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From wiki
"
The Volvo Open 70 class boats in the 2006 around-the-world Volvo Ocean Race are perhaps the most well known boats to use canting keels for ballast. While previous years' boats showed a few percent improvement in speed each race (the race is held every three years) the VO70 class are showing a 30% improvement in speed. The 6.5 ton ballast bulb, hanging over 16 feet (5 meters) below the water and capable of canting up to 40 degrees, produces a tremendous amount of righting moment (over 130,000 ft·lbf, or 176,000 N·m with the hull level), allowing the boat to reach speeds of over 30 knots.
[edit]"

The righting moment is balanced by the rig. The volvo 70 has a 5.7 metre beam. To apply 176,000 Nm of torque between the mast step and the windward shrouds. X * 5.7/2 = 176,000. X =61,700 newtons (6 tonnes) of compression in the mast and similar tension in the shrouds, give or take the weight of the rigging components. So what is the cross section of the mast? Couldn't be more than about 30 cm diameter at the top? Say 61,700 newtons on 1/10 th of a square metre. That's a pressure of at least 617,000 newtons/ square metre or 617 kpa. About twice what you might put in a car tyre.

That's a fat mast though, not very aerodynamic, and to be as tough as a car tyre all the way up, pretty heavy. I also doubt it.

I think if it did come to pass it would be a total rethink of the sails we use now. I think there are probably people in lofts doing r&d on what sails will look like into the future. I reckon DR J may be on o something with attaching the boom and then attaching the sail to the board.

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choco said...

Looks great, but does it work on the water on just in the car-park ?

It looks like they also make inflatable number plates !

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Sailhack said...

^^^ This is begging for a kiter to troll re; natural progression from sail/mast to 'inflatable luff'-style sail with no mast - just add strings...

...or are you guys just taking the p!ss, and encouraging a troll from the other side?

Arr crap, Ya beat me to it. Gotta be quick around here.

Dan Kaesler had a site on the web(can't find it now) which showcased some of his protos while working for Naish, one was a sail with a inflatable batten system looked good

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DunkO said...

DrJ said...

If you could have an inflatable mast, surely everything could be inflatable..... Boom, fins , board......

Missus?.... it may be easier but not necessarily better.

Sorry I forgot to include an emoticon indicating that I was being a sarcastic ****

What's wrong with a conventional mast?
I can't see an inflatable mast happening on anything larger than a kids dinghy...
And that would be a big ask.....what sort of diameter tube would be required for a Volvo yacht section?
Massive I would guess..what would be the benefit?
I would like to see a rubber tube that could support a massive kite as cjw suggests
There's already too many double action air bed pumps lurking around the beaches....

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choco said...

Dan Kaesler had a site on the web(can't find it now) which showcased some of his protos while working for Naish, one was a sail with a inflatable batten system looked good

Yeah remember that, it had shkite style tubes as battens, and was monofilmed either side for a solid foil..

But the thing is, current mast and sail technology works great.. Solid foils are fine if you only travel in one direction, but ours have to rotate.. Bats and Pterosaurs show that there is nothing wrong with membrane foils.. I can't find a pterosaur video, but this is pretty cool..

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snides8 said...

What's wrong with a conventional mast?
I can't see an inflatable mast happening on anything larger than a kids dinghy...
And that would be a big ask.....what sort of diameter tube would be required for a Volvo yacht section?
Massive I would guess..what would be the benefit?
I would like to see a rubber tube that could support a massive kite as cjw suggests
There's already too many double action air bed pumps lurking around the beaches....

indeed the only benefits air has over carbon is transportability and prize
but performance wise there is no hope of air being even close might as well go back to wood, even that would flex faster and be stiffer than a air bladder and hey woods cheap and it floats
but the idea of a bladder sitting behind the mast is quite interesting not sure you would get rid of the cams in a full on race sail but potentially a speed or freerace sail, it would be incredible if you could increase current race sails stability even more with a bladder the feel of the sail would be unbelievable

Apparently the battens in the yacht sails can be connected to diving bottles that inflate the battens or add more air. Don't think that would work on a board.

Yep your right about it being more convenient. I have a sailbag that when fully loaded weighs in at 25kg and is over 6ft long. It has to be strapped to the roof when travelling. If it was possible I would have boards and sails that came apart in sections to fit in the car, yea I know the Pope brand does that. I'm just saying transportability is king here.

Barn your focus on dinosaurs surprises me lol.

Posted 11 hours, 0 min ago
AUS4 said...

choco said...

If they could design a bladder to fit behind the mast and inflate the actual luff sleeve to form a ridged leading edge it would eliminate the need for cams hold the power locked in and best thing is that it would float.
You would rig the sail normally then pump tight the luff pocket....

This image has been resized to fit - click to view as 1200x1800.



Gaastra did this in 1984.


You could fill it with helium!

But then Elmo would float away when he took his wetsuit off!

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gregc said...


Barn your focus on dinosaurs surprises me lol.

Well, when we are trying to build wings, and look for ideas, the best place to turn is evolution where wings have been developing for 500 million years..

At first I couldn't think of a naturally occurring inflatable wing, which was surprising cause every engineering solution has been evolved, to some degree..

And here it is, a working inflatable wing!!.. Still can't see this working on any practical scale, and the aerial performance of ladybugs are pretty pants compared to insects with permanent wings..

http://www.you000tube.com/watch?v=fC61ZA4uWbs

(edited so I don't fill the page with videos)

Apparently the US patents office thought that it should close sometime in the 19th century cause everything that needed to be invented had been. Truth is that what lies around the corner may be the next big step so I don't think every engineering solution has been developed as yet. Actually what is really cool is that this is causing some sort of debate rather than just disappearing down the list. Agreed that 500 million years of evolution have taught us something about wing design and what will and won't work, however, its not to say that its the be all and end all of design.

Like I said maybe someone will come along and say reduce the carbon cogent in a mast and use an inflatable luff to provide the bulk, maybe the design of sails will alter altogether in the next decade. It just takes one smart person to think differently and it will work. I was SUPing the other day and met the bloke that does a lot of production work for Simon Anderson and we were talking about the thruster design. Apparently if Simon hadn't won those couple of contests the thruster may have disappeared into history regarded as a novelty. Its now the dominant design for boards in most disciplines. I think that having to have huge amounts of gear to put on and off a roof or having to buy a trailer to get gear to the coast each time, or having to buy a van to transport kit is painful.

Like Dr J said if you could fit your rigs into something the size of a golf bag how good would that be (and Im not getting kiteboarder on you). Gone would be the days of having to lug around gear, bloody heaven.

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Carantoc said...

CJW said...

evlPanda said...
Yep. Saw it too. The April 2011 edition of Sailing.

Anyone got a copy they could scan and post up because I'm interested in just what they are talking about? I don't see how it's possible in any way shape or form; I'm talking about a rig fully supported by an inflatable mast.

Creating a small inflatable wind turbine (it's a one of those turbines that rotates about a vertical axis), or an antenna mast that has to support ~50kg is one thing but consider this:

Alfa Romeo, the Maxi that has won the Sydney - Hobart numerous times can carry ~1300m^2 of sail down wind. In 20kts that is an absolute ****load of force, there is no way in the world anything inflatable is going to go close to supporting that. Alfa weighs ~25 tonnes, a very large percentage of that is keel to support that amount of sail, consider the vertical loads at the mast base (anyone remember OneAustralia lolz).

I'm open to entirely eating my words if someone can provide more info in this article but sounds fanciful to me

Perhaps the April edition was published on the 1st of April ??

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gregc said...

Apparently the US patents office thought that it should close sometime in the 19th century cause everything that needed to be invented had been. Truth is that what lies around the corner may be the next big step so I don't think every engineering solution has been developed as yet. Actually what is really cool is that this is causing some sort of debate rather than just disappearing down the list. Agreed that 500 million years of evolution have taught us something about wing design and what will and won't work, however, its not to say that its the be all and end all of design.

Like I said maybe someone will come along and say reduce the carbon cogent in a mast and use an inflatable luff to provide the bulk, maybe the design of sails will alter altogether in the next decade. It just takes one smart person to think differently and it will work. I was SUPing the other day and met the bloke that does a lot of production work for Simon Anderson and we were talking about the thruster design. Apparently if Simon hadn't won those couple of contests the thruster may have disappeared into history regarded as a novelty. Its now the dominant design for boards in most disciplines. I think that having to have huge amounts of gear to put on and off a roof or having to buy a trailer to get gear to the coast each time, or having to buy a van to transport kit is painful.

Like Dr J said if you could fit your rigs into something the size of a golf bag how good would that be (and Im not getting kiteboarder on you). Gone would be the days of having to lug around gear, bloody heaven.

well with the right combination of gear i'm pretty sure you could pack a setup down to the size of your booms, a while back i seem to remember someone played with a 2 piece board using carbon rods i think to join the two half's (can't remember details) but pretty simple then north sails made a 3 piece mast (do they still do that) and so with that the rest of your gear would pretty easy fit into a bag of about 150 cm x 50 cm x 40 cm i recon
no fancy tricks needed

i think the biggest part of this argument is knowing what you are trying to achieve, some people are complaining how hard their big and clumsy windsurfing gear is to transport, where others are arguing that they value performance more than anything else, price is another point and then ease of use is the other point of view i can see. they are all relative and there will always be trade offs for one or another. but once you establish what you aim to do you can then try to achieve it

Yea not sure if it's about achieving anything on the forum, just shooting the **** really.

Pope have been making the bisect and the trisect for years with mals. I'm sure the same thing could be done to a board. I like the three piece masts from north. My gear bag weighs in at about 20kg or so when fully packed, could the weight and the size be reduced without sacrificing usability(ie I don't want to be told to leave gear home).

I think it was Winlok that made sails in the early 80's with a molded flexible foam luff section shaped like a wind mast that slipped over the normal mast, replacing the cambers as well. I only ever saw it in brochures and at the Windsurfing show in Melbourne. I don't know how well it worked but it seems it was not practical.