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The Merits of Flat-Cut Junk Rig Sails by Kurt Jon Ulmer

The Merits of Flat-Cut Junk Rig Sails by Kurt Jon Ulmer

The Merits of Flat-Cut Rig by Kurt Jon Ulmer

Cambered sails are better than flat ones. An iPad is better than a Linux netbook. A diesel auxiliary, better than an electric motor. But I’m writing this on an old Linux computer, in the pilothouse of a flat- with electric propulsion. Why, when I could have... all the best? Converting mehitabel to Junk Rig ‘Practical Junk Rig’ and my own brief study and common sense were all the resources I needed to create the junk rig for mehitabel 10 years ago. We still use our first set of junk sails, and they’re lasting well. First set of battens too, with the original scantlings. Our top batten just below the is now doubled, as a preventative. The only-ever bend was minor, caused by my over-sheeting while hove-to for several days. Same yards, but I had to lengthen them because I ignored Hasler &

KurtUlmer Jon McLeod on that detail initially. I cheated Hasler & McLeod for the sake of sail area on a Sail planform of mehitabel. Now that’s flat... couple of other points, and each has shown up as a mistake we live with. New booms, a gift from Paul Thompson. New fendering, since leather is abrasive and polythene is better. I’ve made few other changes, and never had any breakages nor the urgent necessity to repair anything at all. (How far? How hard? How long? Approaching 6,000 junk sea miles, after about 10,000 under Bermudan cat schooner rig. Gales, yes. Lived aboard 17 years. In constant refit of something or other, but not the rig.) By the time I was planning mehitabel’s rig, Arne Kverneland had shared the details of his cambered panel sails, and other inventors had documented a few bend-and-stop batten devices. Why didn’t I go for a then-state-of- the-art junk rig with some form of added camber? I resisted the temptation because: had sailed Well Enough on all the open oceans with flat-cut sails; I had no mentor for making the cambered panel rig offshore-reliable, while I had Hasler & McLeod for the flat-cut option; I could easily have gotten it wrong and then needed to re-sew the sails to put it right; The camber seemed so compromised by KurtUlmer Jon distortion at lifts and , that I wondered, “But is this flat?” ‘Why bother?’; I wanted no flogging, flapping or fluttering problems; I had learned that strains were distributed in junk rigs, and I thought loosening up the fabric would result in point loading; I had only a few months before an offshore trip; Finally, I could foresee expenses, complexity and time going beyond what we were ready to commit. Also, I saw a way to add camber in the future, by retrofitting and perfecting bend- and-stop battens. This gave any over- ambition an easy way out. The change later on wouldn’t require new sails, wouldn’t point-load the spars so, wouldn’t lead to flogging. The battens could be phased in and taken out experimentally. ‘Bend-and-Stop’ sketches led me to ‘Smooth-Curve-and-Stop’ ideas - an intriguing design problem for idle hours, but I put off any work until I reckoned we needed added camber. Later. It is later. The sails are still flat. Flat-cut, that is. David Tyler

Twisty full sails, close-reaching in very light air, with camber enough

Cambered Panels Now and battens, breaking of battens, things by pulling harder than sails banging when rolling in a before on certain points, ignores In 2012 there are excellent seaway, qualms about motor- the fact that it’s the distribution of resources to get one started sailing behaviour, and batten ends strains in the junk rig that makes it cambering. With study and fouling sheetlets because of innately robust even with weaker common sense there’s no reason negative stagger when and individual parts. someone can’t make good-as-can- furling. They’d be called serious be cambered sails today. The Fays Putting skinny slick tyres onto a on mehitabel, that is. None of them did, for Ti Gitu; Anthony mountain bike gives instant happen. Swanston, for Wild Fox; Annie Hill results. It goes faster, rolls for Fantail; Graham Cox for Arion; They are products of departing smoother, steers easier. You David Thatcher for Footprints; from the tried and true, which wouldn’t like it in winter in David Tyler for Tystie. always invites difficulty - now Canada. Risky on jumps. And it we’ve defined the word adventure still won’t win a road race. There are many others, of , pretty closely. and also several methods besides To some people, a mountain bike is adding camber to each panel. Less The problems of cambered sails a whole concept, an organism discussion is heard these days will be solved. That’s what almost. Evolved to be something, about hinged battens, pre-formed humans do. In the process of with its own integrity; best if curved battens, of perfecting their rigs, JRA members uncompromised. If a mountain various kinds, etcetera. But we can are lucky. They get the benefit of bike isn’t Good Enough at be sure there is still considerable each others’ sea trials in real time, something important, well, there ‘messing around,’ some of it with and from all the oceans at once. are other bikes. success. This is a very cool and useful My primary aims for this long bold Association. Some of the people mentioned article are to argue for the above, have had serious problems. But to react with heavier scantlings functional integrity of the basic They include frustrations with sail as solutions, is to use brute force ancient junk rig, and to elevate the setting, severe bending of yards instead of natural toughness. To fix strange idea of Good Enough. Topical Thoughts Genoas and Dipping Lugsails Gorgeous camber, a fine clean leading edge, smooth tailored curves undamaged by the press of mast or lifts - why aren’t we talking about these? We can discount dipping lugs because wonderful as they are, they don’t make for an easy, general-purpose rig. Although some of us would enjoy the lift genoas can provide, sometimes, and some of us would like to win races against them, they offer nothing to compare with the handling advantages and versatility, and the inherent robustity, of the well-sorted junk sail. Theresa Ulmer Junk sails have one huge advantage Reefed fans - more effective than they ought to be over genoas. No, two. They can Nothing happens. Motor-sailing, of lifts and mast, it suffers present a large area of sail, high up rolling in a sloppy sea, anytime the deformations. Excuses can be made and pulling, when a will flop sheets are let go, nothing. that the air skips over the dents pitifully. And they don’t need such and bumps, deceived, and nothing More power from cambered sails strong corners. But there’s more. is lost, but I don’t buy it. Smooth is induces more heeling, all else being Self-, reefing without going smooth, or glider pilots wouldn’t equal. Not only more heeling, but all baggy, sheeting without wax their wings. more changes in heel angle with ... changes in the , self-steering We can hardly praise the junk rig Camber Itself corrections, speeding and slowing for having no standing and over swells, etcetera. On a sport- praise the kind of junk camber I see Imagine that we hang two sailing day nobody minds a little in many photos, in the same breath. bedsheets on a line some breezy excitement. On passage I don’t After all that careful broad-seaming day, one a fitted and one welcome it particularly. There or shelf-shaping, don’t you just plain. Pin the plain one with 8 pins might be a cake in the oven. want to let the lifts go slack? Ah, evenly spaced along the but this is a junk rig, so it’s not clothesline, and the fitted one with It makes sense to position the sheet usually done. It would be more 1 pin, or 4 pins if you like, only at over to windward when hard on work. each of two corners. No, that’s not the wind with cambered sails, in fair. Cambered panels are attached order to make best use of the Yards and Battens to their battens much the same as different, improved entry angle at It's a tough life! Yards press and flat ones. It’s from then on that they the sail’s luff. Athwartships horses then bang against the mast and the behave differently. You may use 8 or other inventions are useful if lifts, and get gusted around pins, then, spread along the edge. you sail that way a lot. A big hook unpredictably, gybe roughly But be ready to catch them. Which on a purchase to the weather rail sometimes, and may even get sheet will unpin itself or tear itself, might be the Chinese answer, and a pulled hard and unfairly against a in a gusty afternoon sea breeze? crew member to manage it. forgotten sail tie. Occasionally. I’m All analogies limp, but I’ll venture Flat-cut sails are more tolerant of getting better. Battens suffer from one more point from that one. The sheeting angle when sailing to sheeting forces that are inevitably plain sheet can feather itself with windward, and don’t need an too-much-downward, from the wind, while the fitted one has answer. You may joke that they’re compression, from or no choice but to pull. Our flat-cut not sailing to windward, but be luff hauling parrels’ demands, and can be left fully raised at kind. from having their smooth bending in very strong wind, interrupted by taut lift spans and a When camber meets the hard lines without damage or drama. mast. A Hong Kong parrel wrenches the stronger than beams made for even especially since we can't predict in wrinkles out of a cambered panel loading. A yard is more than just a which direction nature will try to by taking all the sail-shaping stress beam, but it is that at least. break them. On mehitabel, weight at two points on the battens with helps the fore yard fall all the way With end loading and the powerful one piece of line, whereas a flat-cut to the bundle at once, the moment I peaking-up force required to shape panel pulls along the whole length go forward to drop the anchor. On the sail, how many cambered panel of two battens and the whole multi- a good day. I wish it were a touch sailors have looked up and seen a diagonal matrix of the fabric panel heavier, actually. visible curve in their yard in to do the same job, and hardly normal use, as a welcome to the The cross-sectional shapes that wrinkles in the first place, world of better windward make most sense to me for yards compared to a cambered one. performance? are fat oval and circular. The fat Hauling the throat and/or upper oval is a concession to the routine One could use a bridle on the main luff aft with some combination of weight-bearing direction, which I , plus a gaff-style peak running parrels will solve sail- think is reasonable enough. Our halyard, plus a throat hauling shaping glitches for most of the timber yards are fat ovals. Their parrel. That would spread the load cambered panel boats on the water, thickness was meant to follow to several points, but only when all and Hong Kong parrels will be well Hasler & McLeod’s scantlings, but are properly trimmed at once. Not dispensed with. But the poor old they ended up a little thin - all I in the spirit of the junk rig’s yard ends up taking more of a load could get out of the timber. I added automatic ease of handling. at the throat. Not the idea. unidirectional glass to reinforce A yard has a lot in common with them - a ‘tendon’ let into a groove If the top panel is cambered, all the the that joins a chain to an along the top, and a heavy layer on luff and leech forces weigh on the anchor. It’s a bad place to make the surface. Their middles are ends of the yard. If that panel is lightness a priority. I fail to see a grabbed with substantial wraps of flat, the sail fabric distributes the good reason for aircraft-style . Each yard is lashed all along load along the yard. Beams made lightweight design in yards, its length to a flat panel of heavy for end point loading have to be KurtUlmer Jon

Fan camber pulling well, on starboard & port tacks fabric. If our yards were to break, I whole batten in any direction. say, 10 knots or less. honestly don’t know what I’d do. There isn’t only one diagonal in a One disadvantage is brought out junk panel, there’s a matrix of Uppermost Panels against flat sails: Poor performance forces in warp, weft and bias. If in the region of headings closer People must puzzle over whether camber is added to the panel, the than 60 or even 70 degrees either to add camber to the uppermost fabric can only pull on the ends of side of the true wind, unless there’s panels. In a Hasler & McLeod the battens. And all the battens’ something more than 10 to 15 knots pattern sail, some fan-style camber own loads are unsupported except of wind. Above 15 knots, it gets with twist is naturally present up at the ends. down to 50 degrees for mehitabel. there. I reckon adding fabric to the Thus a Hong Kong parrel can bend top panels doesn’t produce useful Poor performance, we’ll say, means a batten upwards grotesquely in a camber so much as it disturbs an excessive leeway, too little speed to cambered panel sail. airflow that might follow the fan be useful, or inability to with shape if it had its way. Compression - that evil force that authority. Good Enough will take advantage of any out-of- performance is harder to define. In a David Tyler Fantail sail, I think column-ness to bend or break a added camber in the narrow panels First Question arises: How batten - is acting only at the of that beautifully twisty upper fan important is that close-hauled opposite ends, worse than is likely to be detrimental in a region of sailing, to me? compression acting at each lashing similar but sadder way. all along the batten. To simulate the On an ocean passage, pointing high Aphrodite and La Chica follow Van same end-loading with a flat panel, is miserable. The faster, the more Loan’s sail planform with low- picture a batten pocket instead of so. In coastal sailing it’s fun, if the yard-angle sails. They have ample lashings, fairly loose, and smear sea is only a chop. In very light camber sewn into the panels, and grease on the batten so it will let all wind, I almost wish for a big no attempt at fan camber. While the tensions in the panel go to its inflatable dipping lugsail. No, I sailing on Aphrodite, it seemed to ends and compress the batten. should freely admit the wish. I do. me that every panel’s camber was More likely, though, we’ll anchor I allowed you to pin the fitted sheet in line with the path of the air. until the breeze fills in, or take to the line with 8 pins spaced out, Even the top panels could use some help from the motor. (Electric but now maybe you see why I was considerable camber, if we picture motor-sailing is a bit special, and reluctant. a slightly spanwise flow near the seems to suit junk top, and if we ignore the next The taut sail membranes on especially well, but that’s another paragraph. mehitabel are like resonant topic.) drumskins. I can literally send a The top panel or two of a junk Second Question suggests itself: wave through the whole by must become the stormsail when How good is Good Enough, for our banging on the fabric or plucking the lower panels are all safely ? on a sheetlet. When camber is tucked away. Our flat-cut top added to panels, an opportunity is A few fellow junk sailors saw panels make for a pair of sleek, lost - not mainly of playing the mehitabel sailing last year and well-behaved little crab-claw sails drums on your sails, but of every were impressed. She’s lively, on mehitabel, when we’re down to part sharing every strain, of the weatherly, heels little, steers well, that. How much camber, how music... tacks smartly, carries decent coffee, much drive, how much extra cloth, etcetera. It isn’t that she has a do you want in your stormsail? I Performance and Trade-Offs magical , or . And want very little, so for me there’s The points above accent the her electric motor was indeed off no puzzle at all. inherent strengths of flat-cut sails, the whole time. Our top panel is flat, with webbing and the problems inherent in It’s just that a flat-cut junk rig can in the slightly hollow-cut leech; lots cambered panel sails as I see them. be that good! mehitabel is only one of independent lashings to yard Now to turn the tables. example, and not necessarily the and batten; a strong yard above What can be gained with cambered best. and a double batten below. The panels, and what’s wrong with flat- next panel down is flat, believe it or The boat matters quite a lot, of cut sails? not, and has a double batten above course. But the result can be as and the whole bundle below. One advantage has been cited: Sails good as a particular boat could with added camber are more ever be, less a few percent, or x Concentrated Loading powerful with the wind forward of degrees or so, in some conditions, Lashing a flat panel to its battens a beam to broad reach, noticeably off of some arbitrary ideal value. allows the web of fabric to so in light , and especially Small losses, unless your First distribute all its tensions to each when pointing close to winds of, Answer was, ‘Very important!’ If your ambitions do run rather high, what draws you to the junk rig? Not that you need an excuse... If the admission of such inferior performance as I imply makes flat- cut junk rigs, suddenly nowadays, suitable only for downwind sailing in the Trades, my goodness... what has changed? They’ve been everywhere. With and without engines. Ours is surely Good Enough to satisfy us. But here, I should admit that I personally like 6 knots better than 8 knots at sea, and I can be Happy Enough with 4 and a bit for days and days. Her crew doesn’t share all of mehitabel’s ambition, flat as that is, and reefs are normal. KurtUlmer Jon Yard lashing at peak, distributing strains at every opportunity Given 15 knots of wind, mehitabel doesn’t lack power or performance on any , for anything we would want her to do. Most of her offshore sailing has been close- reaching, and she keeps needling me to go to Chile from here. Second Thoughts Suppose all else were equal. That is, the cost and effort of making, simplicity of repair, good behaviour in use and misuse, tried- and-trueness, innate robustness, distribution of strain, storm- worthiness, documentation equal in rigour to ‘Practical Junk Rig’ - suppose all were the same for flat- cut and cambered panel junk sails. What reason would I have then, not to recommend cambered panel KurtUlmer Jon sails to a friend, especially as I Yard sling point, not to be doubted surely wouldn’t want a friend to suffer, as we might be supposed to,

under flat ones. engineless in a light-wind area like No, on second thought, not even British Columbia in summer, or if I then. Accepting such a small loss Well those things are not equal. were more intrigued with the as that, allows us to use sails free And besides, we suffer not at all. problem-solving process than with from vices, and an ancient rig with Annie Hill: “...that last 5% of the actual solution at the masts, its ingenious principles intact. I efficiency comes very expensive.” then I might consider going for accept it. Now the wrinkles and cambered panel sails. extra sewing and adjusting and Maybe if I were a racing sailor, or uncertainty and pioneering that go staying close to aluminium tubing But wait. For the top few percent? with cambered panel sails, as they suppliers, or we were wealthy, or Maybe 5 or as much as 10 degrees? are at this point in their evolution, sailing inshore, or not living on the When the wind’s below 10 knots, need not occupy me at all. I can go boat with our stuff, or trying to go that is? sailing. Flat-Cut is Not Flat - A good chance it will work well me, and it were now, and our boat ‘out of the box.’ were single-masted and smaller Camber in a flat-cut sail comes from than about 10 metres. I intend to stretch within each panel, from - Needn’t be expensive. make one of these for our 4m slight bending of battens, and from Secret One - As Good as Ever. in the next while, but don’t the panels’ fanned presentation to wait for me. the wind, acting with the twist of Choose the best for your the sail. In a Hasler & McLeod purpose, or make the boat you have Make your sail to David Tyler’s pattern sail, these will add up to... as good as you can. Design a junk Fantail pattern, but cut the panels not very much camber. And the full rig with flat-cut sails mainly after flat. Yes, flat. If you want to be in the sail will have, proportionately, the Hasler & McLeod’s position of expecting better least when common sense would recommendations in ‘Practical Junk windward performance in exchange want it to have the most. And it’s all Rig’ but with only one batten near for some added effort and too far aft to be terribly efficient. Oh the yard at the throat, and with complexity, put added camber into my. Yet somehow I’m saying it’s some additional progressive fanning the bottom 3 or 4 panels. Tempting. Good Enough. of the upper battens. There will be camber in any case, when the wind sees the sail and you From my experience of mehitabel, I Refer to Figure 1.4 in Practical Junk play with its twist. put it down to the camber of the fan, Rig - my favourite sail design and mostly. The twisty curve is visually my inspiration for ours. I Handling the sail will be sweet with obvious and yet it seems even more recommend it confidently. I made respect to batten stagger when effective than it ought to be. I reduce all our spars the same length for reefing and furling. It won’t ever sail to what looks like too little for practicality, though, and the lowest flog or bang fabric-wise if you the light breeze, and beat my way 3 panels are parallelograms. Not as choose flat panels. Shaping the sail leisurely into the bay, explore it, beautiful... by gently peaking up the yard and stop the boat and set the anchor. upper luff will obviate the need for Our angles in degrees are about Yesterday afternoon it was light, Hong Kong parrels. Strains will be 10,10,10,10,13,20,60. I might use and switchy and gusty besides. It’s distributed all over the spars and 10,10,12,14,17,22,60 now. As in that easy and more fun than I deserve. fabric, in keeping with the ancient design of Hasler & McLeod’s, make Add more to the breeze, it’s still fun junk rig’s inherent wisdom. the lowest panels the smallest in and easy. Leisurely or sporty, are height, progressing to larger ‘P’ It’s a low-aspect design, but avoid then negotiable. dimensions upwards. It helps with too long a batten length. For We built a little more fanning into sheeting clearance, and gives tidy scantlings, be strong plus a mehitabel’s sails than Hasler & ‘balancing’ first reefs. Check your confidence-inspiring notch, which McLeod’s recommended plan has. variations for their effect on batten will pay more than it costs, or Even better might be a design that stagger. This plan will suit a , weighs. Light fabric will suit the enhances fan camber on purpose. schooner or . Aspect ratios of small panel widths, on a boat of 2-point-something will be fine. suitable scale. For sail size and Secrets - How to Sail Like many other aspects of the design mehitabel Since this is a Hasler & McLeod sail, and rigging, seek David Tyler’s the invaluable guidelines contained I don’t really mean that. What I advice. ‘Practical Junk Rig will be a in ‘Practical Junk Rig’ can be mean is, this is what I would useful companion, but not so applied directly. Follow them for recommend to a friend, or what I directly applicable. planning the sail(s) and rigging, would do myself at this point in centre of effort, the sheeting Secret Three history, to meet these priorities: geometry, indeed all aspects of Sail the rig with an eye to keeping it - Good Enough performance for fitting the rig to the boat, and give evenly relaxed throughout. Watch it practical offshore and enjoyable thanks! Those gentlemen did their - it all breathes together. The wind coastal cruising. homework. Cheat on them at your won’t concentrate stresses if you peril! - Natural robustness and don’t. serviceability. Use light sail fabric if all your Conclusion sailing will be light, and heavy soft - Buildable by mere mortal sailors fabric otherwise. Lash the whole rig An iPad processes images, and most who might even have other projects together with an emphasis on other data, elegantly and easily. For on the go. distributed loading and the computer tasks I most often do, - Proven over centuries, recent maintainable simplicity. it’s powerful enough. Nimble, in decades, many rigs and many sea fact. And using it suits my intuition. Secret Two - As Good or Better. miles - highly evolved, not There are more powerful machines experimental. This is what I might do if it were available, but I really have only myself to please. Beyond keeping it Bibliography of links to relevant Sailplan clean and protected, I seldom need JRA Forum Topics http:// to do anything to it. It’s pretty much Used for background to this article, www.junkrigassociation.org/ perfect as built, and it seems to and containing a wealth of people’s technical_forum? embody for today that timeless idea thoughtful inputs. mode=MessageList&eid=872150&m of appropriate technology. I’m lpg=2&rid=873637 constantly amazed. Titles are approximate, and links are current as of 6 November 2012. Making CFRP Battens A Linux computer requires tinkering to make it work properly, Thanks to the participants. http://junkrigassociation.org/ that is without wrinkles. It’s technical_forum? A Perspective on Junk Rig History especially good at some mode=MessageList&eid=911490&m troublesome processing that, now it http:// lpg=2147483647 occurs to me, I rarely choose to do. www.junkrigassociation.org/ JR Conversion for Freedom 33 - But I could. I’m still learning how to general_forum? Flutterby get the best out of Linux, so it mode=MessageList&eid=490656&m involves me in fine-tuning exercises lpg=2147483647 http:// quite often. It’s fun to tweak and www.junkrigassociation.org/ Flat Sails are Okay customise. There are gurus available technical_forum? when I need advice. It will all come http:// mode=MessageList&eid=531461&m right. I’m sure it will. Soon I’ll have www.junkrigassociation.org/ lpg=2 the performance I’ve dreamt of, and technical_forum? Arion’s JR Conversion - pros & cons I’ll forget the extra work and initial mode=MessageList&eid=490687&tp troubles. g=13&mlpg=2147483647 http://junkrigassociation.org/ technical_forum? I’m not really considering a Flat Sails are Still Okay mode=MessageList&eid=1105936&t Windows computer. No, not yet. But http:// pg=0 then, a lot of people seem to be www.junkrigassociation.org/ happy with them, tacking their Cambered Panel Sails on Ti Gitu technical_forum? and all. mode=MessageList&eid=594527 http://junkrigassociation.org/ So which junk sail is more the iPad, technical_forum? Fabricated Aluminium Alloy Yards and which the Linux netbook? mode=MessageList&eid=766440&tp http://junkrigassociation.org/ g=0 Suggested Sources technical_forum? Luff Parrels for Cambered Sails ‘Practical Junk Rig’ by Hasler & mode=MessageList&eid=868877&tp McLeod g=3&mlpg=2147483647 http:// www.junkrigassociation.org/ ‘Voyaging on a Small Income’ by General Drawing of Fantail Tystie technical_forum? Annie Hill Sail mode=MessageList&eid=1067661& All the documents Arne Kvernelend http://junkrigassociation.org/ mlpg=2147483647 makes accessible through the JRA technical_forum? Possible new mast website. mode=MessageList&eid=1060993&t pg=0 http:// Paul Fay’s articles under the www.junkrigassociation.org/ heading ‘Ti Gitu’s New Sails’ as New Sail for Tystie technical_forum? published on the JRA website http:// mode=MessageList&eid=650160 http:// www.junkrigassociation.org/ Help Point a Newbie in Right www.junkrigassociation.org/ technical_forum? Direction technical_articles mode=MessageList&eid=833895&tp g=2&mlpg=2147483647 http:// David Tyler’s work on the Fantail www.junkrigassociation.org/ sail design. Tystie is at sea as I write, Cambered Panel Sails on Wild Fox technical_forum? so keep an eye... http:// mode=MessageList&eid=936679 https://www.box.com/s/ www.junkrigassociation.org/ e2d899dda29d80e51798 technical_forum? mode=MessageList&eid=770677&m Paul Thompson’s designs for lpg=3 Aphrodite and La Chica - Reports Type to enter text will hopefully come soon... Comments invited on Schooner

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