'Sailing'?? Directly to Windward

High Tacker www.damsl.com

Hello Teddy,

But nothing "alike" your 1,932 posts which I imagine were all pithy one-liners not at all repetitive. Here below are some virgin-to-this-forum photos. I went to the trouble of digging them out of my files just for you.

I also went to the trouble of reading a couple of your posts questioning wind turbine boats and it seems that you might just be tired of reading about such because it hurts your head so much.

Cheers,
High Tacker

 

High tracker - maybe I am reading you wrong - but it really looks like you are trying to be an ***. Am I misunderstanding? If not just one question why?


edit: wring -> wrong

 

No offence to anyone but whats the point being made here, I just don't get the, having to prove it can be done. Yes it can be done, but only under limited ideal conditions and that to me means it's, at this point in time not a pratical means of propulsion. Having said that it looks like a fun project to play around with if for nothing else.--Geo.

 

High Tacker www.damsl.com

Hello kerosene,

I don't know whether you are reading me "wring", but I suspect that you are reading me wrong. I don't have to TRY to be an ***; it just comes naturally. I do try to wring sense out of nonsense, if that's what you mean, usually a waste of time, but somehow I can't give it up. I have even taken the trouble to read (not to say decipher) some of your posts, and it seems to me that you, like me, tend to lose patience with the nay sayers. And I am wondering just what in my scribblings has prompted your question.

By the way, that's a cool video of yours at

http://www.boatdesign.net/forums/pr...ind-faster-than-wind-25527-16.html#post363122

Oh, do I wish I had had the video tools and animation skills when I did essentially the same thing in 1965 to demonstrate sailing directly upwind, showing the analogy between a simple sailboat, sailing on the surface of a cylindrical sea, and a boat with a wind turbine driving a propeller, both boats having the resultant of a helical track, getting directly upwind without tacking, i.e., screwing into the wind. I had to do it in a physically real way, with a long threaded bolt and a truly winged nut.

See www.damsl.com and on the welcome page look to your left and click on Wind Turbine Rig and you'll see my illustration.

And I think you'll come to the conclusion that we're on the same side, trying to get the idea across. Uh, maybe we should try whistling into the wind, a little duet. Somehow, my experiences of the past 46 years seem to indicate that we ain't gonna sell a helluva lotta tickets either way.

Cheers,
High Tacker

 

I was just surprised why you were attacking Teddy - seemed like you were picking and argument when everyone (here) already agrees.

And I was being impatient and on bad mood. Also I was being so absent minded that I didn't recognize your handle from previous posts - I did find your reports of actual experiences very interesting.

hmmmmphhh - here comes.
sorry

 

Actually I've put a photo here of a photocopy of photo in kiwi newspaper of such boat, reckon the same dunno..
To make my self clear I'm very much convinced of your work and the benefits of the concept, so obviously you didn't take much trouble reading my posts I'm also convicted that the subject reopens itself annually..

BTW My plan is to have a non tacking wind turbine hoisted at anchor upto mizzen mast (just for the electricity)..

 

i couldn't help you but maybe we can use this technology in it and perhaps it's should be works for our metal crafts item makers.....

 

Typically, aerofoils produce more lift than drag. (By a large margin). Increasing speed does not affect the lift to drag ratio.

Can you explain what direction drag you are referring to?
Do you mean drag which prevents the turbine rotating faster.
Or, do you mean the drag of the entire turbine opposing the direction of travel directly windward?
Presumably, you don't mean the windage of the boat itself.

 

High Tacker www.damsl.com

Hello All,

I'm traveling and so have limited computer time, so will try here to answer several posts in this one reply.

viking north: The point here is that it seems a number of members still are either not aware of or don't entirely grasp what has already been done in terms of sailing directly to windward, and also know little about the overall behaviour of such craft that has been demonstrated in general sea conditions, yet they insist on voicing their opinions on the practicality of the concept. The need for a bit of education is exemplified by your statement above that it has been done only in "limited ideal conditions". Please see

http://www.boatdesign.net/forums/at...97420937-another-idea-upwind-sailing-real.jpg

Jim Bates put thousands of sea miles around New Zealand on that boat and also on his second wind turbine boat, a catamaran (and I accompanied him on long cruises on the catamaran), and those boats experienced more rough sea conditions than most cruising pleasure boats do in a lifetime. His catamaran averaged 55% of the wind speed straight into it and somewhat better off the wind. Your typical cruising catamaran averages overall about half the speed of the wind, and can't go at all in about one-quarter of the compass.

Conventional monohulls don't even come close to what Bates's wind turbine driven monohull averaged, which was half the wind speed on all points of sail. I repeat, he put many miles on both boats in rough sea conditions off New Zealand. If you have any real interest in "playing around" with this "fun project", then maybe go back and read my previous posts in this thread to get more of a grasp of what has been done, and then perhaps you can make a contribution to the project.

Also see www.damsl.com and look to your left on the welcome page and click on Wind Turbine Rig.

On Bates's catamaran, both the turbine and the prop had variable pitch. Just by turning hand cranks in the cockpit (and far easier than turning a winch handle to sheet a very small sail), the mast was rotated to keep the turbine on the wind, and the blades could be reefed down to nothing in seconds. I was aboard in some pretty rough conditions, and we were still able to make way, albeit often slowly, but gaining ground straight into winds of more than 30 knots, and big seas, more than 6 meters, conditions in which most monohulls would have been motoring with no sail up at all, or heaving to or lying ahull, and most catamarans would have been doing the same or lying to a sea anchor, or maybe running.

Although I came to the conclusion that it is more practical to store wind power from a somewhat smaller turbine, and store solar power, to drive the boat electrically, and also use conventional sails for off the wind, I still think that a purely wind turbine driven boat is quite feasible, with more development, for some uses. It's obvious that not many of your average sailors are going to be converted to such. People in general are frightened at the very idea of a big turbine on a boat, but wrongly so. If done properly, it is less dangerous and more reliable than a conventional rig.

My reasoning in favor of storing power is not about danger or a turbine boat not being able to survive, rather, it's all about convenience, being able to go when there's no wind, or straight into it, on power stored when the boat is moored or at anchor, because, after all, that's where most pleasure boats spend a lot of time. And I love the serenity of cloth sails, and you can put up more and more of them and go faster off the wind than with a turbine...uh, unless you have a REALLY big turbine.

kerosene I don't think I was "attacking" Teddy. It seemed he was trying to be funny, so I joked him back. Uh...I was trying to be funny, too, but sometimes my so-called sense of humor just doesn't come off as such.

backyardbil On the same boat, a multi-bladed turbine giving the same power as a 3-bladed turbine, will have more drag, will be less efficient, will, and probably pretty quickly, reach a point in wind speed where it will not go to windward at all. That is especially true of one without blade twist.

Drag at low wind speeds is still proportional to wind speed, i.e., it increases with wind speed. At higher wind speeds, that effect is greater. Drag has to do not just with frontal surface and overall shape, and twist, it also has to do with total surface area. There is also "interference drag", when a number of bodies are close together...like, a mult-bladed turbine.

You stated in one post that Windmaster's multi-bladed turbine might be advantageous at high wind speed BECAUSE of its inefficiency, your reasoning apparently being that if a turbine were more efficient, that might lead to damage, etc. Wrong. Inefficiency has no such advantage. With a 3-bladed turbine, with blade twist (much more efficient, and less drag) in high wind speed you simply reef the variable pitch blades and reduce rpm.

 

Seems the gadget does work when done right.
Possibly the resistance to its adoption is the necessity of rotating, that is moving, parts, and reducing the sailor to a mechanic whose socket wrenches and grease gun are much more important than his knife and marlinspike. I already have a Ukrainian motorcycle to fix.
This machine would be the same, even with excellent and simple means to alter pitch of both air and water screws; it's machinery and that means maintenance and repair, always.
Sails are the same, though old working rigs had a much much higher ratio of use time to maintenance cost than we do now, and when not in use sails can be covered or stored below. Remember the usual yacht spends 97% of its life bobbing in the slip waiting to be used.
And the experience at sea is a totally different thing.
I went 14 days straight once while barely touching a sheet or the helm and heard nothing but the sea and the NE trades a little forward of the beam. No moving parts really, just the adjustment means of winches and blocks which was little used while we did 2300 miles to windward in 21 days simply on the sail 'wedge' driving the hull 'wedge' as a result of the vectors, no bearings, wings, propellers or other wonderful things needed.
No, we cannot go straight upwind but we get where we're going anyway.
I would love a thrilling ride on a well-developed example of a windmill boat, once, then would avoid it like the plague unless needed for a trade (money making) that required wind powered advance straight up wind.
Of course then there would be others trying to do the same thing, spurring ideas for advantage, and the engineering would get a kick in the rear.
Until that day of wind-powered commerce comes, this is an interesting toy suited for few people or situations.

 

http://www.yankodesign.com/2008/01/24/flying-stick-camera/
More windmills.

 

You didn't really answer my question, maybe I didn't make it clear enough.
Yes, quite true that drag increases with speed, but so does lift.
It's lift that makes the blade push the turbine round and thus connected to the underwater prop pushes the boat along. The lift is produced at approx 90 degrees to the surface of the aerofoil. On blade rigged at a typical angle used on a (for example) 3 blade design the lift has two effects - or components. The first effect, like the sail on a normal sailboat, is to push the the blade around it's circle, (this is where the power comes from) the second effect is to push the blade back in the direction of the rotational axis, (equivalent to heel on a normal sailboat) and when sailing direct to windward this is a force which tends to push the boat back. Rigged in a typical way for a 3 blade design, the lift pushing the boat back is greater than the lift pushing the rotor round.
You may then ask: "If the lift pushing back is greater than the lift pushing around, how then can the boat sail directly windward?" The answer is the gearing, since the windmill blade moves many times faster than the boat, it has a mechanical advantage (leverage) and in this way the "good" lift overcomes the "bad" lift. I ask you spare some time and read the foregoing very carefully.

The second point about inefficiency is that a surfeit of power a higher windspeeds could be an embarrasment and just as a normal sail needs to be reefed in higher winds so inefficiency could be helpful in the same circumstance.

Here is an example from another field which also involves wings (which are the same things as rotor blades).
To prevent excess lift tearing the wings from a sailplane should it reach too faster speed, airbrakes are provided to reduce the efficiency of the wings and these need to be deployed to prevent the aircraft breaking up. This is to illustrate that inefficiency can also be advantageous under some circumstances.

Here is a reason also to use untwisted blades.
One of the limiting factors in determining the efficiency of an aircraft wing is the drag caused by tip vortices. These occur at the tip of a wing, which, if it is at a positive angle of attack are the result of high pressure air taking a "short cut" around the end of the wing. This is why gliders have long thin wings and therefore very small tips.
One way of lessening the effect of tip vortices is to employ "washout" which is a twist in the wing to zero angle of attack at the tip.
By using an untwisted blade for a wind-turbine, the effect is the same ie: the angle of attack becomes less towards the tip, and it therefore is a way of eliminating tip vortices and thus improving efficiency.

P.S. You still didn't make clear what you mean by "drag" - drag of the whole turbine assembly preventing the boat going forward, or drag on the rotor blades preventing them from going round as fast as they could?

 

Hi Tacker, christ I can't even find time to get this dam monohull conversion into the blue let alone experiment with wind driven propeller cats If i could it would be great and to those who have the time and money to do so, fill your boots, I'd do the same.

 

Backyardbil,

'Scuse me, but not only are you not making your questions clear enough, you're not even in the same ball park...uh, like, you're comparing apples to oranges.

Yes, wings on sailplanes are airfoils, as are wings on turbines, BUT they ain't the same thing, in that a wing on a properly designed turbine (for driving a boat) has variable pitch, which a wing on a sailplane does not have, not independent of the ship. In order to vary the pitch on the wing of a sailplane, the pilot must change the attitude of the whole sailplane. In the altogether different case of a turbine driving a boat, there is no need for the brakes you are talking about, IF the turbine has variable pitch wings.

I've tried to explain that you can de-power the turbine by "reefing" if you have variable pitch blades. The blades (sails, wings, airfoils) don't need to be less efficient in their basic structure, rather, that is not at all desirable. They can be temporarily de-powered completely, or partially, by decreasing the angle of attack. On a conventional sailboat in extreme conditions, the analogy would be pinching, or heaving to, but effectively the same as reducing sail area, or, reefing down to nothing. Or, in favorable conditions, simply adjusting the angle of attack, more or less, like, adding or reducing little bits of sail area, to suit the situation.

What's so hard to understand? It's like backing off the throttle on your automobile, or stomping on it. Do you want a less efficient motor in your car, for fear that a more efficient motor might cause you to exceed the speed limit?

I quote some from your last post here below, and my answer is that inefficiency is never helpful and I've never heard of anybody being embarrassed by a surfeit of power until he misused and/or lost it.

[QUOTE...The second point about inefficiency is that a surfeit of power a higher windspeeds could be an embarrasment and just as a normal sail needs to be reefed in higher winds so inefficiency could be helpful in the same circumstance.

Here is an example from another field which also involves wings (which are the same things as rotor blades).
To prevent excess lift tearing the wings from a sailplane should it reach too faster speed, airbrakes are provided to reduce the efficiency of the wings and these need to be deployed to prevent the aircraft breaking up. This is to illustrate that inefficiency can also be advantageous under some circumstances.[/QUOTE]

 

High Tacker

I've now asked the same question twice, and this is the third time. If you can't think of an answer please say so. Maybe you are a politician? (They never answer simple questions directly either).