Wing’soul. Easiest to Build Wing Sail.



Introduction: Wing’soul. Easiest to Build Wing Sail.

About: I quit my career in 2015. Then bought a boat in Cairns, Australia and learned to fix a 30 year old boat with my wife and 8 month son. My prior job description was an electrical engineer, and my day to day was …

Here's an incredible Instructable for building a wing sail, called the Wing'soul. It's the world's easiest to build wing sail because simplicity overrules complexity. Common components (found at most hardware stores) are chosen over custom boat parts. Flat cut canvas is preferred over curved cut. Easy to sail and safety wins over specialized sail wardrobe.

First, there is no rotating mast requirement. The Wing'soul is best paired to a static freestanding mast. An example is the Laser dinghy, with its plain mast. For a larger boat, a junk rig or the Freedom rig is ideal for conversion. If you want to convert a standard Bermudian rig, you'd have to change the mast. The mast must be round (not have a flat side) and without mid-mast spreaders. Due to the change in the center of effort, probably the new mast will need to move forward (about 3% of the LOA), closer to the bow.

Guess why wing sails were invented decades ago, but never got popular? Because almost all of them were designed with a rotating mast. Nothing kills adoption faster than this costly complication.

Another simplification: no hardware hinge. You'll notice a lot of other wing sails require a pivot or a hinge at the boom to switch the camber around. However, when the Wing'soul tacks, the wing sail (mainsail and jib/jiblets) changes camber automatically. It works exactly like a windsurfing rig.

In fact, the Wing'soul is heavily based on the Aerojunk, a rig invented by Paul McKay back in 2012. The Aerojunk is a junk version of the windsurfing rig; the Wing'soul is a winged version of the Aerojunk.

The sail is cut flat. No broadseaming or darting or rounding to create draught, unlike the cut in a Bermudian mainsail. Assemble the mainsail by seaming together long strips of rectangular sail cloths. The teardrop shape of the small winglet battens gives curvature at the luff. Aft of the luff to the leech, there is enough sail slack to produce camber.

The jib is also cut flat. The jib can be one long flat sail, or broken up to several pieces called jiblets. Jiblets are trapeziodal. The battens arrange the jiblets so there is slack, both horizontally and vertically. This creates camber in both axises.

This Instructable is for a small trial sail, perfect for a sailing dinghy like the Laser. It is also a learning tool, prototype, about how to build a bigger one. Fortunately, this rig scales up easily. A larger version will be bigger and sturdier, but has no additional components. I dream of making a Wing'soul rig for my 50-footer three masted schooner.

A lot of the Wing'soul's characteristics can be based off the Aerojunk and the original junk rig. You should find: the Wing'soul reefs easily, handles very well downwind and beam-reach. On a broad-reach, it is possible to ease sheet past square, and "sail in the lee" for best performance. Like a junk, it's superb in heavy seas, mostly because of how well it reduces sail area, hardly ever flogs, and docile because of its semi-balanced design (the jib's CE partially offsets the main's CE).

What about close-hauled? This point of sail needs further testing. However, the main and jib has plenty of camber for upwind beating. Camber can be anywhere from 6% to 12%. Really, it depends on internal lengths of the battens versus the length of the sail's chord. The slot effect, a key to a Bermudian's strength, is also part of this rig. Even better, the main's luff is a wing, further improving the aerodynamics at the main/jib junction, while reducing mast turbulence. Finally, induced drag (drag from vortex creation) is reduced because the planform may be tapered and rectangular. This is an improvement over triangular Bermudian mainsails. The Bermudian does have an advantage over the Wing'soul: higher aspect ratio for equal sail area. How all theses factors play out in the real world requires more testing.

Finally, this rig will be fairly cheap to build, as nearly all the materials can be sourced from non-marine industries. For example, the mast can be a re-purposed aluminum utility pole, the sail material is outdoor utility canvas, the battens from aluminum tubes. This prototype cost $300 USD in parts. $100 was for the light rip-stop fabric. $100 was for the aluminum tubes, to make the wishbone battens. The rest was $100 for miscellaneous parts.

Please comment if you built this rig and tell me how it performed for you!


The most important tool to have is the drill press, when building the battens. You'll want to create clean, straight 90 degree drills. Also desirable is the ability to drill 15 degrees from normal.

A good sowing machine is important. A "yachty" machine is perfect, but any small home machine will work for a small sail.

Tools: ·

  • Drill press
  • Hand drill & bits
  • Hand saw (or jig saw) for aluminum and ply wood
  • Measuring tape, pencil, marker
  • File, sand paper, rasp
  • Rivet gun and pop rivets
  • Nails & screws to hold wood temporarily
  • Sowing Machine
  • Grommet press and grommets
  • C-Clamps to hold things down


  • Light sail canvas; such as rip stop fabric, 100m^2 was used in this small trial sail
    • For a cruising yacht, use UV resistant fabric such as Sunbrella, Top Gun, or Weathermax. The multiple wishbone battens takes most of the sailing loads, so there is no requirement for Dacron. However, you may use Dacron, plastic tarp, or old sail cloth if you wish. Material selection depends on if the sail is a trial, bluewater, tropical-tolerant, or made-on-the-cheap.
  • Plywood for the winglet template
  • Round aluminum tubes, 15mm diameter, 1mm thick walls, 2m long, QTY 11
  • Square aluminum tubes, 20mm each side, 1.5mm thick walls, cut to 40mm length, QTY 10
  • Aluminum flat bars 15mm wide by 2mm thick, 2m long
  • Aluminum flat sheets, to make the C-keepers.
  • Bolts and Nuts, M6, 60mm long
  • Hose clamps
  • Rope for rigging the halyard and sheets
  • Single block sheaves for rigging the halyard and sheets
  • Sticky sided Velcro, 15mm wide, 20m long

Step 1: Learn About the Aerojunk and Junks in General

Before you get started on the Wing'soul, read about its predecessor, the Aerojunk. Big thanks to Paul McKay for inventing the Aerojunk, as the Wing'soul would not be possible without him!

Original Aerojunk Design:

If you join the Junk Rig Association (there's a small membership fee), the 84th newsletter has updated Aerojunk information.

Here's a website to learn about junk rigs in general, and why they make good rigs for cruising yachts.

Here's an article from Practical Boat Owner, comparing the Split Junk vs. the Bermudian, side-by-side. They concluded the junk is best off-the-wind, and the Bermudian is best on-the-wind. Either rig has its weaknesses and strengths, it depends on which point of sail. The Wing'soul is the best of both worlds. It should sail upwind like a Bermudian, while retaining formidable off wind performance and ease of handling.

Step 2: Cut Aluminum Tubes

In this step, you'll make the wishbone battens by cutting tubes to the correct lengths. Don't worry if the battens look complicated, with all its curves. The batten shaping is actually fairly easy to do.

The Aluminum Cuts

Cut the round aluminum tubes (15mm diameter, 1mm thick) to 2m lengths. Even better if the tubes can be bought at those lengths. You'll need QTY 10 of these outer battens to make 5 wishbone battens.

Cut the remaining round aluminum tubes for the removable crossbars. The length is around 320mm, to get a 12% mainsail camber. Shorter crossbars makes the wishbone battens skinnier, and hence less camber. Don't worry about the length too much, it can always be adjusted shorter, later on. Make QTY 5, all of equal lengths.

Then cut the square aluminum tubes (20mm side, 1.5mm thick) to short pieces, at 40mm lengths. Drill a hole through the pieces, big enough to have the round tubes slide through. You'll need a fairly big drill bit, 15mm or 15.5mm diameter. Then rotate the piece 90 degrees and drill a hole meant for a M5 sized bolt. Take a look a the diagram for reference. Make QTY 10.

Assemble Battens Into a Long Legged H

Place two straight, 2m long, round battens side by side on the floor. Slide a square end piece, into each of the battens. Stick the removable crossbar (round, 320mm long) inside the square end piece. Now is a good time to look at the diagram again, to see the end result. What you have arranged looks like a long legged 'H' on the floor.

Before bending the two battens, first secure the removable crossbar to the square end pieces. Use a hand drill and drill a M5 hole at the end of the crossbar, using the hole at the square end piece as a guide/template. Use the same sized drill bit. Once you drill through the ends of the removable crossbar, secure with bolt and nut. Repeat on the other end.

Install hose clamps over the outer battens. Loosely slide the clamps until they are adjacent to the square end pieces.

Now you're ready to bend the outer battens in the next step.

Step 3: Bend to Make Wishbone Battens

Use a measuring tape and mark off the tip of the battens to the location of the crossbar, a distance of 525mm, on both battens. This is shown as points "A" and "B" in the diagram. Once bent, the distance from the tip to the crossbar, will end up as 515mm (roughly).

Slide the crossbar along the battens to the 525mm mark. Lock the crossbar/square end piece, by tightening the hose clamps** on each side. Make sure both battens are equal, so the bends are symmetrical.

With a friend's help, hold down the battens. Then another person can bend the batten tips (points "A" in the diagram gets closer) . The aluminum tubes will spring back a little.

Lock the bend down with bolts & nuts. Use a hand drill to drill holes through the battens and use a long bolt. Another option to a long bolt, is to use a threaded round bar. A third option, what I did, was to use a drill press to drill at 15 degrees offset. Then fitted a small diameter aluminum tube through and rivetted in place.

Now you are finished making the aperture for the jib/jiblets.

Don't worry too much of how long this cross bolt should be (the distance between the "A"s). Its not super critical. Even the distance between "A" and "B" = 525mm is not critical. It is best to start with something, and adjust the battens later.

To make the aperture for the mainsail, the technique is almost the same. The difference is to place a wooden stick about 340mm aft of the crossbar. The diagram shows this as 340mm from point "B". In the diagram, a third (right-most) wooden stick is shown. That's optional.

Make the bend at the tail ends of the battens, with a friend's help. Then lock the tails together with long bolts or threaded round rods and nuts.

Once one wishbone batten is complete, repeat the previous and this step to make the other battens.


** hose clamps to lock the square end piece is preferred. If you look at the example photo, the square end piece was riveted to the battens, instead of a clamp. This okay for a trial sail, but not okay for a "real" sail. A drill hole, for the rivet, will severely weakening the aluminum battens at this location.

Step 4: Make the NACA0012 Winglets

In the previous steps, you learned how to make the wishbone battens. They are the key to the Wing'soul's simplicity. No rotating mast is needed as the mainsail and jib/jiblets rides on the battens; the battens rotate around the static mast. No articulating hinges are necessary because the outer battens allows the wing sail to tack and create camber.

In this step, make the winglet battens. They create the luff pocket for the mast. The airfoil is based off the NACA0012.

Begin by making a wooden template, shaped to an airfoil. Then mount on another wood board.

Start by downloading the airfoil, NACA0012, and print out the shape.


Size the print out so that the mast will fit inside the nose of the NACA0012. For example, if the mast has a diameter of 40mm. Scale the print out so a 40mm diameter circle can easily fit inside the nose section. See the diagram; the airfoil encompasses the mast, with some room to give.

Cut the printout with scissors, then apply it to the wood piece.

Draw the outline to the wood plug, cut out the shape with a jigsaw or handsaw. Only 50% of the airfoil shape is used. One could also use 100% of the airfoil, instead.

Mount the male plug on a flat wood board.

Wrap the aluminum flat bar, 15mm wide and 2mm thick. Secure the bar to the wood plug with C-clamps. Use a mallet to wrap and pound the bar into shape.

Rivet together the ends to finish the winglet so it does not pop open.

Repeat this step to make a total of QTY 5 winglet battens.

Finally, add a small piece at the nose of the winglet. This is the flat plate. The plate prevents the mast from jamming the insides of the winglet. Without the plate, reefing the sail becomes very difficult.

C-collars, Make Later

C-collars prevent lifting and capsizing from the wishbone battens. They are attached to the winglets on both sides of the winglets (windward and leeward). You do not need to make C-collars now. The reason because, the placement of the C-collar is unknown. Once the rig is assembled together, then positions can be marked, and the C-collar can be positioned correctly.

Step 5: Make the Riblets

Riblets are shorter versions of the winglets. Winglets are 50% of the NACA0012 airfoil chord. Riblets are only 25% in length.

Riblets prevents the windward side of the luff to collapse under windward pressure. Aim to make two riblets between panels. Riblets billow out the luff, improves luff shape, and prevent the luff from"sticking" to the mast if the sail gets wet.

Modify the wood plug used in the previous step to make the winglets. Cut the wood plug in half. Mount the front nose of the plug back into the wood mount.

Then wrap the aluminum flat bar, using a mallet just like the previous step to make the winglets. Rivet the ends.

A flat plate is NOT needed for the riblets, as this omission does not affect reefing.

Repeat to make the other riblets. Make at least QTY 8.

Step 6: Jib Sail Canvas

The jib is one long piece. Jiblets are several smaller pieces, when combined, works together like one large jib. This step focuses on making jiblets, as this is preferred over making one large jib. Jiblets tack better in light winds, have deflection to improve performance, and easier to make due to the smaller size.

Jiblets are trapezoidal and cut flat. The luff of the jiblet is the nominal distance of one panel. In the diagram, one panel height is 0.89m. So the luff distance of the jiblet is also 890mm. Technically, the eyelets at the luff will attach at a distance of 0.89m. The jiblet is slightly bigger to accommodate the eyelets, plus overlap to allow rolling and stitching for the edges.

Vertical Camber and Deflection

The angle at the luff corners are 7 degrees. Why 7 degrees? It's a good starting angle. It gives enough slack at the leech to create camber vertically. This vertical camber allows the jiblets to deflect out, with respect to the mainsail. The bigger the corner angle, the longer the leech. The longer the leech, the more slack; extra slack begets more deflection.

Most of the sail "lift"** in the rigid two-element America's Cup wing sail, came from deflection. Deflection is the angle between the chord of the first-element wing with respect to the second-element wing chord. The deflection of the jiblet works the same way: it increases the driving force of the sail.

Horizontal Camber

Camber in the horizontal axis happens when there is slack at the foot of the jiblet. The diagram shows a foot distance of 1020mm. The ideal batten would hold the jiblet at 1000mm apart. That means the jiblet has a 2% slack (1020mm is 2% longer than 1000mm), which creates horizontal camber. Why 2%? It creates about 10% of actual camber. But your results may vary.


** lift is an aeronautical term, but you know what I mean when applied to a sail on a sailboat.

Step 7: Wing (Main) Sail Canvas

I used the book "A Sailmaker's Apprentice" by Emiliano Marino to help during this step.

The basic outline for the mainsail is this:

Start off with making just one panel of the mainsail. Since one mainsail panel runs horizontally, the raw canvas when delivered will be approximately the same size as the final panel. In this example, the final panel height is 0.89m, or the distance between wishbone battens. So the ideal roll of canvas should be slightly wider than 0.89m. Roll and sew the edges and the final panel height will be 0.89m.

The diagram shows where to apply the Velcro. First apply the Velcro for the winglet batten and the riblet battens. Then hand stitch them to the canvas to secure. Velcro may be too thick to sow with a machine. Some Velcro have bald edges, where a sowing machine may penetrate the thinner backing onto the canvas.

The two vertical strips terminates the trailing edge of the wing portion. Temporarily stick the Velcro there, but do not stitch.

Setup the mast, along with two wishbone battens. Install Velcro to the winglets and riblets. Assemble the one panel of the mainsail to the wishbone battens, winglets and riblets --like a dress rehearsal. Once that is complete, examine the mainsail and make necessary changes, measurements or adjustments.

Mark where to punch a hole, or crossbar aperture, on the mainsail. This aperture is there the removable crossbar will go through both plys of the wingsail. The crossbar and aperture are aft of the mast, to allow room to pivot during tacking. Don't forget to reinforce the aperture, or else the aperture will rip.

Once the mock up is finalized, make the other mainsail panels.

Sew all the horizontal panels together to make one large mainsail.

Add the two long strips of Velcro that run up the sail. This holds the trailing edge of the wing together. Hand stitch or machine sew the Velcro to the canvas.

Phew!! That's a lot of steps to make one mainsail. And we did not cover any the details, like grommets, eyelets, bolt ropes, corner patches etc... Luckily, for a small trial sail, you can skip all that.


To tell you the truth, the mainsail for this particular Wing'soul was done in vertical strips, instead of horizontal strips. There are pluses and minus to either case, but not a concern for a small sail. If I were to make a large sail, I'd opt to make the mainsail with horizontal strips, as outlined in this step. Mostly because a completed one-panel mainsail can be hoisted with just two wishbone battens. Then sizing and testing can commence without making the entire mainsail.

Step 8: Put It All Together

Once the mainsail and jiblets are complete, assemble the sails along with the mast and battens.

Install two single blocks at the mast top, to run the halyard. Then raise the mast onto the mast support.

Run the halyard up the mast, through first block, then down to the yard block. Then up again to the second mast top block, and terminate on the second harness on the yard (your top most wishbone batten). The yard is wide, so a harness will balance the battens from tipping.

Slide the top winglet through the mast. Let it sit above the crossbar of your yard.

If winglets and riblets need Velcro, apply them now.

Wrap the mainsail around the top winglet. Secure the leech of the mainsail to the batten end.

Remove the crossbar, by loosening the nuts and bolts. Then re-install the crossbar through the mainsail. Since the crossbar aperture is already there, just slide the crossbar through.

Also install the top jiblet.

Insert the riblets inside the mast, and stick that to the mainsail.

Slowly hoist the yard with the halyard, one panel at a time. Continue adding more wishbone battens, winglets and riblets and jiblets.

After the bottom panel and boom (bottom most wishbone batten) is assembled, your sail rig is completed and hoisted!

Step 9: Final Details

Collars and Stoppers

Once the entire sail is raised, you'll first notice the battens tend to capsize and shift. There are two solutions to remedy these problems:

1. C-collars added to the winglet battens, prevent the wishbone battens from tilting, "capsizing", out of the winglets. Capsizing causes the wishbone battens to not be parallel to each other. The C-collars must not be too restrictive; some play allow the winglets to move around for tacking.

2. A winglet stopper in the middle of the crossbar to prevent the winglet from straying or shifting outside of center. The stopper can be a hose clamp or a pin.


Finally, all the batten ends must be controlled with the sheet line. The preferred method is Chinese junk sheeting.

This features:

1. The ability to set the twist for each batten. This translate to ultimate control of twist from the foot to the head of the sail.

2. The mechanical advantage of running the sheet through multiple pulley blocks; couple this with balanced configuration (the jib's CE partially offsets the main's CE). Therefore, sheeting does not require further assistance. The general rule is, Wing'soul and other junk rigs do not require sheeting winches. The easing and tensioning of the sheet is done solely by hand. Even on my 50 foot heavy steel boat, with 500 sqft (46 m^2) sails, in 20 knots wind, sheeting is done manually without a winch.

Topping Lift

Topping lift holds the sail up when the halyard is eased, so it does not lay on the deck floor when reefed. A small sail would not need a topping lift. However, a practical larger sail would require one.

An excellent reference book for rigging is "Practical Junk Rig" by Hasler & McLeod.

Step 10: Testing and Final Notes

A big problem with this project was the testing. The sail was built in Romania -my land base when not cruising. This part of Europe has few sailboats. A land sailer, made from off-road skateboard wheels, was built specifically to test this rig.

It was difficult to find the right days to try the sail, as few days were windy. And harder still to find a suitable surface large enough, yet open to the wind.

On the day of the test, one of the wheel axle broke, due to poor welding. With a wheel missing, the rig was ballasted on only one side.

Included is a video made to show how well the Wing'soul reefs. There's the dry reef. Which the sail did excellent on. Then the entire sail was doused with a garden hose to simulate a rain squall. The wet reef was nearly as good as the dry one.

Have fun making the Wing'soul! Would love to hear how it works for you in the comments below!

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