Jim Michalak's Boat Designs
118 E Randall, Lebanon, IL 62254
A page of boat designs and essays.
(15 December 2014) This essay will present an essay by David Gray about advances in polytarp. The 1 January 2015 issue will be about rigging a sharpie sprit sail.
THE BOOK IS OUT!
BOATBUILDING FOR BEGINNERS (AND BEYOND)is out now, written by me and edited by Garth Battista of Breakaway Books. You might find it at your bookstore. If not check it out at the....
ON LINE CATALOG OF MY PLANS...
...which can now be found at Duckworks Magazine. You order with a shopping cart set up and pay with credit cards or by Paypal. Then Duckworks sends me an email about the order and then I send the plans right from me to you.
Wojtec Baginski sailing his Robote converted to sailboat in Poland, carefully.
118 E Randall,
Lebanon, IL 62254
Send $1 for info on 20 boats.
This is a guest essay by David Gray. I met David long ago at a Lake Monroe, Indiana, Messabout. Back then he lived in Indiana not far from the messabout and he was exploring alternate ways of making boats and things with cheap and common materials, in particular foam board hulls as I recall. About the same time we were experimenting with sails made from cheap Walmart polytarps. And David grabbed it by the bit and took off down his own road with the material. He has been experimenting with poly sails for decades now and I see his sails, very successful, and messabouts all over. David wrote me and suggested I was way behind the curve in poly sail knowledge and I quickly suggested he reeducated us all. I have also asked him to educate us on his construction and sail shaping techniques in a future essay. Anyway, here is the start...
AN UPDATE ON POLY LAMINATE SAILS BY DAVE GRAY, POLYSAIL INTERNATIONAL...
I have been building polyethylene laminate sails for nearly 20 years now, but for many of those years I didn’t really understand much about the material other than almost everyone called the material polytarp and it was cheap and it could be shaped (or not) into fairly decent sails (or not). I fashioned my first sail out of lightweight green hardware store polytarp in 1994 for my recently constructed Bolger Cartopper. The green sail I built worked well enough to get my son and me out on the water of an Indianapolis reservoir, but it was baggy and lacked the look of a “real” sail. But the idea of a cheap sail that could be built quickly to get others out on the water really intrigued me, so I began reading about how canvas and cotton sails of old were made then applied that knowledge in constructing paper models of popular sails out of sheets of graph paper. Using taped darts, rounding and hollowing to create shape, I wanted to see if a similar technique could be used with the slick, stretchy tarps. At about the same time as I built my sail, Jim Michalak and a couple of others were experimenting with sails constructed from heavy silver polytarps as well as the lightweight blue tarps.
Back then the Internet (then called the World Wide Web) was still in its infancy with most of us on dial up connections to the web via telephone at home; and we had a few rather limited search engine options like the Web Crawler, Excite, Yahoo, AltaVista, and InfoSearch to work with. However, I was an “early adopter” because of my company’s need for information and educational resources at work, and I managed to use the ‘net in my spare time to locate a supplier of all white polytarps and to learn much more about tarps and sails. Being an Indiana guy, I also knew of a company about 40 miles north of my hometown that seemed to be operating a very successful business based on sailmaking kits. That company, located in Columbia City, was called Sailrite, and it looked like a good business model that was also ripe for a little low-priced competition. Armed with a white polytarp prototype sail on the Cartopper, an order or two of white tarps, and a marketing plan to make available the white tarps in different sizes in cheap sailmaking kits for boat builders and Do-It-Yourselfers, I started a part time business in 1996 with a web site on AOL called White Polytarp Sails.
Our first polytarp sail, 1994. Our first efforts at sailing really amused the nearby picnic crowd. I forgot to put the centerboard down, and much to my son’s discomfort, we sailed directly into the brambles lining the shoreline. The crew suffered a few scratches, but the sail was okay. We re-launched and all was copasetic.
My first white polytarp sail at Jim Michalak’s Midwest Messabout at Lake Rend, Illinois, mid 1990’s. I think I gave Jim one of my first ever sailmaking kits, and we stretched out one our large white tarps over the cooking and eating area when a drenching rain approached.
Mid 1990’s. Captain Freddie journeys from New England to Key Largo, Florida, powered by lightweight 2.7 oz. blue polytarp sails. Photo by Fernando B. Silva. Story by executive editor Herb McCormick is here: Cruising World, Sept. 1997, p. 5
Although white tarps are still a scarce commodity in most big box stores here in the US, white continues to be the most popular color for kits and sails ordered from our web site product pages. However, driven by the demands of greenhouse growers and canopy manufacturers in the US as well as agricultural food producers in England and Europe, tarp manufacturers in Pacific rim nations are producing a wider variety and more durable selection of white poly tarps and other poly laminates to meet specific covering* needs. Consequently, white poly tarps and laminates usable for sails can be found in weights from 3 oz. per sq. yard up to 12 oz. or more per sq. yd., in thicknesses ranging from 4 mils to 24 mils, and with scrim counts in the middle laminate ranging from a sparse weave of 6 x 8 strands per sq. in. up to a densely packed 16 x 16 strands per sq. in. U-V protective applications have also been increased by many tarp manufacturers resulting in more seasons of potential use. Greenhouse growers, for example, now have coverings two to three times the durability they once had. Nearly all tarps still carry the identifying “welds” every 6’ down the length of a tarp, but these welds where rolls of material are joined in the manufacturing process appear to be much more uniform and without so much puckering along their edges as they once had. Last year we chose an 8 oz. per sq. yd. polyethylene tarp for the sails to power the 5 ton, 36’ long scow Spirit pictured below. This Civil War era blockade-running scow replica was built by the Crystal River Boat Builders using largely traditional materials and tools. We believe that she carries the largest polyethylene laminate sail made from a tarp in the world. On a recent Gulf Coast voyage returning from Cedar Key, “Spirit” clocked over 8 knots much to the surprise and delight of her crew.
A 30’ x 40’ white tarp provided enough area to cut both the 507 sq. ft. gaff main and the 135 sq. ft. jib. Much of the work had to be done outside. It’s a good thing I live in South Florida.
A crew from the Crystal River Boat Builders and friends puts “Spirit” through her paces on a shakedown cruise up Florida’s Crystal River.
Some of the heavier white poly laminates are now available directly from manufacturers in long rolls as wide as 10’ or 12’, allowing small sails or high aspect sails with a smaller foot to be cut with an entirely seamless or “weldless” surface. Because this poly laminate or polysheet material would come off a roll from a manufacturer rather than folded from a tarp supplier, the roll material would also lend itself to computerized cutting and sewing as well as precise and rapid reproduction of nearly any sail within the foot limitations mentioned. Although this material currently costs more than tarps from wholesale suppliers, economies of scale could easily make the price per sq. ft. of producing sails from this material potentially much less than any other viable material for sailmaking. The manufacturer should not call the sails polytarp sails, however, or he or she would risk losing all the customers who still visualize all tarps as the lightweight blue material Captain Freddie used. Two customers have prototype sails made from this material and have responded very positively to it.
*Most tarp suppliers here in the US still do not understand that their products have alternate uses other than as coverings. I find that it’s important to educate at least one of their salespeople (if not the company president) to our needs as a sailmaking company and wholesaler of their materials in kits so that I get both their better quality products and a discount when I order from them. I’ve also found that you have to be very selective in picking suppliers because quality of service and product varies so much across the industry.
Blue tarps, once available only in 2.5 to 3.0 oz. material without UV protection (and still available in those weights at big box stores and as utility tarps from most suppliers**), have likewise improved primarily because of their use by the Federal Emergency Management Agency (FEMA) in disaster areas. FEMA requires that their shelter tarps meet the following conditions:
Self Help Tarp to be used for small areas of roof damage.
• Size 20’ x 25’
• Woven polyethylene 8 x 8 weave count (10 x 10 or 14 x14 acceptable), 800 Denier
• Thickness 5-6 mil
• UV Resistance - 80% after 200 hr per ASTM G23
• Non-corrosive grommets at corners and minimum of 3’ on center on edges
• Hems folded over
• Corners reinforced
• Color – medium blue
• Packaged in cardboard box with 2x 100’ lengths of 550 pound test parachute cord
These blue tarps work well for small unstayed sails up to about 65 sq. ft. and are ideal for small boat “hatches” since several sails can be made from one tarp. Unlike other colored tarps, blue is not a color that is available in a 6.0 oz., 12 x 12 weave count, and 10 mil thickness. It is, however, available in a very heavy poly laminate that is roughly 8 oz., 16 x 16 weave count, and 16 mil thickness that is appropriate for very large and very high stress sails. On the down side, this is very expensive at approximately five times the cost of a FEMA tarp sail or very nearly the cost of Dacron. We are using one as a prototype jib for a large, heavy planked fishing boat in Haiti.
Many other tarp materials are now available in colors in 6.0 oz. weights, 12 x 12 scrims, and 9 to 10 mil thicknesses. We keep the following 6.0 oz. solid colors in stock in 12’ x 20’ sizes: yellow, orange, red, green, and desert tan. We have made mainsails up to 173 sq. ft. with these colored tarps, but we think it better to limit the colored mainsails to about 155 sq. ft. after seeing them used in the open waters of the Caribbean with a storm front passing through. We note that different suppliers offer two distinct reds and both are likely to fade in areas where there is intense sunlight. One red tends to fade to a rose or even a pink, and the other tends to fade to red-orange color. We haven’t yet noticed a similar tendency to fade with the other colors now available. We hope some enterprising manufacturer will soon come up with a tanbark color, but we haven’t seen it yet.
The first round of colorful sails for a sail replacement project in Haiti.
Recipients for the second round of sails.
**Don’t buy lightweight blue tarps for sails. The materials stretches too much and deteriorates far too quickly.
We are currently engaged with a foundation under the determined leadership of Patrick Beliard that is underwriting a sail replacement program for the fishermen/sailors in a fishing village in Cap Haitien, the nation of Haiti’s second largest city. For us the project is an opportunity to assist a community of people living in barely sustenance level conditions in the Western world’s highest poverty nation and to test our white and colored sails in almost daily use in a truly tropical environment. For the Alfred Beliard Foundation, the cost of procuring the sails is low enough that they can sell sponsorships for each sail, have the company name and/or logo placed prominently on each sail, and use the profits from the sponsorship to buy paint for the boats, clean up the beaches, and assist in promoting tourism for an area that could easily become known as the next low cost tropical paradise if the foundation’s dynamic recovery plan is successful. The foundation’s model, we believe, is also transferable to other struggling community sailing programs elsewhere as a fund raising model. For more information on how it all works, we suggest that you visit their website at Haiti Sailing Cup
In the time between “Back Then” and “Today” I’ve continued to research, learn about, and test the limits of polyethylene tarps and laminates used for sails. A few conclusions that I’ve reached that I think are valid are that: 1) it’s a surprisingly tough material that you suspect might fail, but it doesn’t. It breaks masts instead. It’s like the little plastic bags that the grocery stores use. Nobody quite trusts a single one of those filmy polyethylene bags to hold a bottle of wine, but somehow they do as long as the bottle doesn’t slip out of the top when you fail to grasp both handles. 2) If you use the correct weight and thickness of the material for the size of sail you are building and follow our instructions for shaping and reinforcing the sail edges and corners, it’s surprisingly easy to construct a high performing sail for comparatively little money. In other words, poly sails are a good value. 3) The polyethylene film and laminate business worldwide is a $24 billion industry. There are good reasons to learn more about LDPE, HDPE, and PET, the acronyms standing for different polyethylenes that all start their lives as oil-based polymers and transform into low and high density polyethylene or polyethylene terephthalate. One yields poly films and strands, the other polyester strands that become Dacron and Spectra and a lot of other high cost names. For more on this subject, check out this URL: http://scifun.chem.wisc.edu/chemweek/polymers/polymers.html 4) Sailrite is now under second generation Grant family leadership and appears to have transformed itself more broadly into a Do It Yourself marketplace. It’s time to seek out boat designer partners and return to the sail kit business with a vengeance. 5) A book with directions specific to constructing particular types of sails and even the more popular specific sails using poly laminate materials is long overdue.
Should this brief look at changes in the poly laminate sail business leave you breathless for more, please read and comment on my upcoming article “The Case for Poly Laminate Sails” in an upcoming Duckworks Magazine or the January issue of Messing About in Boats.
Thanks to Jim for inviting me to discuss a few details about advances and opportunities in PolySail sails and kits.