Moth on Foils: 31.1 knots (35.8 mph)

[Doug Lord]

Munter, I've never been under any illusions how hard it is to sail a Moth
foiler in conditions like those in the video. However, a foiler designed for ease of sailing instead of speed would be much easier to sail than a Moth in almost every condition.

[ancient kayaker]

Seems to me first you need to learn to sail, then you need to understand the physics so you can have some idea of what will happen in response to your actions because they clearly happen too fast to figure it out on the fly, it would be sensible at some point to get some instruction, and the final step to find some secluded place to practice, ideally with no other boats swanning around and most importantly of all, nobody with a camera ...

[Doug Lord]

I would suggest, Terry, that a Peoples Foiler might just cut down the learning time, improve the "fun factor", and allow you to take a friend along. Of course,that would apply if there was a Peoples Foiler. And there will be one.......(thanks to the Moth pioneers, the Hobie trifoiler pioneers ,the Rave pioneers and all the other pioneers that have known this since day one.)-watch Hobie later this year.....

[Chris Ostlind]

It's five plus years and counting, Doug, since you first uttered this goofiness... and still, nobody in foildom, nobody in conventional sailing manufacturing and nobody in the hinterlands of foiling reality has seen fit to even try to produce said People's Foiler. Geeez, I wonder why that is so?

It's really easy to issue utterances as to how something that is non-existant would perform and a whole lot harder to actually produce said thingamajig to prove the claims.

You, yourself, have still not sailed a Moth on foils and yet... you want to issue these proclamations based on not even knowing what the state of the art is all about on a personal level. Do you not think that it's vitally important that you, at least, get intimately familiar with the functional realities of the genre before you stake your outpost among the thinnest of branches?

Sorry, Bud, but it is as much about smoke and mirrors as it ever was, when it comes to these boisterous, unsupported claims of a People's Foiler.

Five years and counting.

[Doug Lord]

Check out this new Moth: http://www.yankodesign.com/2009/10/2...hy-up-in-here/

Moth Design by David Valham

[ancient kayaker]

I'm taking a wild guess here, Doug, but I suspect that isn't the peoples foiler

[Doug Lord]

Ah, you'd sure be right-but what a cool looking design!-

[bistros]

Originally Posted by ancient kayaker

I'm taking a wild guess here, Doug, but I suspect that isn't the peoples foiler

It isn't a Moth or a real boat yet either. Reading through the site it is an unbuilt CAD design and model to fit within Moth class rules. I know that somehow designs and models become real to some people, but I hate counting a small scale model of an egg as a full grown chicken.

It is pretty, whimsical and artistic, but the reality of converting a CAD rendering into a functional boat often causes whimsy to succumb to practicality. The arty low aspect ratio "lifting" wings most likely will be victims of the real world, where the theoretical "lift" generated is probably exceeded by real world drag. Same goes for the dual wands - the ventilation problems incited by wand wake hitting the main T-foil are doubled with little practical benefit at the scale of a Moth. I wonder if the dual wands were penciled in more for the balanced insect "antenna" look than for making foil lift symmetrical on both tacks.

The Mach 2, Bladerider and other current designs are the product of practical refinement and experimentation on the water, and there is a world of difference between theory and practice.

--
Bill

[Doug Lord]

Originally Posted by bistros

Same goes for the dual wands - the ventilation problems incited by wand wake hitting the main T-foil are doubled with little practical benefit at the scale of a Moth. I wonder if the dual wands were penciled in more for the balanced insect "antenna" look than for making foil lift symmetrical on both tacks.

The Mach 2, Bladerider and other current designs are the product of practical refinement and experimentation on the water, and there is a world of difference between theory and practice.

--
Bill

I give this guy a lot of credit-he addresses many of the points raised by Bill Beaver in the paper below. One of Beavers points was the high aerodynamic drag of current Moth racks-and this guy has addressed it. You seem to fault him because it is a DESIGN and not a complete boat! This is boatdesign.net where designs are supposed to be presented.
By the way your comment about the dual main wands is way off base: the point of dual wands is two fold:
1) to keep the wand wake off the main foil, and
2) the altitude of a normal single wand boat with the wand offset to the side has lower altitude on one tack than on the other-the dual wands eliminate that problem.
---
I say congratulations on a job well done! Hope somebody builds it.
He is not the first to use dual wands as shown in the pix below:
----------------------------

[Munter]

It looks like it was designed by a man in a tight turtleneck sweater with expensive glasses.

[Chris Ostlind]

While the Valham design LOOKS cool, one has to understand just what all this coolness is going to do to the eventual street level pricing of a boat made in this fashion. A good many of the drawn parts of the rack system are probably going to be molded, rather than filament wound. Molded parts require tooling that is a lot more expensive to produce and the parts, themselves, are more complicated to make correctly.

If the rack wings are designed to create lift, then at what angle of heel do they stop producing favorable lift and start to make it more difficult when seen in concert with the other lift components. Since some here are so very enamored with the windward heeling style, what change in aero balance is being "designed in" to the boat with angle of attack wing shapes? How much additional drag is being added to the boat by the leeward wing form when it is raised during heel? ....and on and on.

Dual wands? Really?.. someone is saying that design elegance is actually steering us away from a simpler form of efficiency to one in which there are actually more complex elements being introduced with dubious benefit?

Has anyone had a look at the boat sailed by Bora Gulari or any of the other top five finishers in the most recent World Championships? Are those guys running dual wands because it's such a wonderful idea, or are they looking to keep their boats as light as possible with fewer mechanical devices prone to breakage?

There seems to be a school of thought in which the answer to obvious questions can only be created by the addition of yet more fiddly stuff on a boat, rather than... How do we reduce this jumble so that the boat is easier to operate, maintain and purchase in the first place? Even without this horrid economy, recreational boat sales have been sagging badly for years. Now, we are looking to make this boat even more expensive to build and trickier to operate?

Say goodbye to the revolution.

[bistros]

Originally Posted by Doug Lord

I give this guy a lot of credit-he addresses many of the points raised by Bill Beaver in the paper below. One of Beavers points was the high aerodynamic drag of current Moth racks-and this guy has addressed it. You seem to fault him because it is a DESIGN and not a complete boat! This is boatdesign.net where designs are supposed to be presented.
By the way your comment about the dual main wands is way off base: the point of dual wands is two fold:
1) to keep the wand wake off the main foil, and
2) the altiude of a normal single wand boat with the wand offset to the side has lower altitude on one tack than on the other-the dual wands eliminate that problem.
---
I say congratulations on a job well done! Hope somebody builds it.
He is not the first to use dual wands as shown in the pix below:
----------------------------

Doug:

It's great that you like new ideas. So do I. I do however distinguish between theory and reality. In my world, things have to be practically proven with real world results before I accept their proposed benefits.

First of all, I did not "fault" the designer or make any personal statements as you represent. I questioned the real world results of design elements - exactly as this site is supposed. You were the one who linked my questions as a personal issue.

You seem to accept that the designer's wings have less drag without testing. You have also stated the design has less drag than current wing designs. How have you reached this conclusion? What data set did you use? You reach conclusions without scientific backup.

You have indicated my comments in regards to the dual wands are "way off base". Two wand wakes are 100 percent more likely to be problematic than one. If you think wand or foil wakes follow the keel of a boat exactly, you've got some research to do. Leeway in a boat causes wakes to never be perfectly in line with a centerline, and the chance of wand wake interaction is higher with two wands than one, unless they are set further away from centerline than expected leeway. Changing boat directions also affects the wand wake. Turning the boat can cause the wand wake to "hit" the foil as well. Two wand wakes make this possible on either tack.

I did clearly express that two wands did address symmetrical lift control on either tack, although you chose to ignore it.

Your critique of my post seems more personal than scientific and rational.

By the way, Happy New Year and I hope you get to show us all your new boat foiling this spring! Best of luck with the build.

--
Bill

[RHough]

Originally Posted by Doug Lord

I give this guy a lot of credit-he addresses many of the points raised by Bill Beaver in the paper below. One of Beavers points was the high aerodynamic drag of current Moth racks-and this guy has addressed it. You seem to fault him because it is a DESIGN and not a complete boat! This is boatdesign.net where designs are supposed to be presented.
By the way your comment about the dual main wands is way off base: the point of dual wands is two fold:
1) to keep the wand wake off the main foil, and
2) the altitude of a normal single wand boat with the wand offset to the side has lower altitude on one tack than on the other-the dual wands eliminate that problem.
---
I say congratulations on a job well done! Hope somebody builds it.
He is not the first to use dual wands as shown in the pix below:
----------------------------

One of the things the crash video shows is boats surging to high altitude, pulling the wand out of the water, then nose diving into the water. It seems to me that the goal is to keep the main foil in the water at the set "ride height". Any longitudinal displacement of the wand creates a situation where the wand is not reading the foil immersion but the height of the wand mounting point. The boats in the photos show two wands that are father aft and actually read the height at the foil. This new design seems to have the wands far forward to give the boat an insect like appearance rather than to gain any performance.

As far as aero drag, looking at the sheeting angles in the videos I've seen, these boats are not all that fast from a multiple of true wind speed viewpoint. About 1.5 - 2.0 X wind speed is my guess? With lower ratios at higher wind speeds.

I think we will see 2X + boats on the water in the next few years. I wonder if a Moth can reach that multiple of windspeed.

Reducing aero drag and reducing heave and pitch would seem to be design goals.

[Doug Lord]

When the wand comes clear of the water the shock cord attached to it pulls it forward which raises the back end of the flap resulting in a crash almost immediately. There are lots of solutions and the Moth guys swear that a crash caused in this manner is now the rare exception. Many Mothies also think the further forward the wand is the better.....

John Harris-2008 world champion:

[RHough]

Originally Posted by Doug Lord

When the wand comes clear of the water the shock cord attached to it pulls it forward which raises the back end of the flap resulting in a crash almost immediately. There are lots of solutions and the Moth guys swear that a crash caused in this manner is now the rare exception. Many Mothies also think the further forward the wand is the better.....

The crash video makes it look common in 2009. Of course all the Moths that didn't crash didn't make the video so perhaps I got the wrong impression.

It sounds like wand placement is still in the trial and error stage. Finding out what works in the real world vs what should work in theory. That is a good thing!

R