wing mast sailboat

Sail Wildling

Why should we care about a rotating mast.

Outremer offers 3 mast options on the 5X. Fixed aluminum, fixed carbon fiber and rotating carbon fiber. Having no experience with rotating masts, my initial reaction was that it seemed unwise to add the complexity of a rotating mast to a boat being used for long distance cruising. As with all boat decisions there are pros and cons, and so I needed to find out if the benefits of the 5X rotating rig are worth the extra cost and complexity.

Outremer 5X under sail with carbon fiber mast rotated

Outremer 5X under sail with the carbon fiber mast rotated. Note the radar dome installed on the spreader.

The first two fixed mast options are pretty easy to understand, as it’s a simple question of weight. The carbon fiber mast weighs 280 kg (616 lbs) less than the aluminum mast. Taking weight out of the boat is important, and it’s especially important to save weight up high, as this has the biggest impact on the pitching motion of the boat. Less weight aloft = less pitching = more comfort and more speed.

So, we know we want a carbon fiber mast, so the next question is fixed or rotating? To figure that out, we need to look at why Outremer has gone to all the trouble of designing a rotating mast for a cruising boat in the first place!

It turns out the benefits of a rotating mast are not just theoretical, and I discovered that for myself when I did the test sail on the 5X Addiction . We were going upwind in a light breeze of about 7 knots just after completing a tack, with the rotating mast set straight on the center line of the boat. Once we had settled onto the new tack, we rotated the mast into the wind and I could literally feel the boat surge forward! Tests at different wind speeds and angles confirm that there is a 10-15% increase in performance with the mast rotated. This is great, but how does it work?

When a boat is traveling with the wind coming from in front of the beam (<90 degrees) the sails operate as airfoils in much the same way as an airplane wing.

Rigid wing airfoil

When the wind strikes the front edge of this rigid wing, the air is separated and must travel a longer distance in the case of particle A vs particle B. This creates a higher velocity on the top surface and a corresponding area of low pressure. So the wing is pulled upwards due to the lift force developed. This force is called aerodynamic lift.

Flexible sail airfoil

In the case of a sail, there is no rigid bottom surface, so it is less efficient than a rigid wing, but it still forms an airfoil because the two air particles A and B must travel different distances, and so a low pressure region of lift is created in the same fashion as a rigid wing. Around 2/3 of the driving force of the sail comes from aerodynamic lift, with the remaining 1/3 generated by the force of the wind striking the inside (bottom) surface of the sail.

This is the case for an ideal airfoil, but on a sailboat there is a mast in front of the leading edge of the sail. The bigger the boat, the larger the mast cross section has to be to handle the force of the sails, and this becomes a factor influencing the shape of the airfoil we are able to present to the wind.

Fixed mast airfoil

This diagram shows the effect that a fixed mast has on the airfoil. Since the wind must make a tight turn around the mast, a turbulence zone is created which reduces the amount of lift being generated by the forward section of the sail. It also drives the lift force direction slightly aft, reducing the ability of the boat to sail upwind.

Rotating mast airfoil

By rotating the mast into the wind, we can clean up the leading edge of the airfoil and eliminate the turbulence. This increases the lift force and moves the lift angle forward, giving us more speed and better pointing ability (how close we can sail, or point, into the wind direction).

There are other benefits to a rotating mast, regarding reefing the mainsail. Normally when reefing, you turn the boat into the wind to take pressure off the front edge of the sail in order to lower it. This puts the headsail into a luffing mode which is uncomfortable and potentially damaging to the sail. With a rotating mast, you can turn the mast into the wind and lower the mainsail. This allows the headsail to keep drawing during the reefing process and is easier and places less stress on the rig and the crew.

Because the rotating mast is in fact a rigid airfoil, it acts as an additional 12m2 sail, so by rotating the mast to the centerline position as the wind increases, you have the ability to depower the sail, which in effect, becomes an additional reef point.

And for the mathematically inclined:

12m2 mast / (12m2 mast + 125m2 mainsail) + 6% lift improvement = 15% performance increase from a rotating mast vs a fixed mast of the same size. And conversely, straightening the mast when the wind increases will de-power the mainsail by 15%.

So what’s the catch?

As always, all this goodness comes with a price, and in this case there are three issues that have to be considered:

The additional mechanical complexity needed to operate the mast rotation system
Compensating for the error in the wind angle reading when the mast is off centerline
Dealing with the error in the radar signal when the mast is rotated

For us to be able make the decision to choose the rotating mast option, we needed to find a solution to each of these. Here’s what we came up with:

Mechanical compexity

This one was actually pretty easy. Outremer has done a nice job of designing a simple and robust system for securing the mast, and operating the rotation controls from the cockpit. It does add a little more complexity when sailing, but to me it’s negligible, and since I am a committed sail tweaker anyway, I am looking forward to having another power control on the boat. Our conclusion: Outremer’s system is fine for our needs and has been proven over time on a large number of their other boats. We are happy to install it as designed.

5X Rotating mast

Rotation control lines led back to cockpit

Wind angle error

When the mast is rotated, the wind angle measured by the sensor at the top of the mast will be incorrect. This is because the wind angle instrument measures angle with respect to the mast center-line. So if the mast is rotated 20 degrees, the wind angle will read 20 degrees less than than actual apparent wind. This is a problem, but it can be corrected in software by the instrument system as long as we can provide an accurate reading of the actual angle of the mast.

To read the angle of the mast, we need another sensor:

NKE mast rotation sensor

This rotation sensor from NKE has been used by many offshore racing boats and has proven very reliable. The only concern I had was the cable that connects the mast sheave to the sensor body. If it breaks, there is no way to fix it without taking the mast off. NKE claims a 10 year life for the cable, and Outremer has never had a failure, but they add a second spare cable at the mast base that can be fitted if there is a failure of the original cable. Our conclusion: The benefits outweigh our concerns over the reliability of the sensor. If the sensor did fail, it will only affect the wind angle reading, which is a non critical data point, so we’re OK with this.

Radar image error

Most sailboats install the radar dome on a spreader located at the top section of the mast (see the first photo in this post). A high elevation for the dome provides greater radar range and minimum interference. On a rotating mast, the radar will provide significant errors when the mast is rotated. For example, if you have the mast rotated and a ship is approaching in the dark and headed straight for you, it will appear as through the ship is actually approaching from the side. This is not good.

As I write this, in September 2014, there is no reliable solution to this problem. The radar image angle should be able to be corrected in software in the same way as the wind direction, but in practice, other owners have experienced system failures where the correction angle is lost, so the radar reverts back to a non-corrected image. Although this can be resolved by rebooting the radar software, there is no way to tell if and when the system has stopped processing the angle correction input. I expect this will be resolved in a future version of the software, but it still leaves us vulnerable if there is a fault in the mast angle correction sensor.

We feel that a reliable and accurate radar, is an essential safety element when voyaging offshore, so installing the radar dome on a rotating mast is not acceptable to us. Our solution is to install the radar dome on a carbon fiber pole at the back of the boat, keeping it fixed with the vessel centerline. We will lose some range due to the lower mounting location, but it won’t be enough to compromise our safety at sea.

So all in all, the rotating mast option is a good one. It does add some complexity, but we found ways to deal with that and we are happy to be able to take advantage of the significant benefits that a rotating rig provides.

Rotating Wing Masts—Part II

By reuel parker.

Sail Plan for the Australia 47, featuring L-Head rotating wing masts.

In 2003 I received a commission to design a 47′ aluminum schooner for a doctor in Australia, who wanted a fast, shoal-draft racer/cruiser. I designed new rotating wing L-Head masts for her, using modern hardware, winches and aircraft-grade plywood for the mast sides. The new masts, while based on my earlier low-tech L-Head masts for the Conch 32, were designed considering the conditions likely to be encountered in the Southern Ocean. I designed the schooner to ABS requirements for offshore racing yachts—all aluminum scantlings being carefully chosen for weight, dimensions and strength. We did a full hydrostatics workup to ensure self-righting abilities in capsize conditions. My engineer Tom Lokocz Adams collaborated with me on this project. I featured her in my article for Professional Boatbuilder Magazine on shoal-draft stability (issue #139), and included her in my IBEX session on the same subject in the fall of 2013.

Sail Plan for the Trimaran 40.

I also designed my first multihull, the Trimaran 40, in 2003, and gave her a similar rotating L-Head mast. The prototype for this design is being built in North Carolina. I put weeks of work, and years of thought, into my trimaran design. I was especially impressed with the generous open space manifested in the interior and the cockpit. I have concluded that trimarans can be an excellent choice for cruising, and I wonder why I don’t see more of them. The design is complex and simple at the same time, and I drew many pages of detail drawings, creating one of the most thoroughly documented sets of plans in my portfolio (most of my designs being frankly simple and less thorough).

I had also been working on a “Basket Boom” concept (an aluminum wishbone with a bottom strut), which would be self-vanging, and would contain the sail and battens when lowered. A sail cover fits into the Basket Boom with a zippered flap to cover the sail when lowered. I later retrofitted the Basket Boom for my Australia 47 design—but first featured it on the Trimaran 40.

The L-Head mast, the fully-battened sail, and the laminated yard/gaff/head derive directly from the Chinese lug rig. Having been interested in Chinese Junks for many years, I researched the type as extensively as I could and then began designing Junk rigs, starting with two commissioned custom designs (the Scow 45 Junk in 1991 and Snowy Egret 39.5 Junk in 1994). A remarkable feature of the Junk rig is the ability, through a vast complexity of rigging, to completely control sail shape, including depth and location of draft, and vertical twist. The Chinese lug rig has both positive and negative aspects that are too involved to delve into here (perhaps in another blog?)—but what I was trying to achieve was an articulated wing of very modern design and construction that would epitomize the qualities of the Junk sail .

The primary purpose of the inverted L-Head is to support the large upper panels of an articulated bat-wing sail. The secondary purpose is to automatically align the mast to the sail, creating a continuous optimal foil shape. By adding a mast tiller at the base of my L-Head wing, the sail becomes completely articulated: twist and angle-of-attack can be totally controlled by using the sheet, L-Head, Basket Boom and mast tiller in concert with each other.

In 2012, after thirty years of study, observation and numerous failed attempts (on paper), I designed my first cruising catamaran, the Sharpie Cat 42. I also adapted my L-Head mast for the cat.

Sail Plan for the Sharpie Cat 42.

The mast designs for these three boats are very close, with dimensions altered to suit the individual requirements of each. I provided jumper struts and stays for the Australia design, and included them as an option for the multihulls also, as the wide stability platforms impose high loads on the mast despite the correspondingly wide shroud angles.

While I specified five-ply aircraft-grade 3mm plywood for the mast skins, it is possible that Lloyds-certified three-ply 3mm marine plywood will suffice. Quite frankly, an L-Head mast must be built and tested to know how strong is strong enough. In the world of racing, it is often said that “if you can’t break it, it’s made too heavy!” A certainty is that these masts will be very light. Again, as for my Conch designs, I eliminated the infamous “Jesus shackle” and replaced it with a system of five eyebolts supporting a rotating mast tang for attaching shrouds and forestay. I also incorporated internal halyards using Schaefer Delrin sheaves.

Mast design sections for the Sharpie Cat 42, page one.

I opted for Harken mast track and “bat-car” slides that plug into fiberglass full-length battens. Key West entrepreneur Sonny Eynman used this system on his charter version of my Exuma 52 design SUNNY DAYS (later sold to Danger Charters and re-named DANGER’S PRIZE). During sail trials for the new boat, he called us on his cell phone complaining that the boat was going 10.5 knots in 15 knots of wind—he feared this kind of speed would terrify his charter guests. When I inspected the new boat, I was very impressed with the Harken system, and realized it would make an excellent choice for a rotating wing.

Mast design sections for Sharpie Cat 42.

Mast design sections for the Sharpie Cat 42, page two.

As I think about a sailing retirement home for myself, I am torn between my love of the gaff-rig schooner, with laced on sails—and a fast multihull with my L-Head mast. I am also tempted to build my Australia 47 design in cold-molded plywood instead of aluminum. I simply may have to build one of these three because no-one else is doing it, and I want to experience it first-hand!

2/3/2014 St. Lucie Village, Florida

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Information on the home-buildable Waters-Wing carbon-fiber mast

A very detailed (90+ page) illustrated manual is now available for building a very efficient and good looking CF wing mast of 8m, 9m, and 10m lengths, that sells for US$179 via Paypal , with rights to build ONE mast. (Last updated Jan 2021). Design data to extend mast design validity to 11m is now also available. (This design is now referred to as the Waters Wingmast Mk.l, to differentiate from a more elliptical Mk.ll design that, while using the same basic construction principle, is now being developed for wingmasts in the 11-15m range). This Manual will be available after the prototype Mk ll has been well tested .. date previewed late 2023. Mk.ll manual cost targeted to be US$249.

May 2022 Update. The first Mk ll (12.2m- 40ft) CF WingMast is now complete and ready for a full season of racing this summer on a F28R, and the builder says 'all looks great'. (For more complete detail and tests of the Mk.ll - see below)

The Mark l manual contains over 100 photos and sketches and shows all details, as well as defining all the procedures and cloth layup required for each mast size. See reviews added below.

This enables one to build a CF wing mast at 10-12% of the cost of a pro-built mast, so the savings are very significant. The trade-off is that, without vacuum-bagging** and/or resin infusion, the weight is a little greater, but still measurably less than an alum mast of the same section, as well as being stiffer and less expensive. The 8m mast, c/w all fittings and the diamond stays, weighs around 45 lbs - but keep in mind that this design covers a wing section of close to 3:1 (depth to width) and not the more typical section of about 1.5:1 that of course uses much less material but is far less efficient aerodynamically. The advantage of the deeper rotating wing (approaching 3:1) is in its performance efficiency upwind, and this more than offsets the slightly extra weight.

**NOTE: For those who have the equipment and extra manpower to get the resin and bags on quickly, there are now suggested ways to add vacuum-bagging to this build method. Details available for anyone who purchases the manual

To date (May 2022), six masts to this design have been built, and one has been extensively tested over 6 seasons. Many others are now under construction. See below for Comments.

The completed mast has proven strong and durable and has a structural advantage over most other masts by having a built-in transverse web for its full height, rather like the 'spar' within a plane's wing. This not only adds considerably to buckling resistance but also creates 2 compartments; one for the internal halyards, and a larger one that may remain sealed as an air chamber, depending on how halyards are arranged. Also note that this mast has an attractive built-in taper above the hounds, in both width and depth. If built and finished well, this mast can look totally professional.

The purchase process is defined below:

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Added April 2022: Introducing the Mk.ll Waters Wingmast ... and how to purchase.

The first thing is to sign the Waiver that is at the bottom of this page, and return it to: [email protected]

Then, the fee for the appropriate WingMast Manual is sent by PayPal to the same email address. and you will then be sent the PDF files. Data for the 11m mast is now included in the Mk1 manual so one can interpolate the dimensions, thicknesses and cloth lay-up to suit the final mast length. If your trimaran has a beam much in excess of 55% of the mast height, please contact the mast designer as you may need to use a larger section to handle this unusually high righting moment, depending on your ama buoyancy.

For masts of 11m and over, the new Mk ll mast** is recommended but this manual will not be available until late 2023 (check latest update below), giving time for writing up the Manual in detail after testing of the prototype that has just been completed.

Please note that this wingmast is for a multihull that does not 'sail on its ear', so such wingmasts are not recommended for mono's, unless stabilized with foils.

** For those wondering: why the Mkll, and what are the differences with the Mk l ?

Basically, the Mk.ll uses the same construction method, but as the nose of the Mk l is a radius closely based on the mast width, this starts to get too blunt and large for the larger mast sections over say 90mm wide. So for the Mkll, the nose is made more elliptical. Also, the rotation force of the larger masts can get quite high, so the pivot (and central web) has been moved back relative to the chord dimension. In addition, the supporting cables are attached to a rotating (not fixed) beak, the base pivot support is stronger, and the masthead cap can be arranged to take up to 4 internal halyards.

Finally, most larger masts over 12m will use a track for batten-slides or cars, so that's also been factored in. While the elliptical nose gives a finer, less resistant air entry, the more rounded nose of the Mk1 will be less critical to stalling when the approach angle to the apparent wind is less well matched.

Also, because of the larger size and material cost, a few jigs are suggested to further control construction tolerances for the larger Mkll, added steps that are just not considered necessary for the Mk.l masts under 11m. The Manual for the Mk.ll wingmast will also explain how and where, vacuum bagging and/or resin infusion can be used to advantage.

NEW: For those wanting more information on the differences between the Mk.l Wingmast & the Mk.ll ... GO HERE

Mk.ll Test Results

In June 2022, the first Mark ll Waters Wingmast was really put to the test. It was stepped on a racing Farrier F82S and though untried and untested, entered into one of the most gruelling races in Europe ... a 900 mile race up the entire length of the Baltic, starting in Wismar, close to Denmark and ending in Torn, only 100 miles from the Arctic Circle. To sail this distance and back home again, involves over 2000 nmls of sailing over about 2 weeks, with winds from all directions.

Well, the mast performed flawlessly and helped this relatively small boat beat other multis that were up to 50% longer, and break a 7 year old record by 17 hours for the fastest time ever by a multihull for this race. If you want more of the story, .. HERE it is. The boat (and wingmast) competed in the same race in 2023 but in lighter conditions, yet once again she finished 1st Multihull.

While the Mk.ll Manual (11-15m) will now not be ready before Spring 2024 due to other priorities taking longer than expected, if someone is really eager to get started, an arrangement can be made to start making the mast bench and the central web, based on the Mk.l Manual, as these parts are of the same design - just larger. We can give you the exact size for your particular mast. The Mk.1 manual is presently still US$179, but if you purchase the Mk.ll Manual later on (keep proof), you will be given a $120 rebate on the cost of the Mk.ll or Mk.lll Manual, that may vary with your specific mast size and needs.

This approach is offered for the benefit of the builder, but to build more than one mast, a full manual must be purchased for each mast to cover the Design Royalty. (The design and testing of these masts runs well into 5 figures, so just a small part of this cost is shared by each builder via the Manual purchase).

Because enquiries are already coming in for masts in excess of 15m, a slightly modified Mk.lll will also be offered later, that will use the same basic design as for the Mk.ll, but have double diamonds to safely deal with the greater height.

Mike Waters, n.a. for Small Trimaran Design

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Waters wood wingmast: .

The build method is described through 3 sheets of detailed plans and a 15+6 page Manual full of illustrations. Material cost (using high quality) was about US$200 (in 2019) and the plans sell for US$95 via PayPal . This design has now been used for numerous wingmasts of this format and works fine for its intended use. The CF design is however inevitably more efficient as the material enables it to be stiffer and slightly slimmer. Again, please accept, sign and return a copy of the Mast Waiver below before ordering or I will not be able to send out the plans.

Comment by the designer (2020)

One point that I will add that I’ve not seen mentioned elsewhere, is this.

Because a rotating wing mast assures a better entry to the flow around the soft sail that sets behind it, the smaller the sail hoisted, the more proportionally efficient the rig becomes. I became very aware of this when setting a small but high aspect storm mainsail behind my own wingmast a few years back, and was very impressed how efficiently this small rig performed. Most boats, certainly all cruising dinghies, just struggle in high wind and waves to get anywhere upwind. For them, the W17 is a total revelation. Despite the increased waves due to higher winds, I have been able to make 9 kts (!) to windward and even hit 14.4kt with my W17 on one wild reach … and this storm mainsail is only about 4m2 ! Check here and watch the Storm Mainsail performance Video

As a performance-loving octogenarian, I can tell you it’s a really fun way to sail. Fast but Safer, so I enthusiastically recommend such a stormsail with a wing mast to all builders, for all high wind use.

Comments by builders:

"My CF-wingmast is finally done, and bringing it out of the basement yesterday was like a birth to me! It is truly a spectacular piece of complex design and fabrication inventiveness. I am both proud of the final product and impressed with the build method, all the way through. The build-manual was key to my success. It is extremely complete in design and structural detail and also very helpful with build techniques. In summary, building the carbon fiber wing mast was a three month project which I will never forget. I have a mast that rivals or equals professionally built ones and is probably even stronger. I also learned a raft of new skills, saved quite a chunk of money, but beyond all of that I have the tremendous reward and pride that comes from this special DIY project. It is actually quite amazing to work through this unique design with a process that enables one to start with a bunch of soft carbon fiber cloth and a couple of gallons of epoxy, and end up successfully constructing a state of the art rotating carbon fiber wing mast. Thank you Mike! " Jim van N, USA, 2020 See photo of JIM'S MAST .... first time builder too ! ---- >>

"I am having so much fun making this mast! Just to see each piece come together from a piece of cloth and resin to form a rigid, strong yet lightweight structure, is quite amazing. The design is clever and intriguing and your detailed manual takes most of the stress out of this build so giving me, the builder, every confidence that I will end up with a good result. Thanks a million!" Joe-V: USA, 2019

"I have read through the CF mast manual and am very impressed with your techniques and also how comprehensive the manual is. The depth at which you cover the subject makes this a real bargain for anyone who has thought about building their own wing mast in carbon. It's really a gem of a publication". Alan-J, WA-USA, 2019.

"Hi Mike; thanks for the CF-mast building instructions. It's a great piece of work and I thank you very much that you share your techniques and knowledge in this way". Günter-K, Germany, 2017

"I really enjoyed building my carbon fiber wing mast and would even enjoy doing it all over again! I am very happy with my results and the skills I developed during the building and now have the confidence to use carbon fiber far more than I used to. Even the cosmetics of my mast came out acceptably well as I've received many compliments from friends ... "You BUILT that !!". My mainsail also fits the sail groove perfectly so I am really looking forward to getting it out on the water". Ron-E, USA, 2015

"I received the manual and it looks great! It is indeed an ingenious construction method and the incorporation of a central web further adds to my confidence in the end result. The amount of detail is stunning and everything makes a lot of sense (I skimmed it twice and then gave it a more thorough read-through). I find it well-written and the detail gives a potential builder a lot of confidence that this can indeed be done. There is nothing about this method [from my perspective], that is any more difficult than typical boat building, and most of it even seems a lot simpler than that. So, great work, and I see many more masts being built using this method. I also completely understand your need for a waiver and would do the same in your position, as after all, you have no control over the end product materials, construction or use." Todd-B: USA, 2015 (builder/sailor, experienced with composite construction)

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By requesting these wing-mast plans, I confirm having read and agreed to these Terms and Conditions:

Licence : As purchaser of these Mast Plans and/or Manual, and on behalf of a potential builder / operator, I acknowledge that I am granted a licence for the building of ONE mast only. I agree to request an expanded licence if planning to build more than one. As noted under general Terms & Conditions, information in this Manual is considered IP (Intellectual Property), so no refund can be granted after this Manual has been delivered.

Copyright : I further acknowledge that these plans, drawings, and building manual are copyright material and that any distribution of their content or part of, requires prior written permission from the designer (or his assigns). Any disregard of this will be deemed a violation of copyright.

Acknowledgement of Indemnity : I acknowledge that while the designer may be fully qualified to design this mast with adequate strength for its intended pleasure use, he has no control over the final selection of materials, quality of workmanship, or weather conditions to which the mast may be subjected. As potential builder / owner, I therefore agree to accept the following:

Waiver : That, neither the builder, owner or any skipper, nor their heirs or assigns, will take legal action against the designer, his heirs or associates, for any damage of property, loss of use, injury or even death arising out of construction and use of this design, whether considered as caused by any deemed negligence of the designer or otherwise, and agree to indemnify and hold harmless, the designer, his heirs, successors, and associates, from any loss, liability, damage or cost that may arise relating to the building and use of this design.

Link to Contact Page

Wing’soul. Easiest to Build Wing Sail.

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

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.

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
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:

https://www.yumpu.com/en/document/view/38970140/t...

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

http://www.junkrigassociation.org/

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

http://www.kastenmarine.com/junk_rig.htm

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.

https://www.pbo.co.uk/seamanship/bermudan-rig-vs-junk-rig-17481

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.

Try http://www.airfoiltools.com/

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 Lif t

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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Rotating wing masts

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Lately I’ve been reading a lot about rotating, free-standing, carbon fiber, wing masts. By all accounts they’re much more efficient than the usual arrangement. If this is true why don’t we see more of them? I understand the problems that it would create for racing, but not everyone cares about racing. I also understand that they’d be more expensive, but carbon fiber spars now proliferate all sailing sub-genres. I also understand taht it may not be practical to redesign an existing boat’s rig, but why don’t we see these on more new designs? I, for one, am always trying to find ways to make my boat more efficient and faster. And I feel like this is a trend among all sailors, even devout cruisers. Why is such an obvious leap forward in sailboat evolution being ignored?

Pretty sure it isn't just expensive, its very very expensive.

I assume that you indeed mean wing *mast* and not the wing sails that proved so devastating in the last America's Cup. Wing Masts are like many ideas which really well work in narrow applications. Wing masts offer very small gains in performance but with a high degree of complexity. Wing masts work very well on high efficiency, low drag applications. In that mode they offer an efficiency that can actually be used by the vessel. They are great on high speed vessels like ice boats and racing multi-hulls, because these crafr have apparent wind that is almost always from forward of abeam. But that small gain in efficiency comes at a price; a very big price in terms of practicality when applied to more normal vessels. For example, wing masts need to be free to rotate, but with their angle of attack controllable, so that they can offer the proper angle of attack for the wind direction. That means that the crew needs to be able to adjust not just the mainsheet, but the mast angle of attack. Around here there are folks who argue against the advantages of a fractional rig by suggesting that it is too hard for the average sailor to learn to use a backstay adjuster. Visualize the average sailor learning to properly adjust the angle of attack of the mast (remembering that a wing mast is only more efficient when the angle of attack is correct, but greatly increases drag when it is improperly adjusted). Allowing free rotation requires a single axis of attachment for the shrouds or else a cantilevered connection. If a vessel is very beamy then the vertical staying of the mast can be isolated from the bending sideloads on the spar itself, which is part of the reason that wing masts work really well on multihulls or iceboats. But on a monohull this makes staying very tricky without something like the side struts seen on open class boats. If the choice is to use a cantilevered connection, there needs to be adequate fore and aft as well as side to side bracing of the bearing points for the embeded portion of the mast, and either an above deck set of bearings or else a set of bearings at the heel or the mast and at the deck, with the deck bearings being water tight. Proper support of the deck mounted bearing would in all probability require fore and aft as well as lateral bulkheads or knees occupying much of the interior in the area of the mast. Wing masts have a lot of 'sail area' in the mast alone, at times more sail area than the boat can safely use and so for a cruising boat, which encounters winds of a variety of forces and directions, this inability to 'reef' the sail area of the mast can be a dangerous liability. This can be a significant problem at anchor or tied up at a dock. In the past, vessels with wing masts were generally daysailors and boats which are small enough that the mast could be unstepped at night. There have been experiemental boats with wing masts which have allowed their masts to feather, but that can mean a lot of noise and a lot of vibration. Then there is the weight versus cost issue. While a wing mast can be lighter than a conventional stayed spar, for the most part, they tend to be a heavier rig, due to the isolation of the side support from the structure resisting the bending of the spar. This can be worked around by using exotic materials but of course this has serious monetary consequences. And even if these complications could be effectively addressed, the offshore sailing community tends to be pretty conservative. Here we are nearly fifty years after aluminum spars with modern engineering became the norm, and yet the cruising community still argues that deck stepped masts are somehow less safe. So if you can visualize that, now try visualize trying to convince them that a mast supported on a ball-joint with a single shroud lead to a strut on either side makes sense. I don't see that happening any time soon. In terms of retrofitting a wing mast to a conventional monohull, there would be little to no real gains in performance, but even if there were measurable gains in performance, the costs and complication would be prohibitive, especially since there are a wide range of less expensive alternatives which would be more effective in improving performance. Jeff

Red, by 'wing' mast do you mean the aerorig? Resultados da Pesquisa de imagens do Google para http://upload.wikimedia.org/wikipedia/commons/a/aa/Paratii_2.jpg

Jeff, thanks for the excellent (as always) explanation. I think all of your points are very valid and make perfect sense. I'd be interested to hear your thoughts about this design that I just stumbled upon while researching wing masts. To my very untrained eye it looks like it would be a very efficient rig, but based on what you've said above it would be more trouble than it's worth, and for that hull it wouldn't add much in the way of preformance. Globetrotter 45 Copa, I'm referring to a mast with a cross section similar to a wing. Not a wing sail or any other rig anomalies.

Low hull-speed due to a short waterline length relative to length overall,
Displacement hull form,
Comparatively low stability, and

One of the worlds main developers of Wing masts for yachts is I believe based near me in Inverness,Scotland and there are several examples to be seen locally-one in particular fitted to a big catermaran(suspect this might have been the test bed) Can be very efficient in large scale commercial applications.

Wow, Jeff, quite an explanation! I pulled the motor out of my boat and glassed over the aperture, thus I'm completely at the mercy of wind and tide. I've spent many an hour on light air days either drifting or swinging on the hook contemplating ways to improve my rig. I have concluded precisely what you've said above, that it's just not worth all the trouble and expense for such marginal gains in performance. I bought my Triton because it was the best boat that I could afford at the time. And since I've had her I've identified many traits in her that I do not wish to have on my next boat. If I get any wild hairs to make major rig modifications I will wait to do it on an appropriate hull. I was curious about wing masts because they seem like they would offer many advantages over traditional rigs when married with appropriate hulls. I wanted to know that if this was indeed that case, why we didn't see more of them. Jeff, you've more than answered my question and I really appreciate your insightful responses.

You are very welcome.... I tip my hat to you sailing a Triton without an engine. I should say that I too enjoy that unique aethetic to sailing an engineless boat, and admire the skill required to do so with a boat like the Triton. (I did the same thing with a Folkboat back in the 1970's) You learn all kinds of tricks and you really become one with the boat (or else spend a lot time in trouble). Jeff

Thanks Jeff. I totally agree with you about becoming one with the boat. I used to work as a sailing instructor for Outward Bound’s Hurricane Island sailing school where we did a lot of engineless sailing. It was always amazing to watch inner city kids who’d never even seen an ocean before deftly handle their vessel after just a few weeks. It was also interesting to see them form an affinity for a craft that dealt out much more pain than pleasure. I thought a Triton would sail like a hotrod compared to the schooners and dumpy OB boats I grew up sailing. Man, have I been disappointed. My next boat is going to be quite different; light air performance is now my number one criteria (hence my initial posting). I used to moor in Woods Hole and the current there could best my little boat 50% of the time. Now I’m out of NC’s Cape Fear river and I spend about 40% of my time getting skunked.

A little advice from someone who has sailed mostly offshore for over 50-years now, if you spend much time sailing offshore, anything that moves, pivots or goes up and down, even if you take good care of it, will eventually become a problem. The simpler the systems on your boat are, the easier it is to care for, the less likely it is to fail and the easier it to repair when the time comes - and it will.

I totally agree. But I think that in some ways a rotating mast would be simpler. Yes, the joint on which it was mounted could become a problem. However, you wouldn't have all the standing rigging creating problems or chainplate issues.

I should add that I’m not a proponent of wing masts, I’m just playing devil’s advocate. I also know that there is some standing rigging associated with this configuration, just not as much. (or so I've read...)

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How wingsail technology could revolutionise the shipping industry

October 26, 2022

Do superyacht designers have the answers to the future of efficient sailing and shipping? Mark Chisnell reports on why variants of wingsail technology could be coming to an ocean near you

On a summer weekend there’s always a bustle of activity on the foreshore at Hamble-le-Rice, on England’s south coast. The whirr of electric air compressors has been the soundtrack to the rise and rise of the inflatable paddleboard . And it may be about to initiate another transformation, simplifying sailing to the point where it returns to its birthplace; commercial shipping.

Matt Sheahan reviewed the Inflatable Wing Sail (IWS) for Yachting World more than three years ago and was impressed by the invention of Edouard Kessi and Laurent de Kalbermatten. Based on an unstayed, telescopic mast, the IWS inflates via an integrated air compressor to a surprisingly low pressure, just two millibars.

It creates a soft, symmetric wingsail with many of the efficiency advantages of a hard wingsail (amply demonstrated in America’s Cup and SailGP racing) but none of the problems – it’s very simple to raise and lower, and just disappears down to the deck when you don’t need it. Matt predicted that the much-simplified handling could mean a significant future for the IWS in superyachts and commercial shipping.

The simple to handle Inflatable Wing Sail (IWS) we featured in 2019

Simplifying the way that sailboat rigs work is far from a new idea. The IWS follows in the wake of many of these initiatives with its unstayed mast, an idea that has its origins in the Chinese junk rig.

Gary Hoyt’s Freedom Yachts utilised this approach in the mid-1970s. Meanwhile in the 1980s, a building beside the very same River Hamble produced the AeroRig, a free-standing mast with a rotating boom on which both headsail and mainsail were set. The forces were easily balanced and controlled by the mainsheet alone.

A descendant of the AeroRig is the Dynarig, developed by Dykstra Naval Architects and built by Magma Structures in the UK for two spectacular superyachts, the Maltese Falcon and Black Pearl . A recent partnership agreement with Southern Spars means that the Dynarig will now be developed with the support of one of the marine world’s most sophisticated technology providers. The rig is targeted at the people who want to keep it simple, and this can include superyacht owners interested in reducing crew numbers and handling issues.

Dykstra has a Wind Assisted Shipping Project (WASP) in process, a multipurpose cargo ship which uses the Dynarig masts as cranes, and is working with Veer on the world’s first emissions free cargo fleet. The Dutch design house, responsible for some of the most iconic superyacht and J Class projects, also tells us that it is currently working on a couple of new classified Dynarig superyacht projects.

This is where most of the momentum is headed with these new technology rigs in the superyacht world. VPLP is perhaps the world’s most successful yacht design groups since Marc Van Peteghem and Vincent Lauriot Prévost set up their business in 1983.

They’ve won the Vendée Globe , the Jules Verne , the Route du Rhum , and in 2010 the America’s Cup with the huge wingsail on BMW Oracle. “Marc [Van Peteghem] saw the potential of that highly efficient automatable wingsail,” explained Simon Watin, president of their maritime division.

“He’s been at the forefront since that period, really pushing in parallel the maritime transportation and the yachting together,” continued Watin. VPLP started drawing the concept in 2016 and built the first Oceanwing to fit on a small trimaran. It’s an automated wingsail that hoists on an unstayed mast – similar to the IWS but using battens to create the wing’s shape, rather than inflation. It’s a two-element rig though, allowing for a more efficient foil and higher performance. VPLP built two 32m2 Oceanwings for Energy Observer , a former racing catamaran now circumnavigating as a technology platform. They also started to pitch eye-catching concept designs into the superyacht community.

“The people we are looking to convince are people that would normally go for a pure motor yacht,” explained Watin, “and who would not be so much interested in the sailing aspect itself.” Watin pointed to the gains in fuel economy, range, comfort and autonomy. The Seaffinity is a streamlined, concept trimaran from VPLP, “with a large main hull and two smaller floats featuring two Oceanwings, one behind the other,” explained Watin. “And this is really an illustration of a new superyacht that could have been a pure motor yacht, but actually benefits from the Oceanwing.”

Dykstra’s Dynarig projects, made famous by Maltese Falcon and Black Pearl (pictured), are being adapted for shipping

Superyacht concepts

Another VPLP/Ayro collaboration has resulted in the radical Nemesis One superyacht concept, a 101m/332ft foiling catamaran capable of 50-knot speeds. The fully automated, push-button craft uses a modified Oceanwings wingsail which can furl and reef and automatically adjusts its angle of attack. There’s no question that this and the Seaffinity are striking vessels, and that the technology could make a significant dent in the operating carbon footprint of yachts that might otherwise have been engine-only.

The first large scale Oceanwing will be a commercial shipping project. The step came when VPLP and the shipping company Alizé successfully bid for Ariane Espace’s tender for a new concept ship that could carry parts of the Ariane 6 rocket from European ports to French Guiana. Once it had the contract, VPLP created Ayro as a separate business to develop the cargo ship Canopée. She is scheduled to launch in late 2022, at 121m long, and will be powered by four 363m² Oceanwings set on 36m masts. VPLP thinks the wingsails will reduce fuel consumption by 15% without compromising speed.

“The technical concept is aerodynamic efficiency with the solid sail with two elements: so reaching maximum lift coefficient. Automation; so no lines, no unnecessary human intervention for trimming, adjusting, hoisting. And much less impact on the deck plan, which is quite major, especially for a superyacht,” said Watin.

The WASP uses its masts as cranes to unload cargo

The difference in the physical and mechanical realisation of the Oceanwing for superyacht and commercial shipping markets is interesting. The version for merchant ships will stick to industrial suppliers as far as possible – electric actuators that would normally mobilise cranes, for instance. The wing will use a reinforced PVC fabric skin, the type of material that would make a truck tarpaulin.

The masts will remain in place in normal use, and the fabric wings will raise and lower on cables powered by electric rams, so the sail area can easily be reduced. A tilting mechanism will allow the mast height to be reduced for ports and bridges.

Unsurprisingly, the superyacht version will be a lot more sophisticated, but is still based on the same self-standing mast and 360° rotation of the sails. “We would use higher technology material, lighter fabrics as well… and for the yachts, we have to be more cautious about the weight of the installation itself, because the sail area is going to be quite a bit larger in comparison to the boat. And obviously, the design is going to be important so we will package all the actuators in a much nicer way – you don’t want a ram sticking out.”

The 48m VPLP design Evidence uses automated and stowable wing sails

Bold initiatives

Ayro is now responsible for all the design and engineering on the Oceanwing, with its own 35-strong design office, but VPLP remains involved. “Ayro has successfully raised quite a bit of funding to sustain its growth,” Watin told me.

It was 2019 when Matt Sheahan made his prediction for the future of the IWS in his Yachting World review, and three years later it appears that the commercial shipping development is also well ahead of the superyacht market.

The WISAMO system is an initiative from Michelin, with two-time Vendée Globe winner Michel Desjoyeaux associated with the project and testing. It’s the same concept as IWS, an inflated wingsail, set on an unstayed telescopic mast.

“When I discovered that system, I thought it has checked a lot of boxes compared to other systems,” said Desjoyeaux. “It has a plug and play system which is very easy to install and use, whether it is for a refit, meaning an addition to an existing boat, or for a newly built ship; you lower the mast into the boat, plug it in and off you go. Once you are out of the harbour, you push a button and the machine does everything. It unfurls the wingsail and automatically chooses the correct setting for cargo ships. This is crucial because there aren’t many crewmembers on the bridge, and they don’t necessarily know much about sailboats. They need a system that operates autonomously.”

VPLP Oceanwing projects on Energy Observer

At the beginning of 2022 Michelin announced a partnership deal with Compagnie Maritime Nantaise to test the WISAMO. The system will be fitted to one of their roll-on roll off vessels travelling between Bilbao in Spain and Poole in the UK. The plan is to have the ship in service by the end of this year. Meanwhile, tests with Michel Desjoyeaux’s own boat continued through last winter in the Bay of Biscay.

Michelin are claiming the system could save up to 20% on fuel costs. It’s in the same ballpark as the Oceanwing, and while it sounds good – particularly at today’s fuel prices – it’s actually only half of what the shipping industry needs to achieve by the end of the decade.

Reducing emissions

The shipping industry pumps out a lot of carbon dioxide – the most recent (2012) estimates being that shipping is responsible for 2.2% of global emissions. The International Maritime Organisation, an agency of the United Nations, has published a strategy for reducing carbon. Global shipping must achieve an average 40% reduction by 2030, increasing to 50% by 2050. The European Union is acting to give these targets legal force, and the first deadline is just eight years away. The task is immense, and the clock is ticking. That’s why the money and energy pushing these new sailing technologies forward is coming from commercial shipping.

Radical superyacht concepts such as Seaffinity feature Oceanwing wingsails from VPLP

One thing that’s been learned in the 150 years since sail last dominated the world’s oceans is that changing the world’s merchant shipping fleet takes time. In 1866, the year of the Great Tea Race, an auxiliary steamer left China eight days after the clipper ships and it arrived in London 15 days ahead of them. Steamships already had a significant speed advantage, but it was more than another 80 years before the last sailing ship ceased trading. This is the problem for the shipping industry; ships are built to last. The world once again needs to restock the entire global merchant fleet with a new technology, but this time there’s a deadline.

The same pressure is unlikely to be felt in the superyacht market for a while, and perhaps it never will. Still, once these new technologies have been developed and proven in the highly competitive shipping industry, it seems likely they’ll start to migrate to superyachts.

No easy options

There are many possible technical solutions but the easy changes – more efficient routing through weather systems for instance – will not get the industry to anything like the 40% required by 2030. The developments that will – new propulsion systems, fuel sources or hull designs – are still in development and/or will require massive capital investment. It’s taken a while, but the shipping industry has finally woken up to the scale and the timescale of the challenge it faces.

“They’ve got a massive problem on their hands,” said Simon Schofield, chief operating officer of BAR Technologies, a spin-off from the British America’s Cup team led by four-times Olympic gold medal winner, Ben Ainslie.

Nemesis One is a 101m foiling supercat concept capable of 50 knot speeds thanks to a fully automated Ayro Oceanwing rig

“In the last two years we’ve seen a marked difference in the industry. Two to three years ago when we were talking about this [wingsail] technology, people were like, ‘Yeah, it’s nice. People have been talking about this for years, but no one really wants sails…’ And now it’s, ‘How quickly can we have wings? What else have you got? We’ve got to move, we’ve got to get going.’”

Unsurprisingly, there is no shortage of people trying to solve this problem. The reward for developing any cost-effective way of reducing a significant chunk of those 40% of emissions will be a massive new business. The scale of the shipping industry is enormous, it’s a global business with a total value of more than US$14 trillion. So, there’s no shortage of ideas either, and kites were early leaders in this field.

The SkySail was a stand-out that got tested at full scale, installed in a custom-built ship, the MV Beluga Skysail , and tested on an Atlantic crossing in 2008 after 10 years of development. It fell at that hurdle, with the company turning instead to developing airborne wind energy systems for power production. The fate of the shipping project is sadly recorded on their website: ‘The SkySails propulsion system for vessels is currently not marketed any more.’ There’s no mistaking the significant risk in these ventures.

Fortunately, risks have never stopped people trying to innovate and there are plenty more projects with potential. The Flettner rotor is a tall, smooth cylinder mounted vertically, that rotates in the airflow passing the ship. It uses the Magnus Effect (the same thing that causes a spinning ball to curve in flight) to generate a force that helps to push the ship along. Norsepower have already installed a rotor on one tanker and it provided just over 8% fuel savings – good, but still nowhere near enough.

Oceanwing projects also shown here on cargo ship Canopée due to launch this year

It’s now the wingsail that seems to be grabbing the bulk of the investment. A Swedish group, led by Wallenius Marine, has formed a joint venture with Swedish industrial company Alfa Laval to develop the Oceanbird, a wind-powered car carrier with fixed wingsails that will stretch an extraordinary 100m into the air.

More sailing ships to come

In France, Neoline have developed a more conventional sailing cargo ship and agreed a letter of interest for its construction. They plan to use the Solid Sail being developed by the French shipbuilding and fleet services company Chantiers de l’Atlantique. It’s a freestanding mast with a rotating boom setting a fabric headsail and solid panel mainsail – panels that Multiplast are building.

There are several projects in the UK. British yacht design firm Humphreys Yacht Design and sailing software tools designer, Dr Graeme Winn, are involved with Smart Green Shipping. In late July, they announced a £5m investment from a mix of private industry and Scottish Enterprise for a three-year R&D project to develop and test their FastRigs wingsail and digital routing software. They plan to put a demonstration unit on a commercial ship by 2023.

Also out of the UK is the Windship project, with a board of directors that includes yacht designer Simon Rogers and former Sparcraft director David Barrow. They’re proposing sets of three vertical wings, each 35m high.

Oceanbird is a Swedish programme with a car carrier in development using folding 40m high wingsails. The company estimates each sail will save around 480,000 litres of diesel per year

“We believe,” Simon Schofield told me, “that wind technology has become mainstream in shipping… we’re seeing announcements almost weekly of new technologies being trialled and fitted to ships and we are set up specifically with a supply chain for volume. We’re doing a run now, but we want to be doing hundreds next year.”

Yes, that’s right. Hundreds. If there is such a thing as first-mover advantage, BAR Technologies appear to have it.

BAR started the WindWing project with a computer simulation, but merchant ships presented new problems. “The ships have a yaw balance [weather or lee helm] problem,” explained Schofield. “They’re not designed for wings. So, you’ve got to monitor rudder limits.” This is exactly the kind of problem that’s fundamental to designing well-behaved, fast and comfortable superyachts, and it’s no surprise the same approach was taken by VPLP with a similar background in elite yacht racing design.

BAR Technologies predicts there will be hundreds of ships using its WindWings by next year

Complications

The problem is even more complex with commercial ships. The leeway the wings induce has other side effects. The loading on the propeller changes, and that impacts its efficiency. “We also needed to model the engine plant, because we are moving engines away from their optimum efficiency points, so their fuel consumption changes,” said Schofield. Eventually, using these tools, they developed the design parameters for the WindWings.

“They are three-element, rigid wingsails,” said Schofield. “The first ones we’re doing are 37.5m aerodynamic span, about 20m in chord and rising to about 45m off the deck. So big bits of kit… We operate in up to 40 knots of true wind speed, with a 25% gust factor on top. So if it’s 40 gusting 50, that’s fine.” After that the WindWings are feathered, much like a wind turbine.

Despite the advanced state of BAR Technologies’ WindWings project, it’s probably too early to predict who the big winners will be in this race. In fact, given the demand from the world’s merchant shipping fleets, it’s likely there’ll be several.

We can also be sure all this energy, innovation and investment is going to produce significant advances in sailing technology. Perhaps, in a few years’ time, the gentle whirr of electric air compressors will have found their way from the paddleboards on the beaches of the River Hamble, to former motoryachts in the river’s many marinas.

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how does a wing mast work

Over the past few seasons it has become quite clear that many people who have been experiencing speed or power problems have had little basic knowledge of what they can do with the mast settings. It is clear what do with the cunningham, simply pull on it to get the pressure out of the sail as you need, but often the mast is left unattended to, as a last priority.

In fact it is one of the most important speed controls on the boat. It is important to understand how to use it, and what you want to have in the sail shape for different conditions. It is not so easy to just come up with numbers and angles that will suit every mast and sail so I will try to make some key points to help understand this correctly.

The more pre bend set in the mast the more effect mast rotation has on the sail shape.
The effect of the spreaders means that the more the mast is rotated backwards, the more the lower mast section can bend forward (in the direction of the boat) and the stiffer the top section becomes. Leaving the cunningham tension out of the discussion at the moment, the result would be that the sail becomes flatter in the bottom and fuller in the top.
Rotating the mast more forward allows the spreader to start to work and the lower mast section becomes stiffer in the forward direction and the top becomes softer backwards. The result is the sail will become deeper in the bottom and flatter in the top.
Cunningham pressure flattens the sail and will tend to flatten the top more than the bottom since the top of the mast is unsupported and more free to bend. Understanding the sail shape that works best in the differing conditions is then very important. For example in Flat water you would like to have a very even profile through the sail from top to bottom with good power in the top and the possibility to pull the mainsheet quite hard without stalling the back of the sail. On flat water you can sheet hard and point higher. By wave conditions you would want good power down low in the sail and have the top more open and twisted. This gives you power and the twisted top allows the boat to accelerate easily letting you steer around more and power the boat through the waves easier. Generally you can’t point as high as the boat on flat water but because of the waves you can achieve a much better VMG (velocity made good).

The typical example is that with increasing wind the sailor will pull the Cunningham hard but not adjust the mast rotation to go with it. The effect of the Cunningham is flattening the sail, but more in the top. This allows the leech to open. The boat may feel ok but often the leech is to open and you can’t point high enough. This setup can be good in big waves but on flat water the sailor would like to have the leech standing much straighter so they should rotate the mast further back. If you go back to our original points you can see that the mast becomes stiffer in the top and can bend more in the bottom. This is therefore powering up the top and flattening the bottom of the sail. With the Cunningham pressure you can sheet on hard and point high with good speed.

The other typical mistake which occurs, is that the sailor by strong wind, simply pulls the mast back in line with the boom and pulls full Cunningham pressure. Because the mast rotation is too far back the sail becomes too full in the top and too open in the bottom. The sail will have a lot of twist which some sailors think is good for strong wind, but because of the top of the mast reaching its maximum stiffness in the aft direction of the boat the sail will remain too full in the top. The end result is a sail which is twisted to far and with too much profile for the strong wind. The twist causes you to loose pointing ability and the depth is causing excessive drag, just slowing you down. You are in effect going slower and lower than the correctly trimmed boats.

Spreader rake is also another significant factor in setting up you rig. It also plays a part in how much the rotation angle affects the depth of the sail. That can be a whole subject of its own, so for now I make just a few comments. Try to think of pre-bend as controlling the position the mast takes its bend. The more pre-bend you make in the mast the lower the mast likes to bend. The lower the mast tries to bend the straighter the top section becomes. The flatter the pre-bend the more the top section tries to bend. The normal reaction of sailors is to increase the pre-bend for strong wind to flatten the sail and reduce it in light wind to increase power.

Principally that is correct, but it must be incorporated with the rotation to get the right balance in the sail. Like most things, too much or too little can be harmful. It is a great failure made by many sailors to flatten the spreader angle to far reducing the pre-bend in the mast to almost straight. For light wind this is doing more harm than good. The heavier sailors also often request more luff curve because they are looking for power.

With more luff curve and flatter spreaders light wind speed can quickly come to an end. The sail will become very full down low with a deep entry angle from the mast and a very closed leech section. When you get the first wind in the sail you may get a feeling of power, but you may also experience the boat just wanting to fly a hull but not wanting to go easily forward. The boat will not point and will not accelerate.

In many cases it is actually better to go the other way. By very light wind you can increase the pre-bend to open the lower part of the sail and reduce the entry angle of the sail behind the mast. With the rotation angle set correctly to get the head standing up just the right amount you can be very fast. Just remember flat is fast and deep is slow. It has a lot more to do with entry and exit angles of the sail to achieve height and power.

Amongst sail makers there are many different ideas, and history has proven that there are many ways to build fast sails. The most important thing is that the sailor can understand how the sail should work and manage it well. Also restrictions on materials and designs in the boats themselves change the way the sail has to work to achieve the best results. We design our A class sails to allow the mast to be rotated well back. The reason being, that the mast itself creates a lot of profile over the rig and therefore it is very important to be able to reduce the wind age over the mast by rotating back as the wind increases. At the same time the sail must flatten rather than get fuller. That is the secret to success.

Good sailing.

sail loft Egner

Landenberger OneDesign Neustaedterstr. 75 79822 Titisee-Neustadt Germany

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Our range of sails covers a wide variety of boat types. Whether regatta or cruising sails for catamarans, dinghies or keelboats - we have the right sail for you! Our years of experience in various international boat classes make it possible to build sails perfectly matched to your requirements. As a sailmaker, we are also the right partner for sun sails, canvas tarps and sail repairs in the Freiburg / Black Forest, Lake Constance and Switzerland area.

Soft wing-sails are the next generation of sails

Why soft wing-sails .

Why do we keep using sails like the old Dutch windmills rather than wings like the modern wind turbines?

Why do we try to make the sails look like wings rather than using the real thing?

Why do we use sails, knowing that wings are more efficient in terms of driving force and upwind pointing?

As a fighter pilot and an enthusiastic sailor for long time, I discovered that there are lots of similarities between flying and sailing, such as driving a machine on fluids, no brakes, windage effects on the bow / stern, the propeller walk, etc., However, the most and remarkable similarity is the use of lift force .

Airplanes use lift force, created on the wing due to the air flow around it, in order to hold the airplane up in the air. Sailing boats can use the same lift force, created on the sails as their driving force.

The answer to the questions "why" above was to make Omer Wing-Sail which is a simple structure wing-sail , easy to use, reliable, and good for all cruisers / cruiser racers in any weather condition.

Extensive sailing with the Omer soft wing-sail, strongly convinced me that wing-sails are the next step in the evolution of sails.

Omer Wing-Sail

Why free-standing mast?

The idea of a mast without wires is foreign to most people. It is hard to fathom how a sailboat mast can stand, all by itself, without something to hold it up. However, those airplanes that long ago got rid of the wires holding the wings on in exchange for a spar, fly very safely. No one really thinks that the wing spar is not strong enough, and that an airliner wing will fall apart.

Unstayed masts are designed to take the heeling and sailing loads the same way wing spars take the loads of the airplane.

The unstayed mast is held up by two parts - the heel fitting and the deck fitting. It puts no downward compression loads on the hull, which makes for a lighter hull structure as well as saving chain plates, shrouds, turnbuckles and other fittings.

There are already many boats sailing out there with free standing masts such as the Superyacht "Black Pearl" that has three 64 meter free standing masts and the "Dwinger" with its 63 meters long free standing rotating mast.

In order to be efficient in almost all wind directions, the wing-sail should be able to freely rotate into the wind and maintain it's 0°-10° angle of attack. A free standing rotating mast is the perfect solution.

Omer wing-sail design

Omer wing-sail is based on a rotating A frame mast, that supports both sides of the wing, having an accurate wing cross section as well as high moment of inertia.

The wing is made of three different sails: two main sails and one U shape leading edge sail. All three sails are sliding independently up and down the mast. When all three sails are hoisted, we get a wing that one can reef and drop down like any other conventional sail.

With the same sails area, we get a 10%-15% faster boat while pointing higher.

Main design differences between America's cup wing and Omer Wing-sail

Omer Wing-Sail cross section

AC 40 wing and jib cross section

37' Omer Wing Sail Cruiser

37' omer wing sail racing (optional), america's cup ac40, patents granted: .

US 6863008, 7603958, 8281727

EU 1373064, 2404820

NZ 529216, 586805, 593939

AU 2002236181, 2008344923

SA 2010/04809

OMER Wing Sail Ltd.

23 Hohit St. Ramat Hasharon,

Israel, 47226

Tel: +972-3-5401675

Mobile: +972-54-4277617

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Building, restoration, and repair with epoxy

The Wingmast Advantage

By J.R. Watson

One of the original experimental components of Adagio was the rotating wing mast. In 1970, a plywood mast (a fore runner to our 050 mast design) was stepped on Adagio.

The rotated airfoil-shaped wing mast makes a smooth transition from mast to sail on the leeward side. This provides cleaner airflow around the mast. The benefit is better attached airflow, thus less drag and more power driving the boat.

A standard aluminum, oval mast provides improved performance when rotated. But supporting an aluminum mast when rotated becomes complex. The wing mast solves this problem with its greater dimension in the fore/aft and lateral planes of its cross section. This can be used to produce a spar that has better column load capability than one of smaller dimensions.

In other words, the wing mast structure can take greater compressive loads without buckling. It therefore requires fewer support wires, spreaders, etc. This advantage allows the rotating spar to be fully exploited with few trade-offs. The wing mast is very attractive from a performance perspective.

We have built wing masts for a variety of multihull craft using a variety of building techniques. Our most successful design, the 050, has been used for racing and cruising boats for over a dozen years.

…Royal Huisman, Dykstra Naval Architects and Mark Whiteley Design. This 100m / 330ft ground-breaking concept expressly focuses on the highest standards of environmental sustainability with proven technology for worldwide reliability. Its advanced systems platform easily accommodates future technological advances and regulatory requirements.

The innovative, aluminum-hulled WING 100 is a true sailing yacht – not a heavy sail assisted motor yacht – yet one with an important difference. She can be easily and securely handled and quickly deployed without the least fuss or drama. WING 100 has been conceived not only to appeal to sailing yacht owners, but to provide the perfect cross-over for motor yacht owners who want to minimize their environmental footprint by reducing the weight of their yacht, but retain the highest standards of amenity and comfort.

These benefits – and many others – arise because WING 100 is no ‘normal’ supersized sailing yacht: she has a highly advanced rig by Rondal. The wing masts have airfoil profiles; are free standing, and rotate to provide very powerful, integrated airfoils with the sails. The shape of the airfoil can easily and remotely be adjusted to maximize or reduce power. Being free-standing, the wing masts have no standing rigging or associated deck clutter, maximizing safe, clean amenity space on deck. The wing masts are easily and safely remote-controlled to ensure fast, energy-efficient sailing, providing a comfortable experience for all onboard.

To put the WING 100 concept into perspective: she is a true sailing yacht that will properly earn her ranking among the world’s top ten sailing yachts, along with Royal Huisman builds ATHENA and SEA EAGLE II; soon to be joined by the exciting new 85m / 280ft New World Sloop, PROJECT 410, currently under construction in Vollenhove. The supersized and highly innovative WING 100 would not only be a top-tier yacht in this elite group, but would also become the acknowledged pioneer among the even more prestigious ‘true’ supersized sailing yachts.

Royal Huisman is the only shipyard in the world with the expertise, infrastructure and continued technological evolution required to build the largest and most advanced of the top ten true sailing yachts. The range of new technologies applied by the shipyard to maximize the energy efficiency of WING 100 will bring substantial advantages to the owner – and not just while exploring the outer corners of our vulnerable planet.

WING 100 and a high performance foiling boat: one picture worth a thousand words

The combination of the concept’s pioneering board systems and advanced wing mast rig, alone, qualifies WING 100 as a defining breakthrough in mega yacht design. A host of additional smart refinements ensure that WING 100 can also claim distinction as the world’s most innovative sailing yacht – a role model for the industry. “Watch this space” to see these technologies develop through the mega yacht and superyacht sectors and, almost certainly, be embraced by wind-assisted cargo sailing ships, too. And that is why this significant project stands to benefit the whole planet.

WING 100 offers the perfect platform for a visionary owner looking to minimize footprint. The concept is well advanced towards fully sustainable technology and Royal Huisman expertise is on hand to ensure the owner realizes the full potential of his or her dreams.

Royal Huisman supersized sailing yachts: SEA EAGLE II (81m / 266ft), PROJECT 410 (85m / 280ft) and ATHENA ( 90m / 295ft) . WING 100 (100m / 330ft) would be a top-tier yacht in this elite group.

Editor’s notes featuring:

Main specifications
Eco-focus and fast, easy handling: wing mast rig is the answer
Fresh and dramatic looks
Generous and bespoke accommodation
More eco credentials
Who could build such a ground-breaking superyacht?

The editor’s notes can be found in the full press release: click here (opens new tab).

“A dramatically innovative Royal Huisman concept that redefines supersized sailing yachts – delivering unprecedented performance, amenity, easy handling and energy efficiency.”

“The emergence of sailing yachts on this scale, with the level of energy efficiency and eco-responsibility offered by WING 100, would have been unthinkable just a decade ago.

The team is incredibly excited to be at the forefront of this conceptual revolution. we look forward to applying our renowned innovation and engineering skills to the realization of this highly ambitious project – creating the fourth and largest royal huisman build yet in the global top 10 of supersized sailing yachts.”.

Royal Huisman CEO Jan Timmerman

Supersized sailing yachts by Royal Huisman: an attractive (and possibly even better) alternative to motor yachts

In general, the comfort of motor yachts is enjoyed by their owners while “on location” – in a pretty marina or at an idyllic anchorage. Sailing yachts provide the same enjoyment, but are also much (more) fun while…

Read on at this website > news > inhuis stories & updates [ link ]

Energy-saving and green energy features in more detail

Thanks to her efficient and easy to deploy rig, WING 100 will consume less than 20% of the energy required by an equivalent-sized conventionally powered motor yacht on passage.

Under sail, 200kW can be produced by the hydro generator equivalent to over 40,000 liters / year fuel saving.

480m 2 / 5167ft 2 of solar panels are integrated on the carbon Rondal masts to generate 250kW / day equivalent to a further savings of over 20,000 liters / year.

The main sails and staysails of the wing mast rig can be set in few minutes making sailing the easy choice. This results in 750kW average power saving, equivalent to over 166,000 liters/year.

The electrical system provides for flexible and economical electric propulsion when under power, saving more energy.

The system of WING 100 is calculated to save in total over 225,000 liters of fuel per year compared with similar sized, conventional engine-powered mega yachts.

More features and background information about WING 100 can be found in the editor’s notes in the full press release: click here (opens new tab).

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Wing Masts, Rotating Rigs, and Solid Wing Sails

Discussion in ' Technology Discussions ' started by Dick Lemke , Aug 12, 2009 .

Dick Lemke Administrator

I agree with Claudio that we were moving off-topic in the AC120 Build thread, so with apologies to Ray for jumping too early, will start this one up witht he illustration I had from an article on sail evolution from soft to "hard wing". While I thought there was more information accompanying the drawings, it appears these just supported the article. I will now have to search further, as I believe this came from an article on solid (hard) "wing" development for the 18 Square Meter, and the C Class catamaran. (And now, also for the A Class catamarans). At one time, we were blessed with a poster who has gone on to be crew on the most currrent C Class cat champion from Toronto, Canada. On " Sailing Anarchy " he can be identifed by his handle of " Blunted " and the skipper posts under the name " Fredo " - but I will give " Blunted " a call to see if he would be willing to return to this forum and provide some technical insight into the Canadian championship boat. If you can't wait, you can visit Sailing Anarchy and search for "C Class" for a lengthy discussion and some great photos. Here is the illustration I was thinking about when I posted my reply to Gary a.k.a. " Dreamwakes ": PS - before posting on this thread, lets agree to terminology? 1. A foil shaped mast - is where the chord is only slightly longer than the width of the mast 2. A wing mast - is a foil shaped mast with a much longer chord, and which still requires/uses a soft sail. 3. A solid (hard) wing - is a complete structure which may be shaped similar to the wing of an aircraft, and while it may use a sof sail material, it is primarily of a lightweight structure covered by some form of covering, material or film. 4. A rotating mast/rig is one that if there is no tension on the mainsheets (or lines) it will weathervane into the direction of the true/apparent wind. 5. A swing rig - usually used on r/c boats, is a self supporting rig that controls the angle of attack of both the jib and main on a rotating structure. (not allowed in many classes) By understanding these basic definitions, I hope to prevent two different visions of topic discussion by a reader.

Attached Files:

Here are some interesting (and som very technical) article links - the first two being (in my estimation) the best discussion and theory. Enjoy http://www.boatdesign.net/forums/sailboats/rotating-wing-mast-theoretical-discussion-14714.htm http://www.tspeer.com/Wingmasts/airfoils.html http://www.sailingcatamarans.com/rigs.htm http://www.sailmagazine.com/cclasscats/

claudio Active Member

Caludio - one very popular (and International) monohull class is the International 10 Rater. They are one of the few (maybe only) large monohull classes to use the rotating mast concept, and I would guess that if they are here in the U.S. and in the U.K. - they must also be sailed by a few in your country. Boats are close to the same size as a Marblehead, so it may be worth looking into when you have time. Regards, Dick [/unquote] Hi Dick, I tranfer here your message. Yes I knows the 10R, very few in France. Time ago I was busy with special rudders equiped with adjustable foils and at that time I contacted Mark Gee aswell Mr. Grubisa of ISAF asking permission for the Class M. The answer was "no". 10R are too large for easy transportation and they lost interest for that reason. Some years ago , Mark wrote an article on the rotating mast on Model Yachting magazine n°138. Unfortunately this article do not says very much about the forestay and its attachment to the mast if is a fractional sail plan. I'm not so certain how many ball bearings has been used to compensate the compression load, if any. My actual design deal with these details. I'm expecting to receive soon the bearings, the idea is to use 2 bearing one on top of the other on both ends. Ciao Claudio Click to expand...

Hello Claudio - on my beach catamaran (5.5 meter) with an approximate 10 meter rotating mast (18 feet long hulls, with 30 foot mast) was accomplished very easily, and lasted on my boat from 1982 until I sold it in 2006! Basically it is a vertical stainless steel post with a nylon ball on top. It went through the front cross-beam, and there was a "cup" shape to fit the ball, located on the bottom of the mast base aluminum casting. The multihulls and probably the 10 Raters do NOT use a backstay. Only a forestay, and two side shrouds were used, allowing rotation up to about 75 degrees each side from centerline to windward. Masts "usually" have side bend controlled by diamond wires. As the mast rotates, it is allowed to bend sideways, which pulls the luff in middle of sail forward and effectively does an automatic flattening of the mainsail. A set of loose diamond wires allowed mast bend, and a flat sail depowering in heavy winds and if diamond wires are tight to prevent mast bend, the mainsail stayed full and very powerful for sailing though waves. The skipper only had to have diamonds adjusted to on-water wind conditions, and the mast was also fitted with a rotation limiter, to prevent mast from over rotating - and for keeping it at the proper attack angle for the sail shape. The fullness of the sails were easily adjusted on the water and for different points of sail - mast bend to flatten sails, downhaul to move maximum camber forward, and outhaul to add camber for downwind reaching. The mainsheet tension on the rear of the boom controlled leech tension. Very sophisticated, yet simple. EDIT - ADDED Photo of Mast base "cup" and rotation limiter (color) and drawing of cross-beam with mast post and ball and how mast base fits on top of ball. Pin shown is a retained to keep base on ball as mast is raised or lowered.

1-Mast Base.jpg

Mast post.jpg, earl boebert administrator.

Here's L. Francis Herreshoff's patent for the wing mast on his masterpiece "Live Yankee." This was an R Class boat (same rule as the J's, but smaller) and it killed the class in Marblehead, being the most expensive and fastest R ever made. It came out in 1927, but he was designing wing masts as early as 1924. It was the national champion as late as 1935, and of course the New York Yacht Club banned "rotating masts, double luff sails, and such contrivances" as soon as they got wind of what it would do. The boat was full of innovations, including a hull built of formers and stringers like an airplane fuselage a rudder that bent like a fish fin rather than rotating on a pivot. Cheers, Earl

LiveYankeePatent.pdf

Earl - he was sure the "innovator". Wonder where we would be if the "stuffed shirts" would have left him to his design ideas and let him demo them in a practical manner - rather than just "killing' them? Do you have any links to his many patents? Would be great reading. Dick

Dreamwakes New Member

Ok, thankyou Dick for taking this thread up. My main area of interest was in the fixed mast and the advantages/ disadvantages in choosing round or foil shaped sections..I am sure there is trade offs in either option and the aerodynamic variances would have alot to do with the method of actually attaching main sail to mast. From the info presented thus far, I read that unless your foil section mast is rotating then you are better off with a round section. . Which brings me to the conclusion that there are gains to be made with a foil section but because of the technical problems with building a rotating mast with fractional rig then the logical step would be a swing rig with foil section mast..the best of all worlds and simple. Unless, you could develop an idea of a semi ( and free)rotating fractional rig with foil section mast. I have owned beach cats with semi rotating masts and understand the simplicity as you described in your own beach cats but in the Rc world where ultra fine tuning does matter as well as weight and engineering complications , then I cannot for the life of me think up a easy method of building a effective semi rotating fractional rig. Claudio, interesting that you are looking at the bearing idea, i had given this method some thought and considered it the only idea that could succeed, but I did feel bearings would create a set of problems..compression, environmental degradation, light wind effectiveness..etc..I look forward to seeing how you progress with this concept. Cheers Gary

Ahh, the bearing idea. Well, it was some time ago, I think around 2000 or so, I think the second Mystic Seaport RC regatta, there was this guy, I don't remember his name, from Newport RI, at the time he was working there as a sail maker/boat builder (big boats) (he was making 10R/M keel from broken CF mast spreader pieces .... something so stiff it was unbelievable), anyway, that year he brought an IOM and USOM he build, the USOM had a rotating rig, the mast was fixed per rules but he incorporated two bearing, one at the top of the mast and one at the bottom and made it so that the rig was rotating around the the fixed mast. If I remember correctly Jim Linville, the USOM secretary, found nothing illegal with it (the mast was in fact fixed). The rig was technically not fractional, it had a head stay jib, but the whole contraption was working fine, a little top heavy, but functional. We sailed the boat, but the hull had problems, it was a skiff design and when it was healing water was coming in, it had a really strange shape. The next year he brought a wonderfully wooden build 10R with this incredibly stiff keel, no deflection at all, and he said that he did not do much more on the USOM..... unfortunately he did not had internet (or a computer for that matter) and problems with the land line (apparently none), and the year after he did not show up....... This just to say that it has bee done before.

Hi All, obviously what is done on real boat is no evident that can be done on models. Here where I am : Starting point = developping a rotating mast for the AC33 .................................... my problem is the forestay attachment ! ............. the principle retained : ................ ........ 140g for 180x4x0.75 cm so far.......... Last sketch ...................... This is my contribution to the tread ! Any ideas ? cheers Claudio

Another source for wing "mast" theory/use is the world of landsailing. While many are wing "masts" there are also a few that are solid wings. It is truly unfortunate that my good friend Bill Korsgard has passed on, as he was an avid big boat sailor, ice boat sailor, and also a landyacht sailor. One might do a search on this site for some of his mast/sail combinations for some of his land sailing creations. In his absence, here is a link: http://www.ircssa.org/ And heck - if it works on wheel or on runners - give it a try...... although keep in mind that most are used on boats that "Create" their own apparent wind.

smStory Build 1.jpg

P1160008.jpg, nautibuoy new member.

Well, been a bit occupied fixing a computer hardware issue but now that's fixed I guess I should pitch in.... I'm working on plans for both wingmasts and wingsails as experiments but my thinking is further along on the former so I'll stick with that for now. I'm basing my wingmast on the paper by Thomas Speer: http://www.tspeer.com/Wingmasts/teardropPaper.pdf The paper, at least to me, presents an understandable synopsis and suggests a practical approach to designing and building a wingmast. Ray

To me the key to getting maximum benefit from a wingmast is to treat the mast/sail as an aerofoil, optimised for the air velocities that we operate in, i.e. low speed. So if we treat the mast/sail assembly as a single aerofoil it follows that we should try to keep the flow on the 'top' of the aerofoil as smooth and continuous as possible in order to maximise the 'lift' and not introduce drag. The paper I mention previously has some good info on this. Masts that are aero shaped and fixed fore and aft are, IMO, less effective than a round mast with a pocket luff or ring attachment, where the sail can rotate and to some degree approximate to a smooth aerofoil. rotating aero masts are better but if used with a conventional luff chord will be compromised by the disconinuity at the boundary between the mast and the sail. At the end of the day of course its still likley to be sailing skills that win races and installing a highly efficient wingmast rig will not make you a fleet leader overnight. My interest is simply to experiment and do something a little different. I will be very glad to have anyone point out my misunderstandings or errors if it helps me to learn more. I'll post some thoughts on the rig I'm working on shortly. Ray

IanHB New Member

Hey Dick, is that Bill in the picture?

Attached is a conceptual diagram of the wingmast I'm working on; apologies that its neither quite a 2D or a 3D diagram but hiopefully it will be understandable. I'm planning to use a swing rig, the thick green line is the swing rig boom and the sheeting of that is what gives the rig the necessary angle of attack. The blue teardrop shapes are the actual mast and this is allowed to rotate, within adjustable stops, seperately to the swing rig boom. This is to allow the mast to tack and also to allow some adjustment of the fullness of the rig. The soft sail part will be fully battened and the red lihes represent the battens. You will see that these extend into the back two thirds of the mast, the idea is that they 'flop' over from one side to the other as the rig tacks, maintaining the aero section and by resting against the inside of the mast should provide a mechanism for the battens to take on the necessary curve. The purple line is the jib. As you can see, I've included two wing mast sections, one representing the bottom of the rig and the other the top. Both sections use exactly the same aeir section, just scaled to different sizes to allow the rig to taper further up the mast, however, you will also see that the actual mast section retains the same dimensional depth all the way up so at the top it constitutes a much greater percentage of the overall chord of the aerofoil at the top - the reason I've done this is that you will see that it produces a twist in the rig as you go up the mast, I think its around 15deg. I have to get to work now but I'll post some thoughts on the actual approach to construction later. Ray BTW, the black line is the pivot line of the mast

Hi Ray, interesting, but if it is a fractioned rig (ex. at 80%) you have to solve the forestay attachment problem or not ? Cheers Claudio

Hi Claudio, the attached diagram will probably help to explain my thinking - essentially I would apply some rake to the mast. By keeping the pivot line vertical and raking the mast it can be arranged that the top of the forestay can be coincidental with the point at which the pivot line cuts the leading edge of the wing. With the addition of some extra local reinforcement it should be possible to use a simple wire hook through a small hole in the leading edge to attach the top of the forestay. Remember that the mast only pivots around 20 or so degrees either side of the pivot line and because this is a swing rig I only need to accomodate a small degree of movement but the principle should hold for a conventional rig. Ray

Wingmast.jpg

IanHB said: ↑ Hey Dick, is that Bill in the picture? Click to expand...

Just looking through the thread and picked up on the comment Dick made when referencing land yachts - he mentioned apparent wind. I guess that if the forward movement of the rig creates apparent wind then that apparent wind doesn't have the same velocity gradient as real wind (affected by drag as you get closer to the ground or water surface on which you're operating) so perhaps the need for twist higher up the rig is reduced? Thoughts? Ray

Claudio, I've been looking at your swivel arrangements, you appear to be putting a lot of load onto quite a small pivot? I plan to pivot my wing mast on a short (say 20cm ) stub mast of a good diameter (say 15mm) made of a substantial CF tube that will slot into a tube embedded inside the wingmast. I'm planning to use PTFE tubing as bearings. I think using a longer and thicker pivot arrangement will spread the loads effectively. Ray

Found some more of those "hidden computer photos" I had stored. 1) Good example of mast on cross-beam with rotation control on leading edge of mast. Also note small white nylon ball at end of a "lever". Pulling down on lever tightens diamond wires, which can be adjusted on the water for mast bend control. No turnbuckles, just diamonds and a lever. 2) A photo (old) of friend's 18 Square that shows mast on ball for rotation. 3) An 18 Square "theory" design of a very large chord wing mast with trailing soft sail. Worked OK but had twist off problems assocated with the deep chord. 4) Solid wing 18 Square ( WILD TURKEY ) and if you look close to top photo you can see how side shrouds and forestay connected. Under the "hood" on leading edge was a curved rod on which the shrouds could slide to allow wing rotation. I'll probably unearth even more hotos I didn't realize I had in my "archives" Cheers :zbeer:

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The Ultimate Guide to Sail Boat Designs: Exploring Sail Shape, Masts and Keel Types in 2023

June 4, 2023

Sail Boat Designs have changed over the years, image shows a historical sail boat with large masts and multiple sails

When it comes to sail boat designs, there is a wide array of options available, each with its own unique characteristics and advantages. From the shape of the sails to the number of masts and the type of keel, every aspect plays a crucial role in determining a sailboat’s performance, stability, and manoeuvrability. In this comprehensive guide, we will delve into the fascinating world of sail boat designs, exploring the various elements and their significance.

The sail shape is a fundamental aspect of sail boat design, directly impacting its speed, windward performance, and maneuverability. There are several types of sail shapes, including:

1. Bermuda Rig:

The Bermuda rig is a widely used sail shape known for its versatility and performance. It features a triangular mainsail and a jib, offering excellent maneuverability and the ability to sail close to the wind. The Bermuda rig’s design allows for efficient use of wind energy, enabling sailboats to achieve higher speeds. The tall, triangular mainsail provides a larger surface area for capturing the wind, while the jib helps to balance the sail plan and optimize performance. This rig is commonly found in modern recreational sailboats and racing yachts. Its sleek and streamlined appearance adds to its aesthetic appeal, making it a popular choice among sailors of all levels of experience.

2. Gaff Rig:

The Gaff rig is a classic sail shape that exudes elegance and nostalgia. It features a four-sided mainsail with a gaff and a topsail, distinguishing it from other sail designs. The gaff, a horizontal spar, extends diagonally from the mast, providing additional area for the mainsail. This configuration allows for a taller and more powerful sail, making the Gaff rig particularly suited for downwind sailing. The Gaff rig offers a traditional aesthetic and is often found in vintage and classic sailboats, evoking a sense of nostalgia for a bygone era of maritime exploration. The distinctive shape of the Gaff rig, with its graceful curves and intricate rigging, adds a touch of timeless charm to any sailboat that dons this rig.

3. Lateen Rig:

The Lateen rig is a unique and versatile sail design that has been used for centuries in various parts of the world. It features a triangular sail that is rigged on a long yard, extending diagonally from the mast. This configuration allows for easy adjustment of the sail’s angle to catch the wind efficiently, making the Lateen rig suitable for a wide range of wind conditions. The Lateen rig is known for its ability to provide both power and maneuverability, making it ideal for small to medium-sized sailboats and traditional vessels like dhow boats. Its versatility allows sailors to navigate narrow waterways and make tight turns with ease. The distinctive silhouette of a sailboat with a Lateen rig, with its sleek triangular sail and graceful curves, evokes a sense of adventure and a connection to seafaring traditions from around the world.

Number of Masts

The number of masts in a sail boat design affects its stability, sail area, and overall performance. Let’s explore a few common configurations:

1. Sloop Rig:

The sloop rig is one of the most popular and versatile sail boat designs, favoured by sailors around the world. It consists of a single mast and two sails—a mainsail and a jib. The sloop rig offers simplicity, ease of handling, and excellent performance across various wind conditions. The mainsail, situated behind the mast, provides the primary driving force, while the jib helps to balance the sail plan and improve manoeuvrability. This configuration allows for efficient upwind sailing, as the sails can be trimmed independently to optimize performance. The sloop rig is commonly found in modern recreational sailboats due to its versatility, enabling sailors to enjoy cruising, racing, or day sailing with ease. Its streamlined design and sleek appearance on the water make it both aesthetically pleasing and efficient, capturing the essence of the sailing experience.

2. Cutter Rig:

The cutter rig is a versatile and robust sail boat design that offers excellent performance, especially in challenging weather conditions. It features a single mast and multiple headsails, typically including a larger headsail forward of the mast, known as the cutter rig’s distinguishing feature. This configuration provides a wide range of sail combinations, enabling sailors to adjust the sail plan to suit varying wind strengths and directions. The larger headsail enhances the boat’s downwind performance, while the smaller headsails offer increased flexibility and improved balance. The cutter rig excels in heavy weather, as it allows for easy reefing and depowering by simply reducing or eliminating the headsails. This design is commonly found in offshore cruising sailboats and has a strong reputation for its reliability and seaworthiness. The cutter rig combines versatility, stability, and the ability to handle adverse conditions, making it a preferred choice for sailors seeking both performance and safety on their voyages.

3. Ketch Rig:

The Ketch rig is a sail boat design characterized by the presence of two masts, with the main mast being taller than the mizzen mast. This configuration offers a divided sail plan, providing sailors with increased flexibility, balance, and versatility. The main advantage of the Ketch rig is the ability to distribute the sail area across multiple sails, allowing for easier handling and reduced stress on each individual sail. The mizzen mast, positioned aft of the main mast, helps to improve the sailboat’s balance, especially in strong winds or when sailing downwind. The Ketch rig is often favoured by cruisers and long-distance sailors as it provides a range of sail combinations suitable for various wind conditions. With its distinctive double-mast appearance, the Ketch rig exudes a classic charm and is well-regarded for its stability, comfort, and suitability for extended journeys on the open seas.

The keel is the part of the sail boat that provides stability and prevents drifting sideways due to the force of the wind. Here are some common keel types:

1. Fin Keel:

The fin keel is a popular keel type in sail boat design known for its excellent upwind performance and stability. It is a long, narrow keel that extends vertically from the sailboat’s hull, providing a substantial amount of ballast to counterbalance the force of the wind. The fin keel’s streamlined shape minimizes drag and enables the sailboat to cut through the water with efficiency. This design enhances the sailboat’s ability to sail close to the wind, making it ideal for racing and performance-oriented sailboats. The fin keel also reduces leeway, which refers to the sideways movement of the boat caused by the wind. This improves the sailboat’s ability to maintain a straight course and enhances overall manoeuvrability. Sailboats with fin keels are commonly found in coastal and offshore racing as well as cruising vessels, where stability and responsiveness are valued. The fin keel’s combination of performance, stability, and reduced leeway makes it a preferred choice for sailors seeking speed and agility on the water.

2. Full Keel:

The full keel is a design known for its exceptional stability and seaworthiness. It extends along the entire length of the sailboat, providing a continuous surface that adds substantial weight and ballast. This configuration offers significant advantages in terms of tracking and resistance to drifting sideways. The full keel’s deep draft helps to prevent leeway and allows the sailboat to maintain a steady course even in adverse conditions. Its robust construction enhances the sailboat’s ability to handle heavy seas and provides a comfortable ride for sailors on extended journeys. While full keel sailboats may sacrifice some manoeuvrability, their stability and predictable handling make them a popular choice for offshore cruising and long-distance voyages. The full keel design has stood the test of time and is often associated with classic and traditional sailboat aesthetics, appealing to sailors seeking reliability, comfort, and the ability to tackle challenging ocean passages with confidence.

3. Wing Keel:

The wing keel is a unique keel design that offers a combination of reduced draft and improved stability. It features a bulbous extension or wings on the bottom of the keel, which effectively increases the keel’s surface area. This design allows sailboats to navigate in shallower waters without sacrificing stability and performance. The wings create additional lift and prevent excessive leeway, enhancing the sailboat’s upwind capabilities. The reduced draft of the wing keel enables sailors to explore coastal areas and anchor in shallower anchorages that would be inaccessible to sailboats with deeper keels. The wing keel is particularly well-suited for sailboats in areas with variable water depths or tidal ranges. This keel design offers the advantages of increased manoeuvrability and improved performance while maintaining stability, making it a popular choice for sailors seeking versatility in a range of sailing environments.

In the vast world of sail boat designs, sail shape, number of masts, and keel types play pivotal roles in determining a boat’s performance and handling characteristics. Whether you’re a recreational sailor, a racer, or a cruiser, understanding these design elements can help you make informed choices when selecting a sailboat.

Remember to consider your specific needs, preferences, and intended use of the boat when choosing a sail boat design. Each design has its strengths and weaknesses, and finding the perfect combination will greatly enhance your sailing experience.

By gaining a deeper understanding of sail boat designs, you can embark on your next sailing adventure with confidence and make the most of the wind’s power.

Sailing Navigation equipment, a compass sat on top of a rope and a map

Sailing Navigation: Exploring Modern Techniques for Navigating the Seas in 2023

June 10, 2023

Sailing in Different Directions. Image showing a view down a boat with a winch in the foreground and the mast sails in the background

Sailing in Different Directions: Harnessing the Wind’s Power in 2023

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May 28, 2023

Did the enormous 246ft-high mast on Mike Lynch's yacht cause disaster?

T he enormous 246ft-high aluminium mast on Mike Lynch's superyacht the Bayesian could have been what caused the vessel to capsize and sink rapidly, according to an expert.

British tech tycoon Mr Lynch, 59, remains missing alongside his 18-year-old daughter and six other tourists, including four Brits and two Americans after the ship sunk near Sicily.

The billionaire's boat, which had the tallest aluminium mast in the world at 246ft, was anchored off the coast near Palermo when a tornado hit the area just before 5am.

But during the storm the mast broke, causing the ship to sink rapidly after the weight of the mast took the hull beyond the 'down-flooding angle', according to a yacht industry source.

A local fisherman told reporters he saw a waterspout, a form of tornado that occurs over water rather than land, nearby the boat.

Salvo Cocina, head of Sicily's civil protection agency, said the Bayesian passengers 'were in the wrong place at the wrong time.'

The 183ft long yacht was built in 2008 by luxury shipmaker Perini Navi in Viareggio, Tuscany and was previously known as the Salute, meaning 'health' in Italian.

Technical consultant and nautical expert Gino Ciriaci told Italian website Corriere Della Sera even if the mast was made of steel it would not have changed anything.

He said a mast that tall would have exerted a pressure of 'tens of tons' due to the wind and said it is 'normal' that the boat could sink based on its technical characteristics.

The Bayesian is classified as a 'pleasure vessel' due to its length, very tall aluminium mast and being 37ft at its widest point.

Mr Ciriaci, who was a shipyard manager in Rome and is authorized by the Italian Ministry of Industry (Consap) to carry out technical assessments following accidents, said a mast can break in 'particularly extreme conditions'.

He said once the mast has fallen, the boat pitches and rolls with the waves much more vigorously without the mast and sails to dampen its movements.

In the case of the Bayesian he said the whirlwind was so violent that the boat heeled over, tilted and put the edge of the deck under water, and at that point, the water began to enter and the boat sank.

Mr Lynch's wife Angela Bacares, 57, was among the fifteen people who were rescued from the 180ft yacht, which she is reported to have owned and had been carrying ten crewmembers, the owner and 11 guests.

Mrs Bacares told Italian media that both her husband and their daughter Hannah, 18, are missing after the yacht sank.

She told Italian outlet La Repubblica that she and her husband woke up at 4am when the boat tilted. Mrs Bacares said that they were not worried initially, until glass shattered and created confusion.

She sustained abrasions on her feet during the sinking which have reportedly left her unable to walk and sitting in a wheelchair, La Repubblica reports, while she also has bandages elsewhere on her body.

Mr Lynch had invited guests from legal firm Clifford Chance as well as his own company Invoke Capital to celebrate him being acquitted of fraud charges in June, vindicating the entrepreneur after a 12-year legal battle over the $11bn sale of his firm, Autonomy, to Hewlett-Packard in 2011, the Telegraph reported.

Divers have been desperately searching the wreck 160ft beneath the water for the survivors.

Tragically, the body of a man - believed to be a Canadian national who was working as the boat's chef - was found floating alongside the vessel earlier today.

There are fears that those who are still missing became trapped in their cabins, with divers earlier reporting that they saw 'bodies through the portholes' of the yacht, according to Italian media .

The Bayesian several awards for its styling when it was first made, taking home the Best Exterior prize at the World Superyacht Awards in 2009, and the Best Interior at the International Superyacht Society Awards in 2008.

It was also a finalist in the World Superyacht Awards' Best Sailing Yacht in the 45m+ size range in 2009.

The Bayesian could hold up to 12 guests in six cabins, one master, three doubles and two twin rooms, as well as 10 crew members.

Who is Mike Lynch?

Mike Lynch was celebrated as a British business success story.

Born in Ilford, Essex in 1965, he earned a PhD from Cambridge before founding one of the UK's most successful technology companies, Autonomy, in 1996.

The married father of two daughters was awarded an OBE in 2006 for services to enterprise.

That same year, he was appointed to the board of the BBC - and was later elected to then-prime minister David Cameron's council for science and technology in 2011.

He advised Mr Cameron on subjects including 'the opportunities and risks of the development of artificial intelligence (AI) and the government's role in the regulation of these technologies'.

But he later became embroiled in a bitter fraud lawsuit stemming from the disastrous $11billion (£8.3billion) sale of his company Autonomy to Hewlett-Packard in 2011.

The legal battle endured more than a decade, and in March this year Lynch found himself in a San Francisco courtroom to defend himself against fraud and conspiracy charges.

The 59-year-old tycoon had spent much of the previous year living under house arrest with an electronic tag attached to his ankle.

Mr Lynch had potentially faced up to 20 years in a US prison if found guilty of 16 counts of conspiracy, and securities and wire fraud, which he denied.

Earlier this year he was cleared of all charges - a major victory for the tech guru.

Both the hull and the superstructure, the part above the main deck, were made from aluminium.

According to KM Yatchbuilders, a Dutch shipmaker, aluminium is three times lighter than steel. On top of this, aluminium alloys do not rust, and yachts made from them are 'easy to repair.'

On top of the sails, the Bayesian was powered by two 8-cylinder 965hp engines made by German manufacturer MTU that are capable of running at 210rpm.

This allowed the vessel to reach a top speed of 15 knots (17mph). This, combined with the 57,000 litre fuel tanks, means it had a range of up to 3,600 nautical miles.

The tragedy comes just weeks after Mr Lynch was acquitted of criminal charges by a jury in San Francisco in June, vindicating the entrepreneur after a 12-year legal battle over the $11bn sale of his firm, Autonomy, to Hewlett-Packard in 2011.

The 59-year-old, who was a billionaire at the height of his wealth, has previously been dubbed Britain's Bill Gates after he made his fortune thanks to his company. Its software drew on the Bayesian mathematical theory after which the yacht was named.

The passengers on board were mainly British, according to reports, while citizens from New Zealand, Sri Lanka, Ireland, Canada, the US and two dual British and French nationals were also said to be on board.

Some of the group are reported to have been colleagues and their family members who were on holiday together in Sicily.

The yacht is owned by Isle of Man-based firm Revtom, according to the BBC, the legal owner of which is Bacares, Mr Lynch's wife.

A member of staff who worked at Mr Lynch's Chelsea home has told The Times that the businessman 'clearly had a lot of pride in the yacht'.

The ship is managed by Camper and Nicholsons International. The company says it is assisting in the search efforts in Palermo.

The firm said in a statement that the boat encountered 'severe weather and subsequently sank'.

The ships managed by Camper and Nicholsons International. The company says it is assisting in the search efforts in Palermo.

Did the enormous 246ft-high mast on Mike Lynch's yacht cause disaster?

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Special report, 1 dead, 6 missing — including 2 americans — after tornado sinks yacht, the bayesian, off sicily.

A luxury superyacht capsized off the coast of Sicily after a tornado hit the area early Monday, killing one passenger and leaving six others missing — including a tech tycoon known as “Britain’s Bill Gates,” officials said.

The Bayesian — a 184-foot luxury sailboat with 22 people aboard — sank off the port of Porticello when it was hit by a violent storm at sunrise, the Italian coast guard said.

The coast guard deployed a team of divers to search the submerged vessel for survivors some 160 feet beneath the water’s surface, with authorities fearing some of the missing passengers could be trapped inside their rooms, BBC reported.

The passengers were reportedly from the UK, the US, Canada, Sri Lanka and Ireland.

One body, believed to belong to the ship’s chef, Canadian-born Thomas Recaldo, who had been living in Antigua, was found near the wreck, the Palermo Port Authority told CBC News.

Six others were missing as of Monday morning, including the vessel’s owner, British tech tycoon Mike Lynch, sources told Reuters and the Independent .

The last photo thought to have been taken of the yacht at 10pm on Sunday in Porticello.

British tech tycoon Mike Lynch, and his 18-year-old daughter Hannah, were among the missing, according to Lynch’s wife, Angela Bacaras, the Telegraph reported.

Bacaras, who is the sole shareholder of the firm that owns the yacht — Isle of Man-registered Revtom Limited company — was rescued along with 14 others from the yacht.

One of the survivors, Charlotte Golunski, 35, described to Italian newspaper Giornale Di Sicilia how she and her 1-year-old daughter survived the harrowing experience.

Divers jump into the waters looking for the missing people after the storm struck the yacht.

“For two seconds I lost my baby in the sea, then I immediately hugged her again amid the fury of the waves,” she said.

“I held her tightly, close to me, while the sea was stormy. Many were screaming. Luckily the lifeboat inflated and all 11 of us managed to get on board.”

The captain was also among the survivors, an Italian coast guard spokesperson told CNN.

What to know after a tornado sank the yacht Bayesian off the coast of Sicily, leaving one dead and six missing:

A superyacht capsized off the coast of Sicily after a tornado hit the area early Monday, killing one passenger and leaving five others missing — including Michael Lynch, a tech tycoon known as “Britain’s Bill Gates,” officials said.
Lynch had invited guests from the legal firm that represented him, Clifford Chance, and Invoke Capital, his own company, on the voyage, according to the Telegraph .
Captain James Catfield, who piloted the 184-foot, British-flagged craft, was among the 15 crew members and passengers to survive after the tornado struck Monday before sunrise.
Security camera footage shot from 650 feet from where the Bayesian sank Monday shows it slowly disappearing.
Italian authorities have said the chances of the passengers surviving the disaster was very small, but “never say never.”

Map of Italy highlighted with a red sign, representing a yacht sinking in Sicily

A helicopter and rescue boats from the coast guard, carabinieri, fire rescue and civil protection service were at the scene early Monday searching for those who had not been accounted for, according to the Australian Associated Press.

The massive yacht, the Bayesian, flies under the British flag and can reach a maximum speed of 15 knots (17 mph). It comes equipped with six cabins, including a full beam master suite, according to yacht charter websites, which list the ship as available for rent for up to $215,000 per week.

Twelve of its passengers were guests while 10 were crew.

The boat left the Sicilian port of Milazzo on Aug. 14 and was last tracked east of Palermo on Sunday evening, according to vessel tracking app Vesselfinder.

Lynch, often referred to as “Britain’s Bill Gates,” is one of the UK’s most prominent tech entrepreneurs.

He founded enterprise software firm Autonomy, which he sold for $11 billion to Hewlett Packard for $11.7 billion in 2011.

However, HP later sued Lynch claiming he overstated the value of the company, and ultimately took a $8.8 billion writedown on the purchase, later blaming “accounting irregularities” for overpaying for Autonomy.

Last year Lynch was extradited to the US to stand trial for fraud charges over HP’s allegations, but he was acquitted last June. The jaunt on the Bayesian was intended as a celebration of the tech magnate’s acquittal, according to the Telegraph .

Lynch had invited guests from the legal firm that represented him, Clifford Chance, and Invoke Capital, his own company, on the voyage, the outlet reported.

The doomed vessel was on its way to Palermo, originally departing from Positano, a village on the southern Amalfi Coast, on July 30, according to marinetraffic.com .

Its last docking location was in the town of Milazzo on Wednesday.

The ship’s manufacturer, Perini Navi, says on its website that the Bayesian’s aluminum mast is the tallest in the world — measuring nearly 250-feet.

With Post wires

Who was onboard tech mogul Mike Lynch's Bayesian yacht?

Topic: Disasters, Accidents and Emergency Incidents

Six people are missing, including a man dubbed the British Bill Gates, after a luxury yacht sank off the Sicilian coast.

British tech entrepreneur Mike Lynch — freshly acquitted from a decade-long trial — had invited his work colleagues aboard a trip through the Mediterranean coast when a freak storm saw the yacht sink within moments.

Fifteen people escaped from the sinking vessel. The search for the missing continues.

Here's what we know so far:

What happened?

The Italian coastguard said the yacht — the Bayesian — was anchored off the shore of port city Porticello, near the Sicilian capital Palermo, when it was hit by bad weather sometime after 4am on Monday, local time.

Eyewitnesses said it vanished quickly beneath the waves shortly before dawn.

Managers of the sailing vessel Bayesian, Camper & Nicholsons, confirmed to the ABC that the Bayesian encountered severe weather and subsequently sank.

"Our priority is assisting with the ongoing search and providing all necessary support to the rescued passengers and crew," they said.

"The wind was very strong. Bad weather was expected, but not of this magnitude," a coastguard official told Reuters.

Sicily's civil protection agency head, Salvo Cocina, said a waterspout — a tornado over the water — could have struck the yacht.

"They were in the wrong place at the wrong time," Mr Cocina added.

Storms and heavy rainfall had swept down Italy in recent days after weeks of scorching heat, lifting the temperature of the Mediterranean Sea to record levels and raising the risk of extreme weather conditions, experts told Reuters.

"The sea surface temperature around Sicily was around 30 degrees Celsius, which is almost 3 degrees more than normal. This creates an enormous source of energy that contributes to these storms," meteorologist Luca Mercalli said.

A group of rescuers gather around a stretcher

Rescuers recover the body of one of the people aboard the Bayesian. ( AP: Lucio Ganci )

Captain Karsten Borner of the Sir Robert Baden Powell vessel told journalists he noticed the Bayesian nearby during the storm, but after it calmed he saw a red flare and realised the ship had simply disappeared.

Mr Borner said he and a crew member boarded their tender and found a lifeboat with 15 people, some of them injured, who they then took aboard and alerted the coast guard.

Search crews, including helicopters and divers, are continuing to search the wreckage, lying at a depth of 49 metres.

Specialist divers reached the ship on Monday but access was limited due to objects in the way, the fire brigade said.

The UK Marine Accident Investigation Branch is deploying a team of four inspectors to Italy to conduct a preliminary assessment.

The Foreign Commonwealth and Development office said it was "providing consular support to a number of British nationals and their families".

Sicilian prosecutors have also opened an investigation into the event.

Who is missing?

Lawyer Chris Morvillo (left), entrepreneur Mike Lynch, and Morgan Stanley chairman Jonathan Bloomer are among the missing.

There were 12 passengers and 10 crew members aboard the yacht.

Mr Cocina said the crew and passengers hailed from a variety of countries, including Britain, the United States, Antigua, France, Germany, Ireland, Myanmar, the Netherlands, New Zealand and Spain.

Of the 22, one man is confirmed dead and another six people are still missing.

They are believed to be inside the hull, fire rescue spokesperson Luca Cari said.

Fabio Cefalù, a fisherman who said he responded to a flare from the vessel but found it sunk, said he stayed at the site for three hours without finding anyone.

"I think they are inside, all the missing people," he said.

Rescue teams recovered the body of the yacht's onboard chef on Monday, identified as Antiguan citizen Ricardo Thomas.

The still missing people include:

Mr Lynch's 18-year-old daughter, Hannah
Jonathan Bloomer, chairman of global financial services company Morgan Stanley International
Chris Morvillo , a lawyer at the British multinational law firm Clifford Chance. He worked on Mr Lynch's lawsuit against Hewlett-Packard
The identities of the remaining two missing are still unconfirmed

Who was rescued?

Fifteen people escaped from the sinking ship.

Eight have been hospitalised and others were taken to a nearby hotel.

Charlotte Golunski was among those rescued, recalling the harrowing moments she held her child Sofia above the waves. ( Supplied: Facebook )

Among those rescued were:

Mr Lynch's wife, Angela Bacares, who was the owner of the yacht
Charlotte Golunski and her one-year-old daughter, Sofia. Ms Golunski is a partner at Mr Lynch's firm, Invoke Capital. She says she momentarily lost hold of Sofia in the water but managed to hold her up above the waves until the lifeboat was inflated
Ms Golunski's husband James Emslie
New Zealand captain of the yacht James Catfield. He told Italian newspaper La Repubblica the crew didn't see the storm coming
A lone Dutch citizen was identified by the Dutch foreign ministry as being rescued, but was not identified

Who is Mike Lynch?

Mr Lynch, once hailed as Britain’s king of technology, was recently freed from a Silicon Valley lawsuit that tarnished his legacy.

The 59-year-old Cambridge-educated mathematician created Autonomy , a search engine that could pore through emails and other internal business documents to help companies find vital information more quickly.

He received the OBE for his innovation in 2006.

He then sold the software to Hewlett-Packard (HP) for $US11 billion ($16 billion) in 2011, with Mr Lynch personally netting $US800 million.

HP valued Autonomy at $US46 billion ($68 billion) in the months leading up to the deal.

Mike Lynch in 2019 leaving the High Court in London. ( Reuters: Henry Nicholls/File Photo )

But the deal quickly turned sour after he was accused of forging the software's financial records to make the sale.

As part of a decades-long legal battle against HP, Mr Lynch was extradited to the UK on criminal fraud charges.

He steadfastly denied any wrongdoing, asserting that he was being made a scapegoat for HP's own bungling.

He was eventually cleared of all charges in June this year.

Although he avoided a possible prison sentence, Lynch still faced a bill from a civil case in London that HP mostly won during 2022. Damages haven't been determined in that case, but HP is seeking $US4 billion.

Following the San Francisco trial, Mr Lynch said he would return to the UK and do what he loved most: "[being with] my family and innovating in my field."

The holiday appeared to be something of a celebration after Mr Lynch's acquittal, with guests including some of the people who had stood by Lynch throughout the ordeal.

This picture shows the rescue operations off the Sicilian coast. ( AP: Italian Coast Guard )

In a separate act of tragedy, Mr Lynch's co-defendant in the trial, Stephen Chamberlain, died on Monday, after a road accident left him critically injured.

Mr Chamberlain — Autonomy's former vice-president of finance alongside Mr Lynch — was hit by a car in Cambridgeshire on Saturday morning and had been placed on life support.

What is the Bayesian?

The luxury yacht is 56m long sailboat, with a 75m mast labelled as the tallest aluminium mast in the world.

It was previously named Salute when it flew under a Dutch flag.

The yacht, built in 2008 by the Italian firm Perini Navi, can accommodate up to 12 guests in six suites and a crew of 10, according to online specialist yacht sites. It was last refitted in 2020.

Online charter sites listed it for rent for up to 195,000 euros (about $AU 321,000) a week.

This picture taken on Sunday shows the Bayesian (left) and the Duch sailboat Sir Robert Baden Powell anchored off the coast line. ( AP: Fabio La Bianca/Baia Santa Nicolicchia )

The ship also won a string of awards for its design.

Ms Golunski said the yacht had travelled through the Aeolian Islands, Milazzo and Cefalù before sinking.

It is likely the yacht's name would resonate with Mr Lynch because his PhD thesis and the software that made his fortune was based on Bayesian theory.

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