Skiff Design Thread

Discussion in 'Boat Design' started by TimClark, Jan 29, 2006.

  1. Baronvonrort
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    Baronvonrort Junior Member

    Doug
    Do you have any photos of your sailboat actually sailing on the foils instead of seahugging?
     
  2. Doug Lord

    Doug Lord Guest

    No

    It's only barely foiled and not well at all because of problems I've previously mentioned.
    The boat is currently being rebuilt with those minor problems corrected ,with buoyancy pods and with sliding bench seats so it can be sailed as a singlehander (or doublehanded).The biggest problem, as I mentioned earlier, was not having a facility to adjust the angle of incidence of the whole mainfoil-not just the flap.
    It has only sailed in a max of a little over a 10k wind but sails very well as a seahugger. The boat uses a MANUAL altitude control which proved very difficult to use under the original set up but shows promise down the line.
     
  3. granite
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    granite Junior Member

    If you are going for a foiler then you probably do not need an Asymetric as the wind is likely to be too far forward of the beam for it to work.

    If you do not need spiniker do you need a second person

    If you go single handed then it cuts the weight massivly making foiling much eisier.
     
  4. CT 249
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    CT 249 Senior Member

    Errrr, the Tornado and 18' skiff carry kites and they go downwind pretty quickly. Even Rohan Veal is not always skiff speed downwind, so the foilers are surely in the region where (all else being equal) a spinnaker is a massive help.
     
  5. Doug Lord

    Doug Lord Guest

    Foiler Skiff/spinnaker

    Here is an I14 on foils w/spinnaker:
    aus14_2.jpg
    http://www.monofoiler.com/images/aus14_2.jpg
    I'm not convinced that a well designed foiler with an efficient rig like the Moth's rig would benefit from a spinnaker-maybe a Screecher though. Dr. Sam Bradfield used a Screecher as standard on the Rave multifoiler -very flat cut, small, offwind sail.
    Part of the reasoning is the performance of a non spinnaker equipped Moth-faster than a 49er and recently matching speed with Tornado flying a spin..
    ----------------------------
    Here is a short primer on what a Screecher is; just substitue "foiler" for multihull:
    Harken: Code Zero, Asymmetrical, Screecher Sails
    Address:http://www.harken.com/furling/codezero.php
     
    Last edited by a moderator: Feb 5, 2006
  6. CT 249
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    CT 249 Senior Member

    Hang on Doug, where is the detail about the Moths knocking off 49ers (in fact the 14ers from Rohan's club don't think he's any faster than they are even in his ideal conditions) and Tornadoes?

    Yes, I know there was one Mothie who speaks of going faster than a T. That was on a very gusty day in a very gusty place where there were some fairly slow Ts about (as well as very quick ones), and certainly the Ts seemed to be going a lot faster than the Moths whenever I saw the Moths that day.

    I'm not saying he's wrong, just that it may not have been a consistent performance - any more than Rohan's performance in a regatta where he was generally lots slower than the NS14 and Cherubs was a true indication of the Moth pace.

    In one race where I've raced against Rohan, he was probably slower than a Laser Radial. In another (strong winds) he was slower than the good Cherubs.

    That's NOT (repeat NOT) saying that the foiler Moth is not an incredible performer. It's just saying that ONE race or ONE series or ONE time when boat X passed boat Y does NOT mean that boat X is really "faster".

    PS - how many times have you seen a foiler Moth in the flesh? How often have you raced against them?
     
  7. Doug Lord

    Doug Lord Guest

    Speed/ spinnaker

    Gee, CT I live in the USA where, unfortunately we don't have any foiler Moths-yet(that I know of-though there are at least two being built in Fl. and maybe one in SF). However, we can read up here and there have been numerous accounts of the speed of the Moth written by or about Rohan, Simon Payne , John Ilett and others including Phil Stevenson, that illustrate the incredible speed of the Moth-like Rohan beating a fleet of A Class cats and Phil matching speed with a Tornado and Moth foiler speeds of nearly 27 mph.And the estimate that the foiler Moth is 15% faster than a 49er. Most of the accounts I've read have been first hand accounts by people who were there or who actually did the deed. And most accounts are in conditions that suit both boats.
    But the subject at hand was whether or not a new larger "skiff" foiler would use a spinnaker or not-right? And the answer-again- is probably not.
     
  8. granite
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    granite Junior Member

    I was possibly a bit criptic in my earlier post.

    What I was thinking was that If I were to design a foiler I would go single handed.

    The Moths weigh in at about 30Kg all up plus a helm 65Kg gives 95kg to lift.

    If you go two man taking a small High tech boat as an example the R class Skiffs have no min weight and are about 40 to 45Kg hull weight plus 15 to 20 kg for the rig (Verry Approx) Add to that two people 65Kg each and you have a total of 180Kg to lift.

    The power required to lift goes up by the cube of the weight (I Think)

    I think that the extra effort required for a two man boat outweighs the advantages of having a kite.

    Of course you could take it all to another level and have a single handed foiler with (flat) spinaker, it would keep the helm proparly buisy
     
  9. CT 249
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    CT 249 Senior Member

    Granite, there's an interesting debate on

    http://www.moth.asn.au/forum/viewtopic.php?t=340

    about heavier boats and foiling. There are apparently fairly good opinions on both sides (from those who have actually foiled).

    Doug, do you know when and where Phil matched the T? How good was the T? Was it racing?

    I'm not saying Phil DIDN'T match the T (he's a very honest guy) but I was there and it is possible that it was a poorly-sailed T on its way to the start or just trying to survive in gusty winds. It may also have been a top-class T at full speed - but until we know whether it was Olympians at full pelt or slow sailors struggling, it seems a bit rough to imply that foiler Moths are faster than Ts downwind.

    If you want to use one quote to draw conclusions, you could say that 420s and OKs are faster than foiler Moths because Rohan says he spent "a lot of time sitting in the water getting passed by Formula 15's, OKs, 420's and Tasars" at a recent regatta.

    Obviously it wouldn't be fair to use that to say Moths are normally slower than 420s, so why is it OK to quote just as selectively to imply they are normally 15% faster than a 49er and match a T?
     
  10. Doug Lord

    Doug Lord Guest

    Moth speed

    249, it's not just Phil or Rohan: there are dozens of reports from people that have been passed by or have seen the Moth fly by boats that it shouldn't beat. The Australian A Class forum ,before it self destructed, had testimonies from a half dozen or so A class skippers that were left in the dust by the foiler Moth.You should read Phils comments-he said he was nearly the slowest Moth that particular day and still matched a Tornado. This phenomenon is still in it's infancy but the numbers of reports of incredble performance just keeps getting larger. Any little sailboat with 85 sq.ft. of SA that goes 27 MPH is trully a breakthru boat.
    On the other site the position that only Moths can foil or foil upwind or foil around a course is just simply wrong as shown by David Luggs I14 (2000)and the original monofoiler the Monitor(1950's)-and maybe others I don't know about yet.
    There is HUGE opportunity for somebody or maybe numerous people to design and build a "Peoples Foiler" that fixes some of the problems of the Moth and brings foiling to the people in the same way Hobie brought small multihulls to generations. It can be done and it will be done sooner or later....
     
  11. CT 249
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    CT 249 Senior Member

    I DID read the comments, Doug, and all my previous comments still apply.
     
  12. Doug Lord

    Doug Lord Guest

    Foiler Moth/ Tim

    According to Tims comments on SA it looks like he's going to build a foiler Moth-good move ,Tim! Good Luck!
    I saw where Phil S. said you should sail the thing as a seahugger for a year-he may be right but go to the Moth forum and look under "Training" (I think-see url below)).Another guy that has sailed the foiler Moth has a different take on it-he thinks you should start out foiling whenever possible and others on the UK forum suggest that by using buoyancy pods initially you could avoid the pitfalls and frustration of constant capsizing when first learning a skinny seahugger. After all, you MUST have the rudder t-foil anyway. And have another look at the Sebastian Josse video-his first time sailing a Moth as far a I know.
    Australian Moth Class Association :: View topic - Optimist to Moths
    Address:http://www.moth.asn.au/forum/viewtopic.php?t=315&postdays=0&postorder=asc&start=0
    ======================
    Also read this:
    Australian Moth Class Association :: View topic - Moth for beginners?
    Address:http://www.moth.asn.au/forum/viewtopic.php?t=273&start=0
     
    Last edited by a moderator: Feb 9, 2006
  13. TimClark
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    TimClark Senior Member

    Yeah I at first was going to build a moth, then I wasn't going to, but I recently got a new job so I'll see if I have enough funds to get this started. As stated on SA, the foils, and rig will be the most expensive part of this whole building proccess.
    Tim
     
  14. Baronvonrort
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    Baronvonrort Junior Member

    Doug
    If you put buoyancy pods on it then that makes it like a trimaran.
    The problem arises when you capsize of then having to re right something with great stability when upside down.
    The pods will make it turn completely upside down much quicker when capsizing.
    If foils are the future why are all the speed sailing records set with planing hulls?
     

  15. Doug Lord

    Doug Lord Guest

    Buoyancy pods/ foiling

    Tim, good luck but before you start building please do the research on such things as buoyancy pods which would allow you to foil the very first day the boat goes in the water without having to spend long frustrating hours mastering a skinny Moth w/o foils.
    See these comments by top Moth guys on how pods will help beginners:
    http://www.int-moth.org.uk/IsthisamothSP.htm
    ==================
    Baron, see the above reference about buoyancy pods; while most of the guys think they are illegal in the Moth class they almost all agree that they would help beginners learn faster.The pods can be made removablein the Moth class; they are likely to be standard in newer classes of foiler. No question that they would allow beginners to foil soon after they launch their boats instead of waiting two or three seasons while they master sailing a seahugger Moth. See the Sebastian Josse video for an example of someone who foiled (well) the very first time he sailed a Moth -and w/o buoyancy pods. They would have helped him a bit and would surely help anyone else that maybe didn't have his natural talent. By the way, Josse was so blown away by sailing Rohans boat that he bought it and committed to sail in next years Worlds! The pods are just that-not hulls. They are backup to prevent capsize so you can get up on foils where the boat is much more stable.Designed right they would cause no problem on a capsize because they are not that big.
    -----
    Hydrofoils will be most effective and fun between about 4 and 40 knots for the time being. The fastest Moths have done 23knots(27mph) which means there is a long way to go to max out effective foiling. Planing hulls currently appear to have an advantage above 40 knots though even they have to use vertical foils to sail. Much is still to be learned about how to foil under sail above 40 knots because of the onset of cavitation.
    For the time being what is most important and fun is taking off in the lightest wind possible and high relative speeds, as compared to other boats, in a given windspeed in the range of 5-15/20 knots. This is the range in which the Moth excels and will be the range in which newer foilers excel.If you haven't foiled you owe yourself the pleasure-do it once and you will understand why I am so enthusiastic about them.
    A "trick" on foils that has so far only been done accidentally is jumping intentionally. Some newer boats will will have the facilty to bypass the wand and jump any time the skipper wants to which, when successfully mastered, will be loads of fun and pretty cool to look at. Plenty of room for developing foilers larger than the Moth and all kinds of room to go faster.....
    ++++++++++++++++++++++++++++++++++
    Regarding planing hulls and
    "SKIFFS"- The era of the skiff is OVER-the era of the foiler is just begining. In the contests so far that I know about the 11'(12.75'LOA) Moth has shown itself about 15% faster than a 49er in conditions that suit both boats. That's a boat with 85sq.ft. beating a boat with 600 sq. ft of SA!! And there are more and more stories coming in like a guy at the back of the Moth fleet matching speeds with a Tornado catamaran flying its spinnaker or beating an A Class fleet repeatedly in conditions that suit the boats concerned. We're just at the BEGINING of what hydrofoil monohulls can do and do much more efficiently than any other form of sailboat including what are now "traditional Skiffs".In fact, if you can believe CT249 traditional skiff classes are so concerned about hydrofoils that they have banned them.
    Not only is the Moth probably faster than or at least as fast as most traditional skiffs and most multies under 20' it is probably among the least expensive of all of them-more bang for the buck without a doubt;now that is real technology making a serious difference!
    Like it or not the Moth has made history. And what it started is going to continue to make history for a long time to come.
     
    Last edited by a moderator: Feb 17, 2006
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