Evolvement of foiling sailboats over the last 70 years

Discussion in 'Sailboats' started by Angélique, Feb 4, 2019.

  1. Angélique
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    Angélique aka Angel (only by name)

    My interpretation of the Artemis video about going upstream the Amazon on a windless day is that it's a thought experiment, and they explain what they expect to happen if they would place their boat there under the named conditions. The narrator says at 0:21 ‘‘let's place the Artemis racing boat in the Amazon River’’ while moving the boat over the map, and then goes on with ‘‘imagine . . . ’’, they don't say the boat was actually there and that they did the experiment for real. I see it as they tried to make the whole thing imaginable with some video shots of tacks from elsewhere. I have a hard time to believe it would be possible if it was done for real though.


    Below some talk from the bottom of the video comments, click also on view answers to see it...

    ‘‘ But...when you're generating your own wind by speed, then the wind you're generating can only be coming from the direct direction in which you're traveling. This would prevent the sails from being filled, because the direction of the wind would just be coming from directly forward. ’’

    ‘‘ True of traditional sails but not fixed wing sails. ’’
     
    Last edited: Feb 6, 2019
  2. Ad Hoc
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    Ad Hoc Naval Architect

    I would strongly suggest you not use the term "patented" in this context.
    That is merely a ploy that ppl/companies use to suggest they have the best thing since sliced bread and do not want others to copy it.

    It has nothing to do with basic principles of physics.
     
  3. trip the light fandango
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    trip the light fandango Senior Member

    Thanks yes that explains it, catch phrases, corporate waffle, instant exciting climactic music, the drumming, and an emotive message about a sustainable future, I would have switched off but kept watching only catching part of the spiel, brain glazed over. Personally I'm really sick of this style of package to grab attention, it's fake.
     
  4. OzFred
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    OzFred Senior Member

    It is a matter of public record that DSS has patented one of its designs. The phrase was used to distinguish that particular DSS foil design from its many others, nothing more.
     
  5. Ad Hoc
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    Ad Hoc Naval Architect

    Then perhaps referring it to....DSS foil etc...rather than a "patented" foil etc, floats my boat and is not a subjective confirmation of such.

    I should say, I am biased. Since as a naval architect/engineer....i seriously despite the term...patented. It stifles creativity and further research.
     
    Last edited: Feb 6, 2019
  6. Doug Lord
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    Doug Lord Flight Ready

    =========================
    You're partially right for "normal" DSS but not for full flying DSS which is based on surface piercing foils that also act as planing surfaces.
    Normal DSS can work as a fully submerged foil, as a partially submerged surface piercing foil or as a planing surface: DSS looks like 36.jpg
     
  7. Doug Lord
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    Doug Lord Flight Ready

    ===================================================
    Apparent wind sailing is not new-that's how so many foilers can sail so much faster than the wind.
    Moths can do 2-3 times windspeed , F50's probably 3-4 times windspeed ,iceboats up to 5 times windspeed.
    -------------------
    Just discovered this commentary by John Perry in the Artemis thread in the "Boatdesign" forum:
    Press release: AC50 catamaran will do 20mph SOG against a 10mph tide in zero wind? - Amateur Yacht Research Society https://www.ayrs.org/phpbb/viewtopic.php?f=28&p=3527#p3527
     
    Last edited: Feb 6, 2019
  8. Doug Lord
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    Doug Lord Flight Ready

    ====================
    According to Hugh Welbourn both "normal" and full flying DSS are covered by his patent or patents.
    --
    I think the patent system used to be a valuable way for inventors to protect their intellectual property for a specific time. However, the cost of getting a patent has skyrocketed and the cost of defending a patent has become ridiculous. In many respects patent coverage is now only available to wealthy big companies.
     
  9. tlouth7
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    tlouth7 Junior Member

    I was not aware that the UpTip foil was intended to be flown with the tip above the surface. My understanding is that this is a slow way of achieving ride height control because (1) you get additional drag and (2) air may/will be drawn down the low-pressure side of the foil moving it out of its design envelope.

    I would disagree with the statement above because the thing that makes UpTip clever is its "passive" control of ride height. I don't believe any implementation of a surface piercing V-foil is attempting to use leeway in this manner; thus their operating principle is different. The physical similarity is merely coincidence; note for example that the angle between the horizontal and vertical elements of an UpTip foil will be less than 90 degrees, whereas on a V-foil you would expect 120 degrees or more. It is true though that any angled foil that progressively leaves the water as it rises will see a progressive loss of lift and will therefore act as (and be) a surface piercing foil in that circumstance.

    The leeward foil seen on IMOCAs (e.g. Charal in post #33) is much closer to the traditional V-foil, just cantilevered out rather than on the centreline of the vessel. The use of foils on either side developing unequal lift and therefore righting moment at non-zero heal (e.g. IMOCA, Quant 23) is also not really new, though the implementations that use a wand on each hull each connected to a trim tabbed T-foil are quite innovative. I think this is the only current way of achieving active heal control without surface piercing foils.
     
  10. OzFred
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    OzFred Senior Member

    You must consider every foil ever used on every boat ever to be "technically" a surface piercing foil, as at some point, at some attitude of the boat, they will be only partially submerged. Even T foils.

    Surface piercing is typically used to describe a foil where changing the level of immersion is a fundamental principle of its operation, usually to control ride height but not always. If applied to every foil that happens to breach the surface from time–to–time, it would include a traditional centerboard, reducing the term to meaninglessness.
     

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  11. Doug Lord
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    Doug Lord Flight Ready

    =====================================
    According to Tom Speer, letting the Up "tip" breach the surface is slow.But according to Martin Fischer and others it is not(significantly). The picture of the GC32 with it's up "tip" showing was going faster than any GC32 had ever gone. You frequently see the tip on many cats and tri's with UptiP foils-that doesn't make it the best way but it's just the way it is. See Gitana Mod 70 pix below.
    I don't think that is correct-take a look a Doug Halseys foiling tri with "V" foils. The angle between the two foils that comprise a "V" foil is less than 90 degrees on every one I've seen .
    My Fire Arrow and WOLF use two altitude control systems simultaneously: 1) as part of the lee ama UptiP foil and, 2) a wand controlled foil on the daggerboard. The wand controlled foil sets the flight altitude of the main hull while simultaneously determining the angle of heel of the whole boat while also working with the rudder T-foil to control pitch of the whole boat. The wand controlled main foil automatically develops downforce as required......
    The 100' tri's and Maserati(that also use two altitude control systems simultaneously) control the heel of the whole boat by changing the angle of incidence of the main foil(on the daggerboard) manually with an electro-hydraulic system (exactly what Fire Arrow/WOLF do automatically with a wand controlled main foil.) The big boats will eventually use a flight control autopilot that will adjust all the foils as required but most frequently the mainfoil on the daggerboard. As of right now such a thing is illegal in the Ultim class. But Gitana 17 is already set up for that system when it becomes legal.

    Doug Halsey's foiling tri "Broomstick" with "V" foils:
    Terry Curtis photo--

    Broomstick_4.jpg

    Gitana Mod 70(later Maserati) Uptip ama foil breach of tip:
    ---- photo by Team Gitana
    Gitana Mod 70 uptip foil.jpg
     
    Last edited: Feb 8, 2019
  12. Angélique
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    Angélique aka Angel (only by name)

  13. Angélique
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    Angélique aka Angel (only by name)

    There's a subject thread about the Artemis video about going upstream the Amazon on a windless day.
     
  14. Angélique
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    Angélique aka Angel (only by name)

    Now I was thinking, what happens if you leave the windward foil in the water, but transfer that foil into a downward force, wouldn't the boat be able then to carry more sail area and go faster . . ?
     

  15. sharpii2
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    sharpii2 Senior Member

    It appears to me that vertical lifting foils are the last word in sailing performance. I have never seen so much invective spewed at a newly introduced sailing technology since multihulls were introduced in the 1960's. IMHO, like multihulls, foiling sailboats are here to stay. I would certainly like to get a ride on one. But owning one would probably not be my thing. Fast sailboats of all stripes tend to have limitations of their own, usually: limited payload, higher cost per displacement, higher levels of complexity, and ofter longer set up times.
     
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