Sailing Dinghy Design

Discussion in 'Sailboats' started by Tim B, Mar 12, 2003.

  1. Phil S
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    Phil S Junior Member

    You guys had best start a new thread if you want to discuss the history of boats with lead. Lets get back to dinghies.
  2. Doug Lord

    Doug Lord Guest

    Foiling Dinghies

    Seems to me the design of a trully alround foiler with retractable main foil offers an exciting design challenge and a way to bridge the gap between "normal" hull and a flyer. We already know the speed potential thanks to the Moth guys and David Lugg in the I 14 class. We know that-according to those that have done it-foilng is a blast and relatively easy to learn with practice like anything else.
    Cost is always brought up in any development class discussion like this but if you were to analyze foils in terms of cost per unit speed you'd find that NOTHING yet done offers a greater return on money invested for speed gained.
    I think designing a Moth or 14 with retractable main foil is a target that once it is achieved will revolutionize dinghy sailing and design.
  3. Andy
    Joined: Aug 2003
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    Andy Senior Member

    And possible destroy the existing class too?

    As some have noted on the forum, foiling as a different mode would lead to completely different hull shape, rig details, sail shape (more speed, different shapes). The whole class would become obsolete overnight (except in sub foiling conditions). Look at what is happening in the moth class. Are people rushing out to buy hydrofoils? Astevo (I think it was) made the point that the opposite is happening. The turnouts are dwindling instead. I certainly wouldn't buy a conventional moth as I'd be worried about getting thumped by a foiler, whilst I wouldn't buy a foiler because with the class in its current state it would be very unsportsman-like to thump everyone else with a boat which was designed around a completely different operating mode (I wanted to say, at least in terms of the other boats, unfair advantage). OK that hasnt happened yet, but all it would take would be a WC with consistently right conditions, and even that will become less of a priority as the technology develops.

    I think the mothies should consider banning the daggerboard foil and that the guys who are putting pressure on the existing classes should get together and decide on a more open rule to foster healthier development. Then when the moths and 14's feel ready they can adopt the new technology. maybe the right time would be when the class is going through a lull, at which time the technology could rejuvenate a flagging class. But not just now when the 14's are experiencing some of the biggest fleets and closest racing in their history.

    I also suspect that the Rave with 3(?) lifting points is a good deal more stable and easy to sail than the moth with 2. The lateral separation of the foils contributes a great deal to stability, therefore more power, speed etc. than the moth. It makes perfect theoretical sense but if anyone has first hand experience of both then please post!!!

    Finally, (and Phil this is the last time I'll mention big boats!) Paul the 4 '92 A3 boats were Defiance, Jayhawk, A3 and Kanza. Mighty Mary was definitely '95 built and designed. The rumours about why Peterson was 'excluded' from Prada centred partly around the idea that he refused to go with the Davidson bow. I don't know if any differences between the two may have had a part in this decision as everyone else was convinced about the technical superiority of the double knuckle bow. When he left, the first thing Prada did was add this bow to both boats. I would find it difficult to believe that this didn't have a significant part in the improvement to Pradas performance, as published figures about the configuration suggest significant gains over a boat without this one feature. I hope Rod Davis clears this up in the second part of his Prada dissection currently running in Seahorse.

    The GS50 was a far more bulbous boat forward than the Frers designed 52 (for example), and all the Sinergia/Rodman/GS/IMX 40's which the Match 38 was targeted at seem a fair bit finer lined up forward. The MORC boat you showed does look nice. The 5.5metre looks nice too!

  4. Paul B

    Paul B Previous Member

    No Flying in 14s

    The I14 class has taken steps to ensure there will be no Moth-type "flying" foilers in the class. ref. Rule 6 of the current I14 Class Rules.

    Also, last "lead" boat reply: The B 38 is not anywhere near the same type of design target as the "full-race-semi-custom IMS boats" masquerading as production C/Rs.
  5. Guest

    Guest Guest

    Doug, you implied that people against foilers in Moths were suffering from fear of flying, afraid of innovation. I'm afraid that if you look at the record of innovative classes such as the 12' skiffs and A Class cats, you'll find one other member of the board who is against Moths has been a leader of innovation, and he remains so in his current class (albiet with a slightly different slant).

    There is no logic in saying people don't support foilers simply because they are afraid of innovation. It's just not true.

    There are things that offers much more speed for the dollar than foils - cats and boards. If you want to junk an existing class and line of development in the Moths in the name of speed, why not go all the way and simply windsurf or get an A Class?

    astevo, you're right about technology, maybe a Frankenboat development class would allow spars etc from a moderately popular OD (49er, 16, Moth whatever). The idea is to allow people to put cheap second-hand stuff on to reduce cost and allow other areas to be developed. I'm basically musing about ways to have a class in which we can encourage the thinking that created cheap, quick boats like the Stevo tortured ply Moths.
  6. Doug Lord

    Doug Lord Guest

    Foiling Dinghies

    Give me a break Guest:you used one sentence in one post out of several to accuse me of saying all those opposing foiling in the Moth class were afraid to fly and opposed to innovation. That is ridiculous and no way to discuss an important topic like this. I have personally talked to John Ilett, Ian Ward and several others and they HAVE run into some -very few- that are afraid to fly. All those guys and the majority posting on the Moth forum(
    )feel that the response to the foiling Moth has been and will continue to be good for the Moth Class.
    John Ilett related a story of sailing past an A cat like it was standing still: these boats really perform! And are a huge and positive breakthru not only for the Moth class but for sailing in general.
    David Lugg who designed and built the first fully foiling two foil International 14 which incidently was the first two foil sailboat ever to fly an asymetrical and to sail with two people told me that the way the I14 class works will allow "demonstration" boats to be shown over the course of the next few years--with the idea of possibly amending the rule.
    I believe that once a retractable main foil is demonstrated on either the 14 or Moth that the floodgates will open and the foiling boats will win the development debate--at any rate thats what I hope will happen and I trully believe that foiling dinghies can bring new life to the small boat world!
    To ignore flying dinghies and the design challenges they still offer is to ignore one of the most exciting areas of modern sailing design!
  7. Ok Doug, if it's not your view, I retract my statements but it was easy to read your post that way.

    Having sailed against the guys who won the last 3 A Class worlds, and the guys who won the last 4 Moth worlds, I'd have to say that must have been a slow A Class that John Illet sailed past!

    As for the reaction of the Moth class, experience shows that posts don't give a true indication of the feeling with a class. I'm not against foilers or innovation, it's just that anyone looking at the decline (hopefully not the fall) of the Moth class numbers will see that there are problems with chasing speed above all.
  8. Doug Lord

    Doug Lord Guest

    Foiling Dinghies

    Another Guest: you sailed against the last three or four Moth World Champions and A class World Champions and there fore Johns story of passing an A class cat must be suspect? Now, as far as I know no Moth World Champion has yet sailed a foiler in a World Championsip!
    Have you sailed anything against a Moth foiler? In foiling conditions? I think not.....
    Where does the resistance to foiling dinghies come from? And what is the object of a development class? Speed, high performance, fun sailing, cost effectiveness, racing within a status quo?
    Sure seems to me that there is a major psycological identity crisis in many "development class" sailors where the desire to preserve what exists now is the paramount objective replacing the great historic drive to improve what used to exist by developing the newest wildest ideas into viable race winning machines. The history of the Moth Class and the International 14 class is a history of the most exciting development ever to take place in sailing. And now again we're at one of those great crossroads where the choice is to protect the status quo or say GO FOR IT!
    If these great classes are let doown by conservative defenders of the status quo then new classes will be born and some great classes will pass away--that would be a shame.
    This is truly a time of great opportunity for designers and sailors to embrace the new technology-a time to FLY in the greatest traditions of the most important development classes in the there(ha)!
  9. Andy
    Joined: Aug 2003
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    Andy Senior Member

    Hi Doug,

    I know that Chris? (Another Guest) will have some ideas to post in reply to your suggestions, but I feel that there are some issues with what you are saying that others might wish to comment on.

    You stated that "If these great classes are let down by conservative defenders of the status quo then new classes will be born and some great classes will pass away". I supsect that the opposite is true - a new class SHOULD be born for foilers and that the reason the moth class is passing away a bit is due to the foiler debate. This is what I suggested a few posts ago. The mode of foiling is so different to current sailing principles that, for the present, it can only do damage to existing fleets.

    I think the technical arguments also go against foiling moths. All the reports I have heard say the boats are difficult to sail. Sure this will improve, but with the current rules its difficult to see how much. Do any of the 'pure' foiling boat look like foiling moths? Nope. Ive mentioned the Windrider Rave before, but perhaps the biggest clue is the boat which has been developed by the guys who were first with the foiling moth. Suffice to say, the new boat is a catamaran foiler.

    You also asked "Where does the resistance to foiling dinghies come from?". Again, nobody is actually against foiling dinghies per se, its the damage they can do to class racing which is the current problem.

    About the A-class comparison - nobody should draw any conclusions from hearsay! Were both boats racing together over the same course in the same wind conditions etc. etc.? Or was the A guy eating his lunch at the time? Only a VPP could tell you the truth...

    Because you feel so passionate about the concept, Doug, wouldnt it be a better idea for you to start a new thread to formulate some rules for unrestricted foiler development? The current 'pure' foilers have a lot more stability AND speed than foiling moths, with the result that they are able to experiment with big wing masts and the like which cause stability problems in moths. The other classes still have plenty of life and development in them with rigs, sails and conventionsl foil profiles etc. They will switch when the time is right for the whole class, and abandon any of the current technical limitations imposed by their rules. Just because a class doesnt adopt a new idea immediately doesnt mean it isnt leading edge in the present (foils are only one part of the jigsaw) nor will continue to be leading edge in the future.

  10. Give me a break Doug:you used one sentence in one post out of several to accuse me of saying that John's story of sailing past an A Class cat is suspect. I never cast any doubt on John who (in the tiny contact I've had with him) appears an honourable man. That is ridiculous and no way to discuss an important topic like this.

    I assumed that you would be referring to regularly out-performing an A of high standard, for nothing else is relevant. Almost any boat can sail past a much faster boat at some time or another, or regularly sail past a badly-sailed example of another class. Hell, I've passed 18 foot skiffs in a 420. That's irrelevant if it's a one off, we all know that.

    The Moth is about 70% of the speed of the A Class. This is demonstrated by current yardsticks in the country where the best Moths and As come from, slightly adjusted by me through input from the Moth world champions (ie they reckon the Moth yardstick should be 98-100, not 106).

    The foiler is not the world's fastest Moth; Rohan's results on the foiler were very close to his results in the previous worlds in a conventional boat.

    Ergo, it's hard to see how the foiler Moth is suddenly faster than a good A Class, when the foiler Moth is slower than conventional Moths that are 70% of the speed of an A.

    Re "the great historic drive to improve what used to exist by developing the newest wildest ideas into viable race winning machines. The history of the Moth Class and the International 14 class is a history of the most exciting development ever to take place in sailing"

    The fact is that the Moth has NOT developed the newest, wildest ideas all the time. It did NOT develop the idea of cats into the class, it banned them. It did NOT develop the idea of tunnel hulls, it banned them. It did NOT develop the idea of windsurfers, it banned them. It did NOT develop the ideas of trimarans,it banned them. It did NOT develop other things like the assymetric spinnaker, the sliding seat, the trapeze, it banned them.

    The I-14 also has many restrictions; minimum weight, mid-length measurements, no tunnel hulls, cats, tris, etc.

    The I-14 and Moth have long histories of banning ideas. That's not to say they are not world leaders. If they didn't ban some ideas, the Moth would now probably be just another sailbooard, cat or tri class.

    re "If these great classes are let down by conservative defenders of the status quo then new classes will be born and some great classes will pass away--that would be a shame."

    If uncontrolled development is so great, wsuch a path to popularity, why is the International Moth so much less popular than the Europe, which is a one design version of a '60s Moth? Why is the NZ Restricted Moth, a 1940s one design version of the Moth, something like 10 times as popular in New Zealand as the modern Internaitonal Moth? Why is the British Moth, a 1930s one design version of the Moth, about 10 times as popular in Britain as the modern International Moth? Why did the modern Moth die in the USA in favour of the Laser??

    Why am I conservative on this point? Because I sailed Moths, still have one, and I think it's a crying shame to see the destruction wrought on this class by the pursuit of speed above all else. In fact, I have no great problem with foilers, they are interesting. But if they kill the Moth, or other great classes, they will be a tragedy. And the previous jumps in performance in the class tend to come with a drop in numbers.

    If speed is all that counts, I can get similar speed or better (using the yardstick of the Thorpes) for less than $1000.00. My craft can pace Les Thorpe in light air, which is more than the foiler can do judging from some results in France, and they perform much better in a breeze.

    If speed is all that counts, I can get much more from a cat or skiff.

    I'm not anti development (though I haven't won a championship in a development class for.....gee, exactly a week now- mind you it was only a Master's title in a development class that is, like most development classes, almost dead) it's just that speed is NOT everything.
  11. shu
    Joined: May 2003
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    shu Junior Member

    I think we are getting way off topic with many of these discussions. This thread was started with the intent of designing a high performance dinghy to a development class rule. Very early on, the I14 was selected, although some wanted to look at an International moth with certain restrictions lifted.

    Many of these "what if" discussions are very interesting, but I think they belong in a separate thread. I would like to see the discussion remain focused on the design of an International 14, within the existing limits of the rule.

    Perhaps the modified Moth would also do well on its own thread, since many of the off-tangent discussions seem to start there.
  12. Doug Lord

    Doug Lord Guest

    Foiling dinghies

    International 14's use rudder T-foils and therefore foils are a definite part of the discussion of a 14. Also if you read Tim B.'s first post setting the tone for this thread it would seem the discussion of foils is extremely pertinent.
    Seems to me that discussing better ways to adapt foil technology to modern dinghies is an area wide open for design input and innovation especially in coming up with an ultimate all round foil boat with a retractable main foil.
    Fully flying foilers like David Luggs International 14 may still come to pass in that class over time so why not investigate what a foiler with a retractable main foil would be like; what the changes to the hull would be if the speed spectrum of the hull was zero to takeoff? The answers would be fascinating!
    I think comparing the choice between whether the Moth class continues to allow foils with whether the class allows trimarans, catamarans and windsurfers is ludicrous: foilers fit the current rules -nothing has to be changed and the boats are showing remarkable performance .If a "normal" Moth is 70% of the speed of an A class cat then as best as I can tell the foiler Moths are significantly faster than A cats! But maybe some of the foiler Mothies will add to this.
    "Pure foilers"? Raves use a three foil system to fly the boat; the important part of the Rave system is that the wands on the foils allow them to develop the righting moment for the boat. On the Moth and on David Luggs International 14 the crew keeps the boat stable while the hull is lifted by the foils. On John Ilett's boat altitude is controlled in a manner similar to a single Rave mainfoil; on David Luggs's boat altitude is controlled by the skipper. Wand systems have the advantage of allowing the skipper to mainly concentrate on sailing not flying whereas a manual system such as Davids adds more to the mix.
    But for "pure foiling" whether its a 14 or Moth I don't think you can beat a two foil system as compared to the three foils of the multihulls or the three of Brett Burvils first Moth that used two surface piercing foils forward.
    I don't think many people appreciate the historical significance of the two foil systems developed by Ian Ward,John Ilett and David Lugg: they are the firsts of their type ever sailed much less raced; they are breakthrus that present a fantastic opportunity to learn from and to refine.
    The biggest challenge in sailing dinghy design in my opinion is to find the right combination for an all round foiler: one that retracts the main foil in light air and deploys it at X speed. And probably the best approach in really developing a breakthru boat is to do it in an existing hot development class and as a practical excersise in what is possible I think the I14 or Moth is an excellent place to start -most especially the I14 because it has more room to make a retratable foil work...
    The arguments against foils aren't very good since from what I can tell the foils are generating a lot of excitement both in and out of the Moth class. The arguments against DISCUSSING the possibilities within this thread seem shortsighted and unfortunate...
  13. tspeer
    Joined: Feb 2002
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    tspeer Senior Member

    Re: Foiling dinghies

    I think that rather than trying to come up wth a foil that retracts, it would be sufficient to have two sets of foils - one for flying and one for displacement sailing. Like the skiff classes that have three different sized rigs. You make your best guess as to the foil set that is best for the conditions of the race and go with it. You need to have enough overlap between the two sets to cover marginal conditions where the choice is not obvious or for changing conditions.

    Current I-14 hulls are clearly designed for good planing performance at the expense of some wetted area. Interchangeable foils would allow the hull to be optimized for light wind performance. The boat would be a little faster in light winds, fast on foils in heavy winds, and slower in medium winds if it could neither plane as early as the current boats or takeoff on foils. Whether this would be a regatta-winning combination would depend on the conditions, of course, but still well worth investigating.

    It'd be interesting to take a classic round-bottomed I-14, slap a couple of foils on it, and have at it with the current fleet! ;-)
  14. Re "I think comparing the choice between whether the Moth class continues to allow foils with whether the class allows trimarans, catamarans and windsurfers is ludicrous: foilers fit the current rules "

    It's NOT ludicrous to anyone who knows their class and history. Cats, tunnel hulls, windsurfers all fitted the current Moth rules when they were introduced. The rules were then changed. This is exactly the same as the foilers.

    Re "If a "normal" Moth is 70% of the speed of an A class cat then as best as I can tell the foiler Moths are significantly faster than A cats!" Sorry? The world's best 2 Moths (and the 4th,5th, etc) are 70% of the speed of an A, but the world's 3rd best Moth (the top foiler) is faster than an A???? Huh?

    How does a boat that gets beaten by the Hungry Tiger suddently become faster than a boat (A) that's much faster than the HT?

    Anyway, no more foiler talk from me.

  15. astevo
    Joined: Sep 2003
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    astevo Junior Member

    i think we should be careful with the talk about retractable foilers. the ultimate objective should be to design a boat where you dont need to change things depending on the wind/waves etc. This sort of boat is typically going to be faster than the boats withmultiple configurations.

    for example at the recent moth worlds rohans foiler won 2 heats out of 4 races he used the foils in. remember that rohan only used the foils on 2 days and won 2 heats on those days. The fact is that 3 yrs ago in perth brett burvil also won some heats. (exactly the sme number), in those three years the Ilets have put a lot of effort and experience behind their foilers and have done an excellent job. the low speed drag of the big surfaces is large. also the horixontal area dampens much of the boats pitching through the waves and so the drags are higher than the flat water tanktesting conditions might indicate. in the end the foier is brilliantly fast 3/4 reaching and in heavy winds but dog slow in the light.
    Also by having to make the call of swapping between the two configurations leaves the possibility of messing up and getting it wrong.

    my point is that the foilers are very fast and efficient within a narrow wind range.
    sure you could say that the allround speed would be faster by having them removable but in my opinion real development involves something that is fast in all conditions. it is this philosophy that the moth has developed to a point where even though we dont have a rule to determine so almost every compeditor has only one set of equipment (those extras are whale tail rudders which are slow but safe in strong winds).
    this is an idea which rule makers have attempted to put into regattas notice of race (though unsucessfully). in my opinion this would lead to faster development in the foilers as they would have to think serioisly about marginal conditions not just all out speed.

    real development to me is something that is faster than previous boats all of the time, not just in strong wind and reaching. i just fell it is leading the wrong way to suggest that we should have multiple sets of foils, much the same as i think it is bad that windsurfers might have 5 or 6 sails to us in a regatta. it is not something that existing classes like moths would look kindly at simply because of the costand complexity it would involve. if the foiler enthusiasts like the idea of multiple equipment start another class and dont destroy good boats like the moth.
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