New High Performance Monofoilers

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Not true: the conversation was about an all moving foil that I thought was similar to the Japanese Mothie who doesn't use a flap but moves the whole foil. Turns out the guy I had addressed the question to had a vertical fin/foil joint just like normal but moved the whole foil instead of a flap. Leaves the control system vulnerable-it seems to me. However, he and others discounted my concern as I do on "normal" well designed main foil systems that are structurally very strong and capable of taking major impacts w/o damage.

 

Cough, cough.... you realize, of course, just how transparent that argument might be, Doug?

You are saying that an incidental smack on the foil would damage the control system in the acknowledgment. You are also intimating that said damage would just drop the boat like a rock because the tweaked control system, (you know, that stuff that moves the, "entire foil") would put things so out of whack that the guy would not be able to just continue on as if nothing had happened. If that was the case, my boy, then why bother asking what should be so obvious... especially for a guy like you who is the self-anointed guru of all things foily?

Doug, you can not have it both ways. Either the foil control system (control rods, cables, linkages, settings, etc.) can be damaged by incidental impact, or it can not. Everyone knows that the system would be tweaked and controlled flying would be a whole different exercise, so what difference does it make whether it’s the foil flaps themselves, or the alignment of the whole foil? The facts are still the same, as is the outcome.

Nevertheless, lifting foils are extremely susceptible to impact damage in a wide variety of ways.

You go to great lengths to tell us all about how fast these boats can go and then wish to wave-off the fact that this same high speed contributes to much greater damage whenever the critical components hit something. Check with your local automotive body shop if you need a corroborative comment or two.

For those of you who even care to bother with it... here's the URL to the entire conversation in question where all sorts of control surface and control input issues were being discussed. You can make your own call.

http://forums.sailinganarchy.com/index.php?showtopic=86254&st=0

 

Hi Paul,
FB designed the Tasar in '76 which went on to influence the B14, 49er and 29er. He was involved with his son with the 49er and 29er projects - he financed the projects and was heavily involved with the designs. The 49er is an Olympic class, the 29er is an ISAF Youth class. He also designed the Laser 2 with 10,000 boats sold, and his thinking continues to influence NS14s, Cherubs, and countless 'skiff' classes even though he isn't directly involved with them. Seems a better CV than most designers.

 

1976 was not 20 years ago. Saying the Tasar influenced the other designs mentioned is like saying a Cross 3 influenced them.

FB did not design the 49er or 29er. Many sailors think the 49er has some serious flaws.

The 49ers Frank built were not very good quality.

The Yngling was recently an Olympic class, so it must be one heckuva boat.

Seems Bieker's GT60 is a pretty nice alternative to the 29er, and seems to be nice as a Cherub. I suppose someone might take a leap and state that it is "influenced" by FB's work as well. Others might not.

The Laser 2 was not a very good boat. If it had not been mandated as a youths boat with the Laser name it would not have sold in numbers. Today you can't give one away. I don't think that design had any influence on the art.


Honestly, every designer is influenced in some way by everything he sees. In that sense FB "has influenced" development over the past 20 years. I don't think any current designer thinking about doing a skiff is pulling out the offsets of a Tasar for inspiration.

 

Well, that's not what I said is it? Which designers have had more influence in the last 20 years? Morrison, maybe. Howlett - not really. Bieker - only in I14s (and the GT60), and not really copied elsewhere. Murray? No. Ian Bruce? Not since the Laser in any big way. Julian Bethwaite - possibly, but clearly he is influenced by his dad. Anyway, this is going wildly off topic.

 

You continue to say "influence" but you don't define it.

Let's say Frank B was never born. Would the current 18s be any different? No. Ditto 14s. What about 12s, 16s? You tell me.

You mention Julian as being influenced by Frank. Probably. But anyone else? How is that influence manifested?

If Julian had never been born would anyone be talking about Frank today?

When I think about "influential" designers I think of Bob Miller and Taipan, that led to a whole new way of approaching the class.

Andrew Buckland's idea to use an assymetric spinnaker was very influential in skiffs and now keelboats.

Doug Peterson's designs absolutely changed the way IOR boats and especially keel and rudder foils looked, then his heavy/long/narrow ACC shape defined the class (after showing Frers' wide and Farr's shorter skiff avenues were weaker).

Davidson's ACC double knuckle bow was a huge influence on the class.

Bruce Farr's 18s changed the class, and then his IOR boats ushered in lighter weights and fractional rig acceptance. His early IMS desings were the benchmark for others to follow.

Uffa Fox's I14s changed the thinking in the class.

Tom Schnackenberg's approach to sail design has had a huge influence in sailmaking, and also in design, matching his ideas with the yacht designer's to produce a harmonized winning combination.


To me, this is what influential design is. I don't know of anything Frank B did that really caused others to follow. Perhaps his NS14 work was significant during his time, but even the boats in that class now show no influence of his designs.

So who is the "most influential" designer" of the past 20 years. I would not make that statement without a lot of research. I just don't see Frank's influence prominent in the recent work of designers.

If someone said who was the most influential designer of the past 40 years I would say Bruce Farr, for his work in Skiffs, IOR, IMS, One Design, and production boats.

 

Paul
On keel boat designers do you rate Joe Adams in your part of the world?

By the way I agree with Bruce Farr in this part of the world as well. High water to land ratio in his homeland encourages sailing. Certainly New Zealanders punch well above their weight in this field.

Would be interesting to see some good research on the development and influences on yachts over the past 50 years. From my own experience I saw Adams first heading toward good sailing boats uncompromised by rating rules. Adams 10 was a classic here.

Rick W

 

I am aware of some Adams boats and particularly like the 10 for it's era. I doubt most racers in North America ever heard of an Adams 10, or know there was a designer called Adams.

I should have mentioned Ben-Bob's 12 metre winged keel in addition to his 18 footer Taipan. Every 12 built after AII showed his influence and sported a winged appendage.

 

From Julian Bethwaite on SA: "...there is no intention whatsoever of putting the Tasar on foils". But they are going full tilt on a 49er foiler...
See post # 40 below:

http://forums.sailinganarchy.com/index.php?showtopic=86543&st=0&#entry2154143
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49er comments from SA:
"Yes we have gone the Canard route, because the Canard is inherently more stable than the tractor route. Firstly moths are quasi Canards anyway, secondly there is a huge difference in crashing a 30-40kgs moth at 18-20 knts compared to crashing a 130kg 49er at 25-30 knts. The 49er has another 50% of the power of a moth, it will take off at double to treble the speed of the moth. It should go 1/2 as fast again with the existing rig. If we go to a smaller rig, say 600mm shorter, it should go significantly faster again.

I also find it interesting that people are bemused about steering from the front when none of them drive cars with the steering wheels at the back. Stupid!

No we dont expect to fly first time perfectly, yes we expect to have some very trying days before we get it right. But we are very confident of what we are doing and we believe strongly that in 2-3 months we will be flying and operating in the mid 20 knts.

From the speed boat testing, we are now very confident of speeds up to 20knts, and have had a couple of successful runs at speeds mid and high 20 knts bracket. We are also confident we can do it without hurting people!"

 

Doug

When testing our large Kooee model, we discovered why front wheel steering has not been successfully applied to sail boats. I certainly thought that, when used with a canard configuration, it had stability and performance advantages and the theory shows that it does. However we found, as did some ot the moth guys that tried it, that there is a boat handling problem. If you get into irons then it is almost no chance of backing out as you can with a stern rudder. The centre of drag of the sail relative to the forces and moments generated by rudder and centre board push you back into rather than accelerating you out of irons.

Putting a steerable forward strut for the canard and a stern rudder is less efficient than "conventional" configuration. Stability wise there is actually no difference if the elevator is linked into the active control system. Hence my latest Kooee configuration is a tail dragger

 

Alan,Bethwaite also calls the Moth a "quasi-canard"-which makes no sense to me. John Ilett told me long ago that the nominal design of the boat was with 80% of the all up weight on the main foil. Now, I know that in the past a "quick lightair takeoff" technique loaded the rudder foil a bit more than that but according to a Mothie who races now that technique isn't used any more.
A guy who races Moths(Bora Bgulari) said ,on SA, that he sails with up to 70% of the all up weight on the rear foil and also called the Moth a "canard" configuration. His comments were contradicted by another experienced Mothie.
The Main foil on the Moth is larger than the rudder foil(elevator)-is there anyway to define that configuration as a canard?

 

Doug
This probably should be corrected at the source.

Having done this on a conventional boat there is a very good reason for having stern mounted rudders on most boats. The CoG is usually well above the steering force generated by the rudder as is the hull drag. The response of the boat is that it leans into the turn. A bow mounted rudder provides lean out, which is not a nice feel and with some boats would cause instant roll.

With a foiler they are already unstable requiring dynamic stability control so the steering force is just another applied force to contend with. A bow mounted ruder might take some getting used to though.

Try riding a bike with back wheel steering!!! Can be set up to work but the geometry requires some careful thinking.

The comment above lacks insight into the dynamics involved in many boat applications.

Rick W

 

Rick, the comment you quoted was made by Julian Bethwaite -I was surprised
at it and at his attitude toward canards( not sure of his definition there either). I don't yet know what he means by "we're going the cannard route".
Every time it(as I understand it) has been tried-so far-on a monofoiler it has been less than succesfull with the possible exception of the Miller foilboard.
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More from Mr. B from SA on the foiling 49er:
"Do I think a foil borne 49er will be faster than a conventional 49er around the bouys, doubt it, but would be estatic to be proved wrong!

Do I think a foil borne 49er will go bloody fast at 135d, yep, thats why we are doing it!"

 

Doug
I know you were quoting from another forum. I do not visit it so the suggestion was for you to point out the problems to him for conventional boats. There are other issues as well like being out of the water a lot of the time on planing hulls. Stern tends to stay attached to the water for longer periods than the bow.

I always look around for experience in other areas to add to understanding. Not many aircraft with forward mounted steering surfaces??? Don't think his car analogy is very good.

I can do the stability analysis as time domain modelling is something I have done a lot with over the years in my paid work. However setting up the model takes a lot of time to come to grips with all the significant degrees of freedom. It often pays to try something and then set up the model based on initial learning.

Rick W

 

Thanks,Rick. I just can't get the picture in my head of what he is actually doing. The only picture there is of his intial testing doesn't seem to show a forward rudder. Seems to show a "conventional" Moth configuration with a bow wand: