MICRO MAGIC SAILS, RIGS & FITTINGS By Mike Eades November 30, 2010 Al Stiewing has been bugging me to set down some information about how I go about making alternative sail rigs for my MM and, in particular what materials and fittings I have used and where I find them. That is easier to say than to do since I have accumulated bits and pieces and fittings over the years as I have built or modified sail rigs for my SeaWind, 36/600 and now MM and many of the original sources have gone out of business or moved elsewhere. However, since MM skippers may be motivated to try to experiment with alternative rigs, spurred on by the articles in the recent AMYA MM feature, I decided to give in and see what I can set down by way of information you may find helpful. My earlier note on my alternative “B” rig is a starting point and contains references to sources where alternative sail rig thinking is displayed and of course there is a lot more in the MY articles. I will try to set this out as the steps I go through in the process of making an alternative rig. I am not a professional sail maker and only make single panel sails. Professionals may cringe at some of my methods but they have worked for me. 1. What sort of rig do I want to make? - Replacement for kit “A” rig - Smaller rigs for windier conditions, B-E rigs etc - Conventional “pin head” rigs (see Thomas Dreyer article) - Tushingham “Graphite - fathead” rigs (see Tushingham’s sail profiles) - High or Low main sail height rig? - Conventional kit style gooseneck (Graphite Red label or Dreyer style sails) - “Graphite” style smaller gooseneck with lower main sail (Graphite Black label style) height above deck? 2. A word about luff curves/luff allowances. Pretty much all sails, jib and main, single panel and paneled are built with the luff of the sail slightly curved. The deviation from a straight line is called the luff curve or luff allowance. For more information on this check out Rod Carr’s articles on Sails displayed on the AMYA web site under the “Sails” tab. Further information specific to the MM is contained in articles by Dennis Futterlieb and Thomas Dreyer in the AMYA MY #162 MM feature. For single panel sails which derive a lot of their shape from the relative curvature of the sail luff and the feature to which it is attached, forestay or mast, these luff allowances are a critical part of a sail’s shape. In summary the forestay tends to sag slightly and increases under load. A straight cut luff would produce a lot of excess sail material when this happens resulting in a very full curve which is undesirable especially in lighter air. As a consequence jib luffs are cut with a negative luff allowance to reduce the amount of excess sail material and produce a flatter sail profile. The main sail however is cut with a positive luff allowance so that if the mast is straight there is still some excess material behind the mast to stretch back into the sail under wind pressure and produce a nice sail profile. As the mast bend is increased under back stay tension it more closely matches the luff curve which flattens the sail. The kit “A” rig sails on the MM are cut with specific luff allowances that work well for the size of sails. In general for smaller sails the same basic luff curve seems to work but it is very easy for makers of single panel sails to cut sails with various luff curves and see which works best for specific wind conditions. 3. Everything begins with a base template. - A .pdf file can be downloaded from the US MMCOA web site under the “Class Info” tab containing a base template with all the dimensions needed to draw out actual size of a jib

and main sail for the “A” rig. There are also .pdf files available that will plot at full size if you have access to a large scale printer such as for blueprints. Since MM Class Rules require that any alternative sails shall fit inside the “A” rig sail profiles the “A” rig profile is a good starting point. I draw this out on plain paper and draw in the outline of the “A” rig jib and main sails in black ink. Be sure to include the negative luff curve on the jib and the positive luff curve on the main using the dimensions given. - To draw the outline for the sail I have chosen to make I measure a dimension on the chosen sail profile, say Graphite “B” main luff, and compare it with the Graphite “A” main luff which is the kit “A” rig dimension and put a point on the template diagram. Repeating this enough times generates a new sail profile for the “B” main. [For example: On my printout of the Graphite Black label sail profiles the “A” main luff measures 224 mm while the “B” luff measures 190 mm. Since the actual “A” main luff is 700 mm the “B” luff should be 700 x 190/224 = 594 mm.] - Having drawn the outline of the new sail I want to make I make sure its outline is dark enough to be seen through my sail material. 4. Base sail material and cut out of new sail. - Any number of materials have been tried for sail making, TriSpi (fiber reinforced polyester), Mylar drafting film, cellophane etc. I like the kit material and found what appears to be identical material at “Hang’em High” online kite store; http://ecom.citystar.com/hang-em-high/ushop/index.cgi?ID=9UBGWQ (Part 12PCxxx - 1/2 oz. Polycarbonate Coated Ripstop Polyester) which is available in several different colors. The slate color seems identical to kit cloth. - I lay the cloth over my paper template and trace the outline of the chosen sail in soft pencil on to the cloth and with sharp scissors carefully cut out my new sail. I repeat the process for both jib and mainsails. The material has a built in pattern that shows the orientation of the weave. I am not sure if at this scale it makes any difference but skippers can play around with various orientations within the sails if they care to. 5. Sail accessories - Luff tape Since the sail luff is both under tension during use and is the place where the sail is attached to forestay or main spar some form of luff reinforcement seems desirable. I use a glass fiber reinforced adhesive tape (~1/2” wide) that I got from Great Basin Model Yachting, which became Mid West Model yachting that is no longer in business. I don’t know of a direct substitute but probably for this scale of sail a simple polyester adhesive “Scotch” tape would be adequate? To apply the tape I lay the sail on a clean hard flat surface (countertop), cut a piece of tape ~1” longer than the luff and attach ~1/4” at one end to the surface holding the other end up off the surface with the tape stretched straight. I slide the sail under the tape so that the tape overlaps the luff edge of the sail by ~1/4” (this will vary along the edge due to the luff curve in the sail). I then smooth down the tape gently along the length of the luff, carefully peel the excess tape off the surface and trim off the excess tape along the sail luff and at each end with sharp scissors. - Sail corner reinforcement/decoration For sail corners and other reinforcement uses (see below) I use self-adhesive deck patch material I got from GBMY/MMMY that came in a variety of colors in sheets with a peel–off backing. What looks as if it might be a satisfactory alternative is Insignia Cloth obtainable in 1/3 yd min x 54’ wide sheets and in a variety of colors: http://www.seattlefabrics.com/marine.html#insignia%20cloth

Alternatively Hang’em High has a product: Part 2.0xxx - 2.0 oz. Adhesive Sheets 5"x8". Adhesive backed, 2.0 oz. Dacron Sheet. Also available in several colors which may also be suitable. For corners I cut pieces roughly to shape for each side of the sail then stick them in place with some excess overlapping the sail edges then trim off excess. You can use shapes similar to those for kit sails or use your imagination staying within class rules. - Attachment point reinforcement I use the same material as above to reinforce the attachment points for jib and main sails. For the main sail the kit uses 16mm diameter circles folded over the edge. Unless you have a sharp suitably-sized cookie cutter cutting out small circles by hand is a pain. However squares cut from a 15-20mm wide strip work just as well leaving triangular reinforcement areas when folded over. For attachment of the jib to the forestay you can either cut small strips of sailcloth and fold them over and attach to the leading edge of the sail with Insignia Cloth strips, similar to how the kit jib sails are done or tape small pieces of small diameter plastic tube to the leading edge as a guide through which the forestay runs. I use pieces of Teflon tubing I got from GBMY/MMMY but I have also used pieces cut from the tubing supplied with cans of WD40 that work just as well. - Battens and holding strips For battens I have used self adhesive backed epoxy/fiberglass strips cut from sheet supplied by GBMY/MMMY. I don’t know of an exact alternative product but 12” x 12” sheets of .010” thick epoxy/fiberglass can be obtained from ACP Composites: http://www.acpcomposites.com/home.php?cat=257. Strips 4mm wide cut to length can be applied to your sails using Seamstick double-sided tape obtainable from Hang’em High. Circles, squares or triangles of Insignia Cloth can be used to secure the ends of the battens to avoid them lifting off the sailcloth as is done on the kit sails. - Sail numbers and class insignia Once the sails are finished sail numbers and class insignia can be applied using printed out templates placed under the sails and using permanent markers, fine point to outline each number then broad point to fill in. - Attachment point holes I simply heat a large sewing needle in a gas flame holding it with pliers and pierce the sail at each point where a line is to be attached. This seals the hole against further tearing. The sails are now ready to be attached to the spars and rigged. 6. Spars & Fittings - Jib Boom & fittings Since all the alternative sail profiles use a standard kit dimension for the jib sail foot I use a 4 mm carbon tube (Tower Hobbies Product # LXJDP8 .157” OD tube) cut to length and a set of Graupner jib boom fittings from Graupner USA: http://www.v-eastonline.com/products/Jib-Boom-fitting-racing-MM.html - Main Spar & Fittings For my “A” rig I use the standard kit-supplied gooseneck and main spar with wood dowel insert and aluminum 6 mm outer sleeve. For my alternative sail rigs with high main sail I also use my kit gooseneck and boom, simply sliding the main spar with its aluminum outer tube out of the gooseneck and replacing it with a 6 mm wound tube carbon spar (Skyshark 2P obtained from Goodwinds kite supply: http://www.goodwinds.com/merch/list.shtml?cat=carbon.wrappedcarbon ) The Skyshark 2P tube is slightly larger than the gooseneck tube and needs careful sanding down to make a smooth fit. I hold the tube in a drill chuck and spin it while lightly sanding down the end up to and just above where the gooseneck will go. I also protect the lower end

of the spar from wear and splitting by reinforcing with an inner 5mm carbon tube to just above the gooseneck top bearing and a wood dowel insert in the base as for the kit spar. I have recently built a Graphite rig with a lower main sail using a Graphite low profile gooseneck and boom fitting obtained from: http://www.rcyachts.org.uk/epages/Store3_Shop2540.sf/en_GB/?ObjectPath=/Shops/Store3. Shop2540/Categories This comes with a 5 mm stub mast which has a 6mm collar that is glued to a deck plate. I made a new deck plate from scrap CF/Epoxy sheet laminated up to required thickness and with holes drilled out to match the kit deck plate and CA glued it to the mast stub collar. The gooseneck and boom fitting slides on to the top of the mast stub and the Skyshark 2P mast slides down on top of the stub above the gooseneck fitting. - Mast Crane and Jib Attachment Point For my alternative high main sail rigs I have built custom mast cranes from scrap CF/Epoxy sheet. The “B” rig uses a standard kit jib so that both main and jib are attached to the spar at the same height (masthead rigs). The mast crane is made out of a three ply laminate epoxied together and cut out to shape using a hacksaw and filed to fit. A tongue projects from the center base of the crane shaped to fit into a slot cut into the top of the Skyshark 2P spar which has been cut to length and the mast crane is epoxied into place. Cranes made out of alternative materials, sheet aluminum or epoxy/fiberglass laminates could also be used. My ”C” rig is also a masthead rig but with smaller jib and main. [ I tried a Graphite Black label “C” rig profile but, as a single panel sail, it seemed too floppy at the top so I cut another sail with the same luff and foot measurements and cut the head profile to be very close to the shape of my cut down “B” fathead rig. With limited competitive use yet it seems to set and work nicely. The good news is that once you have made a sail rig the next is even easier and experimentation is quite easy.] For my Graphite lower main sail rig I used a Graphite mast crane fitting suitable for fathead B-E rigs obtained from RCYachts.org.uk as for the gooseneck and boom fitting. This slides down into the top of the Skyshark 2P spar.