What is the sexiest foiler on the market today ?

Discussion in 'Boat Design' started by Alan Cattelliot, Jan 29, 2024.

  1. Alan Cattelliot
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    Alan Cattelliot Senior Member

    My eyes just pop out seeing the cover of the next Wooden Boat No. 297 (March-April).
    This boat is a foiling hull developed jointly by the English builder Spirit Yachts and the foiling specialists BAR Technologies.
    upload_2024-1-29_9-47-18.png

    Love at first sight it is. And you ? What is your favorite foiler ?
     
  2. Will Gilmore
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    Will Gilmore Senior Member

    There are a lot of sexy foilers out there. I'm more a sailor than a power boater, but I'm interested in where electric propulsion is heading, and it's important to have a good tender.

    No worries about No Wake Zones.
    [​IMG]

    I am, as a native born Floridian, worried about manatee and other surface dwelling sealife. When pushing a long thin blade across the ocean surface at high speed, how do seals, whales, and tuna know to dive out of the way? Do foils propagate a lot of noise ahead of them?

    -Will
     
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  3. Alan Cattelliot
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    Alan Cattelliot Senior Member

    enough for this noise to put us in interaction with the sealife ? Probably. Lifting profiles do emit some perturbations in the medium. At first glance, it is modelized by the "Strouhal number", this number being the proportionnality factor between the flow speed and the frequency at which vortices are shed. Although that does not answer the first question. I know that foil transducers are monitored on many racing boats, like IMOCAS. Perhaps someone on this forum could have an answer for that ?
    upload_2024-1-30_9-12-10.png
     
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  4. wet feet
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    wet feet Senior Member

    I like the look of that Spirit foiler from a distance.I'd like it a bit more if I could see any way to moor it and hang fenders from it to avoid damage.How do you store it between trips?Those minor quibble aside,it is an interesting exercise.
     
  5. Paul Scott
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    Paul Scott Senior Member

    There’s a hydrofoil locally, and I was asking her owner about kelp, and the foils cut right through it. Logs not so much…..

    Didn’t ask about sea life, but with baby orcas around here, I kind of wonder…. props have been chopping up stuff for more than a century.

    Our boat Amati has a composite wooden hull (hence the name) and she resonates like a wood instrument- there’s a lot of noise going on under the water- it’s got to be confusing at some level to sea critters. Even a Laser hums at some speeds.

    Still, the Spirit foiler is a gorgeous beast.
     
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  6. Paul Scott
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    Paul Scott Senior Member

    Since acoustics have been used as a measurement approach for foil design/ measurement, maybe there’s an approach there for acoustic DEW for sea life?
     
  7. Will Gilmore
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    Will Gilmore Senior Member

    Yep, and a concern, for sure. However, most props have a small profile or danger column through the water and usually there is a full boat hull's length ahead of them, give a fraction of a second reaction time.

    Luckily, the waterways are gigantic areas with much more space then sealife.
     
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  8. Skyak
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    Skyak Senior Member

    Post 1 reminds me of the argument that the highest esthetic value requires complete absence of function. The entire point of foils is that drag is independent from hull shape above some minimum speed (just a function of speed and weight).
    If you haven't been paying attention, that argument has now been decisively lost with the advent of generative AI.

    On a form and function basis my favorite power foiler is the Candela C8.
     
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  9. Alan Cattelliot
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    Alan Cattelliot Senior Member

    Do you mean that advent for generative AI has made shadow to advent for foils, or do generative AI has created hull shape whose drag is independent from the hull shape ?
    For the record :
    upload_2024-2-6_18-40-54.png

    When I was young, a long time ago, in another galaxy, i discovered this foiler, in a video from Yamaha, explaining its full development. I think that a book has also been made. I really enjoy the way it banks in steady turn, like an airplane.
    upload_2024-2-6_18-43-59.png
    Yamaha engineers resurrect 32-year-old jetfighter-style hydrofoil https://newatlas.com/marine/yamaha-hydrofoil-ou32-restoration/
     
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  10. David Cooper
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    David Cooper Senior Member

    Sail GP is keen on being environmentally friendly (as much as it can be with all the travel involved), so I wonder if they've stuck hydrophones in the water to see how loud they are. It would be good to know how they compare with the chase boats. Anyone with access to a foiling dinghy could do the experiment too though and compare it to the rescue boat, while I'm guessing that a waterproof phone can record sound underwater well enough to serve as a hydrophone, and there are plenty of apps for registering sound levels. I'd like to hear the sound recordings too if anyone's made any.

    Edit: but if you're trying it, do it by a fixed buoy in water shallow enough to dive for your phone if you drop it.
     
    Last edited: Feb 8, 2024
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  11. Waterwitch
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    Waterwitch Senior Member

    This is sexy and foiling, beautiful handling of an air foil like a kid with a kite but a wing.
     
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  12. Alan Cattelliot
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    Alan Cattelliot Senior Member

    And a chase boat.
     
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  13. Alan Cattelliot
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    Alan Cattelliot Senior Member

    Here is another one, less glamour than wingfoilers, more brutal. I didn't know this event. Wonder how the power consumption is going, compared with IC, non foiler serie, same speed....

    upload_2024-2-11_11-29-39.jpeg
    upload_2024-2-11_11-29-51.jpeg
    upload_2024-2-11_11-30-2.jpeg
     
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  14. Will Gilmore
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    Will Gilmore Senior Member

    That leaves me wondering about drag. Would a boat like those above have less drag or more, then a similar vessel that used actual wings to lift it out of the water?

    What I'm asking is if the smaller air cross section created by having no wings, or tiny wings, in the case of the above racers, with the relatively smaller foils, give a vessel less drag over all, then if those boats used air foil wings to lift them out of the water? Those racing boats make me think of flying just above the waves with nothing but a shaft extended down into the water for propulsion.
    [​IMG]
    -Will
     
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  15. wet feet
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    wet feet Senior Member

    I don't know how many copies of the UK magazine Watercraft make their way across the Atlantic but the most recent edition has a feature on home built Ekranoplans.
     
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