Oh Lordy (Doug)

Jon, if you want more ammo against helicopters.....
The military up here decided some 40-odd years ago that maybe we should put some choppers on our boats. Enter the Sea King. In recent years it has definitely earned the name Sea King.
http://findarticles.com/p/articles/mi_hb3542/is_200303/ai_n8357853 for one story on them.... http://www.cbc.ca/news/background/cdnmilitary/seaking.html ..... Google will turn up plenty more.
Maintenance to active time is now at over 30 man-hours of repair for every hour of airtime on these things.

 

CT249, you often use a pair of debate tactics which would get you thrown off any junior high school debate team. Extrapolate to the ridiculous and reduce to the ridiculous. If I "insult" your intelligence, I have insulted every designer, sailor and boat owner who ever lived (the first) and if you can find widespread counter examples--even if flawed--you have conclusively "proven" your point (the second). You may be unaware you are using these devices, but I rather doubt it.

Doing so makes it tiresome to correspond with you, though I often take your point and would love to continue the conversation (I renew my offer to buy the first round of beers, whenever we share a continent next). If you'd take a bit more effort to address the issue and less time trying to "score" points and win arguments, I for one would enjoy the experience more. (Comments such as "I take your point, however..." are often especially appreciated) You have infinite permission to say anything you like, of course, just like any other poster. I don't offer the above as a command, only a suggestion. (And yeah, I know I'm gonna get slammed by Water Addict and others for saying this, but it doesn't make it any less valid, IMO)

As to Jim Drake's position; he has told me that he didn't know about earlier windsurf-like devices, too, and I believe him. Jim is a very nice man. It has also been determined that he had access to both Popular Science and to AYRS magazines prior to his invention, both of which ran feature articles on the earlier devices. It is not unusual to read about something, honestly forget entirely, then later use the pool of "general knowledge" resident in all of us to re-create the earlier thing, unintentionally.

All inventors understand this. There is also another concept--that multiple people working on an identical challenge will devise similar solutions, and yet a third which says that the simple knowledge that a thing has been done--with no details of any sort--is sometimes sufficient to "spark" a similar--even identical solution. Last, it matters not one whit whether Jim stole the idea outright or honestly invented the thing from dot zed. It was ruled to be in the public domain, thus not susceptible to patent protection.

As you (sort of) mention, it is perfectly legal to patent an improvement to an earlier device--patented or not--and claim patent protection for those improvements. Jim's mistake, almost certainly unintentional, was not to do this. You can be sure he regrets it.

Last, regardless of your thoughts and opinions--which I respect--the patent was negated due specifically to the earlier Darby and other devices. Call if unfair if you like, but we are nations of laws not popular opinion; the same law which protects one valid patent holder's rights takes those rights away from another. Both positions are a crapshoot in court, absolutely, but them's the rules we play by. It's no use wingeing about it; play or don't play, the choice is always the players.'

Dave

 

I really have to disagree with you big time there. I should really wait a week before posting it, because I have some info promised on the HSP project, but never mind. But assuming that what's in the book is what actually happened then that surely cannot be the case.

When Bethwaite started the HSP project he had, as far as I can tell, no contact with the skiff people at all. His background was from NZ and in straightforward low power dinghies. I'm not sure that he got involved with the skiffs much until at least the late 1970s or early 80s when Julian, his younger son got involved with them. Julian's elder brother and sister (FD, Laser, 470, Yngling etc at championship and Olympic level) don't seem ever to have had any involvement in skiffs.

Then we have to consider the sheer scale of what he did. Twenty two prototypes starting with asymettric proas with inclined rigs, and not getting onto the planing main hull/tip floats semi trimaran format until about the 15th. Its got to be one of the most sustained efforts in something different in sailboat design, there's no way it was just an attempt to prove the superiority of skiffs, especially as the end product is in no way a skiff relation anyway. The skiffs have quite different dynamics. Now to spend that much effort to prove the superiority of something you weren't involved with in the first place sounds monumentally crazy to me, and he's not that... And incidentally doesn't that make him one of the few people to have made a planing multihull work. Bethwaite may not like calling the HSP a multihull, but it is in my book.

Now I'll agree with you that he never evaluated true catamarans properly, nor ever seems to have sought to do so. The project started with evaluating the Bernard Smith concept, and he ended up considering that the concept doesn't really work in practice. In front of me I have a photocopy of an article from David Pelly on Speed Week in 1988 and I quote "Some day someone will succeed in making a sloping rig boat work" and then goes on to catalogue a collection of failures by sloping rig boats that year...

I think if it can be made to work it will only work in the speed week context of get the perfect gust and ride it, like, say, Sailrocket, and 500m speed records, rightly or wrongly, is something Bethwaite never seems to have been interested in.

 

Hsp

Jim, Bethwaite did describe the HSP as a trimaran
and ,of course, it was a very fast planing multihull. When you get more please post it!
Of course, if the "ama's" hadn't been shaped like hulls maybe it could have been a monohull with buoyancy pods?!
(p185 of THE BOOK)

 

Got the degree? Yep. Got the post-grad qualifications? Yep. Admitted? Yep. Working? Yep. Layman? Nope.

Yep, being good when you're up on your back legs in court is a help, but it's not as good as having the law and facts right.

 

Kiteship, I appreciate your points. This is an internet chat room, I don't spend a lot of time honing arguments. I do get careless in here, I have said that quite a few times. I do get rather hot-headed when people seem to intimate that most sailors or designers, and the best sailors and designers, are overly conservative or get it so wrong so often. I have never seen any evidence of this. I do feel that excessive criticism of successful current boats is damaging to the sailing scene, which IMHO needs other much more important changes if the health of the sport is to revive. This does affect my arguments at times. Some of my counter examples may be flawed, but I think that you just throw many of them into the "flawed" pile because they refute the case you are trying to present.

Having said that, I think you may also have some imperfections in your own arguing style too. Saying that because modern planes (300-2000? knots) are enclosed, 30 knot yachts should be enclosed sounds to me a lot like using ridiculous examples. You are also ready to impute motivation for Bethwaite's long-term project with absolutely no evidence. Frank loves the HSP, and I think his new boat is a multi. You stated that Drake "copped the original idea from another inventor" when there is absolutely no evidence that he did; just your assumption that he read about the earlier inventions in publications he had access to, and then forgot about it. That seems to be two leaps of logic that would see your high school debating teacher wagging his finger at you, too.

I find it a bit tiresome (albiet interesting at times) to chat with you, because in the past, you have shown a tendency to ignore facts disproving your case. Case in point, an old SA thread where I pointed out that most people sail old boats and your reply included the line "Sure, there is a burgeoning Star class, with new-ish boats coming online all the time, but do those new-boat numbers more or less equal new 49ers hitting the water, at about the same cost? If not, your argument seems to fail."

I then gave ISAF figures that showed that the Star numbers DID more or less equal new 49ers hitting the water. Therefore, my argument did not fail. And did you say "I take your point, however".....? No, you then said that you would "find some useless statistics to beat you about the head and shoulders with."

You proposed numbers as a test, then referred to those same numbers as "useless statistics" when they were shown to hurt your case. How would that go down in school debating?

I'm not whinging about the fact that the Windsurfer patent went down. I said Drake invented the windsurfer. Common language does not have to reflect the results of legal decisions. Everyone in the legal field knows that the lawyers sometimes get it wrong, especially when (as can be argued with the Windsurfer case) the legal advice involved may be bad. We get lots of engineers etc saying the lawyers get it wrong, why can't we say the lawyers got it wrong when it was decided that Schweitzer and Drake didn't invent the windsurfer?

 

I know of at least 3 people, Kiteship, that you have insulted on here, myself being one of them. And I can surmise from numerous other posts on this site that you have insulted more. Gotta wonder when everyone else is wrong and you are the only one who seems to get it.

Then again maybe not. Perhaps you are on the level of other revolutionary thinkers, and it is just my ignorance preventing me from overlooking your enlightened communication style.

 

Looks like Sailrocket has stolen a march on Monfoil. http://www.yachtsandyachting.com/news/?article=135526
Monofoil seems in many ways the better design, but is further from reality at present.

 

"Looks like Sailrocket has stolen a march on Monfoil. http://www.yachtsandyachting.com/news/?article=135526
Monofoil seems in many ways the better design, but is further from reality at present.
12-11-2006 12:42 PM"

Good luck to them, they are nice people and they have worked very hard for it.

Jon.

 

that's awesome that sailrocket found the money to go there.
i guess they have done their homework, but i always thought the winds down there are best in spring and summer...

i'm sure we'll see rapid improvements from sailrocket in the next few months.
but they've got a loooong way to go in regards to prove that their boat is up to record speeds. by the time they are getting there the bar might be raised to a whole new level with the european windsurf and kitespeed season coming up.

jon,
how far is your project off for hitting the water?
i would be very keen to see your craft in action. there are still a few things about your concept that i can't quite get my head around... like steering it properly with a single foil in the water.

all good stuff and like a thriller to watch and follow.
boogie

 

A real bad week for Sailrocket. The boat was totally uncontrollable by the sound of it and is now in several pieces. Whilst I know very little about either project, it is these control issues that Monofoil seem to have considered in greater detail.

Good luck to all trying to break 50kts. There seems to be a real race on to break this barrier, and its exciting to watch.

 

Some thoughts on this, without any guarantee of being correct!

Monofoil has two key features that are relevant here:

1: A free feathering, mass balanced rig

2: Stable about a single point of water contact in all three axes

1: The rig. If the rig has a sheeting angle constrained with respect to the foil incidence the boat has one stable course. If the boat is off course, then due to the large separation of foil and rig, big forces are needed to force the boat to remain on course. This was anticipated and then tested on monofoil model four by fixing the rig incidence (jamming the rig pitch pivot). The boat could be entirely steered by sheeting angle. A free feathering rig is just a force producer and it always (if mass balanced) stays in its low drag zone.

2: I have always been nervous about boats that sail fast and rely on two points of lateral resistance. Big yaw couples can build rapidly if yaw balance is not achieved by aerodynamic balance and Monofoil only sets the single foil yaw angle relative to the rig position (the fuselage is slaved to the foil angle, ie, points the same way). Monofoil does not have a rudder, either air or water, it has a servo tab at the back of the fuselage to provide aerodynamic force to change the cross-boom angle and hence the foil to rig angle. Control forces are therefore very low (relatively) and rudder loading is not an issue as it does not have one.

At a first look (1) looks like a strong culprit with a bit of (2) as well in that a second, highly loaded, surface is required for course keeping.

Could all be rubbish of course as we have not run Monofoil at full scale yet and cannot until we get some money from somewhere. I hope they fix it, find the problem and move on.

Jon.

 

Jon; can you reveal any details about the superventilating foil? I would be very interested in the shape, and how well it transitions from low speed to full ventilating operation. What sort of L/D are you seeing, or expecting?
Matt

 

Superventilating foil

I will try to post an image of the section and its coordinates, not now, it is too late at night!

It is actually quite simple. The pressure face does all the work, the "suction" face has a zero pressure coefficient, ie, it is a bubble surface. Aft of the trailing edge the pressure coefficient of the pressure face is also zero, ie, another bubble face. As the "suction" face does no work it can be cut off at any point woth no impact on the foil at design lift (CL=0.2), this gives a lot of freedom in terms of section structural properties since, if it is in the bubble, it does not damage performance.

This section only applies to the tip of the foil, the rest is out of the water at high speed and so the low speed bit can be a little more conventional as it is only in the water when it needs to be.

The 2D section L/D is 22. What this turns into when 3D is arguable for various reasons but I have estimated 12 for the geometry that I am using... time will tell although the models seem to support this.

Jon.

 

Ventilated foil section

I have attached three files. The first, "Basic Foil", is simply the output of my 2D design programme, this gives the pressure face and the zero pressure, bubble surface which continues into the wake, there is a pressure face bubble surface with a zero pressure differential also continuing from the trailing edge aft, this is not shown as it is a very boring, slowly curving line disappearing off to infinity! In reality it will close back in again but hydrostatic pressure, which drives this, is so low compared to dynamic pressure that it was not included in the calculation so the wake in this calculation shows a diverging bubble.

The second, "Practical foil", shows the trailing edge cut-off on the upper surface via a sharp chine. This would seem to be destructive of low speed performance, however, the amount of foil with this section is tiny (0.6 sq feet) and the foil above this has much greater area for low speed and acceleration, this low speed foil is lifted out of the water as the speed builds via a secondary planing surface just above the high speed section. The pitch control on the boat is used to trim the running angle of this planing surface.

The third file gives the coordinates of the practical version of the foil if anyone wants to play with it. Design lift coefficient is 0.2. The datum incidence as plotted gives this CL in 2D flow, obviously the 3D case suffers from downwash but this angular correction can be found by the usual, well known means from wing theory.

Jon.