Polysails - The Sheet Sail Alternative

Novice sailboat builders often find themselves in a quandary once their plans actually go 3-D. A quality sail for their new craft invariably costs much more than expected and often exceeds their investment in their newly completed hulls. Invariably, these newbie builders begin seeking advice and alternatives on the Internet, and chances are high that they will eventually encounter other builders or web sites where they will learn about polytarp sails, a polyethylene sail made from a lowly, but inexpensive, tarp.

Ray Hodsdons beautiful little shellback dinghy underway powered by a PolySail. Ray, who formerly sailed 18’ Hobie Cats, provided a very positive testimonial on his polysail's performance. (click images to enlarge)

A few years back, the tarp-equipped sailboat would have been easy to spot. The homemade blue or green sail flopping in the wind was a dead giveaway. The irrepressible Captain Freddie, who sailed his fiberglass cruiser equipped with blue tarp sails from Massachusetts to Florida is something of a cult hero to the tarp sail crowd. A follow up article in Soundings a few years ago found Freddie in Rhode Island writing a book about his adventures. (There is a photo located HERE. Over the past few years, however, a heavier white polytarp material has made spotting tarp sails much more difficult.

Popularized by PolySail International, a garage-based, part-time business offering white polytarp sails in inexpensive kit form, PolySails now appear on smaller home built boats around the world. Over 500 of these kits have been sold over the last ten years. Kits have been mailed to all 50 US states, and numerous foreign countries, including Australia, Canada, England, France, Greece, Italy, Ireland, New Zealand, the Philippines, and Thailand. A few of the white polytarp powered sailboats have even appeared in the builder’s photo section of Wooden Boat magazine.

Spiros Mamais of Athens, Greece built a lug sail for his homebuilt craft from a PolySail Kit.

What are PolySails? These are sails constructed from three ply white polytarp material imported from factories located in China, India, Pakistan, and South Korea, and other Pacific Rim countries. The tarp’s center layer is created of polyethylene strips in a 12 x 12 or 14 x 14 weave per square inch. This center layer is bonded on both sides by flat sheets of the same material, creating a plastic-like material about 12 mils in thickness and weighing between 5 and 6 ounces per sq. yard (not a sailmaker’s yard). Occasionally, the material can be found in “canopy grade” weighing about 8 ounces per square yard. Compared to the common blue tarps which weigh about 3 ounces per square yard, usually have a 6 x 10 weave, and lack the ultraviolet protection of the white tarps, the white polytarps have less stretch and are considerably more durable. Up close, the plastic-like surface, the lack of sailmaker’s seams, and the characteristic wrinkles in the material distinguish the PolySail material from more traditional sail materials. To prove the material’s strength, I have suspended a 10’ x 12’ tarp in the air and stood in the middle of it. I weigh about 190 pounds.

Because PolySails are made from a single sheet of material, they usually depend on edge rounding and a dart or two to define their shape. Shape is also aided by the manufacturing process which uses heat and pressure to “weld” doubled edges and lapped seams into the material. This process shrinks the edges and seams and allows some stretch in the tarp’s interior. To make a PolySail, a builder uses double-faced tape to create the sail outline. After removing the tape backing, a reinforcing line is run around the interior of the tape. Afterwards, the exposed tape edges are lapped back over the line, creating the sail type of the builder’s choice. A taped and grommeted sail made to my directions, usually takes about 4 hours to complete and will last about a season before the tapes used in construction begin to lose adhesion and a stitch must be run around the perimeter of the sail to preserve it.

Nearly every type of sail has been made from white polytarp over the past few years, primarily for smaller boats up to 16 feet in length. Favorites seem to be the 60 square foot leg o’ mutton sail used by designer Phil Bolger on a number of his small boats and the Weekender gaff and jib for a small cruiser designed by Stevenson Projects. We have surveyed our customers over the years, and about half these amateur sailbuilders report performance equal to other synthetic sails, such as Dacron, constructed in traditional sailmaking fashion by professional sailmakers. However, as one customer pointed out, there were other factors besides performance that were involved when comparing an inexpensive PolySail to a commercially made sail that cost nine times as much.

Typically, PolySails are used in protected waters in light winds, although there is one report of a PolySail surviving a tornado with minimal damage. Three years of surveys with response rates approaching 40% have shown customers to be overwhelmingly positive about their kits and finished sails.

Me sailing my 16’ sharpie "Essence" down a channel near my home. "Essence" sports a jib-headed, sprit-boomed PolySail.

In ten years only one customer has ever reported a material failure in a PolySail. However, when we offered a replacement kit, the customer blamed himself for the failure rather than the material. More survey details and PolySail research are available HERE.

Given the positive results for the customer-constructed kits, Gray has recently started producing ready-made sails for some popular boats and custom sails for others. He anticipates continued growth for his PolySails and kits as the sails appear on boats across the country and as the media begins to report on their quality and performance. While he doesn’t anticipate immediate acceptance by some of the more tradition-bound sailing clubs and media, he predicts that price and performance will continue to drive growth with the less well-to-do sailors and with home builders. Kits and sails are currently available from PolySail International, complete with shipping, in a range from about $60 to $200.

More articles about Polysails:

• Survey of Polysail Customers - 2004
• Making a Polytarp Sail
• High Aspect Marconi Polysail
• A Polytarp Junk Rig
• Shaping White Polytarp Sails
• A Polytarp sail for Lil'jon
• PDRacer Sails Down Under
• Decision Time
• Sail Dart Calculator

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