'Sailing'?? Directly to Windward

Thanks for the detailed contribution, Tom. Nice also to see that you were doing this 30 years before the other chap claimed the some of the ideas as belonging to him in a patent dated 1995!

 

You have certainly put "Windmaster" straight on a few points. However, I followed his linked video http://www.youtube.com/watch?v=8Rw_qJytbG8 . It does show that a multiblade approach seems to work albeit slowly. I wondered if you have some sort of equivalent test to show that a (for example) 3 blade design would work better against the wind. The boat in the video moves against the wind slowly, perhaps the 3-bladed one would work better. Has anyone tested this? Perhaps these kind of tank tests would settle the argument.

 

I think it has been proven in practice. And I think its easy for knowledgeable person to test it on paper - no need for tank tests unless guessing is the preferred method of design.

 

I didn't really intend to be so critical of the guy, but he was claiming ownership of ideas that others had come up with many years before.

The trade off with wind turbine design is difficult, because power output is proportional to the cube of wind speed. Windmaster chose to use a design rather like that used on wind pumps. This gives good starting torque (which allows it to start turning in very low wind speeds) but poor efficiency and very high drag in high winds. The reason his boat is so slow is largely because the turbine isn't getting anything like the full potential from the apparent wind. This is particularly noticeable into the wind, where the high turbine drag is significantly adding to the total boat drag. This is made worse because the blades have no twist, so are only working at their best at one point on their radius, everywhere else they will be way off best lift drag ratio.

Using a more efficient turbine would, without a shadow of doubt, improve performance over the 6 blade design. Two blades, or even a single counterbalanced blade, would give best efficiency, but two blade wind turbines tend to be harder to start and also make more noise than three blades ones, so the best compromise seems to be three blades. It isn't an accident that the vast majority of commercial wind turbines use three blades and look extremely similar. They are at the "sweet spot" in terms of performance vs complexity and reliability.

 

You are certainly right Jeremy about the blade issue and what makes an efficient turbine. But I can't help thinking that a design such as the Windmaster one, which, as you say gives good starting torque and allows turning in low wind speeds could be an advantage when going direct to windward. A boat equipped in this way could be moving off in a light wind when another boat with a less bladed design was still waiting for the wind to be strong enough to start. Since also, at the top end of the windspeed scale -as you say, the power is proportional to the cube of the windspeed, if the multi-bladed design was inefficient, that would not be so serious because the power available would be plentiful anyway. In fact, too much power could be positively dangerous and lead to breakages.

Yes, Windmaster's design was certainly slow, but what was that in comparison to? I haven't myself been able to find any other examples that went quicker direct to windward, which by it's very nature may be a slow point of sail anyway.

 

A wide chord, multi blade design does help overcome the inevitable friction in the drive at very low relative wind speeds, but will inevitably create more drag than a design with fewer blades of a narrower chord.

Going directly into the wind is a good case, as the relative wind velocity will be high (boat speed + wind speed) so the turbine needs low drag and high efficiency to deliver best performance.

Going directly downwind might be a case where increasing blade chord, or the number of blades, could give a benefit, as the relative wind velocity will be low (wind speed - boat speed).

 

High Tacker (www.damsl.com)

Jim Bates's 3-bladed turbine design was good at both low and high wind speeds and on a sea-going boat

I have been involved with wind turbine sailboats since 1965 and, as far as I know, New Zealander Jim Bates's second boat, the catamaran Tango, was the best so far, that is, I don't know of any boat, with the possible exception of Jim Wilkinson's Revelation, that performed as well in real sea conditions. I have no idea how well Wilkinson's boat performs, but his turbine looks reasonably good.

Re the points you are just now discussing, 3-bladed versus multi-bladed, Bates settled all that as early as the 1980s, after experimenting with every imaginable configuration, including vertical axis turbines, beginning in the 1950s.

Bates was Sir Edmund Hillary's chief engineer on that famous overland expedition to the South Pole in the 50s. Indeed, without Batesy they would not have made it. Hillary had great faith in Bates, uh, up to a certain point. Bates told me that he had tried to convince Hillary to let him build wind turbines to power their tractors over the ice and snow, because there was plenty of wind. Hillary's response was, "You're nuts!"

I met the Mad Master Bates (my nickname for him, which he did NOT like) in 1985 when he was scaling up to the 40-ft catamaran with 35-ft. diameter 3-bladed turbine driving a 3-ft diameter 3-bladed prop, both with variable pitch. The prop was retractable and when only half in the water would still drive the boat straight to windward. Bates was way ahead of me, so I invested in that boat, helped him finish her, and cruised extensively with him around New Zealand in 1986-87, and then, with Malcolm Tennant, we started designing and building my 63-ft cat Revolution.

See www.damsl.com and click on Wind Turbine Rig

See also www.tennantdesign.co.nz re Revolution, which is listed under 15-20m Sailing catamarans, NOT under Powercats

See Bates's first sea-going wind turbine boat, the monohull Te Waka, here on this forum: www.boatdesign.net/forums/attachmen...97420937-another-idea-upwind-sailing-real.jpg

See also the photos Jeremy Harris posted, above in this thread, of Revelation and Revolution.

Bates's catamaran regularly averaged 55% of the wind speed straight into it. She was somewhat faster off the wind, but not much, and not as fast as the same boat would be with conventional sails. Mind you, your average cruising catamaran averages overall about half the speed of the wind, and there is some 90 degrees of the compass, about a quarter of the area, where a conventional boat cannot go.

In 2 knots of wind, Batesy's boat could go straight into it at a bit over 1 knot. So how's that for low wind speed performance?

In 20 knots, she did 11 knots. In 30 knots, sea conditions often caused too much pitching and gyroscopic twisting of the mast when going straight into it at top speed, so reefing and slowing down was usually necessary. Reefing down to nothing, complete feathering of the blades could be done in a matter of seconds. And she could accomplish the ultimate in heaving to, just hovering, still straight into it, not gaining much ground but not losing, and not being pushed sideways the way a conventional boat is.

Rob Denney's boat, admittedly built from recycled and inadequate parts, and with advice from Bates, apparently did 6 knots in about 20 knots. A video of that boat is somewhere on this forum. Again, 3-bladed, and pardon me, Rob, but I think you would agree that your mast rotation and variable pitch system was rather Rube Goldbergish in comparison to Bates's quite slick system. Batesy sat comfortably at the helm in his cockpit, turning his hand cranks for mast rotation and pitch control.

Windmaster's design would not survive in sea conditions. And it would not go well, if at all, into a strong wind even in flat water. With increasing wind speed, drag increases faster than lift, and his multi-bladed design has very high drag. Furthermore, as Jeremy Harris has pointed out, with no twist, Windmaster's blades have decent efficiency, i.e., optimum pitch, really at only one point along the blade length. You have to understand that the farther out along the length of blade, the faster the apparent wind relative to a point on the blade, and thus that section of the blade experiences a different wind direction, and therefore needs a different pitch, otherwise you get too much drag and not enough lift.

Windmaster has proved one thing especially, that it is easy to build a small model with even a rather unrefined design that can go to windward in mild conditions. As Jim Bates said, the idea wasn't original with him. As he put it, it had already been proved that a crude windmill could push even a bathtub straight into the wind. It's remarkable how much useful work you can get out of all that leverage if you let the sails rotate instead of pushing the boat over.

3-bladed is the optimum design. 2-bladed would be better, BUT, an odd number of blades is necessary because, for a big turbine, at the top of the transcribed circle, the windspeed is much greater than at the bottom. The vibration caused by an even number of blades on a large turbine is quite astonishing, so Batesy told me and I believe it. Batesy destroyed a lot of turbines in his day, more than 30 years on the project.

Not to worry, the bits don't come flying off like a stone from a slingshot; they just fall, so he told me. But seriously, with today's wind turbine technology, a very safe system is quite possible, hey, much better than when Bates and I were doing it, and his design was already pretty safe.

Mind you, the big ones don't whizz around with the rpm of the little ones. The 50-ft. diameter turbine on my boat had a maximum rpm of 80, and the tips of the blades passed so high off the deck that you could not jump up and reach up and touch a blade.

But if there was not enough wind to sail, you could go up on the cabin roof, where the tips passed at 5 ft. above the roof, and you could grab a blade and give it a fling, and then another and another...and row the boat along quite smartly. Or you could put the props in reverse and row her backwards. Of course, if there was wind, you could sail her in reverse, straight into the wind.

 

Hi Bil
You have recognised my design strategy quite well. Yes the "Multiblade approach" is certainly optimised to work in light winds, this is probably a reflection of my preferred sailing area which is the Norfolk Broads (for those who don't know, it's a region of about 150 miles of winding rivers and small lakes in Eastern England). I think the ability to sail direct to windward is particularly useful in narrow rivers where there is no room to tack. As indeed also is performance in light airs. Some have tried to think of extreme sailing conditions such as "it wouldn't go round Cape Horn" or "Cross the Atlantic in a hurricane" and advanced this as a criticism. Well, who said it needs to try to do these things Neither would a lot of other boats be able to do this. You couldn't fly non-stop at 500 miles an hour to Australia in a Cessna 172 either. That doesn't mean the Cessna is not an effective airplane of its type.
One thing you maybe did not devine was a reason for the "flat" blades. For parking up, mooring etc. You need to feather the blades. Twisted blades can never be completely feathered because some parts will always have an angle of attack and therefore produce drag.
I notice your question. "Where can you show one that goes faster direct windward?" remains unanswered, and I mean "show" not just hearsay from 30 years ago.

 

Here's a picture of the sign next to Revelation II in Guernsey, taken in March 2011.

 

Seems like this designer has done his homework and chosen to optimise the turbine well. Also interesting to see the comment about the ability to tolerate high winds, which indicates that he has managed to get the blade and mast drag down to a manageable level, an advantage that I've mentioned before with using a small number of relatively high aspect ratio blades (and confirmed by High Tacker in his very informative posts). Nice to see that Revelation II seems to still be in use, the implication from an earlier post was that it maybe wasn't used now.

 

Bernhard Schmidt (http://en.wikipedia.org/wiki/Bernhard_Schmidt) tired to patent a Windmill driven upwind boat (Gegenwindschiff) in 1925. Patent was denied due to lack of novelty. Ironically even decades later the author of Schmidt's biography Barbara Dufner thinks that "it is physically impossible to go directly upwind with an wind-powered vehicle":
http://books.google.com/books?id=Qi...BQQ6AEwAA#v=onepage&q=gegenwindschiff&f=false (German text)

Some pictures from his patent submission taken from: http://www.friedensblitz.de/sterne/schmidt/Schmidt3.html

 

High Tacker (www.damsl.com)

Windmaster

I've read enough of this forum to realize that all too often the comments degenerate into petty oneupmanship and even outright insults instead of maintaining a proper detached scientific approach. So I feel compelled to answer when so challenged. When you say at the end of your last post: 'I mean "show" not just hearsay from 30 years ago', you are obviously saying that what I had just posted about Jim Bates's boat was mere hearsay in comparison to what you have 'shown' on Youtube with your models.

What I've said about Bates's boat and the speeds attained was a firsthand account of my witnessing of Bates's very scientific work, not hearsay, and I might add that I had quite a lot of formal university training in science myself, including physics and thermodynamics, as well as a fair amount of experience as an observer and science writer and journalist professionally employed for a number of years by the American Chemical Society. And mine is not the only account of Bates's work. See the link that I posted just here above, to the picture and text regarding Bates's first boat in "Another idea" thread on this forum. You will see it said there that Bates's speeds were recorded in steady winds with a carefully calibrated knotmeter, and that a large number of measurements were made. The fact that that was done more than 30 years ago does not make it hearsay, nor does time diminish the evidence in any way; it only serves to show that Bates was way ahead of both you and me that long ago. That you haven't seen it in a Youtube movie is altogether beside the point.

Are you insinuating that we are exaggerating, or lying? I assure you that I have no axe to grind here. I am not trying to sell a windmill boat or lay claim to the idea. I took the turbine OFF my boat. I have nothing to gain by promoting Bates's boat. After his turbine was damaged in Hurricane Bola by a flying tree, Bates put a conventional rig on the boat and sold her. Nevertheless, you and I are on the same side when it comes to feeling that all sailors should understand the possibility in turbine boats, and we both should want to contribute to any possible future for such boats.

I think the big difference between us is that although I would dearly love to see further development so that windmill boats were all over the place, unlike you, I make no claim whatsoever to any rights in the idea. I arrived at the idea independently in 1965 and proved to myself that it would work, but it turned out to be a very old idea, dreamed up by many, and long since in the public domain.

I found a patent on the basic idea from 1924, and there is at least one other patent from around 1985, both of which, and yours, I consider to be invalid because the idea was already in the public domain. For example, the results of indoor models very like mine, and yours, were published in the 1950s by a physicist in Nova Scotia, and others, including apparently Herreschoff, had done models before 1924, and most especially Jim Bates had already done considerable development work beginning in the 50s, and Bates built real sea-going boats in the 80s that would also without doubt beat your boat(s) (or any boat with your turbine design) hands down in low winds in a mild twisty river in England or anywhere. And Bates told me that he had seen yet another different model, earlier than any I knew of, in some magazine like Popular Mechanics, he wasn't sure exactly where or when, but it had given him the idea. Bates was a very savvy, successful, self-made businessman as well as a genius inventor, and he held a number of commercially successful patents, in different fields, for some processing machinery in the dairy industry for one example, but although his boats were the most successful ever that I know of, he felt that it was futile to seek patent protection on a wind turbine boat, because of prior knowledge in the public domain. Nevertheless, because of his mad scientist bent, he just could not resist experimenting with the idea for more than 3 decades. And he went through many, many turbines, some of his earliest very like yours. And I would think that his family preserved his voluminous records, drawings, etc. He never threw anything away. I imagine that anybody interested in challenging your patent could dig up more than enough evidence.

Your patent, Windmaster, isn't worth the paper it's written on, or, rather, it's worth however much you're willing to spend to defend it, which of course would be a waste of money, because, as Jeremy Harris has already said, it is for the most part indefensible, because there is nothing novel about your claims. And your vaunted tip speed ratio is virtually meaningless in terms of the gyroscopic effect. Big turbines MUST turn very slowly, too, even 3-bladed ones, yet any big turbine WILL have gyroscopic effect. The gyroscopic effect boils down to momentum, which involves MASS as well as velociity, and the bigger the radius of the turbine, the bigger the effect of the mass.

It's like a flywheel, Windmaster. And the more blades you have, obviously the greater the mass of the turbine. You haven't noticed the gyroscopic effect because your turbines have been so small, and low down on the boat, and you haven't had them out in anything more than barely a breeze on a millpond. Even on a small riverboat, you would need a bigger, heavier turbine, and would need to get that thing up high, for safety, for better and smoother wind, and also so that you are not sitting or standing in front of it obstructing its wind. Weight up high means greater pitching moment, and even on a river you will eventually encounter some wave action, if only in the form of wakes from large rivercraft. Then would come your rude awakening. A 3-bladed, slender, low-drag, LIGHT-WEIGHT turbine has a chance, not yours.

But back to your "proof", your "show it" attitude. From this latest and other comments of yours, you seem to think that since you have movies of your models, you have the only valid proof of a working model. Well, I've watched your videos, and in no way do they demonstrate any speed with any certainty, although they do seem at least to imply that even crude contraptions can sort of move upwind, maybe, but I don't think that many viewers would say that the proof of direct upwind motion is certain. And when you say that you've been accused of having a hidden motor, I don't wonder at that. So, seeing a movie is not necessarily believing.

Your video of the indoor tank test does demonstrate that a very crude model can move directly to windward. Well, to me it demonstrates it, but then I already knew that it would work.

But there is value there. I hope every sailor in the world will eventually view your videos and come to realize that even in such a crude contraption, there is a remarkable amount of useful work in all that leverage when you simply go ahead and LET the sails rotate instead of just knocking your boat over. In that sense, your efforts have not been wasted. Once so enlightened, what sailor could ever again be really satisfied with beating to windward no closer than 45 or so degrees? He'd be bound to keep thinking back on your contraption and maybe all those thoughts would lead to an even better way.

But in all the posts of yours that I've managed to find, you give no speed numbers, indeed you complain of being asked for such, by whining that nobody ever asks for speed numbers from other sailboats. But of course they do. Pardon me if you have given out actual numbers anywhere, and please point me to them.

In any case, what you are obviously unwilling to accept, and backyardbil doesn't understand, is that an inefficient, high-drag turbine design has no advantage whatsoever, in low wind or high wind, whether in operation or feathered and parked. And, as Jeremy Harris has said, it is no accident that 3-bladed turbines with long, narrow, twisted blades are almost universally the choice.

As Jim Bates put it, the trick to going to windward in strong winds is to let a substantial part of the energy pass you by, by varying the pitch on the blades so that you are actually capturing only an optimum portion of the energy of the wind, and with the lowest possible drag. In order to do that, your turbine must be highly efficient, i.e., the best possible lift to drag ratio ALONG THE ENTIRE LENGTH OF THE BLADE. Yours doesn't even come close to what's possible. I repeat, Bates started off with primitive blades like yours, no twist.

At the low end of the wind scale, with a variable pitch 3-bladed turbine, you simply crank it up so that you are capturing more from the wind. Still, the most efficient turbine will get the best speed. Yours would not come close to the best possible efficiency in low wind speed either, never mind that it MIGHT start at slightly lower wind speed. As I said, Bates's boat sailed at better than 1 knot in 2 knots of wind, and that was very carefully measured, on many occasions.

Having witnessed all of that, and watched your videos, I cannot believe that your boat(s) in your videos are doing anywhere near half the speed of the wind. Havilah Hawkins, on the coast of Maine, in the 80s I think it was, with a blade design very similar to yours but not as many blades, got his best speed of 3 knots in 18 knots of wind. Those numbers stuck in my mind, because I learned of his work just as we were doing better than half the speed of the wind. I don't completely trust my memory on his number of blades for that speed, but I think he started experimenting with more blades but finally got down to 5 or maybe it was 3. In any case, with so many blades of pretty much the same if not an even more primitive design, I think your boat would go backwards in 18 knots of wind, if the turbine structure didn't fall apart first. Hawkins also remarked that the gyroscopic force became quite a problem.

I think you should stop trying to defend the inadequacies of your present design and move on if you want to advance the total system. For example, when it comes to parking the boat, your many flat, wide-chorded blades, even when completely feathered, will have far more drag than a properly designed 3-bladed turbine when feathered and at rest. And in operation, even in the normally mild locales where you sail, there will likely come a time when you will realize that such a turbine just can't cut it. So I recommend that you always take along an outboard motor, and an axe and a chain saw to get rid of the turbine when you desperately need to.

 

As an engineer that appreciates true innovation, it is clear that High Tacker's experiences speak volumes. To the contrary, I noted that the small craft in the video showed nothing even close to a breakthrough in the areodynamic efficiency needed for practicality.

Those who pioneered the engineering of functional turbine powered craft deserve a lot of credit. Some craft preformed OK even though they did have limitations as noted by those involved.

The basic laws of physics can be rather tough on those that do not want to face facts. For a traditional turbine boat (3 blade rotor on an unstayed rotating freestanding mast), modern material may be able to reduce blade mass and achieve better performance, but the gains will not be huge.

There are probably alternate configurations are possible that take a modern turbine an support it with a structure that would handle the required loads better. However, the gains would again not be all that large. For dead into the wind, you may get good performance. For other headings, the turbine is just not as efficient. The frictional losses created by the relative speed of air over the blades are way higher than for a stationary wing. Add in the extra maintenance of a turbine and it is easy to see why a turbine is not real pratical for most uses.

If you are using one to navigate narrow channels where speed is not needed, and the "green" aspects are a priority, there may be a place. However, real success is more likely if you are nice to those who made the most progress with a specific technology in the past and ask them to share what did and did not work. Most real inovators of neat but not-so-practical technology are usually very open and willing to help a new participant that wants to push the idea a little bit further. Just give them a little credit and all will be happy.

 

I don't claim ownership of the idea and never have. Seeing a patent concerned with wind-turbine boats does not necesarrily mean the the owner is claiming novelty of the whole idea, that's a gross over-simplification. Obviously, the patent examiners (having searched the prior art) considered what was in it novel (but not the concept itself). I myself have studied the subject for years and know of proposed examples going back to the 13th century.
I am the first to believe that videos are not proof of anything, consequently, some time ago I published plans on the internet for a simple model to demonstrate how, the "multiblade approach" - if we can call it that - is superior to the fast-spinning thin blade (electricity generating type) for this application (driving a boat directly to windward). The publication of these plans was after extensive practical tests which compared this type with the aforementioned fast spinning type.
If any person was fair-minded enough to make this simple model and test it, they would immediately see how effective it is. However, no one has made one, and many would rather spout dogma on this forum than actually investigate anything themselves. The plans are here:
http://www.sailwings.net/windspinner.html
It's unfortunate that Mr Bates's achievements were made before the days of the internet, and were largely forgotten. However, his efforts have now been extensively described by T. Bradshaw who has applauded his activities considerably. I'm sure his boat was very good, but that doesn't mean that it is the last word in design. Surely, there is nothing in this world that cannot be improved upon or made more user friendly. It seems I have been accused of heresy to suggest anything different.
As an experimenter and investigator I have certainly found it heavy going to suggest any new ideas on this forum where the prevailing sentiment is "don't suggest anything new - we know everything already" - which may I say is not a very scientific approach. However, my ideas mentioned here are not just a suggestion, they can be tested. Please test them. If I am proved wrong in a fair test, I would be glad to acknowledge it.
I am not wealthy enough to spend over 300 thousand pounds on an experimental boat (which looks nice) as Jim Wilkinson has (Revelation II) in Guernsey, nor the no-doubt very expensive wind-turbine boat in NZ built by T. Bradshaw. I am a back-yard experimenter and consequently my efforts are scorned upon and labelled "crude contraptions" Rube Goldbergish (Heath Robinson in the UK) which is a shame.

 

Actually, it seems from your patent claims that you are, indeed, trying to claim ownership of the idea of a horizontal axis wind turbine powering a boat via a shaft running down inside the mast, which is, I suspect, part of the reason that one or two of us are taking issue with your claims. For example, your first patent claim states:

Obviously this claim is invalid, as there are many examples of prior art showing that such systems as you have described had been built and experimented with many years before 1995, when you filed this.

Such is the nature of open debate. FWIW I agree that it can be hard going trying to convince people that they have misunderstood the principle by which something works. There were some good examples of this in the "directly downwind faster than the wind" thread. It is commonplace for people to confuse velocity and power, for example.

On the other hand, this forum does get more than its fair share of wild dreamers, who extol the virtues of wholly impractical devices. Inevitably this has created a general feeling of scepticism amongst some of the long term contributors. Furthermore, the boat building industry as a whole tends towards conservatism, meaning there is a reluctance in some quarters to accepting new ideas.

One thing that seems guaranteed to make people here sceptical seems to be anything that looks like a hard sell. Your first post on this thread from 2009:

came across (at least to me) as being a bit arrogant, technically dubious and a bit of a sales pitch (in as much as you wouldn't discuss anydetails without entering into a contract - a CA is a contract).

As I've mentioned before, I commend you for your experimental approach; in my experience few take the time and trouble to try and put ideas into practice. What I, and I suspect others, find a little odd is that you seem to be unwilling to accept that your design could be significantly enhanced by a much more efficient wind turbine design. In many ways this seems, to those reading your comments, as if your own mind may be as closed to new ideas as those you have criticised for not believing that the system you have put together works.