The
Blivit 13 with a Jiffy-Sail:
Tyvek
is that tough plastic paper stuff used for the envelopes that
you can't tear. Mainly it is used for house wrap on building projects.
I've seen it stapled to stud walls out in the wind and weather,
exposed for months. It is a breathable material, to stop the wind
but let the moisture out.
All
of the above plus the stretch resistance should make it ideal
for a cheap and dirty JIFFY-SAIL ... Will it work? The answer
is a BIG YES! D.I.Y. sails are a natural companion to D.I.Y. boats,
especially when they are so easy to make.
The
fact that it comes in a 9-ft. wide roll means that a small sail
can be made without joints. The price is right, less than $1.00
per ft. for the 9ft wide material. There is one hitch...most of
the lumberyards are reluctant to sell less than a full roll at
about $150.00. You can always go to a friendly builder and buy
a few feet from him. Another option is to form a small co-op with
some of the guys from the Club who would also like to experiment
with sail making.
The
actual construction is almost too simple to explain. No sewing
or gluing is required. It is simply a matter of using some double
stick carpet tape to secure a fold along the foot and leach. A
pocket is formed to slip over the mast, also secured with the
tape. I used some strips of duct tape to reinforce the high stress
areas where grommets were inserted at the clew to attach the sheet...the
same deal for the down haul.
Why
mess around with cheap sails? Well, my reason was that I wanted
to try a larger sail area for light air conditions on the Classic
12. Being reluctant to spring for another store bought job combined
with my nature to innovate is reason enough to try something different.
How did the experiment turn out? I might be prejudiced, but I
would say the results were terrific! The larger sail really livened
up the performance of the boat. Most important, nothing let go.
The tape joints held up just fine and no tears developed in the
Tyvek.
One
disadvantage is the stuff is rather stiff. Creases sort of become
permanent pressed, however no harm seems to come of it. Another
characteristic, perhaps a disadvantage is that it is noisy as
the Devil. In a way this is advantageous, when the sail is drawing
right it is quiet. As soon as it luffs there is a rustle &
rattle, a great tell tale. Let it lie free in the wind and the
noise will really wake you up.
I'm
convinced that it will be serviceable for a good long time. Perhaps
the best testimonial to its endurance is a 500-mile round trip
to Mystic, at 60 MPH on the top of my Blazer. It was wrapped around
the mast & tied down. At one point I was aware of an awful
lot of flapping, so I stopped and tied some more rope around the
loose stuff. No damage was apparently done but the flapping didn't
seem too healthy.
A
2nd generation update to experiment some more, a larger (70-sq.
ft.) sail is working just fine on the new BLIVIT 13. This is still
cut from one piece of material off the 9 ft width. It has a batten
pocket that consists of a piece of Tyvek taped onto one side of
the sail. A 6" strip of VELCRO holds the batten in the pocket
quite nicely. This permitted building a 9" roach in the leach
of the sail for more area and better set.
The
10-mil Mylar window was just stuck in place with the same double
stick carpet tape. This sail has a 2" draft built into the
luff edge. I simplified the peak and deleted all those flaps and
folds...just used some duct tape and grommets, same as the downhaul
detail.
The
end result was sort of like a WIND SURFER rig with stays. After
one days sailing I realized that I bad to be able to lower the
sail without striking the rig. This meant patching the holes cut
for the rigging; then sliding a 5/16" braid bolt rope into
the mast pocket. Now I had to build a luff groove onto the mast.
Sail track & slides would have also worked. Taking the mast
out of the pocket left the peak sort of floppy so I taped a 1/8"
ply headboard to fill up the top of the pocket.
TURF
TAPE is double sided glass reinforced outdoor carpet tape, 2"
x 75-ft. roll, manufactured by: Custom Tapes Inc., Harwood Heights,
Chicago IL 60656 (312) 867-6060 from: TruValue hardware stores.
The
hardest part of making one of these Sails is laying out the shape.
You need a flat smooth surface (Loft) like a playroom or whatever.
I used a straight wood batten as an aid to drawing lines on the
Tyvek with a pencil. The hard part comes in the crawling around
on your hands and knees (use kneepads).
Now
I have stated that the nature of this project was experimental.
I tried to build draft to the sail by bending the leading edge
forward 1" as shown on the sketch and this is where the batten
is used. This seemed to work okay however the results were not
too certain. The mast was quite bendy, which, of course, as an
effect on the sail shape.
Getting
back to laying out the shape. The mast pocket is tapered from
the C/L starting at 8" to 4 1/2" at the top. Start by
drawing the swept forward centerline. Then draw the cut line,
paying attention to following the same sweeping curve as the centerline.
Now (about every 16") measure the distance from the C/L to
the cut and transfer that same measurement back from the C/L to
the tapeline. Then draw that line.
The
folds that create a pocket at the top might seem a little confusing;
if they do, simply make a trial top section pattern with some
heavy brown craft paper to test out the way it works. This pattern
can then be used to layout the actual sail.
The
completion of the layout is now too simple to spend much time
explaining. Just make the cut line distance from the foot and
leach fold line, the same as the tape width (1 1/2" - 2").
I used a metal level as a straight edge, running the top of my
thumbnail along the edge to set a crease to make the fold.
Probably
two sets of hands would be easier while applying the tape 'cause
it is mighty sticky. If it starts to run away from the line, don't
try to lift it from the Tyvek, just cut it off and start again.
Lifting seems to pick up some of the material, which will mess
up the bond. Lay down the folds, starting at the base; then do
the foot and leach. Before closing the mast pocket add some duct
tape for the down haul grommets. (2) 32" pieces 2" wide
were used. Center them about 2" on each side of the pocket
C/L. They wrap from the inside around to the outside of the base.
The
top of the pocket is next, then do the main pocket in sections
from slit to slit. This accommodates the curvature at the leading
edge. A little bit of scrap material with some tape on it makes
a good patch to cover the slits. You could use Duct Tape here;
however, the white Tyvek becomes almost invisible. You have just
learned how to make a repair if you should have an accident!
The
clew is done by making a miter fold about 3 1/2" wide and
taped in place. Then (add) 3" wide duct tape around the corner
extending about 24" on each side (foot and leach). This wraps
the edge and is on each side of the sail. Another 32" piece
of 3" tape is used to bisect the angle and wrap the corner.
(See the sketch)
Now
take a rag and bunch it up, then rub it hard over all of the taped
areas to sort of "set" the tape.
The
toughest load on the sail is at the clew. I've used double 1/2"
grommets and they show no tendency to pullout. They are in 1"
and spaced apart 1 1/4" on centers. I can't tell you how
to set the grommets without an installing tool. A good hardware
store carries kits with tool & grommets for about $12.00.
Now that is a lot to spend on a $10.00 sail...just think of it
as an investment in a tool that you will be able to use for years.
The
holes for the grommets take a little doing because it is important
that the holes be round with smooth edges. A punch can be made
with a piece of pipe or tubing sharpened on one end. (See sketch)
Another method is with a drill fixture made with a couple of hardwood
blocks as shown.
When
using the sail there is no need to set the downhaul very hard.
(It might just poke the mast through the top). On my lightweight
boats NEVER EVER use a Jam cleat on the sheet!
(This image has been scaled down slightly to better
fit your screen and printer)
(These images have been re-arranged (but not
altered) to better fit your screen and printer)
Tyvek
is DuPont's registered trademark for spunbonded olefin house-wrap