Building Logs

Winging it

Posted by Paul

When Jo and I first got the notion to go cruising it occurred to us more than once, that we dont know the first thing about sailing. Jo had a little experience as a small girl sailing on a 14ft mono sail boat with her dad, but sailing on a very small trailer sailer on a nice day in sheltered water is a long way different to sailing a 40ft cat in whatever nature throws at you. And its fair to say we are both fairly cautious types. Danger and adrenalin is not something we seek out. So after much reading and research and inspiration from other non sailors that had gone long distance cruising (most notably Pat and Ali on Bumfuzzle) we settled on the idea of building a catamaran with the bi rig being one of the selling points that got us (me) over the line.

What the folks at Schionning (Craig Schionning and later Brett and Jeff Schionning) sold me on was the safety reasons they had designed the bi rig in the first place for. Back in the day (the 70’s and 80’s) catamarans were considered unsafe to go to sea on because they had a bit of a reputation for flipping over. The sailing world is very conservative so with that goes aversion to change. And apart from a few hippies, everyone sailed mono’s despite Catamarans being recorded as one of the oldest forms of ocean crossing vessels. But because white men from the then known world (Europeans or “the west”) travelled the world in singled hull vessels they dismissed catamarans that people used to cross the Indian and Pacific oceans long before white men were discovering what was on the other side of the Atlantic as novelties but not serious ocean crossing vessels.

I was temporarily dissuaded from cats by a book by the 70’s Australian sailing guru who’s name escapes me, that said cats were not safe. After more research I realised that this thinking was way out of date. Cats can and do flip over but they dont usually sink. Traditional pro mono sailors conveniently dont mention this one important fact. Because they dont rely on ballast (weight in the keel usually lead) cats are usually positively buoyant and if they do turn over, they remain afloat as a survival platform so you can await rescue. You may even have access to precious stores of food, water or shelter that are not afford to sailors whose mono has sunk and they either take to a life raft if they have one or they bob around with a life jacket on waiting for rescue.

Anyway, all of that is worst case scenario, cats are inherently safe and many of them now cruise the world. But Schionning recognised one of the arguments against cats and acted to design that perceived fault out. The standard “bermuda” rig (mast with sail forward of it – foresail and one on a boom after it – mainsail) is tall which makes the centre of effort (roughly, if you were pushing a boat with your finger on a sail the point at which it would most easily push, the geometric centre) and centre of gravity,(again very roughly, the point where the bot would spin if you found the centre of it and pushed a pin through it and spun it) higher on the rig and can contribute in the right (or wrong!) conditions to tipping the boat over. This is not so much a problem on a keel boat, it can use its weighted keel to “right” itself, cats cant do that, hence knock downs on monos are not as hard to fix as cats that flip over. So if you lower the coe and cog you reduce the chance of the force of wind against sails from flipping the boat.

That’s how the bi-rig was explained to me. With 2 smaller masts and only mainsails the coe and cog are lowered and with it the chance of flipping the boat from wind forces on the mast by lifting the windward hull, then wind getting under the hull and pushing it over. (there is still the chance to flip it end over end called pitchpoling usually as a result of surfing down a big wave, the bows bury in the trough and the wave continues to lift the sterns and flips the boat over, but you cant remove all risk). There were a number of other safety advantages of the rig. Carbon masts would bend and self spill some of the overpower if you were caught in a sudden gust with too much sail up. If that power gets to be too much for the crew to handle, reefing (lowering the sails) is somewhat easier because the wind can be taken out of the sails without having to steer away from the wind, which may be dangerous because of wave direction, by releasing the sheets before lowering the sails. Sails that are full of wind dont come down easily. And then there is releasing the sheets, which allows the rotating unstayed masts to rotate past where stays would be on a normal rig, and then the power spills out. If I panicked I could release the sheets or cut them, and the boat would be instantly depowered. To me, that sounded like brakes. Perfect.

I was told of a couple of downsides with the rig, firstly resale value. People are reluctant to be different, so the market for selling the rig would be more difficult and I may lose some of its value. Fair enough. I banked on the efficiency of the rig perhaps speaking for itself eventually and maybe even prove popular. After all it made pretty good sense to me, a layperson with little knowledge. The boat would also be slower in some ways than a regular rig but faster in others, so I didnt pay much to that negative. What is slower? Its relative. Some monos, or heavier cats can barely do 5 knots flat out. So speed is relative. And if the boat averaged out to be almost as fast as a regular Schionning, even with the rig it would end up faster than many others. And later in the build we heard that perhaps the boat might not steer through a tack as well as a regularly rigged cat, because on a normal rig, the foresail (jib) fills with wind and pushes the bows the rest of the way through the turn, and you dont have that on a bi rig. So we increased the size of the rudders by about 10%.

If all of the above is all old hat to you, sorry for the boring and rudimentary run down of my understanding of sailing and rigs. Perhaps this next part might not be so new to you though?

Over the years, for a number of reasons, the rig got changed from my initial description from Schionnings. Firstly, and I dont mean this as a criticism, but for me it wasnt good form, Schionnings dragged their feet a bit from selling the concept and plans for their boats on it, to actually completing the engineering work and instructions on what needed to be built, how and where, to run the rig. So much so, that one of the 5 that committed to the rig pulled out and reverted to a normal rig. There are some points in the build that you must know what to do, otherwise you do things that need to be undone later to do something else that has to be done. The normal rig has chainplates for stays and what is called a striker on the forebeam that balances the loads of the forestay over the beam. We as bi rig builders dont need them, but if you find out later that you dont like what does need to be done to build the bi rig and have foregone building in the normal rig parts, it is somewhat more difficult to build them later. So, losing patience that the engineering would ever be done, the remaining 4 of us shared the cost of getting independent engineering and a mast design done.

Then Schionning made another change to the rig thinking. Originally the masts were to be mounted on the outside of each hull against the first main bulkhead and against the inside of the hull skin. But part of the delay in getting the engineering done (I am speculating based on the outcome) was that the sheeting points, the place where the rope that controls the boom angle would fix to the deck was causing problems getting the leverage and angles they need being out on the edge of the hull (Ideally the sheeting point should be directly below the mast in the straight ahead fore and aft position) and of course we dont have travellers that move that sheeting point that a regular centrally mounted rig has. So it was decided that the only solution was to bring the masts inboard to be against the inside skin of each hull. A move of about 500 mm inboard each, closing the gap between the masts by 1 meter from 6.4 meters to 5.4 meters. When Schionnings sent me the sail plan, I immediately saw that the booms were 6 meters long. I let them know about this and they said that there was no other way they could see the rig being correctly balanced. This of course meant the sheets could no longer be released to spill the load. I just lost my brakes. A deal breaker. But I was already building! Not fair. I was sold on a set of abilities of the boat that were now no longer going to be possible.

The new engineering took this into account. We all agreed we wanted to be able to release the sheets and clear the masts with the booms. The new engineering came out with taller masts to make up for the power lost through shorter booms. Hence they became 17 meters tall. I didnt like it, but I thought releasing sheets was more important than a shorter mast. Perhaps I am mistaken in that, but nevertheless that is the way the new masts went. Wing masts on rotating posts, and booms with a solid vang and the sheeting point would be elevated off the deck initially to a point directly below the now inboard mast position, so that the sheets would clear the cabin roof when sheeted out over it.

bi polar launched

Last year a bi rigged Schionning with this new rig launched in Melbourne. The owner immediately found the boat to be over powered. At first he thought he was unused to the rig and would feel better about it as he learned to sail it. But then a near disaster struck. In a storm one day the boat broke its moorings and sailed across the bay. Luckily for the owner it beached on a soft sandy beach. Had it been rocky, this may have been a much different story. The owner decided to reduce the mast height. He cut nearly 3 meters off their length and advised me he would happily cut even more off. He is now very happy with the performance, has mastered how to rig the masts to cancel each other out on anchor so that it can no longer power off the mooring. I feared that the boat would be driven by one wing, then the other, then the other and be like a wild bronco on its ropes but he assures me that to the contrary, the wing masts actually stabilise the boat so that it wanders around less on the mooring or anchor than boats around it with non driven regular single masts.

small bi rig beached

I still fear this feature of the rig, even in its shorter form. In certain conditions the boat will still sail quite fast with no sails up simply under the power of the masts alone. This too scares me. You have power up there that is difficult to control for experienced sailors so I would need to learn fast. Another builder and I have contemplated fold down masts, and if I progress with the wing masted bi rig this is now going to assume new importance to me. And the mechanism to lower the masts would need to be very easy, because lowering them in a storm that suddenly and unexpectedly arrives is not something that is doable if not easy. (I know, good seamanship would dictate that the weather is no longer unexpected, but we all know that no forecasts are infallible).

bi polar shortened masts

There is also one other aspect of the rig that I have been made aware of. With a regular round mast (one of the 4 bi rig boats will launch with round masts) there is no optimum angle that the sail exits the back of the mast, round is round all the way around. With a wing mast, the angle of the wing to the sail is adjustable and if you tweak that and get it just right the rig performs very well, if you dont, it does not. Now of course I understand some sail trimming is going to be necessary on any rig. But one thing I know I will never be is a tweaker. I am a lazy person. I want to sail lazy. I want to set and forget. I dont want to constantly tweak to wring out performance. I just dont care enough.

So perhaps wing mast are not for me, the negatives are starting to pile up. The bi-rig is definitely for me. Wing masts, not so much.

And then this happens.


Wing sails. Yep, wing sails. Never heard of them until now? Surely not? I first saw them in the Americas cup winning Oracle. Solid wing masts. They cant be reefed or lowered and are sooooper expensive. So forget it.

Since the Americas cup last year a number of iterations of soft wing sails have been fast tracked in their development. Now that I know of their existence research shows that they have been around for 20 years or so but none commercially. Last year Benetau decided that soft wing sails have a lot going for them, not least of which is their simplicity to sail. They are talking my language. Benetau fear that as baby boomers age and drop out of sailing, young people find sailing too complex and lose interest and numbers in sailing are dropping off because the young are not replacing the old at the rate that boomers are ageing and if the rig can be simplified they will attract new people to the sport and renew their market for sail boats.

This is their take on the rig.

The problem with this rig for me is that firstly it is still being developed and could be years off ready for production, but when available may only be available with a Benetau group boat (Lagoon cats?) so unlikely to be made available for sale to other boats or owners. The method of cambering the wing is very simple, the wing shape itself is limited to just the front third of the overall wing, then the rear 2 thirds or so of the surface follows as a double sided sail on hinged battens that just form the camber shape one side or the other with a lever on the rear of the boom.

So next I found these guys. In this vid, the wing sail cat smokes the regular rigged cat, now for all we know this was deliberately slowed for dramatic effect, nevertheless there is little argument in the various forums that wing sails can be much more powerful than a similarly sized regular rig.

For me there are a couple of problems with this rig. First, it is stayed. I am sure that it would still work just fine with an unstayed mast and the masts are only stayed because of the platform, a beach cat, that has no bury in order to mount an unstayed mast that a cruising boat has. And also the mechanism for cambering the wing is complex and looks delicate. Thats fine for a racing boat that doesnt move far from home, but for a cruising cat you need robustness and simplicity. But man that wing mast cat flies.

According to the makers of the wing sails I am most interested in is that wing sails are 20% more powerful than an equivalent size sail. What that means to me is that I can build a 20% smaller rig and maintain sufficient power to meet my cruising needs and that means the rig will be cheaper to produce and safer because it is that much lower. Check it out.

I have spoken to Onesails Sydney loft and they are making enquiries about how to adapt the rig to my requirements, bi rigged cat. It is already an unstayed rig. I cant imagine it could not be done, the issue will be how fast they can develop it to suit and the all important question, how much it will cost? I imagine the sails would be more than double the cost of a regular sail but the additional sail cost should be more than offset by the cheaper mast construction costs. First it would be a round non tapering mast not a wing mast so that should be much cheaper to produce if not buy off the shelf. And second it would be a fixed mast glassed into the boat not a rotating mast so there would be no post, no bearings so again cheaper to produce.

What I like about the rig is how simple it is. How simple the batten system for keeping the wing form is. How simply the wing camber is adjusted from side to side. There is a bar attached to the front of the wing and hinged on the mast that rotates to the same side as the boom which causes the wing to bend in that direction. The rig will be is simpler to construct and being simple should also be less prone to breakage and simpler to repair. The wing is simple to deploy and retrieve, simple to depower and would work in exactly the same way as the bi rig was sold to me (release the sheets to allow rig to rotate with the wind to depower) and would be smaller than the existing rigs or at least the same size as the now depowered existing wing mast bi rig and of course round masts dont power the boat at anchor or in a storm under way. I accept there will be some tweaking of wing camber but I dont think it looks difficult to master.

1sail mast

In other words it ticks all my boxes. Lets hope it pans out. Should the manufacturer be not ready to adapt it to other customers needs or the cost is way over the top, another option is to build this kind of wing. Here is a link to a similarly simple home made version of the rig that I might be able to build myself. My only concern is that I would need plans or templates of the exact wing profile or batten profile to make the wing the correct profile:’s

This idea is very new to me, no doubt very new to many people. I would love to get a discussion happening on any cons it might have. It cant all be good news can it? Please comment if you have anything at all to say about it. Most of the time all I get is spam, so make a comment, if you dont want it public just say so and I wont approve it for viewing, but I would love to hear the thoughts from readers on this development in sailing.


I am a bit exited by it all. I will post updates on the idea and where it leads me as the answers start to roll in.

You May Also Like


2 thoughts on “Winging it

  1. Mike

    Paul, have you had a look at the Omer wing sail, arguably the more highly developed of the wing sail choices out there today?

    I think this one may check your “lazy” box, as well being significantly less complex that the Softwing.

  2. Paul

    Hi Mike,

    I have seen that site and the Omer wing sail. In fact the one I have settled on is made by the same company developing the Omer, Onesails (you can see the onesails logo on the sail). The system I prefer is the Ori.

    The Omer would certainly tick the lazy box due to the hydraulic rams and push button nature of the rig. But the fact it is a rotating A frame rather than just round fixed carbon poles and the hydraulics themselves makes the system a little more complex to build. Also, my understanding is that the rig is actually 2 sails, so you have to raise the wing section in front of the mast independently to the cambered section aft of the mast.

    If I was gungho on performance and only had one central mast I might agree, but I think for a more conservative cruising rig, the onesails Ori wing is more suited to a Bi Rig set up and a self build.

    Thanks for the email, keep them coming.


Comments are closed.