|I've been messing about with polytarp sail construction for about
nine years and selling polytarp sail kits under the name of PolySails for
over half that time. During that time, I've probably cluttered up my mind
with way too much information on polytarp sailmaking, old boats, and
online marketing as nearly any visitor to my PolySail website can attest.
To make this proliferation of data even worse, I try to dream up tests for
the tarp materials I supply in the kits. I also send out surveys to people
who buy kits from me to learn what they think about the polytarp sails
they make. Of course this obsession makes a convenient scapegoat for
lapses of memory, an overflowing job jar, and a failure to sock away
adequate funds to retire even by 90. Fortunately, I have a forgiving wife
and a family history of eccentricity to fall back on if I really get
desperate for excuses about spending time with polytarp sailmaking.
The gist of what I've learned so far is that some kinds of polytarp
make pretty damn good sails for some people who just want to mess about
with small boats. Now immediately some readers will think to themselves,
"Well, he's just a biased so-and-so who wants to drum up some business,"
or some similar thought. So I'm going to admit from the outset that
self-interest is 90 percent of the reason for writing this article and
sharing what I've learned is only about 10 percent of my motivation. After
all, retirement is looming; and a part time income from selling sail kits
is better than no income at all.
Let me clarify what I mean by "some kinds of polytarp make pretty
damn good sails..." Polytarp is generally made from three to four layers
of polyethylene. The inner layer is woven from strands of the same stuff,
but the weave can be very loose or fairly tight. Only when the weave is
fairly tight is the polytarp material much good for sailmaking. Much of
the common blue polytarp that you buy from your friendly home improvement
store has only about a 6 x 8 scrim, or weave, per square inch. My white
and light gray tarps have at least a 12 x 12 scrim and a 14 x 14 scrim if
I can get it. In terms of weight and thickness, the cheap polytarp might
be only a 3 mil; 2.5-oz./sq. yd. material while the better grade is an 8
mil, 6.0-oz/sq. yd. material.
Another differentiating factor is color. White and some other light
colors of polytarp tend to be U-V (ultra violet ray) treated. Dark colors
are not. If you've ever used one of those cheap blue tarps outside for a
boat cover for a season (if it holds up that long), you might know what
happens when one of those tarps disintegrates. The darker, lightweight
tarp tears at a touch and rains down microscopic flakes of tarp that are
harder to get rid of than head lice. On the other hand, a marine firm that
supplies the 14 x 14/sq. in. scrim, light-colored tarps to the US Navy has
to meet a standard that their tarps will last for at least one year in any
weather conditions. One of my white tarp boat covers is now in its third
year with no patches or visible signs of deterioration except that the
bright white color has dulled somewhat.
I've attempted to do some backyard tests on the polytarp I offer
versus some other plastic types of material other people have tried for
sailmaking. One is the popular house wrap Tyvek and the other is a pond
liner material that a West Coast business uses in sails and kits they
offer. I used a spring loaded fish scale to check stretch on the warp,
weft, and diagonal. The polytarp showed the least tendency to stretch each
direction. I also used a 16-penny nail attached to a small postal scale to
measure how much force was required to penetrate the materials. The
polytarp offered about twice the resistance as the heavier pond liner and
considerably more resistance than the house wrap. However, I'd highly
recommend keeping all these materials away from sharp objects if you are
planning on using them for sails. Of course, I'd follow that
recommendation with any sail material unless you just like that patched-up
To check the strength of the white polytarp material, I supported a
42 lb. battery on a 3' x 4' piece of white polytarp that I suspended from
a couple of two by fours with six nails, three on each side. If my
calculations are correct, the force exerted by the battery is about ten
times more than would be exerted on the material by a gale force wind
under the Beauford Scale. Even so, I wouldn't want my customers to test
their sails or their luck in that kind of wind. For more detailed
information on this particular test as well as other tests I've tried,
check my web site at
Earlier, I qualified my thesis by saying that some kinds of polytarp
make good sails for some people. If you are a big boat, long-range ocean
cruiser type, or one of those overly serious club or class racers, then
polytarp sails are definitely not for you. Similarly, if you are of those
Wooden Boat aficionados with a fat wallet, a penchant for classic boats,
and friends in high places; then tarp sails probably seem like a travesty
to you and your commercial sailmaker.
I usually get to talk with people who are buying my kits, unless
they simply decide to pay online. Most of the time, I try to find out what
kinds of boats they've built or what kind of boat will carry
their finished sail(s). Of the folks who buy my kits, it turns out, many
are novice builders and sailors. (I have to insert here that messabouters
are universally nice people to work with.) Their projects are smaller
boats with one sail, or at most, a jib and a main. Inevitably, their boats
have unstayed masts they've built themselves, too. I speculate that as
these builders get near the end of their initial boat projects, they start
calculating how much more they spent than they intended on their
boats--and how much they still might have to invest in a functioning sail.
That's about the time that many of these folks start seeking out a less
expensive alternative and end up calling me.
There also appears to be a group of customers who just want to be
able to say that they've constructed everything, including the sail, all
by themselves. For some reason, this group of customers seems to be
dominated by professionals--you know, doctors, lawyers, consultants, etc.
I'm always a little puzzled about why someone with an MD or PhD attached
to the name would want a cheap sail kit. That's one question I probably
won't be asking in my surveys, though.
Another group of customers seems to be made up of experimenters. A
customer from this group usually buys a kit with the idea of making more
than one sail from the material. This customer expects to find the best
sail shape(s) for his or her boat, with the idea of developing a
completely unique sail and/or upgrading to a "real" sail later.
Recently, Sam Hamlin, a teacher at the Shore Country Day School in
Massachusetts, contacted me for material to make nine D-4 sails for the
boats his class of 15-year olds had constructed. We were able to work out
a deal using the "economics of scale" so that the sails cost considerably
less than $40.00 each. This was the second school order I've processed;
and, as a former teacher myself, I'd like to reach far more of this group
For the last two years, I've sent out surveys with self-addressed,
stamped envelopes to everyone who purchases these PolySail kits to get
feedback on product quality and service. (My real job often involves
evaluation projects.) The response rate was a phenomenal 38% last year and
30% (so far) this year. Altogether that means 36 individuals took the time
to fill out this survey. (Those numbers should tell readers that this is
not a high volume or high profit business - just in case one of you was
considering selling polytarp sail kits.) I asked 23 questions in four
categories that covered everything from the ordering process to the
performance of the finished sails. Customers could also add comments and
did not have to respond to all questions, but most did anyway. In the
interest of space, I'll try to sum up their responses.
Everyone who responded was very positive about the service and the
product. I got high marks in the categories of Price/Value and Ordering,
Shipping, Handling, and Packaging. Nearly everyone thought the kit was
fairly priced, advertised accurately and fairly, and would consider
purchasing another kit if the need arose for a new sail. One customer
suggested that I didn't need to include some items that were duplicates of
items already owned by most messabouters, such as the utility knife and
measuring tape. Another person said he would probably buy all the kit
materials locally if he could find the white polytarp. Everyone responded
positively to the questions about how we handled their order and
Another category where we asked questions was identified as
Instructions/Construction. Here we asked about problems following the
generic instructions, construction time, and whether customers stitched or
taped their sails. All but two of the customers responded that they had
encountered no major problems following the generic instructions or using
the kit materials. Of the remaining two customers, one reported problems
making the tapes adhere in high humidity areas such as Florida and
suggested that we warn others of this potential problem in the
instructions. Another customer indicated that we had allowed too much for
the shrinkage of taped edges, reporting that his sail ended up four inches
too long along one side. When asked how the instructions could be
improved, one customer recommended more diagrams, while another suggested
a short video. Most customers, however, seemed to agree with the people
who said, "They worked for me!" or "Instructions were fine."
Construction time was a major variable, depending upon the number
and complexity of the sails, and whether the edges were taped or stitched.
Most of the fledgling sailmakers reported taping their sails and said the
construction time was about 4 hours or about what our ads had led them to
expect. One poor fellow reported taking 16 hours to construct a taped jib
and main for a 12' dinghy. A couple making a jib and main for a Weekender
said it took them a full day to complete. Another man reported 8 hours of
construction time. No one else reported over 6 hours construction time. At
the opposite end of the spectrum was Steve Bosquette, a customer who
reported taping up three sails for his schooner in only two hours. I think
that's quite a feat.
Chuck and Sandra
The fourth category was identified as Performance/Appearance. I
first asked about the kind and size of the sail(s) customers were making.
Again, the responses were highly varied. Shipp Webb of Sewanee, TN made a
little Leg 'o Mutton sail for his small canoe that couldn't have been much
over 10 sq. ft. Chuck Leinweber and his wife Sandra, on the other hand,
used up a 550 sq. ft. PolySail Kit to make a 200 sq. ft. lug main and a 30
sq. ft. mizzen for Pearl, their Jim Michalak-designed
Caprice. Sprits, Bermudas, lugs, gaffs, junks, crabclaws, lateens,
jibs, mizzens, genoas, spinnakers - our customers have made them all from
polytarp. Occasionally, I'll find that the material was not used for sails
at all. Paul Gray noted that he had built a roof for his kids' playhouse.
Others have made bimini tops, boat covers, and temporary boat-building
shelters. Our most common requests, though, are for kits to build sails
for the Stephenson Projects' Weekender or one of the many Phil Bolger
designs that uses the 59 sq. ft. Leg 'o Mutton sprit boom sail.
The survey next asked what kinds of boats the sails powered. Once
again, the responses were many and varied. Up to the time Chuck Leinweber
told me of his plans to use PolySails on his Caprice, all of the boats
that I knew carrying PolySails were within our recommended limits of 20'
and 1000 lbs. I think that, as sailed, Chuck's boat was pushing those
limits at 25' and about 1300 lbs. with three crew aboard. Smaller
Bolger-designed boats, such as the Brick, Teal, Featherwind, and Surf are
among the more popular boats using PolySails. Jim Michalak's designs also
carry their share of polytarp. However, PolySails have also been
constructed for a 14' Lund fishing boat, a 14' West Wight Potter, an 11'
Capri, a customer-designed 19 1/2' sharpie, and a 20' Trimward? Kayak.
While I have yet to get a response from catamaran owners, I know several
kits have been ordered for cats, as well. Each call, it seems, broadens
the list of applications that are possible. The limits of the material are
still being tested, with doubled polytarp offering further possibilities
for heavier boats.
When we asked if the sail performed as well as the customer
expected, the answers were nearly all positive from those who had actually
had a chance to try their sails. (Some northern customers who responded
were still ice-bound when the surveys went out.) One first timer reported
a "hard experience," but that was our only negative response. Some sailors
said the performance was "fine,""better than expected," "exceeded my
expectations," or "surprisingly effective." Most simply answered "yes."
A similar question asked if the sail measured up to their
expectations in appearance, and whether they had received any comments
from others. Again, most responses were positive. The fellow from Florida
who had trouble with the tape adhering offered the only outright "no"
response. Others would probably agree with Don Williams of Olympia, WA who
responded, "Yes. However, I was not able to make it wrinkle-free 100%."
Other comments ranged from, "That's a tarp!" to "Could not tell that they
were not Dacron." One man stated, "It looks great. It would be perfect if
sewn." Another said, "Appearance is good. May be heavier than necessary,
but don't know if lighter material would hold up." Another customer said,
"People are stunned that I made them myself."
Only a few of our customers were sailors experienced enough to
respond to the question about whether PolySails were comparable in
performance to commercially made sails. Five who did respond replied "yes"
to the question; however, one of the five qualified his response with
"...relative to price/value."
I also asked questions about the adhesion of the tapes used in
construction and the overall durability of the sail. It was clear from
five of the customer responses that the vinyl tape tends to lift after a
period of time. How soon that happens depends a great deal on the location
of the customer, the relative humidity, how the sails were stored, how
often the sails were used, whether the sails got wet, and other factors.
One customer responded, "I regret not stitching the sail. After wet
storage, the [vinyl tape] edges came undone." Another said, "The vinyl
tape did not stick all that well. I would have liked it to be wider."
Still another customer reported, "Tape has let go in last four months
since sail construction." Two other customers whose projects (not sails)
were constantly exposed to the elements reported that the double-faced
tape failed after a year of exposure. However, most of the builders,
including four of the ones that reported troubles with the tapes,
responded "yes" when asked if the sails were as durable and long lasting
as they expected. "Only used one season, but seems fine," was the
description by one customer. Another commented, "Hasn't fallen apart yet,"
while still another customer said, "Tape stayed put, even though we didn't
sew the sail." The man in the middle seems to be the fellow who said,
"Vinyl held almost all season."
I recognize that the vinyl tape presents some adhesion problems, as does
the double-faced tape offered in the kits. However, our backyard tape
tests demonstrated that only a very, very expensive tape offered better
adhesion than the vinyl tape we were using. Of four double-faced tapes we
tested, the brand we supply held best in our weather conditions. Stitching
the sail perimeter still offers the best long-range results, but taping is
great for getting a new boat out on the water or trying out a different
For people who like to mess about with homebuilt sailboats, polytarp
sails offer an inexpensive, easily constructed means of powering a boat.
As Emeliano Marino, author of The Sailmaker's Apprentice, wrote,
"Perfectly acceptable [dinghy] sails can be made from Tyvek, polyethylene
tarp, London Fog raincoat material, bag nylon, or tent canvas, not to
mention old sails. Tarp or Tyvek sails may be taped together and require
no sewing." If my surveys are representative of just my customers' views,
there might well be over 100 polytarp sailmakers from the USA, Canada, and
Australia who agree with this veteran sailmaker. And judging from the
number of hits on my website instructions, there could be hundreds more.
(If you want to try your hand at making a polytarp sail, see the
instructions on my website at
http://hometown.aol.com/polysail/HTML/instructions.htm or call
me to order a kit at 317 915-1454.)