KissCut-new Swiss Foiler

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Did you miss the part about the reefable rig? I don't think you mean "bruce foils"(which are usually defined as low aspect ratio foils) but sort of a mini hydroptere? Why do you think that configuration would be better than a bi-foiler?
Here is Brett Burvills foil design for a surface piercing(SP) foiler Moth-the first Moth to win a race on foils-and banned as a "catamaran configuration" according to the class rules. Is this similar to what you had in mind?
(also good shot of hydrop foils in 2005)

 

Yip a mini hydroptere is pretty much what I would come up with. I did see the bit about reefable sails but from experience they dont work very well, I havent seen a rig that has good gust response with a reefed sail, the bend characteristics/luff curve of the mast usually turn to custard, have a look to see how many of the OZ/NZ sport boats have reefable rigs.... or even almost any other dinghy

 

One of the best performance dinghy designers of our time just did this to the 49er. Frank Bethwaite made a bolt-on kit consisting of:
- a lateral horizontal foil between two "leeboard" like vertical foils attached to the sides of the boat - and -
- a front mounted "canard" style steerable lifting foil to enable "tractor" style front steering.

This "kit" is (theoretically) removable and the boat involved can be brought back to class legal. Frank's son Julian indicated that the project was an exercise in investigating foiling for his 70+ year old father. You aren't alone in your "highly experienced" interest.

A Laser is a tough target platform. Heavy, and underpowered.

I think it would be easiest to start with a clean slate and design a low cost foiler from scratch. I've not put a huge amount of thought into it, but my first thoughts are that a very lightweight catamaran may be a good place to start. Stable, light and fast is a good place to start. You get the very narrow fast hulls that make reaching take off speed possible.

I haven't got any built-in dislike of multihulls, and don't think a monohull is the only way to play. Occam's razor is an old friend. I bet it is possible to build a really lightweight cat without resorting to exotic materials.

A lightweight cat may be a better place to start than trying to build a skinny aka with two tiny amas and call it a monohull, labelling the amas as "buoyancy pods".

I really like Frank Bethwaite's simple "main" lifting foil on his 49er experiment, and a similar design would possibly work on a cat. Simple and it would not prevent the cat from being sailable without the lifting foils.

Not a bad place to start though ....

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Bill

 

Terry, all small cats that have been tried with foils so far have proved problematic and ,generally, not faster than their non-foiled counterparts. In a small size a trimaran configuration with fairly small amas/buoyancy pods would be the simplest especially if you went with just two foils rather than three, but a three foil system-like the Rave- would allow the foils to develop all the RM so you could just sit in the middle-it is the least athletic configuration you could come up with. It would probably require a main hull with a L/B of at least 10/1 and a square or over square overall beam-and would be close to the least weight sensitive configuration. The Rave is rotomolded and is 368+ pounds and foils singlehanded in about 10 knots of wind. A boat like this has advantages in the skipper being able to sit in the middle, simple retractable foils but requires serious engineering because the loads when the foils develop the RM are huge.
A small surface piercer would require some crew movement but not as much as a monohull foiler and a wide beam. It has advantages in not requiring an altitude control system and you could make the foils retract like Hydropteres do-folding up under the cross arm.

 

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According to Linton Jenkins of Full Force boats(that build the RS600FF) their reefing system works quite well. And don't forget Hydroptere: she has set records with her main reefed.
Check out Bradfields 18' NF cubed surface piercer here: http://sites.google.com/site/hydrosail/HydroSail-Home

 

Doug:

Terry's interest and that of many is not to be the fastest, most complex boat on the water, and my premature thoughts are for low cost. Although the real world does not frequently intrude in your thinking process, comparing Hydroptere and the Rave to a minimal complexity, performance not-optimal low budget effort is pointless.

Both Terry and I are engineering professionals, and we both thrive on solving problems and working within a well-defined design brief. Terry lives about thirty minutes from Steve Killing, and I think solving problems with a basic foiling cat design may be possible. He's got some relevant experience available in the neighborhood. The resources are there for the asking if you show up with a coffee and good attitude. My personal goals for a project like this would not be to achieve Moth performance - I'd be happy to be able to post photos of an inexpensive garage project foiling. I'd be far happier to be sailing one.

The whole Internet-literate world is far too aware of your positions on the issues - perhaps you could let others carry on a discussion without reiterating your conclusions and grabbing at the microphone constantly. There are many ways to do things, and others may want to try.

I do applaud and congratulate your acceptance that your "designs" are effectively trimarans. It is a milestone worth praise.

Cheers,

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Bill

 

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Steve Killing designed Rocker-notable for its lack of success against other C Class Cats. This is nothing against Steve Killing but only serves to point out that from the 1970's thru to now foiling cats have been poor performers-and ,generally, more complex than tri based foilers. You'd be better off just sailing a cat without foils!
There is a wide range of people that have built foilers simply that work-Doug Halsey who is a member here has built a small simple surface piercer and it is worth doing some research on www.foils.org
This is a thread about Doug Halseys surface piercing foiler and an experiment he did sailing it without the amas-it would be worthwhile for Terry to contact this guy:
http://www.boatdesign.net/forums/mu...ng-hydrofoil-trimaran-without-amas-23293.html

 

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Which designs? The F3 and Flyer are trimarans. The new boat I'm building is based on the boat shown in the pictures below and is not a trimaran because the amas are NOT used in normal sailing. That was(is) Bethwaites rationale on the large monohull shown in the picture below. To be a trimaran it would seem the amas need to be used as they would be on a normal tri...

 

You don't get it. Doing a project to investigate and learn more about foiling on a low/limited budget has nothing to do with how Rocker performed in comparison to Alpha. Since there is no intent to compare performance against anything, why do you persist? Fredo, Blunted and all involved learned a serious amount about foiling by actually doing it. And they succeeded in the learning exercise.

Unlike your projects, the primary goal in a project like this would be to actually achieve (verifiable) foiling while having fun. Yes, the design would most likely be faster around the cans without the lifting foils, but who cares? You learn nothing by failing to try. I think a low cost foiler would be cool, even if there were faster boats around. Personally, I cherish the time in the shop building stuff. It is relaxing.

Steve Killing also designed the world championship winning C-Class catamaran Alpha which unseated Steve Clark's venerable Cogito after many years of domination. Your characterization of his work is unfair. His work is notable and professional with many world-class winning designs.

Cheers,

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Bill

 

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I'm afraid YOU don't get it: there is no reason for this to be the case if a little research is done and the design is done well.

 

And that is why I've built two boats while you've been surfing the net and irritating people. Research is pointless without development, and real knowledge comes from application of theory. Try, fail, fix, retry, fail is far more effective than anecdotally collecting information and drawing conclusions without ever actually trying.

Analysis paralysis is a real problem, especially when people are afraid of failure. People have to make failure their friend, and realize that failure is a better teacher than collecting other people's Internet posts. I could care less if your new project works, but I think it really matters that it get built and on the water.

You seem to have reached a lot of conclusions on what you believe is the "right" way and "only" way to do things. These conclusions are valueless without proof of concept.

Cheers,

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Bill

 

So, Doug... just to make sure that we all have this straight. Are you now suggesting that Fredo and Killing did not do their homework and that their C-Cat foil project was poorly researched and came to sail with a lousy design?

We wait, breathlessly, for your learned response.

Further... since when do you have the temerity to challenge two, rather accomplished persons in the world of sailboat design and performance?

Your only foil equipped example to make it to the water...? It never worked, has been scrapped-out to a windsurf school and you can't seem to get the much blabbed-about latest iteration out of the garage and on the water, some three years later?

Fredo's boat got on the water faster, went through a serious comparison trial against the best C-Cats in the world and then the gentlemen flying the boat went out and captured the C-Class Catamaran World Title on another craft of their own making. All this was done, mind you, in the full view of the sailing public with photos (hundreds of them) posted everywhere in the sailing press.

Yet, here you are suggesting that they don't have a clue while you have no photos, have no working boat and no idea as to when this magnificent world beater of yours will ever actually see the water for a test.

Please, Doug, have the good sense to shut down the noise level when it comes to foiling craft until such time as you get your own boat on the water and prove that you have a degree of accomplishment that gets you into the game.... and no, the little toy boats do not count.


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You don't know what you're talking about! I've given Terry of lot of info he can use in any way he wants to as well as resources to talk to people who have actually done what he wants to do. It is completely idiotic to decide for him, as you have, to build a cat which is one of the worst foiling platforms around-particularly in a small boat. You would benefit from doing research on this matter since your ideas are attempting to "reinvent the wheel" rather than using the knowledge that is freely available to come up with a first class workable, proven design rather than starting with an idea that has been PROVEN to be much less suitable for this application.
You have no idea of the implication on foiling of the beam of a cat or any of the other parameters related to building a multifoiler that a little research would reveal. You blurt out an idea laced with personal zingers directed at me without any understanding whatsoever of the ridiculousness of your comments.

 

-Chris, thanks for the encouragement, I’ll bear that in mind. I haven’t ruled out a multihull but there’s only so many hours in the day and I’m still new to this ...

-Doug: thanks for the suggestions and data. As I noted before, this fits in well with another project, it looks like it will have to wait for next year, but it's all gone into my file. I haven't ruled out a cat (am working on a small design actually) for foiling, but my studies so far indicate increased lateral stability trades with reduced longitudinal stability so I am not yet a cat person.

-Bill: the Frank Bethwaite foiler kit sounds very close to what I am working toward for my experiment, right down to the tractor steering! It's reassuring that it was intended for a 70+ year old, as I am heading into that territory soon.

I didn't want to highjack this thread and I also regret the turn that has been taken in recent posts. When I start to get serious I will resurrect one of my earlier threads on a related issue. In the meantime, thanks to all for your inputs!

 

Doug:

I'm getting tired of this conversation. What matters in a foiler is the foils which remain in the water when the boat is at speed. The hull configuration is pointless except from an aerodynamic drag point of view. Your chum Thomas Jundt proved this point conclusively sailing Mirabaud with and then without a hull. There is no such thing as a "catamaran" in play if Bethwaite-style foils are used - what matters is what is left in the water.

The (hull or) hulls are not relevant once foiling is achieved. A wide trampoline, a lightweight platform are important. Consider this concept with larger amas and no aka - its not that different, except in lowered build complexity and higher initial stability. Using a Bethwaite style lifting foil reduces and eliminates a lot of centerline structure and divides the vertical lifting foil loading to two attachment points instead of one - far easier to build. Now think about a Tomahawk style foil where there is no need for wands.

It may be you that has to rethink your preconceptions.

Cheers,

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Bill