Moth on Foils: 31.1 knots (35.8 mph)

[boogie]

this looks like an air rudder...

and it has a solid wing sail too...

more info on Sailrocket

Originally Posted by Jon Howes

Stephen,

Thanks for the links, interesting reading, especially the Dynaplane link.

This thought is strongly related to a characteristic of my "other" project. That two foils, if expected to provide the ability to generate sideforce to keep a boat under control, will, sooner or later, find a situation where one of them cannot do this (waves for example) and the boat may wipe out. Air is a much more reliable medium so both this suggestion and my main project try to use only one hydrodynamic surface to resist the rig loads and do everything else aerodynamically.

The Moth rules state: "The boat shall carry only one sail when racing, with the total sail area being not greater than 8.00 m2." so it can't be a Moth, just have to call it something else. A Bug?

Jon.

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Jon, welcome to this thread! Your contributions are just great-thanks.
If you haven't already check out Rob Denney's thread: " What would you do with 430 sq.ft.?" paticularly his last post where he provides a link to technical details of his 50' 1200lb proa. Incredibly,the boat is self-righting and uses only one "in the water" foil.. It's the only simple self-righting multihull design I've ever seen and the single foil is very intriguing.

[Jon Howes]

DG:

"Would the less dense of the two fluids offer up a greater amount of control for the drag it produces? Would an aircraft style rudder begin to become innefficient at typical angles of heel quicker than one in the water. Would you need to have two smaller air rudders angled outward to have the same control.
What about the difference in the angle of attack that an in the water rudder is seeing compared to that the air one would see? Isn't the quality of the flow around an in the water rudder going to be considerably better for many reasons?"

The Monofoil analysis showed that low water speeds were a problem for the single foil on that machine in that it could not get sufficient bite at low speeds to get going, this was the reason that the foil has an extreme taper with a surface running horizontal surface near the tip, the tip below that surface is then the high speed only foil. The wing on the other hand is pretty active from the start as the wind speed is much higher than the water speed when at rest and so almost everything can be controlled aerodynamically from the outset. This is why the foil needs to be bigger than 1/800 of the wing area unless something devious is done as on Monofoil.

The air rudder (or mizzen) should remain effective regardless of heel angle as it is balancing the mainsail. Note that the water rudder does not exist in this picture and turn the boat on its side, it now looks exactly like an aircraft where the centreboard load replaces gravity (ie, it is equivalent to an aircraft CG position), the mainsail replaces the wing and the mizzen replaces the horizontal stabiliser. Aircraft still work even when steeply rolled in an uncoordinated turn or "knife edge" manoeuvre so the boat probably could as well.

Quality of flow around a water rudder is always affected by the air-water interface, an air rudder does not have this problem and should behave consistently.

Could all be b*ll*cks of course but it was a nice diversion.

Jon.

18 knots in 8-9 knots of wind is still pretty damn fast. Rohan on the new Bladerider...
See: www.rohanveal.com

[boogie]

give it up doug!!! i don't think you are doing the foiler moths any favours this way.

if pure speed would be the only attraction we'd all be windsurfing....
18kn in 8-9knots of wind? been there, done that, on a formula board.

btw, bjorn dunkerbeck has just recently set a new nautical mile record. 41.14knots
and the nautical mile on production gear anyone can buy in a shop is at 40.33knots now. set by south african hennie bredenkamp.

take care
boogie

[CT 249]

Also from Rohan's site;

"I get asked the question all the time at boat shows about what is the ideal weight range for a foiler Moth, and only by me talking to them, most +80kg seemed guys believe that they won't be competitive, so don't even consider the boats. I always say that anyone up to 100kg can sail the boat, but you need more wind to fly the heavier you are, and it is only then they give it a go and realise it is possible."

There you go, Doug. You CAN sail a foiler Moth! Why not get one and sail in the revolution yourself?

Give it up? Surely you jest-this isn't about windsurfers-this is about bi-foil monofoiler's! And for a "sit down" sailing dinghy this is bloody fast given the conditions.
Boogie, check back when the 7 year old bi-foil technology is as mature as the 36+ year old windsurfing technology!
Bi-foil technology has the potential to be applied to a far greater range of boat sizes and "styles" than windsurfer technology ever will and there is no telling what the future will bring in that regard. But ,please, keep up the rig development-you've been a big help so far.
And if you ever get tired of standing or the noise of a fast windsurfer, I'm sure you could do well on a Moth!
Speed under sail is fantastic anyway you look at it-give credit where credit is due and don't
knock this fantastic revolution in sailing just because it hasn't caught up --yet.
------------------
Gee, thanks CT. Unfortunately, I weigh a bit more than that now. And despite the fact that Rohan said it I don't believe that a 220lb person could EVER be competitive in the Moth class -at least with the current rig. Maybe another monofoiler,huh?

[boogie]

a foiler moth is as much a "sit down" dinghy as a windsurfer is a yacht....

ok. for my next comparisons i'm going to use kitesurfers. their sport is about 7-8 years old, if that makes it any fairer to you....


gosh doug you are sooo easy to wind up

take it easy
boogie

You don't like "sit down"?
DSC01975.jpg
Address:http://www.rohanveal.com/photos/hamburg/DSC01975.jpg Changed:1:04 PM on Tuesday, October 31, 2006
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Boogie, just out of curiosity: have you sailed a Moth or non windsurfer foiler?

[CT 249]

"And despite te fact that Rohan said it I don't believe that a 220lb person could EVER be competitive in the Moth class -at least with the current rig."

Okay, I just had this strange idea that the former world champ may know about what is required to be competitive.


By the way, even old windsurfer technology can be fast; the only time I know that a Windsurfer One Design (the original 1960s 21kg hull, with a different centreboard and newer but still soft 6m sail) had a GPS run, it hit 25.4 knots in bad conditions. God knows what an IMCO (late '80s raceboard) or Mistral Pan Am 1 (1984 design) or a '70s or '80s speed board could do, but they would be much, much faster than the One Design.

Of course, in foiling conditions none of the above can keep up with a foiler Moth around the course. Dem things is quick!

Phil Stevensen weighs 180-if I remember correctly and he has said that's too heavy for competition. I'll go read all of what Rohan said but I'm fairly certain he was talking about people who could SAIL the boat not race competitively. At 220 you would take off significantly later than 140-160 pounders that- as best as I can tell- dominate the class.
There was a great picture of Mark Robinson sailing a foiler with what looked like a 60-80 lb. kid on board so it can be sailed heavy. And it can be sailed fast heavy too: if I remember correctly(again) one of the UK guys is fairly heavy but has done real well with speed trials where low speed takeoff is not a factor.
The sensitivity of a foiler to weight at low windspeed takeoff is one reason a Peoples Foiler should be designed with a wide range of crew weight but a fixed sailing weight so that every boat weighs the same in racing. A viable weight equalization system is more important in that case that in just about any other application I've heard it being used in.
If the Bladerider does offer the 9m² sail then that will help big guys as well and might even spawn a heavyweight division? I understand thats on hold for now, though.

What Rohan Veal REALLY says about weight:

CT 249's original post:

Originally Posted by CT 249

Also from Rohan's site;

"I get asked the question all the time at boat shows about what is the ideal weight range for a foiler Moth, and only by me talking to them, most +80kg seemed guys believe that they won't be competitive, so don't even consider the boats. I always say that anyone up to 100kg can sail the boat, but you need more wind to fly the heavier you are, and it is only then they give it a go and realise it is possible."

There you go, Doug. You CAN sail a foiler Moth! Why not get one and sail in the revolution yourself?

-----------------------------
You neglected to mention what else Rohan said-and I can't imagine how your mind works to try to twist Rohan's and my comments this way. Why??
This is the balance of the paragraph that CT failed to quote( Friday,10 November 2006):
"...and realise it is possible. However, the reality is that not all will be sold into the class as they know they will not be competitive in light airs."
Further comments by Rohan under the same date:
"the weight range will become more and more specific(and probably lighter as well), therefore
creating a barrier to entry for newcomers especially +75kg(+165lb.dl)guys (which just happens to be average the weight of sailors from developed countries). This is a problem for the Moth Class as it will always have a limit on growth."
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I'm just curious ,CT: why did you feel the need to both misrepresent me and Rohan Veal? Did you think I wouldn't check? I can't fathom what you think you gained by this.....

[CT 249]

Gee, Doug, you don't think that perhaps I had second thoughts and therefore edited my post, do you? I was actually trying to be polite; I shan't bother in the future.

I did not misquote Rohan. I quoted Rohan saying that a heavy sailor could sail a Moth. I wrote "there you go, Doug. You CAN sail a foiler Moth! Why not get one and sail in the revolution yourself?"

YOU suddenly decided that I was talking about being competitive. You are the one who changed the subject from what could be sailed, to what was competitive.

I did not misquote anyone - you decided to interpret "sail" as "competitive" for reasons only you know.

Anyway, even if a 180lb+ a sailor may not be "competitive" in a strong Moth fleet, why should it stop you getting a Moth? Exactly why does being competitive in a foiler Moth fleet worry you, when there's no foiler Moth fleet for many thousands of miles from where you are?

If the lure of foiling is so strong for you, why not just get a Moth and sail it anyway? Even a heavy sailor on a Moth foiler will do really, really well in strong winds, especially given the amazingly slow Portsmouth rating the Moth gets in the USA. Why not get a Moth foiler and win every breezy Open race in SE USA?

[foilr]

Give the guy a break. There's few people on the planet who are going to be competitive. Doug is not one of them and he's willing to admit it.

It is a shame he (and others) don't give it a go. Just to be part of the revolution and all.

a foiler moth is as much a "sit down" dinghy as a windsurfer is a yacht

That's a pretty accurate observation from boogie.

Doug, how was the Annapolis boat show?

Terrific, I hear.....