had stored away forever (and thinking
of putting in grommets to hold rings). Any other suggestions? (Our
mast & boom will be aluminum tubes). Thanks!

Sandy

Sandy

By the way....Any suggestions for "rings" to connect it to mast &
boom? Hubby wants to just use some twine. I'm looking at some
plastic shower rings that we've had stored away forever (and thinking
of putting in grommets to hold rings). Any other suggestions? (Our
mast & boom will be aluminum tubes). Thanks!

Try cutting mast hoops from section of PVC drain pipe.