Moth on Foils: 35.9 knots(41.29 mph)

[Doug Lord]

Moth on Foils!

Frankly, your comments are way off base-you use "ventilation" to explain why the boat dives after the wand springs forward. You're flat wrong.
The videos prove my point- thats not ventilation(!) or is it just coincidental that the flap goes max up before every dive or crash?! Watching the video (and there are many more that illustrate my point) every single time the wand springs forward the boat begins to dive-sometimes more quickly that others depending on the set up and some times the wand catches the boat before a dive but many times after the wand springs forward there is a crash. Many times.....
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No I wasn't talking about the trifoiler-it doesn't use wands! I was talking about the Rave, Skat and Osprey all of which use midship wands very successfully. And the guys with the Rave pioneered manual flight control eliminating wands and proving that manual control is faster(and possible!).
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So you're saying that manual control of the Moth won't work because it hasn't been done before?! Really?

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By the way: welcome to the forum!

 

[OzFred]

Frankly, your comments are way off base-you use "ventilation" to explain why the boat dives after the wand springs forward. You're flat wrong.

That, coming from someone who has never sailed a Moth and has probably never seen one in the flesh actually sailing in such conditions is laughable.

The videos prove my point- thats not ventilation(!) or is it just coincidental that the flap goes max up before every dive or crash?!

Absolutely it's coincidental. If your theory was correct, the moment the wand goes fully forward the boat should crash. But it doesn't, it crashes when the foil reaches the surface. I'm talking from experience, real actual sailing over many years. You will not find one single Mothie to support your position. Not one.

Watching the video (and there are many more that illustrate my point) every single time the wand springs forward the boat begins to dive-sometimes more quickly that others depending on the set up and some times the wand catches the boat before a dive but many times after the wand springs forward there is a crash. Many times.....

Yep, many times it doesn't nose dive yet the wand is fully forward. Your theory is disproved by your own words. The wand is always fully forward (in the videos) when it crashes because it has lost contact with water. The flap has been fully up for quite some time, yet it's not until the foil ventilates that the crash occurs.

In the first video, there is a momentary ventilation but the boat is going slightly to windward so manages to not crash immediately.



[…]

So you're saying that manual control of the Moth won't work because it hasn't been done before?! Really?

No. I'm saying someone probably did try it, but it's physically impossibility to manually control the flap while also trimming the main, steering and hiking. It's quite difficult to adjust any thing other than main and tiller while sailing, continuos control of the flap is simply impractical.

Tell you what, go over to Sailing Anarchy and ask Phil S if what you're saying is realistic. You'll be able to hear the groans from where you're sitting.

 

[Doug Lord]

Moth on Foils!

No. I'm saying someone probably did try it, but it's physically impossibility to manually control the flap while also trimming the main, steering and hiking. It's quite difficult to adjust any thing other than main and tiller while sailing, continuos control of the flap is simply impractical.

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You're right and you're wrong: I tried it on a bi-foil monofoiler I designed and built-and it worked.

 

[OzFred]

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You're right and you're wrong: I tried it on a bi-foil monofoiler I designed and built-and it worked.

I didn't say it doesn't work, I said it's physically impossible to operate on a Moth for more than a few moments. How is it operated: a rope to pull? Handle to twist? Lever to push?

Which hand or foot operates the control? If it's a foot control, how do I use it while tacking and gybing? If it's a tiller twist control, how does that fit with the existing rudder twist control? And while tacking and gybing, it's impossible to twist the tiller while swinging it round the end of the boom as the angle between the extension and tiller is too great for the connection to cope with adjustment (typically it's a short length of high pressure hose for flexibility with good torque strength).

So you're left with a rope to pull (presumably with a spring return so it only needs to be pulled). Which hand operates this rope? And suppose I decide to adjust the vang, I'm now holding mainsheet, tiller and flap adjuster in one hand while I adjust the vang with the other. And while tacking and gybing, I have to swing the tiller, throw the main over and keep positive adjustment of the flap, all while crossing the boat, keeping it level and getting to the other wing. And at some point I have to swap controls between hands (the tiller hand is now behind my back).

When you've designed this control, please publish pictures, drawings, whatever. If it has any chance of being more effective than a wand, someone will try it. And if it is more effective, within a few months all the top Moths will have it. You'll be a hero in the Mothisphere, a legend in the making.

But I'm not holding my breath.

 

[Doug Lord]

aeroSKIFF

On my boat it was a kinked end to an extension tiller that was twisted. When it was twisted it moved a push-pull cable that moved a rocker arm that moved the flap. Max movement was 20 degrees up flap, 30 degrees down flap. The AOI of the main foil was +2.5 degrees relative to the static waterline. The rudder foil was rarely adjusted but there was a twist knob on the end of the tiller so its AOI could be adjusted. It's nominal position was zero degrees relative to the static waterline which was parallel to the flight waterline.
Both adjustments stayed where they were left. Constant adjustment of the main foil was not required. You could gybe easily and almost tack on foils.
Both foils were retractable and the boat was trailered with the foils in place.
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I'm confident that someone with the right skills could make this work on a Moth and I imagine someone will.

 

[OzFred]

Your foils aren't remotely similar to those on a Moth (the main foil probably has 4 or 5 times the surface area, the rudder maybe 10 times). The main foil flap is tiny in comparison to the size of the foil, performance of the boat would have been woeful in comparison.

Moths replaced cable connections to the flap with linkages years ago as they have too much friction and imprecise movement. A twist and cable control to a Moth main foil would not be able to be adjusted quickly enough, especially when your hands are already preoccupied with steering and sheeting.

I've already told you it would not be possible to adjust a tiller twist mechanism during tacks and gybes, and it certainly will require constant adjustment. Where does the rudder twist control go? There is an alternative pulley and lever system, but no one uses it (even some guys who persisted with it for years have gone to tiller twist) because it's inferior to a twist system for the rudder. Also, some have high pitch rudder adjustment and use it to control the boat in waves, so they are already actively using a twist control (I don't use one as it creates other problems that I don't want to deal with). I can't see them putting two twist mechanisms on the one tiller extension.

Some English Mothies thought they didn't need a rudder adjustment, but then they tried sailing in waves and pretty soon discovered it's essential, so you won't get rid of it.

So I'll assume that you've accepted that ventilation crashes aren't caused by the flap coming up, and maybe even that the flap doesn't create down force. At least you've moved forward in that regard.

 

[Doug Lord]

Moth On Foils!

You're assumptions are dead wrong.

 

[CT249]

Doug, you wrote (on 12-2-2010 at 6:21pm) that the 16 "didn't meet my expectations as a foiler. The times it did foil were fairly hairy experiences..... The altitude control system was a manual system that didn't work too well."

You also wrote "I finally got the thing to foil-very poorly" and in another post you said "It flew three times-but not well".

How come you now say "the manual foil system worked well"? That is in contradiction to your earlier statements when you said the manual control "didn't work too well" and that the whole boat foiled "very poorly".

 

[Doug Lord]

They're both correct. Initially, the system worked well but then a component bent making it much more difficult. But when it was working well, it was a blast and proved to me the viability of a manual system. There is no question, as far as I'm concerned, that a manual system could be developed for the Moth that, after a lot of practice, could be a winner.
The expectations that weren't met had ,primarily, to do with the hull design which was poor for the short steep chop in the intercoastal and resulted in a later takeoff than would have been possible with a different bow.
I still have access to the hull after the sailing school didn't use it. My sailmaker is storing it.....


PS- thats enough about my boat in this thread-if you have any further questions post them in the aeroSKIFF 16 thread.

http://www.boatdesign.net/forums/sailboats/aeroskiff-16-a-35741.html

 

[OzFred]

You're assumptions are dead wrong.

So despite clear evidence that:

1. The flap coming fully up doesn't cause a crash, and
2. Ventilation does

you refuse to believe it. Your continued denial is absurd, you can't produce evidence to support your claims nor get anyone who actually sails a Moth to concur.

Here's what a twice world Moth champion has to say about manual flap controls on a Moth: "NO WAY".

But what would he know?

PS. Bora's first Moth World Championship was a couple of months later in 2009 and the second in 2013, so I suppose when he said that he was still a wannabe. But not now, so perhaps you can ask him to repudiate his comments?

 

[Doug Lord]

Moth on Foils! / Manual Main Foil Control

The problem is that this requires a major engineering and build challenge as well as a monumental commitment of time to learn to use the system at a top level.
It may be a month, it may be 20 years but I'd bet somebody, who realizes the enormous potential gains, will give it a go sooner or later. The result would be the fastest Moth, period.

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optional considerations:
1) variable mixing between the rudder foil and main foil

 

[OzFred]

The problem is that this requires a major engineering and build challenge…

No it doesn't. As a prototype, it could be done in a weekend by any reasonably competent handy man (you'd be amazed at the stuff done overnight at regattas)

… as well as a monumental commitment of time to learn to use the system at a top level.

Ah, now there's the rub. There's no doubt a human can outwit a simple mechanical device if that's all they have to do. However, whether it's possible when the aforementioned human is also single–handedly grappling with all the other mental and physical challenges of sailing a small foiler is in serious doubt. Even the very best (as quoted previously) don't think they can do it and feel their energies and attention are better directed elsewhere.

It may be a month, it may be 20 years but I'd bet somebody, who realizes the enormous potential gains, will give it a go sooner or later. The result would be the fastest Moth, period.

The AC-72s had manual control, it's certain that they'd have had automated controls if they were allowed. The system would be very tunable (just like a Moth's), but the continuous control would be automated.

optional considerations:
1) variable mixing between the rudder foil and main foil

As if it wasn't already complex enough. Why not go the whole hog and link it to sail trim and rig settings as well?

 

[Doug Lord]

Moth on Foils! / Manual Main Foil Control

Once somebody does this the whole Moth game will change-without a doubt.
And a significant jump in speed and a massive jump in ease of handling will convert even the most unimaginative of Moth sailors.

 

[OzFred]

Once somebody does this the whole Moth game will change-without a doubt.

No it won't, as your idea will not be implemented by anyone of any consequence.

And a significant jump in speed and a massive jump in ease of handling will convert even the most unimaginative of Moth sailors.

I find it difficult to reconcile "ease of handling" with your previous:

The problem is that this requires … a monumental commitment of time to learn to use the system at a top level.

Your revisionist memory seems to have slipped into overdrive.

 

[Doug Lord]

Your revisionist memory seems to have slipped into overdrive.

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Riiight........