16-17' Fixed Keel Self-Righting Foiler

Discussion in 'Sailboats' started by Doug Lord, Aug 30, 2008.

  1. Doug Lord

    Doug Lord Guest

    Munter, in normal sailing the boat's RM comes 100% from the crew moving
    outboard on racks using sliding bench seats. The keel bulb provides no righting moment as on a "normal" keelboat. It's there just to recover from a knockdown and/or pitchpole.
  2. Doug Halsey
    Joined: Feb 2007
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    Location: California, USA

    Doug Halsey Senior Member

    Wow, what a surprise! Here I am innocently reading about hydrofoil keelboats, when I come across a photo of my little hydrofoil trimaran Broomstick. And then to have it referred to as a possible family boat!

    Here's another photo of Broomstick, with a much better family boat in the background. Those guys (& some girls) were really having a great time that day.

    Maybe when I get this boat working better, I'll take a stab at a monofoiler. Should be lots better in lighter winds, at least.

    Seriously though Doug L. : I think you & most other sailors would probably be disappointed in the performance of the boat you're proposing. The extra drag of the foils when you're not foiling & the extra weight of the keel when you are would be real killers, in my opinion.

    Some experience from sailing Broomstick (admittedly a much smaller boat):
    1- I like to sail as often as possible without the amas. I can really feel the difference in performance with 20 lbs. less weight.

    2- I really don't like to use my bigger rig (143 ft**2, instead of 108), in part because of the extra 20 lbs. that it adds.

    3- I tried sailing the other day with a daggerboard, in addition to the foils (hoping to improve the performance going to windward). The drag of the added wetted area made it feel really sluggish.

    You've got a lot of other ideas to work on. Please put this one on the back burner for now.

    Doug Halsey

    Attached Files:

  3. wind_apparent
    Joined: Apr 2008
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    Location: boulder colorado

    wind_apparent wind driven speed addict

    no,seriously, I love your little trifoiler and would love to build one to take my kids out on the weekends. they love fast boats and so do I. sometimes we go out on a hobie 16 on windy days and they love it. Did you design it? Are the plans available?
  4. bistros

    bistros Previous Member

    Reality Check for the Black Knight of Foiling

    I kind of doubt it would be self-righting. 120 pounds isn't a lot of RM on a 5-6' lever arm. Getting a normal two man performance boat back up isn't trivial with a 120 pound person. Generally lifting a wet rig without the vang blown is tough. Widebodies (12') of any configuration have their own issues - not the least of which is that buoyancy pods/amas/whatever aren't selective about how and when they provide buoyancy. Once a boat is turtled, buoyancy pods make it harder and not easier to right.

    Although people have tried unsuccessfully before to table this issue, weight is the enemy of foiling - higher weight requires a higher lift component generated from the foils, and a higher lift component means higher drag. Higher drag means more power required from the rig, and higher righting moment to keep it level and working.

    I just can't see this idea working well, power to weight ratios, SCP and whatever statistical fact mutilation/reality avoidance technique you prefer. "Foiling sportboat" just seems kind of .... oxymoronic.

    I understand the simplistic appeal of making foiling popular and easy - kind of like making rocket science simple, solving quadratic equations easier than adding 1+2 or getting a simple accurate manual on how to figure out what women are thinking.

    Face reality - your "easy to foil" foilers were already built, but there wasn't a thundering stampede to buy Raves or Hobie Trifoilers. Foiling isn't the holy grail of sailing to most people, and years of unbalanced promotion of foiling in any form haven't seemed to made you popular.

    Maybe unskilled operator foiling for big folks and jumping foilers is YOUR personal Holy Grail and you are confusing YOUR hopes and dreams with everyone else's. I know whenever I read another Doug Lord spec sheet on foiling I feel like breaking out the coconut halves to make the hoofbeat noises as you chase the Holy Grail, just like the Monty Python comedy you seem to be emulating.

    I know you will respond in Monty Python fashion (just like the Black Knight) "It's just a flesh wound" as your arms are cut off.
  5. Doug Lord

    Doug Lord Guest

    Thanks for the comments,Doug! This little boat is just an idea for the time being-most definitely on the back burner! However,I think it could work....
    If the boat was designed properly the foil lift would reduce hull wetted surface and wavemaking drag from a surprisingly low speed on up. Total wetted surface including the foils could be equal to or less than other monohulls its length. It's an interesting design challenge with the concept of "foil assist" playing a major role.
  6. Gary Baigent
    Joined: Jul 2005
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    Location: auckland nz

    Gary Baigent Senior Member

    self righting 5 metre foiler

    Doug, thinking about the self righting - have you seen Randy Reynold's ideas of self righting his R33? - such a layout, modified somewhat, could be achieved on the "fictional at this stage" SR5 - or is that cheating? Anyway I'm thinking about it while lying in the bath - where, of course, all the best designs are conceived.
  7. Doug Lord

    Doug Lord Guest

    Haven't seen that Gary-is that a system where the boat "self-rights" w/o crew action ? Tell me about it when you get a chance
  8. Gary Baigent
    Joined: Jul 2005
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    Location: auckland nz

    Gary Baigent Senior Member


    Actually he swore me to secrecy - so I'm not saying anything but like all good ideas, it seems obvious once you see it and his self righting concept definitely has advantages (and a couple of disadvantages too) - but it works.
  9. Doug Lord

    Doug Lord Guest

    Ok, this was two years ago-come on spill the beans(please):
    "Righting System
    There are three different systems being developed to make any capsizing of an R33 a non-event. One of the systems is almost complete with just the finishing touches to be done. It has been tested twice already with four crew capsizing the boat under sail. “It worked so well we can’t wait to do it again, said Reynolds. “It was fun! And we didn’t even get wet…both times!”

    The systems will be very user friendly and once fully operable will make the R33 the only multihull on the market with such a safety system in place. While other performance boats encounter the risks inherent in the sport and adopt a “use at your own risk” policy – Reynolds Design is determined to make their boats their sailboats the safest boat on the market for their size."
    And I found this here-http://reynoldssailing.com/en/update/pdf/NewsletterApril06.pdf
    Refering to a masthead float?

    “It happened real slow – it wasn’t like you couldn’t react. Once we started going up I was concentrating on the
    main and the traveler and I wasn’t thinking about the jib. By the time I said cut the jib, our bow had blown off too
    much to make any difference.”
    The silver lining was that Dunbar was prepared for the situation by having his float bag that included his hand
    held radio, IPERB, tow boat membership and cell phone all in an accessible location. And more importantly, the
    capsize-related Reynolds designs worked excellently. An anchor system that Dunbar had Reynolds provide was
    deployed and the newly designed mast float made the event extremely manageable.
    “The float worked well,” said Dunbar. “It completely floated the mast and did what it was supposed to do.”
    Dunbar was able to call the pre-designated tow company and drive the boat home - with no damage - under its
    own steam.
  10. Gary Baigent
    Joined: Jul 2005
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    Location: auckland nz

    Gary Baigent Senior Member


    The first system - but my lips are sealed.
  11. Doug Lord

    Doug Lord Guest

    Foil Assist Upwind

    I would like to hear some comments from people knowledgeable about foiling on one of the central themes of this thread: the foils would not be retracted but would be designed to be effective upwind from,say, 5-6 knots boat speed on up in reducing hull wetted surface and thereby "paying" for their wetted surface/drag. Off the wind,when the spin is popped the boat would fully fly.
    But the "foil assist" aspect of this concept is important and I'd like to get feedback on the idea. Thanks in advance......
  12. fng
    Joined: Feb 2009
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    Location: new zealand

    fng Junior Member

    some mad buggers had a go on a larger scale, primerily the foils were for stability and windward lift. The foils were ment to be smaller and have less drag, but the engineers wanted more carbon. End results - stability gained, well a carbon rig would have been better. windward lift outstanding at times but very hard to get into the grove out of tacks. In the end it was thought that the gains were not enough to warrent continuing, so the cut it all out and fitted a tone of water ballast each side and the boat went way better .

    Attached Files:

  13. Doug Lord

    Doug Lord Guest

    Upwind Foil Assist

    I'm convinced that a properly designed system that uses "foil assist" to help the boat upwind and then allows it to fly when power is doubled downwind is viable-and a great potential use of hydrofoils.
    We know that upwind foil assist can work with many examples from the I-14 to the Catri and Open 60 tri's to the Stealth beachcat-it just hasn't been explored in the direction I'm thinking of in this thread as best I can tell. But it will be-I'm certain of that.
  14. bistros

    bistros Previous Member


    One of the most active I-14 fleets in North America is at my club, and the only use of lifting foils on I-14 RUDDERS ONLY is to control pitch, not to provide lift for the purposes of reducing wetted surface area.

    People crank on a little rudder lift to help keep the bow down and allow crew on the wire to trap further aft. Keeping the bow knuckle just touching the water is critical for upwind speed. Allowing the crew to trap aft keeps the two people on the traps together - reducing aerodynamic drag and making transitions through the twilight zone safer.

    Doug, please don't represent the use of a T-foil rudder on an I-14 as foil-assist in the same sense as a hydrofoil boat that can "foil" downwind. All you do is provide the guys in the bar with more reasons to laugh at your ignorance of performance dinghy sailing. I-14s have outlawed the use of more than one lifting foil on the boat, effectively preventing foiling as a class direction in the future.

    Alan Smith and Dave Lugg's foiling I-14 many years ago was no longer a class legal race-able I-14 once the rules changed, and there is no I-14 class motivation or interest (democractically) in going further down the foiling path.

    But them again, you won't listen.


  15. Paul B

    Paul B Previous Member

    Of course this is simply another waste of time. The King of Kooks dredges up a 6 moth old thread with more of his repetitive nonsense, asking a rehetorical question he doesn't want an answer to for the umpteenth time.

    He simply needs to divert from the real topic, that he has a garage full of useless parts that will never be a funtional vehicle.

    Same old craziness. It will never end, and no actual boat will ever emerge. Hell, the dolt can't even produce a technical drawing.

    Meanwhile, others are building and sailing, some even foiling, their projects.
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