New High Performance Monofoilers

[bistros]

Originally Posted by Doug Lord

AK, there are significant differences as well as some similarity:

So basically Doug, using the filter of your Dr. Science "ratios" the boats are fundamentally the same, proving AK's point by your own quasi-technical methods.

AK, you are catching on .... the performance level necessary to foil requires the boats fit within a very narrow specification window. This narrow window defines a lot - righting moment, weight, rig efficiency and a lot of details. The boats all "look" similar because they are similar. Some larger, some smaller but fundamentally very similar.

Every new boat in the foiling "revolution" is a minor variation on a theme. It's like proclaiming each new snowflake is a revolution in snowflake design because they are technically different, but when you step back and look rationally, they are pretty much .... the same.

Now I'm going to go outside and use my snowblower to go destroy some piles of "revolutionary unique snowflakes" in my driveway. Another couple inches last night to go with the ten inches the night before.

Actually, the window does not appear to be very narrow at all. If you consider that a boat like the RS600FF which weighs 2.57 times what a Moth weighs has performance essentially equal to the Moth then you could draw the conclusion that singlehanders could foil well at a hull weight from 66-167 lb or more as long as the power to weight ratio was satisfactory and the RM was there for the SA required.
That seems like a huge,wide open, window to me.
===============================================

Originally Posted by Doug Lord

AK, there are significant differences as well as some similarity:
Moth-
SA: 86 sq.ft
Sailing Weight(includes crew): 220lb.
All up weight minus crew=66lb.
main foil area: 1.076 sq. ft.
Foil Loading(Lbs per sq. ft. at 80% max boat weight with crew):163.56
W/SA: 2.558lb. per sq.ft.(sail loading)
SA per sq.ft. of main foil area(a SA/ws ratio shortened to cover planform area of main foil only): 79.92
=======================
For ease of comparison foil area for the RS was arrived at by using the same FOIL LOADING as a Moth. This is a guess and may not be accurate so W/SA is the only accurate comparison possible with known data.
Only upwind SA is considered. Moth crew=154lb.RS crew=160lb.
=======================
RS600FF
SA: 131 sq. ft.
Sailing Weight(includes crew): 327lb.
All up weight minus crew=167lb.
main foil area: 1.6 sq.ft.
Foil Loading: 163.5 lb. per sq.ft.
W/SA: 2.5 lb. per sq.ft.
SA per sq. ft. main foil area: 81.88
=================================
So the sailing weight of the RS is 1.49 times a Moth; SA is 1.52 times a Moth; and the RS all up weight minus the crew is a whopping 2.57 times that of a Moth.
Interestingly, the W(all up weight in lb.s) divided by SA(in sq.ft.) is nearly identical for both boats.(As it is for the 26' Mirabaud!)
The Moth has an L/B ratio of over 10/1 where as the RS is much lower than that with a much wider hull. This can affect take off in that the Moth may be able to reach take off speed quicker than the RS in marginal conditions. One other major difference is that the RS600FF is the first trapeze equipped singlehanded foiler.
Hope this helps a bit....
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[bistros]

Originally Posted by Doug Lord

Actually, the window does not appear to be very narrow at all. If you consider that a boat like the RS600FF which weighs 2.57 times what a Moth weighs has performance essentially equal to the Moth then you could draw the conclusion that singlehanders could foil well at a hull weight from 66-167 lb or more as long as the power to weight ratio was satisfactory and the RM was there for the SA required.
That seems like a huge,wide open, window to me.

Upping the rig "power" and upping the "righting moment" allows the weight to scale proportionately. Fitting within the narrow window nicely. If you could up the weight without increasing rig power and righting moment then you'd have a wider window.

Although the scaled up model fits within your theorem, the much higher wetted surface area and subsequent drag easily explains the take off speed difference. The added crew movement (both distance and agility) required for trapezing makes the RS600FF more of a challenge to sail than the Moth.

Groundhog day. Sis Boom Bah! Long live the revolution!

[ancient kayaker]

Originally Posted by bistros

AK, you are catching on .... the performance level necessary to foil requires the boats fit within a very narrow specification window. This narrow window defines a lot - righting moment, weight, rig efficiency and a lot of details. The boats all "look" similar because they are similar. Some larger, some smaller but fundamentally very similar.

Bistros: actually I'm not sure what it is that I'm supposed to be catching on to, and I wasn't making a point, just asking for information. If you are trying to recruit me in some ongoing argument, please don't, but thank you for the additional information.

Doug: thank you for the information.

[bistros]

Originally Posted by ancient kayaker

Doug, to my uninformed eye those boats look somewhat alike with merely detail differences. Is this a case of the devil's in the details or is there a significant technical difference?

This is what you are catching on to. Your words, not mine.

Your "uninformed eye" is more informed than you give it credit. There are no significant technical differences to be found. Minor variations, yes.

I'm not promoting an argument, just trying to slow the unending, ceaseless, repetitive reposting of the same material again and again.

I was under the impression this was a boat design forum - for people who actually design, build and sail boats. I also thought that in a public forum pointing out misinformation and misleading presentations was an obligation, not a disservice.

Over time, you may learn that public forum quality is a function of the member's willingness to critically evaluate content. You've done a great job of defending and encouraging mediocre, repetitive and misleading crap.

I give up.

"Bistros" I don't know how you can say: "There are no significant technical differences to be found. Minor variations, yes." I pointed out rather clearly (I thought) that the RS600FF that just beat a Moth for the first time( as overall winner) was 2.57 times as heavy as a Moth.
I would say that that was a VERY SIGNIFICANT technical difference between the two boats!
I'd say ,as well, that the fact that these two boats are virtually equal in speed is worth study and discussion. Even more so when the performance of Mirabaud vs a Moth is factored in: virtually equal in speed.

[ancient kayaker]

Originally Posted by bistros

This is what you are catching on to. Your words, not mine.

Your "uninformed eye" is more informed than you give it credit. There are no significant technical differences to be found. Minor variations, yes.

I'm not promoting an argument, just trying to slow the unending, ceaseless, repetitive reposting of the same material again and again.

I was under the impression this was a boat design forum - for people who actually design, build and sail boats. I also thought that in a public forum pointing out misinformation and misleading presentations was an obligation, not a disservice.

Over time, you may learn that public forum quality is a function of the member's willingness to critically evaluate content. You've done a great job of defending and encouraging mediocre, repetitive and misleading crap.

I give up.

Bistros: thank you for giving up. I disagree with your comments entirely, as is my right.
Doug: thank you for providing information that I find useful. Please do not give up.

[Chris Ostlind]

Originally Posted by Doug Lord

I would say that that was a VERY SIGNIFICANT technical difference between the two boats!

Perhaps it is stimulated by errors of ommission?

Maybe the RS performed so well because it has a bigger rig, or bigger foils with a less draggy profile for the given operating speeds... or the driver, Sam Pascoe, who was the 2006 UK National Champion, is a much better sailor... or the simple fact that the Grafham Grand Prix establishes both boats with level ratings... or the guy on the Moth, Alex Adams, made some serious screw-ups at critical times, or..... the list is potentially quite long here, Doug and you know it.

Making a big deal out of a singular event is not.... a big deal, just because you'd like to think that it may be.

There's a lot more to this than just the historic victory by an RS600FF over a Moth......
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1/10/09 Bloody Mary Pursuit Race: Extreme cold and extreme light air. Foilers were dead last. First foiler was a Moth(145th) followed by an RS600FF(146th) followed by several Moths.
RS600(79th) beat all International Moths. International Moth w/o foils placed 96th.
More, from a Moth perspective: http://bristol-moths.blogspot.com/20...razy-mary.html

[ancient kayaker]

Originally Posted by Chris Ostlind

Perhaps it is stimulated by errors of ommission?

Maybe the RS performed so well because it has a bigger rig, or bigger foils with a less draggy profile for the given operating speeds... or the driver, Sam Pascoe, who was the 2006 UK National Champion, is a much better sailor... or the simple fact that the Grafham Grand Prix establishes both boats with level ratings... or the guy on the Moth, Alex Adams, made some serious screw-ups at critical times, or..... the list is potentially quite long here, Doug and you know it.

Making a big deal out of a singular event is not.... a big deal, just because you'd like to think that it may be.

This thread is becoming a slanging match just like so many others have done. I truly regret that.

Originally Posted by ancient kayaker

Doug: interesting end shape to the foils in the middle pic. I presume that's to retain lateral control in the event the boat rides too high. Thanks for staying on the topic.

===================
AK, this is from the "Foilers!-blog of flying vessels"(Dr.Goulu) site-translation by Google. It is an answer to your question:
"The presence of Winglet, like many 60', can increase the surface antiderive, but mainly to reduce the effect of vortex at the bottom of the foil."
There is a good picture there as well(below) He's talking about the tips on Banque Populaire 5.
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Foilers! http://foils.wordpress.com/
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Surface Piercing Moth Foils w/tips--------BP5 tips

[Rick Willoughby]

I conduct most of my boating on a little lake near my home.

There was a rare sight last Saturday when a fellow rolled up with a foiling moth. It is the first one I have seen in the flesh and I am guessing he was a novice who had come to a quiet location to test it without a lot of attention.

He got it all together just inside 2 hours. He had to wade neck deep to get it to float. I was reasonably surprised that he could climb on board without capsizing it on only the third try. THat hull is very narrow. I gather the tramp frame provides a little buoyancy.

The wind was variable from very light to bullets around 20kts coming around the hills.

In about two hours of watching it he managed to get it sailing maybe 20 to 30 times. On two occasions he got it to foil for about 100m or so but was easily passed by a 16ft catamaran. For some reason the foiling looked laboured. It lifted but did not seem to take off. This did bring some interest from the swimmers and other boaters on the shore. The rest of the time he was swimming and trying to board it from deep water. Often he would just get it moving and then it would capsize again. I think it would be really good for fitness because there is a lot of climbing up onto the boat after you capsize.

I expect it would take more skill and practice than a sail board to get one of these things going well and I can see it would have a narrow window of operation.

I can see more sense in a sailing boat with three foils that has some inherent stability that does not rely on dynamic stability.

The wading neck deep to get going is a put-off for me. Man those foils are deep. The bit of weed in the lake would not help matters either.

For me the utility of a recreational boat of this sort is linked to weight so it is easy to transport, ease of preparing and launching, simplicity of operation and speed over a set course in the full range of wind conditions. My pedal boat beats the Moth on all counts. Maybe the Moth would provide a better aerobic workout because you would need to be moderately fit to keep climbing onto it.

Just my observations and opinion. (plus a bit of pedal boat promotion)

Rick W

Interesting comments ,Rick-thanks. The Moth has quite a reputation for being difficult to learn to sail. The fact that the foils have to be installed and removed from the bottom every time you go out is offputting to a lot of people. The RS600FF has retractable foils that would appear to make it much easier to sail from a beach.
Eventually, there will be a "Peoples Foiler" that ,while still very fast, will be much,much easier to learn to sail with foils that retract(and can be trailered retracted), buoyancy pods to augment initial stability and more. Monofoiler development has concentrated on performance but sooner or later the same kind of development time will be spent making the thing user friendly.

[Rick Willoughby]

Doug
There is a small sailing fleet on the lake I visit most weekend. Typical roll up for Saturday afternoon is about 20 boats now. There are a couple of well sailed lasers and a few cats up to 16ft plus a range of dinghies up to about 14ft. I think the smallest are Mirrors. I often pace myself against the fleet when I am doing laps on the 1.5km long lake.

I was once invited to join in the races. They had two short events over about 3nm on the day at the beginning of the season for practicing starts. It was light winds up to about 15kph but plenty of holes. I did both courses in about 20 minutes and the fastest boat, a cat, was about 50 minutes.


I have not raced the sailing boats since but still monitor my performance relative to theirs. In a whole season there has not been one day when I would not be able to beat any of the boats over two or three laps of 3nm triangular course. I can hold around 7kts on all points unless the wind gets up. I really notice the head wind above about 20kts but on the small lake it does not alter my average much because I can make up time downwind.

The point I am taking a long time to get at is how would the ideal foiler perform under a range of conditions?

If you considered a triangular course of say 7nm and a range of windspeed from nothing to 40kts in 5kt increments how often would the foiler do it in less than 1 hour. You have to consider capsizes as well - my feeling is that they would be skittish in 30+kts.

My best days are when there is no wind. Under these conditions the sailing boats abandon racing. The sailing boats become useless ornaments.

As far as speed goes the fastest pedal boat has achieved 18.5kts and that was a long time ago with a person of above average athletic ability but not an elite athlete. I wonder how fast a pedal boat could go with the latest technology and an elite athlete. Or even a person of average ability.

So the Peoples Foiler needs a detailed list of requirements, performance over a range of conditions being one, that sets it apart. All the other aspects of utility that make it user friendly need to be considered as well. Otherwise it will not happen.

There is no doubt that there is a growing band of recreational small boat users. Five years ago I had the lake to myself plus a few sailing dinghies. The sailing fleet has grown to 20 regulars. Last Saturday there were three pedal boats and about 10 paddled craft from sit-ons to touring kayaks and surf skis. Also one electric inflatable and one foiling Moth.

Will be interesting to see if foils catch on.

Rick W

[Chris Ostlind]

Originally Posted by ancient kayaker

This thread is becoming a slanging match just like so many others have done. I truly regret that.

It's, what did you call it... "a slanging match", when someone points out that there are, literally, dozens of reasons why a particular boat could beat another in a given race?

Come on, AK, take a look at the vast list of reasonable descriptions as to why a specific boat would beat another with an exactly equal rating. This isn't slanging, to use your terminology... it's more like reality. To put it another way... Shit happens.

The fact that Doug ignored the reality should be far more telling to a person of common sense. Look at his response and I quote, "There's a lot more to this than just the historic victory by an RS600FF over a Moth......" and tell me that he addressed the issue effectively, then issue your slanging comment in the right direction.