Evolvement of foiling sailboats over the last 70 years

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

  1. trip the light fandango
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    trip the light fandango Senior Member

    Rose coloured glasses is a term that refers to an"optimistic perception of something; a positive opinion; seeing something in a positive way, often thinking of it as better than it actually is."
    This is my perception of how you see foilers Doug, not yours obviously. Foils are dependent on technology that is still evolving and simply isn't practical for my purposes. Who knows one day the technology may be cheap and bullet proof, but I've already stated that about 5 posts ago, stop cherry picking what you do and don't want to acknowledge, please. Keep working on your stuff ,you may strike gold. Please stop selectively omitting my explanations to suit yourself.
     
    Last edited: Feb 16, 2019
  2. Doug Lord
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    Doug Lord Flight Ready

    ==========================
    ????????!
    PS- I have never done what you suggest above-at least intentionally. Since you won't explain what you're talking about I can only apologize for any perceived insult you hold me responsible for. I'm sorry, but I have no idea what you're talking about.
     
    Last edited: Feb 16, 2019
  3. Doug Halsey
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    Doug Halsey Senior Member

    That's not quite right. As you say, the induced drag reduces as speeds increase, but the result is that, at high speeds, skin friction becomes dominant and the total drag increases with speed in a similar way to conventional planing boats.

    That's assuming we are talking about fully submerged foils (like those on Moths). For surface-piercing foils, the situation is more complicated. (one of my favorite subjects, by the way, but probably too much of a digression to go into here...)
     
  4. Doug Lord
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    Doug Lord Flight Ready

    Excellent, recent article(Nov.30, 2018)---
    https://www.sailmagazine.com/multihulls/foiling-is-becoming-a-sailing-style-for-all

    Excerpts:
    As for the future, if you don’t think foiling is fully a part of the sailing landscape yet, just wait a year. Or better yet, just look around, as there are already plenty of designs to choose from, including such European efforts as the French-built Befoil catamaran, or the Flying Mantis, the White Formula Whisper Cat and the F101, all from the UK. “There is not a new [multihull] model if it’s not foiling,” says Luca Rizzotti, founder of the global forum Foiling Week. “I have spoken with many manufacturers this fall. They don’t think about doing a normal catamaran any more.”
    --------------------------
    Bottom line: we live in one of the most dynamic times sailing has ever experienced, as is clear to see with all the marquee events of the sport—from the Olympics to the Vendée Globe—now showcasing foiling craft. Is foiling for everyone? Not necessarily. But it certainly can be for those who can afford those same cruising multihulls with foils we will likely see in the next few years. I also see boats like the UFO being a real game changer in terms of sailing’s popularity with people in general, given they can cost less than a Laser. And indeed, Clark makes a point of holding UFO demos not just at yacht clubs and in front of experienced racers, but at parks and beaches.

    Remember those ads from the ‘70s and ‘80s with hundreds of Hobie Cats and Windsurfers lining the shore of some lake we never heard of? I believe today’s small foilers have a real shot at recreating those same heady scenes, in which life is one big Mountain Dew commercial. And who knows? Things may someday even become so stable and mainstream you can forget the helmet.
     
    Last edited: Feb 17, 2019
  5. Angélique
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    Angélique aka Angel (only by name)

    Saw this cruising cat renders with bruce foils in its preliminary concept, but with winged LAR keels in the final design, don't know if any boats were built from these plans, it was drawn up for an very experienced Oz sailor it says . . .

    from Laurie McGowan in Annapolis Royal on Nova Scotia — Running Tide 43

    [​IMG]

    [​IMG]
     
  6. CT 249
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    CT 249 Senior Member

    1

    I can't believe anyone would think those foils would create significant lift. Only a couple of people can get a featherlight (75kg rigged) carbon C-foiled A Class cat up and fully foiling. If an ultralight carbon race machine can't foil with C foils, then what would a very heavy cruiser do?

    Nor can I find any information on the performance of this designer's cruising multis. Certainly it is hard to see how it can claim the convex roof is "unique" when Lagoons have the same feature. Sounds like a lot of claims with no back up.
     
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  7. trip the light fandango
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    trip the light fandango Senior Member

    Which part of "in my opinion" or "for my purposes" don't you understand Doug?
     
  8. Angélique
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    Angélique aka Angel (only by name)

    I think the Bruce foils were considered as it says for the out of the way trunks inside the hulls, but IMHO the effect of creating a vertical lifting force would mostly be creating extra drag when not being able to lift the hulls out of the water, which must have caused skipping the idea. But if it was working, then in the preliminary concept it had needed to have lifting foils on the rudders too, I think.
    Besides that, in my view the convex roof shape isn't as claimed a reminiscent of a Mercedes 230 SL Pagoda top, maybe only for a preliminary stylistic design sketch . .

    [​IMG]

    But the eventually nickname for the Mercedes 230 SL became ‘‘Pagoda’’ because of the concave roof shape of the final design . . .

    [​IMG]

    [​IMG]

    for sale, pics from all sides....
    [​IMG]
     
    Last edited: Feb 17, 2019
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  9. Doug Lord
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    Doug Lord Flight Ready

    =========================
    With the curved "C" foils the boat would be "foil assist" not full foiling because it wouldn't properly foil w/o rudder T-foils but the "C" foils would be capable of lifting a significant portion of the boats weight. You wouldn't want a "C" foil to lift the boat out of the water, since ,unlike UptiP foils, the "C" foil has no built in altitude control.
    Here is the Catana 59 using "C" foils for foil assist as well. And those foils could probably lift 40-50% of the weight of the boat or more:

    catana59.jpg
    ==========================

    PS-Angel the 450SL is one of my all time favorite cars!!
    Mercedes 450 SL----1979-Mercedes-Benz-450SL-.jpg
     
    Last edited: Feb 17, 2019
  10. Angélique
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    Angélique aka Angel (only by name)

    But what would lifting only 40-50% of the boat weight mean for the boat speed relating to the extra drag caused by creating the vertical lifting force ?

    from post #117
     
    Last edited: Feb 17, 2019
  11. Doug Lord
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    Doug Lord Flight Ready

    -----------------------------
    Angel, the foil lift reduces the displacement thereby reducing wetted surface and wavemaking resulting in less drag and more speed. In the old days, the ORMA 60's used curved lifting foils on the lee ama to lift 50-70+% of the boats weight. Definitely increases speed. One problem they had a few times back then was when the boat got going too fast and the foil lifted the ama clear of the water. Since most Ormas didn't use rudder t-foils, when that happened there was a crash that could result in a pitchpole. These cruising cats wouldn't push the limits like the ORMA tris did but the foils would still produce some extra speed and they would have to be carefully designed to produce a net positive w/o the risk of lifting too much.
    Since there is no altitude control if the hull were to fly, it would pitch waaaay up--and then crash.
     
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  12. CT249
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    CT249 Senior Member

    I didn't say a heavy cruising cat like this would full foil since it obviously won't. The point is that C foils come with significant downsides and inefficiencies even in something as light and fast as an A Class, and in a heavy cruiser those drawbacks could be even more pronounced.

    A comparison with an ORMA 60 is not very relevant, since a very heavy, high freeboard cruising cat will not behave like a very light, very fast ORMA 60 did when driven hard by pro legends under a huge rig. It sounds like putting a wing on a Winnebago because they work on F1 cars.

    Angelique, good point about the "pagoda'!
     
  13. Doug Lord
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    Doug Lord Flight Ready

    ==============================================
    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.
     
  14. 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...
    -----
    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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  15. 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
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