Evolvement of foiling sailboats over the last 70 years

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

  1. Doug Lord
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    Doug Lord Flight Ready

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    Pro legends would ,theoretically, realize the limitations of the Winnebago........ And they wouldn't want the Winnebago to behave like an Orma 60 that was close to the edge all the time.
     
  2. Doug Lord
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    Doug Lord Flight Ready

    Multihulls ,particularly wide trimarans, can be designed to use foil lift and downforce to provide substantial righting moment in a way that is ,generally, not possible on narrower monohulls. The Hobie Trifoiler uses dual independent "feelers"(surface sensors) to change the angle of incidence of the whole,widely separated, mainfoils. Rave ,SKAT and Osprey use dual independent wand surface sensors to change the angle of flaps on the widely separated mainfoils to change the effective angle of incidence of the main foils to provide lift and downforce. Narrow cats such as the S9 and Whisper use dual independent wand surface sensors to control the effective angle of incidence of the mainfoils but because of their narrower beam compared to the tri's it is more effective to use movable ballast for primary RM though the foils can add RM.
    On the Fire Arrow Test Model, Maserati, Gitana 17, Macif,(and the 24' Macif Test boat) and the former Banque Populaire, the angle of incidence of the mainfoil is used to add or subtract RM either automatically(Fire Arrow) or manually via electro hydraulic systems.
    The cats of AC 35 and the new F50's use differential rudder lift to increase RM. One of the guys interviewed in the SA GP thread said the mainfoils have up to a 7 degree differential available. Apparently, they use it when maneuvering...
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    The dynamic lift from foils is also used to increase or decrease RM on some monohulls particularly those using DSS and/or IMOCA type foils. RM is decreased by retracting the foil. But the added RM is far less than that possible on a wide multihull.

    A comment by Vincent Prevost of VPLP on using the mainfoil of Banque Populaire to increase RM:

    "In ocean racing world, we enter in a new era where , as for the Foiling Imoca 60, the righting moment of the boat is function of the dynamic forces generated by the foils."
     
    Last edited: Feb 17, 2019
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  3. Angélique
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    Angélique aka Angel (only by name)

    Nice car Doug!, but they didn't meet US safety standards at the time, so like even Volvo's from the same era, they had to drive around with extra thick bumpers on your side of the pond . . .

    Here's a 450 SL with slim european bumpers — pic topless front — pic aft with the top on — don't know though how that one with its original slim factory bumpers could drive around like that in Washington state.
     
    Last edited: Feb 18, 2019
  4. Doug Lord
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    Doug Lord Flight Ready

    Last edited: Feb 17, 2019
  5. Angélique
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    Angélique aka Angel (only by name)

    Thanks Doug for explaining the use and speed gain of vertical lift foils for non total lifting !
     
  6. Doug Lord
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    Doug Lord Flight Ready

    You're welcome!
     
  7. CT 249
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    CT 249 Senior Member

    Yes, Doug, I realise that a heavy cruising cat or Winnebargo is not like an ORMA 60 or F1 car. They are different and therefore giving them the same set of foils is silly. That was my point!
     
  8. Doug Lord
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    Doug Lord Flight Ready

    ============================
    They would-obviously-NOT be the same set of foils! All "C" foils are not designed alike..........
     
  9. Angélique
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    Angélique aka Angel (only by name)

    I would assume Catana has tested the speed gain of vertical lifting force generating C foils vs lower drag vertical straight boards, so I would like to see the results of that, but in the below vids downwind they don't employ the C foils to generate some vertical lift . . .

    ‘‘ . . . curved foil-type daggerboards to help avoid the risk of “tripping up” and to optimise the pointing angle . . . ’’ no speed gain or vertical lifting claims there.




    [​IMG]
    (click pic to enlarge, click again to shrink)
     
    Last edited: Feb 17, 2019
  10. Doug Lord
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    Doug Lord Flight Ready

    I didn't read or hear any comments ? One things for sure: a fully deployed curved foil is likely to produce some vertical lift. But they don't seem to fully deploy the foils?
    I can't think of a single reason to use curved foils except to generate vertical lift. Somewhere I have the original info-I'll try to find it.
    Less chance of "tripping up"(pitchpole?) if the foil or foils are lifting the front of the boat.
     
    Last edited: Feb 18, 2019
  11. Doug Lord
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    Doug Lord Flight Ready

    Post #1 here: Curved Lifting Foils on Cruising Cats?? https://www.boatdesign.net/threads/curved-lifting-foils-on-cruising-cats.39585/#post-484826
    From post 17:
    All this has culminated in the new Catana 59. A Catana with incredibly streamlined hulls, classically elegant, and offering astounding performance. The sail plan is borrowed from racing vessels, with a short mainsail that is easy to manage and a larger foresail. Moving away from the legendary daggerboards that made the Catana shipyard's name, this catamaran is fitted with revolutionary curved daggerboards, to create a hydrofoil effect. The result is an extremely safe and comfortable boat that achieves astonishing acceleration and an extraordinary cruising speed.
     
  12. OzFred
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    OzFred Senior Member

    I don't know about that. The 62' cat is rated at 19.2t light, so fully fuelled, packed with people and supplies (it has accommodation for 6) it's probably well over 22 or 23 tons. That's 3 times the weight of an AC75 ready to sail with crew and guest racer on board.

    The C foils are likely about as effective boost in performance as the diffusers you see on street sports cars to lower drag. Yes, they help in theory and maybe in certain circumstances they make a tiny difference. If someone with a Catana 62 really wanted to go fast it would make a vastly bigger difference to take weight out of the boat (or just buy something that actually does go fast).
     
  13. Doug Lord
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    Doug Lord Flight Ready

    The Evolution of Foiling Sailboats: there is an interesting race going on in the RORC Caribbean 600. Part of the story is about two of the nearly identical MOD 70's starting 2 hours behind the whole fleet to give the MOD 70 Argo more time to get ready after just capsizing 48 hours ago. The MOCRA multihull fleet would not agree to delay the start, so Giovanni Soldini(owner and Skipper of Maserati) agreed to start late to be able to race Argo and the Race Committee agreed that the two MOD 70's could have their own "class" and a delayed separate start. The fact that some of the MOCRA boats would not agree to a 2 hr later start hurt ARGO most because now she won't be scored under the MOCRA Handicap System.
    Well,it is so very cool that just a few minutes ago when I checked, Maserati and Argo lead the whole fleet including ALL the MOCRA multihulls and two hot shot multies "Fujin"(a Bieker design) and the DNA F4 "Falcon"(the only other full flying multi in the fleet besides Maserati).
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    The other part of the story concerns some recently published comments in this thread about beachcat foilers only gaining around 4% more speed over their seahugging sisters. That comment was not reflective of the real world of foilers and foil assist but was assumed to be by one poster.
    So today, I checked the speed of the MOD 70 multies upwind and downwind. But first a bit of a qualifier: Argo is a standard MOD 70 and as such uses two "C" foils(one on each ama) that provide vertical lift resulting in greater speed than if she was not using them. Maserati is a full flying trimaran using a revolutionary foil system designed by Guillaume Verdier(and very similar to the Fire Arrow Foil System designed years earlier than the Maserati system). Maserati was the first fullsize trimaran to use this system:

    Upwind Maserati was 6.9 % faster than Argo,
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    Downwind Maserati was 11.1% faster.
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    Keep in mind these percentages would be even greater if Argo had not been using foil assist.
    Because Maserati is a full flying foiler, she is also heavier than Argo.
    ===========================
    Stunning Fleet for RORC Caribbean 600 Feb 18,2019 https://www.boatdesign.net/threads/stunning-fleet-for-rorc-caribbean-600-feb-18-2019.61583/#post-848496
     
  14. OzFred
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    OzFred Senior Member

    You really should reference what you are referring to (presumably CT249 in post 101) rather than casting aspersions. What CT249 posted was analysis of race results for small or off–the–beach cats and therefore absolutely is reflective of actual performance, unless you can prove either his data or analysis flawed (which you have not). To say it's not reflective of real world performance with zero evidence is plain wrong.

    The fact that two MOD 70s, which are to beach cats as an AC50 is to a Hobbie 14, have a particular speed differential does not invalidate CT249s analysis in the slightest. It's one result from entirely different boats. Your claim that it counters CT249s conclusions also ignores any effect from Argo's capsize and subsequent rush to prepare for the race that may have affected its performance.

    The VMG difference* was 21.4kn (Maserati) vs 20.9kn for Argo, an overall difference of 0.5kn making Maserati 2.4% faster than Argo over the race. In terms of time difference, it was 38 min after 1 day 4 hrs of racing, again less than 3% difference. And Argo sailed 10nm further.

    So 4% difference is actually over stated.

    * Based on provisional results posted at 2019 Fleet Tracking | Tracking - Players | Race Information http://caribbean600.rorc.org/Tracking-Players/2019-fleet-tracking.html
     
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  15. Doug Lord
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    Doug Lord Flight Ready

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    No its not-only of catamarans using a particular rating system and where many don't foil a significant portion of the time(upwind) --not representative of all foilers and foil assist at all. It presented a false impression of the real world of foilers and foil assist.
    What I said was: "That comment was not reflective of the real world of foilers and foil assist ..."
    The MOD 70 comparisons are among the best and most relevant I've seen yet and much more realistic considering "all foilers and foil assist".
     
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