Retro Tech Sails  
By Bob Booth - Warwick, Rhode Island - USA

A couple years back I was given a fiberglass Cape Dory 10’ sailing dinghy dating from the 1970’s. As so often happens with boats of such age, too many winter’s snows and seeping fresh water had tenderized the once sound mahogany thwarts and fittings into compost. Thus the winter of 2005/2006 was spent taking her to bare hull and re-clothing her with a lavish assortment of hardwoods, traditional bedding compounds and marine oils.

Following post-modernization sea trials I thought it would be nice to replace the original and somewhat threadbare nylon sail with a new one of Dacron. I was also thinking of replacing the sliding Gunter with a lug rig—so maybe two sails? After picking my jaw from the floor where it had dropped with resounding thud upon learning the quote from a local sail maker, I sought and received advice from sailing friends and web aficionados alike concerning new cloth and various companies specializing in supplying sail making items for those inclined to roll their own.

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The Kitchen/Loft

This idea intrigued me but I found the cost of modern sail fabrics prohibitive for a first attempt. So much so, in fact, that I was not surprised to learn of small boat sails being self-made of blue poly-tarp or TYVEK house covering—indeed these materials are even mentioned by Emiliano Marino in his book, Sailmaker's Apprentice.

Being a bit too much of a traditionalist, neither of these materials, though inexpensive, appealed to me. Now cotton, on the other hand...

Until the very recent advent of synthetics cotton was a staple sail fabric. In his web site The Times and Tools of A.P. Lord, From 1868 to 1957... The Working Life of a Maine Coast Sailmaker, Grant Gambell shows us a Wamsutta Mills sailcloth catalogue; no fewer than 17 weights of Egyptian yacht duck, 13 weights of J-H-B American yacht duck and 5 varieties of Wamsutta Light Sail Cloth are indicated. Additionally, Mr. Gambell points out that Lord also specified “boat drill”, a cheap domestic cotton sailcloth for utility applications, and so at least 36 choices.

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Measure twice, cut once - just like wood!

The problem of course is that synthetics are now the staple and the vast New England mills but empty derelicts; cotton, once king, no longer.

Still, the idea held appeal, but, what weave, weight, source, how?

Robert Leslie in his book The Sea Boat, 1892, Chapman and Hall, Ld, London (D. N. Goodchild 2003 reprint) offers sound instruction with regard to sail making and suggests, for fair weather sails, stout unbleached calico of 27” width or “if cost be no object”, cotton duck. For smaller storm sails he recommends strong linen boat canvas of 18” width. He does not; however, indicate weight of fabric.

Robert Kipping does. In Sails and Sailmaking, 1936 (19th impression) The Technical Press, Ltd., London (D. N. Goodchild 2001 reprint) Chapter II, On Boat Sails, Kipping specifies number 7 canvas for the lugsails of ship’s boats.

click to enlarge Laying out the final shape.

Here a couple of observations, (1) the term “calico” can and does cover a variety of cotton fabric types. Whereas here in the US calico is most often thought of as cloth used in shirts and dresses, in Australia (this according to an Australian co-worker) the term also includes canvas type weaves. Exactly what type fabric Leslie was referring to in 19th Century England, is anyone’s guess. (2) Number 7 canvas is a “double fill” canvas that weights approximately 20 oz. per square yard—much too heavy for a 10’ dinghy—and in all fairness to Kipping, the smallest of the ship’s boat he addresses is 18’

A considerable amount of study of re-printed and original boat plans of the period and time spent in correspondence with those involved in other forms of period endeavors—Civil War period tent reproductions for one, supported the idea of drill fabric. For tents 8-ounce drill was the fabric of choice. 7.5 ounce drill was also spec’d by Marino in Sailmaker's Apprentice for “quick and dirty” cotton small boat sails (4 ounce was specified for ‘traditionally assembled” sails). 4 ounce (twill) was also specified by W. F. Crosby in his plans for the 10’ PEANUT, The Rudder from Goodchild.

Four-ounce drill, then, became my first choice; however, while it is a popular fabric in the manufacture of ball caps, finding a retail source for small amounts proved difficult—and in the end the best arrangement I could find would have involved the purchase a 90 yard surplus from a manufacturing company. 7.5 ounce drill was more readily available in retail amounts, though still somewhat elusive, but ultimately I found a mail-order fabric store (Field’s Fabrics) that offered it for $2.97 a yard (40” width) so I ordered 13 yards to begin the process. (Subsequently, I have found a source of 6 oz drill--contact Gabriela Michalowitz of

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Ready for hemming & rope work.

As with any new endeavor, the process of acquiring knowledge and skill is iterative. Book searches concerning “sail making” return various results, investigations into each publication, influence direction and choices. Ultimately the three previously mentioned books formed the basis of my study while four web-sites/web based articles proved especially helpful: the afore mentioned Gambell site; The Site of Traditional Sailmaking; Historic Balclutha Sails & Today's Options, James Brink, San Francisco Maritime National Park Association; and Archaeological Sewing, Heather Jones.

Over the years I had assembled a fair collection of sail tools—a wonderful seaming palm made in 1954, an assemblage of needles, twine, bees wax, thread, fids etc. To this I added other tools suggested by Marino; a roping palm, a 12” wooden fid, “scorpion-tailed” sailmakers hook, and one spool each of 3 ply, 5 ply and 7 ply polyester twine (ultimately I needed a second spool of 3 ply and did not need the 7). I also acquired pine tar, tallow, tarred marline, a few needles in sizes I did not yet have (#16 needles will work with both the 3 and 5 ply twine and one of these is all that is required for seaming and roping although a heavier needle, #13, will be wanted for leathering.), good quality 1/4” and 1/2” hole-punches and a handful of #4 spur grommets with setting dies. Note: the hole-punches furnished with plain brass grommets intended for use with poly-tarps are NOT suitable for cutting through several layers of cloth fabric.

For my somewhat rusty marlinspike seamanship skills I refreshed my splices: eye, back, long, and short in three-strand, learned a new splice-- “Sailmaker’s” and learned to make up rope grommets and rings of marline.

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Marline Grommets.

Marino’s very first chapter is called the “Ditty Bag Apprenticeship” and it is well worth the time to complete for not only does it teach hand stitch construction skills but the effort to assemble the specified materials will force you to find sources—sources of things no longer carried in neighborhood boat stores (nor for that matter by even the larger wholesalers). Welcome to retro-tech!

Speaking of retro tech, this is a good time to talk about how to make tallow and tar hemp. Tallow derives from beef fat and is rendered through the process of melting the fat in water, separating out any meat bits (protein), letting the fat solidify and repeating the process several times until pure fat remains. Completed tallow will have a waxy firm consistency and is a good lubricant for needles when sewing. I also use it mixed with pine tar and bee’s wax when tarring hemp rope.

You can obtain fat from the butcher or treat yourself to a couple prime rib dinners, trim the leftovers for the dog and boil down the fat. The small amounts of tallow required make this option a favorite of mine.

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Time and patience

Tarred hemp is one of two types of natural fiber cordage suggested by Marino for use as boltrope when making cotton sails. Manila is the other. Although tarred hemp marline is commercially available, tarred hemp rope is not (or at least not from any sources I could discover). D&M CORDAGE ( does list it but in actuality they do not offer real tarred hemp. They do offer a good quality hemp line and provide instructions for “tarring” with spray silicone. Mike Speranza of D&M Cordage makes a good argument against traditional hot tarring around the flash point of the tar and the fire risk associated with the traditional method. I ultimately used a mixture of tallow, bees wax and pine tar (about the consistency of bar Ivory soap at room temperature and the color of toffee), heated the hemp rope in an oven set to 200 degrees and worked the cold tar mix into the rope by hand—alternating heating and working the mix until the rope absorbed it.

Manila is not adversely affected by the salt-water environment like hemp and does not require tarring. Properties that suggest it would be the better choice and if it were not for the very inconsistent lay-up of the spool I purchased I would agree. If you have a source of Manila locally and can inspect the rope prior to purchase I suggest you consider it as the hemp tarring process is time consuming and a bit messy. In my case I ordered on-line from what appeared to be a reasonable source. The result unfortunately was a 600’ spool of 1/4” manila of very uneven diameter, poor strand splices and poor appearance—although, ultimately, I did put it to use as running rigging. The hemp I obtained from D&M conversely was very consistent in diameter, splices were well spaced and appearance excellent.

Sail design. In my research I have collected many sailing dinghy plans and ultimately settled on the sail shown in the profile drawing of a 10’ double ender drawn in 1919. Using the spar dimensions given on the plans and knowing the overall length of the boat, I scaled the sail from the profile and sketched it on quad rule paper. Then with push pins, protractor, tape measure and twine I laid it out full scale on my kitchen/sail loft floor.

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Note Hemp Bolt Rope and Marline Grommets — temporary halyard

I will leave describing the fineries of the actual design process to Marino; he dedicates a great portion of his book to the subject, but will make some general comments concerning my choices and experiences. As previously mentioned I opted for 7.5 oz cotton drill in 40” width. Marino’s “quick and dirty” adjective refers to using full width fabric which to my mind results in a sail looking more like a re-cut king sized bed sheet than a traditional sail--I should point out that some fabrics are available up to 102” in width and bed sheet is the only description for such a thing I can think of.

I really wanted a traditionally finished sail, so I applied Leslie’s thoughts concerning cloth widths and cut the fabric in half lengthwise, giving me 20” panels from which to work.

While reading up on laying out the cloths for marking seam allowance, there was one term which crept up in several sources that I found most confusing—broad seaming.

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Reefing Point Grommets

Broad seaming is a technique used to induce curve into the finished sail by means of increasing the overlap of the cloths as the seam approaches the edge of the sail. My confusion derived from differences in how the mechanics were described in my source materials and also in how one compensated for the additional cloth used. The key to unraveling the mystery lies in the intended sail’s design. Older style traditional sails are laid out with the cloths running parallel to the leech (more or less perpendicular to the foot) whereas modern sails are laid out just the opposite. In modern sails, broad seams if not compensated, would reduce the overall sail height, perhaps violating a class rule. In traditional sails the loss, amounting to a few inches along the foot, is not worried about.

The actual mechanics of making the broad seam are quite simple once your normal seam widths are decided. In my sail I opted for 1-1/8” seam widths with ½” fold under on each edge which provided sufficient width and three layers of cloth for the seams to accept reef points. The orientation of the cloth edges in the normal seam are parallel to each other. The broad seam is created by changing the orientation of the upper panel’s edge away from parallel to form to an obtuse angle as viewed along the seam from the middle of the sail toward the foot and is accomplished by leading the upper panel’s edge further into the lower panel. This “adds” cloth to the width of the seam, hence “broad” seam. In common practice a fixed seam width is often maintained for appearances sake. This is achieved by cutting the lower cloth’s edge at the desired angle, thus removing the extra overlapped bit of cloth, then constructing the seam as usual.

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The whole enchilada

In laying out the seams I found it very beneficial to iron the folds flat first. I did this on the floor using a small ironing board laid under the cloths edge and moved along the seam as I progressed. This helps considerably by flattening and stiffening the cloth edge before final layout and pinning, as the cloths will lie flat against each other. Once satisfied with the layout I pinned the seam in two directions, perpendicular to the seam edge and parallel. The pins placed parallel keep the cloths from moving apart along the seam and the pins placed perpendicularly keep the cloths from sliding lengthwise. I pinned about every 6” alternating perpendicular and parallel pinning. Once pinned, I carefully folded/rolled the sail and moved to the sewing area.

I intended to hand stitch the sail and found Grant Gambell’s A.P. Lord Website a real boon of information. On his site are pictures of sailmaker’s benches with sailmakers using them. While I have yet to build my own bench to the style depicted, the practicality and utility of this tool is remarkable. For this sail I employed an old coffee table, which worked well enough, and as my experience grew and techniques evolved I developed a list of traits my bench would require.

The sewing area needs just a few things, (1) good lighting, (2) a clean floor since most of the sail will lay there, (3) a bench/coffee table, (4) a place to tie off your sail hook (closet door knob or table leg worked for me—depending on the angle required on the hook), (5) small tray table within easy reach on which to keep extra thread, needles, and wax (if you build a proper sailmaker’s bench all these things will have their proper place and the tray may be omitted). One other very important item is required, MUSIC. Sail making is a most Zen endeavor and will give you ample opportunity to explore your inner light, for those times when your light becomes tired, music is the salve.

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Plum Crazy

Sewing took place on long dark New England winter’s evenings. But progress does come slowly as the pictures show. One word in closing, based on experience with the final product, the 7.5-8 oz cloth with roping, leathered corners and pressed in ½” metal corner grommets turned out a sail much too heavy for the little 10’ Cape Dory. For such a boat I would try very hard to find a 4oz cloth. The 6oz recently found is slated for a small 37 square foot sprit-s’l (half the size of this sail) for a 10’ skiff and will have far less weighty hardware. 6 oz will also be used for a 12’ gaff rigged 1800’s “sea boat” of William Atkin design.

Sail finish: The sail is finished natural being well sprayed with water/stain proofing, which only darkened it slightly but added no color. Pete Culler’s fond cuprinol will produce a greenish tinged sail.

By the way, aboard a newly retrofitted 1954 Blue Jay hull the 76 square foot lug sail performs well in airs above 8 knots.

Bob Booth