Moth on Foils: 35.9 knots(41.29 mph)

No. None.

 

Moth on Foils

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Tom, both the Bladerider and Prowlers use rudder foil flap adjustment(Prowler) or an adjustment thru moving the whole rudder/foil assembly(Bladerider). I've read comments from Moth foilers that some frequently use the adjustment and from others that they hardly ever do. On the Rave multifoiler you could special order rudder flap adjustment from a lever in the cockpit.On the F³ rc models the boat was initially supplied with servo control of the rudder flap but it proved completely unnecesary.
On my new boat I'm going to spend a lot of initial time experimenting with manual control of just the mainfoil flap and of the mainfoil flap and rudder flap simultaneously.
I still see potential advantages to using manual main foil flap adjustment-perhaps tied in to the rudder foil flap at some particular ratio- in the Moth class. And from my limited experience using manual mainfoil flap control(with separately adjustable rudder foil flap) on a bigger boat I'd say the advantages would be substantial in heavy conditions where I've read that the Moth wand has some trouble particularly downwind in big waves.
But it would take committment and some time to fully develop a good manual system in that class....
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From the Fastacraft site today:

"The current hydrofoil configuration we build for the International Moth is an inverted "T" style on each of the rudder and centreboard. The rudder foil has a trailing edge flap controlled by twisting the single tiller extension to operate a nylon worm type adjusting screw."
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Bladerider X8 as of today:
"The entire rudder assembly can be rotated by the tiller twist grip to manually adjust the angle of attack. Manual lift control on rudder hydrofoil by tiller twist grip. All control mechanisms are stainless steel and therefore will resist any force."
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OUESTION FOR ANYONE WHO HAS SAILED EITHER ONE OF THESE SETUPS :
With a single extension tiller ,it would seem that the direction to adjust the rudder flap would reverse with each tack or gybe; is it hard to keep track of which direction to rotate the twist grip for flap UP or DOWN ? Or is it easy to just remember clockwise or counter clockwise?

 

Yes there have. In 2005 we added a maximum length for bow and stern outriggers of 500mm. There were other clarifications without changing any parameters.

 

We all have a note on the boom to show which way is bow up and which is bow down. This is particularly important when changing boats because the Prowler and Bladerider systems work in opposite directions.

 

What about evolving the sailor?

Doug, some of the variables in flap trim angles, both front and rear that you suggest might be overidden by a skipper working with manual twistgrips or similar in heavy winds could be tackled differently. Talk with the medical genetic specialists to find out the possibility of evolving a human sailor with two brains and a third arm.
I am being very serious about this suggestion, as I cannot see even a sailor of higher calibre than Rohan Veal managing a 12 inch max. beam boat with this much input and biomechanical function required, to control foil attitudes and keep the Moth sailing at max speed under racing conditions, without going for a big swim.
Doug, I realize that you are tryng to push the performance envelope a little beyond what is currently achievable, but come on, often you expect the near Impossible!

 

Moth on Foils

Frosh, didn't you read the previous posts? Moth foilers are ALREADY EQUIPPED WITH A TWIST GRIP HIKING STIK ! Granted my suggestion would increase the importance of the twist grip which as best as I can tell now is used infrequently by many foilers. But since it is already there it's not like introducing something completely foreign
to the crew-a new skill to go along with a new function for the twist grip-yes. Something even remotely impossible-hell no. Only a little difficult to learn.
Potential gain: less drag,less weight= slightly more speed.

 

The rudder twist grip is used as a gear change not as a real time height controller.
Response time between eyes, brain, wrist, and foil are too slow to react to pot holes in the water surface.

 

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In my posts I mentioned modifying the rudder twist grip as to function-I didn't mean to imply(and don't think I did) that it could be used- as is- in place of a wand unless it was hooked up to the flap on the main foil. Again, it would have to be hooked up to the flap on the main foil for the manual system I'm describing.
According to the people who have actually done it(including me) the response time is not outside what a person is capable of. Of course, those results were on a Rave(where the system controlled Altitude,Righting Moment and Pitch Attitude-one more function than required on a Moth),an I14 foiler and a 16' monofoiler and do not predict whether or not a manual system would be faster than a wand. But there is little doubt that the boat could be flown manually based on the real world experience with other foilers.
Would manual control result in a speed gain in the Moth class? Impossible to say for sure at this point- but just maybe.
============edit 6/7/07===================
Manual Control Summary
1) at least two Rave 16' multifoilers where a joystik allowed altitude,pitch and RM to be controlled manually.
2)16' bi-foil monofoiler: manual control of the mainfoil flap/21 foot bi-foiler under development: manual control of main foil and rudder foil simultaneously or separately/interchangeable with wand system.
3) David Luggs I14-first two person bi-foiler to sail: manual control of rudder flap only(small main foil largeer rudder foil)
4)John Slatebo's Slatts 22 and 16: proa's utilizing manual control of righting moment with single main foil.
5) Rush Randle(and others)foilboard: manual altitude control with weight movement /sail movement.

 

Doug, caught out again!

Please don't assume that I know little about the wand system and twist grip on the tiller of the Moth as in the Fastacraft Version.
Give me a little credit please!
Furthermore I once raced scow Moths in big winds and seas in Perth Western Australia, and this much more stable craft is still an absolute handful, particularly for the lighter sailor. How many Int Moths have you raced in demanding conditions? Therefore I will put it politely: most of what say is coming thru your hat.
Also you have an infuriating quality of often denying what you clearly stated a few posts back. I will quote one from you, but there other quotes also, I just can't be bothered to collect them all, and copy and paste. Try this one anyway!

I still see potential advantages to using manual main foil flap adjustment-perhaps tied in to the rudder foil flap at some particular ratio- in the Moth class. And from my limited experience using manual mainfoil flap control(with separately adjustable rudder foil flap) on a bigger boat I'd say the advantages would be substantial in heavy conditions where I've read that the Moth wand has some trouble particularly downwind in big waves.
But it would take committment and some time to fully develop a good manual system in that class.... QUOTE - Doug Lord - Post #527

Try to get some integrity into your own arguments, that means admit to what you have already said, and above all, take responsibility for your own actions.

 

Doug, another stupid comment!

If it is possible but just a bit more difficult to learn according to you;

to the crew-a new skill to go along with a new function for the twist grip-yes. Something even remotely impossible-hell no. Only a little difficult to learn.
QUOTE - Doug Lord - Post# 531

Maybe we can solve the argument regarding all these great ideas you invent to improve the Int. Moth. Only you assume that it is in desperate need of improvement.
Buy one, modify it to reflect the improvements you suggest, test the new version yourself, and learn to sail the Moth reasonably well yourself with your new mods fitted, then tell us on the Forum if it did, or did not work as well as John Ilett's production version. If you can't (and most of us already know the answer) HAVE SOME HUMILITY and keep a much lower profile. You might think that your postings are helping the class develop into a higher performing sailing machine, and that you are responsible for large advances about to occur in hydrofoil sailing, but come on; neither is remotely close to being true!

 

Not sure I understand what you ment here: Are you saying the wand should definately be coupled to the front foil?

On another note, Alans & Co's 14ft in the pic on the prev page, was controlled manually by rudder flap, or rudder incidence?

 

The other advantage of the wand operated main flap is that at low speed and low height the wand pushes the flap down, increasing foil camber and lift coefficient and assists early take off.
When normal ride height is achieved the flap is up near neutral, reducing lift and reducing drag so that the boat can now go faster.
This does not occur with a fixed sytem like Dave Lugg used, nor with the all moving main foil as used by Ian Ward on his present moth.

Conversley the flapped rudder foil works in reverse, and is probably detrimental in this aspect.
Up flap and low drag is used to raise the bow and increase incidence on the main foil for take off and consequently this reduces lift coeff of the rudder foil when more lift would be useful,
and down flap to lower the bow and reduce the incidence on the main foil at high speed, at the same time increasing drag on the rudder foil because of the increase in camber.

The all moving AStevo system used on the bladerider does not have the disadvantage of the rudder flap's increased drag at high speed but also does not have the low drag advantage like the wand operated main flap at high speed.

As Tom said earlier there is some advantage in having both flap and variable incidence on the rudder foil to get the best of both worlds.
An intersteing mechanical challenge to build.

 

Moth on Foils /manual

Sigurd, David Lugg/Alan S's 14 used a flap on the rudder foil for altitude control connected to the ext. tillers and activated by twisting except that I think they had two tillers.
On the 14 the main foil was quite small and the rudder foil was larger....
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Phil, somewhere in this thread(edit- wrong: in the "Foiler Design" thread) is an illustration by Tom of an interconnection system between the mainfoil, rudder foil and wand. I'll try to find it later.
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Comments Tom Speer made in "Foiler Design" post 324 about the difference between an all-moving foil and a foil with a flap:

 

Mainfoil+Rudder foil Interconnect-Manual/Wand

I think that the following represents a great idea with a wand system-at least as an experiment. I also believe that it would be ideal to try a manual setup with manual inputs where Tom shows "wand input" in the sketch below. Anybody that's ever sailed a wand system knows there are conditions where the wand puts in too much input to the flap-a manual system would eliminate this-among its other potential advantages.
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From Tom Speer page 23, post 35 of Foiler Design:

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Sketch of Toms idea:

 

Hello Jon, I had stopped reading this thread for a while until now (no sleeping):

Then I read this, and thought you might find this one sheet kite proa funny?