Dynamic stability

[Bertil]

I want to put a movable wing on my 40-footer as described on "dynamicstabilitysystems.com". I do not know what kind of profile to use on the wing. I know that it should be assymetric perhaps with a camber. It should be working with as little drag as possible between 6 - 18 knots, but at the same time I like it to give me CL over 1.00 and more. The AR (=span/chord) will be appr 4,5 - 6.
Do you any suggestions and reason for your suggestion?

[JesperW]

I would suggest looking up their patent to see what info it provides.
http://www.uspto.gov/index.html

/j

[Bertil]

Sorry but I could not find it there. I have read the european patent, but it does not mention anything about the profile.

You might have more success talking directly to the DSS people to see if you can work out a deal-rather than using their technology without permission.
http://dynamicstabilitysystems.com/#/profile

[Chris Ostlind]

You can use the technology for a personal craft. You just can't manufacture the thing for profit without making arrangements to pay a royalty under license.

One of the biggest reasons for having to post the description and drawings of the patented object is so that other creative individuals can utilize the form as a jumping-off point for potential improvements to the product.

Companies are buying and/or borrowing the patented products of competitors all the time. They take the thing apart, subject it to non-destructive testing, reverse engineer the mechanical, metallurgical and electronic aspects and look to find a better, more efficient method for making their own version.

Go ahead, make your own... just don't sell it or you open a new can of worms.

Best course is to try to work a deal with the patent holder! Below is advice that is identical to that explained to me by my patent attorney:

http://www.research.uwaterloo.ca/ttl...ingapatent.pdf

"There is considerable confusion on the question of whether or not infringement can occur if the
use of a patented technology is personal or non-commercial. The USA and the Canadian Patent Acts do not
sanction such activities and therefore they constitute patent infringement. This would also include the use
of patented technology to conduct research in a university or a corporation. The “urban legend” of
experimental and personal/non-commercial use being excluded as infringement likely derives from the fact
that there are few cases brought to court for this type of infringement. The reason is that it is usually
impractical to pursue such infringement cases since they are difficult to detect and even if detected, the cost
in time and money of pursing legal action would ordinarily far exceed the damages that could be claimed and collected."

[Chris Ostlind]

Oh, and don't speed on your way to your workshop, don't spit on the sidewalk, don't act friendly to married womenfolk... and a whole host of other Dudley Do-Right offenses for which there is only one remedy.... to be consigned to patent purgatory for eternity.

Sheesh...

If this process, as mentioned in the post just above, were ever truly undertaken in global business, it would shut down the works for years. Literally, for years. So, the point is...?

I'd be willing to bet that there were two or three "patent infringements" of the work of others in Doug's last sailing "creation". The folks who hold, or have even specious claims to them, can't be bothered by the one-off builders and the entire tinkerers marketplace of ideas and low-key testing that is going on out there.

If someone does bother to write to you about your adventure on all this, then simply tell them sorry and move along the path.

The big issue for the folks who go to the trouble of filing a patent application is all about manufacturing of said patent outside the loop of control and gain of the holder. Most folks I know who hold patents are rather tickled when someone fiddles with their creation, looking to possibly improve the item. If you stumble onto something cool in your journey, you may even be able to approach the original holder and then everyone wins.

This business of stifling discovery at the tiniest end of the foodchain in this fashion is the result of an overactive paranoia combined with an excess of hours with nothing else to do.

[Cheesy]

Originally Posted by Doug Lord

Best course is to try to work a deal with the patent holder! Below is advice that is identical to that explained to me by my patent attorney:

http://www.research.uwaterloo.ca/ttl...ingapatent.pdf

"There is considerable confusion on the question of whether or not infringement can occur if the
use of a patented technology is personal or non-commercial. The USA and the Canadian Patent Acts do not
sanction such activities and therefore they constitute patent infringement. This would also include the use
of patented technology to conduct research in a university or a corporation. The “urban legend” of
experimental and personal/non-commercial use being excluded as infringement likely derives from the fact
that there are few cases brought to court for this type of infringement. The reason is that it is usually
impractical to pursue such infringement cases since they are difficult to detect and even if detected, the cost
in time and money of pursing legal action would ordinarily far exceed the damages that could be claimed and collected."

In this case I doubt it would matter at all, this concept would fail the 'prior art' requirement so the patent is not really enforceable anyway

[JesperW]

Talking about prior art... (And Bertil, since you're Swedish): Actually this product was propably invented by Arvid Laurin, silver medalist sailing 1936 Olympics, yacht designer of Laurinkostern, Monsunkryssaren etc.

He died 1998, having talked to others about the product...

[Bertil]

Thank you for your answers according the patent. I have by help of Excel made a "program" where I get very good performance mostly with apparent wind between 50-100 degrees, using as I call it a "leeway-ving". I have tried it up to 18 knots when the boat weighing 5400kg has lost almost the entire displacement. I think I made too big a ving, so now I will make it smaller, or put it in a bit in the boat in my calculations. It is my private boat, so I will not make any profit using the idea. Last season I put a bulb on the keel weighing 430kg(deep 3,2) on the keel that is made so you by a hydraulic pump can cant it up backwards.
My excel program tells me that I can get rid of the bulb and my waterballast-system. By the way I am very surprised that there isn't any discussion of this leeway-ving here on the forum, as the idea is so very good! It is much better, cheaper, more simpel and gives better performance then the canting keel. The faster you go with the leeway-ving, the more you get increasing righting moment and decreasing displacement. Perhaps is it the way to outperform multihulls. Still I haven't got any answer on my question.

[fcfc]

Just a side note.

Seems that this wing provides lift that counteract the heeling moment of sail. So far, so good.

But alas, in the real world, a wing that provides lift also provide DRAG.

Would be interesting to study.

[Bertil]

Of course it creates drag. But less than the decreased drag when the boat heels about 5 degrees less, and decreased resistance of friction and wave drag as the boats lifts when the dept is decreasing.

[SevenFeathers]

Please pardon the intrusion of a forum newbie (well, I'm not really new... just new here).

I too am curious about the validity of foil assisted stability, but I keep getting stumped when theory meets practice...

What happens when the boat stops moving forward through the water?

Picture what happens when this lightweight speedster gets into a less-than-ideal situation like heavy seas on the nose or a botched gybe... or even just down-speed maneuvers where boat-speed through the water is minimal... or the extreme case of a survival situation offshore...

... that dynamic stability disappears and unless the boat is carrying enough form or ballast-borne stability it is going to be very, very tender... if not dangerous.

It will go like a bugger, then stop and fall over.

If the vessel is inherently able to handle these situations, then I think the stabilizing foil might be mostly redundant, no?

7F

[bistros]

Originally Posted by SevenFeathers

I too am curious about the validity of foil assisted stability, but I keep getting stumped when theory meets practice...

What happens when the boat stops moving forward through the water?

It will go like a bugger, then stop and fall over.

You have committed the gross error of allowing theory to meet practice. As long as you keep the two separated adequately, you can theoretically do anything!

This forum has distinction of providing a soapbox for one of the world's theoretical leaders in foiling technology, and he seems quite able to keep theory pontification and personal practice from colliding.

[Bertil]

I propose you look at the internet: "dynamicstabilitysystems.com" and read what they say. Off course you need to have a keel with weight giving enough stability to meet the requirements for a safe boat. It is the added kilos for performance you can switch out by using the leeway-wing.