Foil Assist Monohulls

Discussion in 'Sailboats' started by Doug Lord, Jun 14, 2018.

  1. Doug Lord
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    Doug Lord Flight Ready

    Whether this boat is full flying or foil assist -it seems to do both some of the time-it is very interesting:
     
  2. CT249
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    CT249 Senior Member

    Just to make it clear, I did NOT pin the reduction in new builds purely on the hydrofoils. As Paul said, there are bigger trends at work such as reduced cash and time and increased cost.

    Yes, the T foils did make the 14 faster and easier to handle. They also have a very positive effect on the handling of seahugger Moths and As. No one's ever denied that.

    Paul's reply seems to confirm one point I was making, which is that factors such as affordability and time are more important that increasing speed when it comes to maintaining a critical level of popularity in the sport. Therefore when we say "skiffs are the future" or "foilers are the future" it's critical to consider the importance of accessibility. If people have less time and money then we have to re-orient the sport towards classes that are cheaper and less time consuming.

    Secondly, the drop in skiff numbers that OzFred correctly points out should show that hype that claims that a high-performance type is the future can very well be wrong - and in fact probably normally are wrong.

    Thirdly, as Ovington say, there has been a shift towards singlehanders which may be a factor in the drop in the 14 fleet. However, the same factors apply to foilers - therefore if a singlehanded class adopts foils and then grows or maintains its numbers, it can be partly or entirely because more people are sailing singlehanders, rather than the attraction of foils themselves.

    It may be significant that, for example, the seahugging class that is arguably most closely related in design to the A Class cats (the one up version of the Taipan 4.9) has grown much faster than the A Class has itself over the last 15 years or so. Strangely, a certain breed of foiler fan only seems to use this factor to excuse a drop in numbers in doublehanded foilers and not to explain stronger numbers in singlehanded foilers.

    None of this means that foilers and skiffs aren't great, but it does mean that attempts to paint them as the future of the sport are silly.

    PS - Australia has also seen a fall in skiff numbers. However, that has occurred during the world's longest period of economic strength, and in an era when people over 35 are wealthier than they used to be. So the poor economy in the northern countries certainly doesn't explain all the drop in skiff numbers.
     
    Last edited: Sep 3, 2018
  3. Doug Lord
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    Doug Lord Flight Ready

    =================================================
    More technical detail from the press release:
    The IMOCA 60 CHARAL in detail-

    Enormous foils
    Jérémie Beyou: “We chose to make foils that are strong to get a maximum power and lift (for the
    foiling effect). The shaft is very long as is the tip and has a double surface and angled elbow, which
    highlights the visual impact. They are reasonably thick too because we are going to put quite a lot of
    arching pressure on the tips. If the boat appears really wide, it is because we can’t raise both foils at
    the same time : one will always be lowered.

    An innovative hull
    As the plan was to use the foils to get power, we had to come up with a hull that limits drag knowing
    that the measurement rules do not allow for full flight. This means we have a very innovative hull with
    a warship-like bow and rounded and closed transom.see picture below
    Jérémie Beyou: “the transom is completely different to anything we have seen before in the IMOCA.
    The bow has had a lot streamlining to reduce the amount of carbon and gain on weight. We have
    pushed the boundaries to the maximum with one exception, allowing me room to maneouver on the
    foredeck.”

    A condensed living space
    Pierre François Dargnies: “Jérémie’s brief put both the living and work areas on a par just like on the
    Ultimes. It became apparent that it would affect the centre of gravity and so we had to adapt. We
    designed a boat where the skipper can spend the part of time in the cockpit and virtually reach without
    moving, the winches, the helm, the chart table and the galley. The idea is to go below the least
    amount of times needed. Jérémie will be outside permanently but in a protected area from both the
    wind and the water thanks to the non-retractable coach roof.”

    Sensors fit for F1
    Jéremie Beyou: “All that supports important loads - the rig, the appendages – has sensors with optic
    fibre sending back information in real time to my navigation console to then be treated by software
    that gives me the right reading of the situation.
    However, unlike the F1 or the Ultime, this information is not relayed to shore. I am the only one who
    can access this and therefore am then able to act manually as needed.”

    Photography Copyright: Yvan Zedda / ALeA / Charal

    Graphic –
    The new IMOCA 60 CHARAL in some numbers:
    2 km of lines on board the IMOCA
    Top boat speed - 40 knots
    70,000 Number of hours worked on the construction of the boat – or 8 years, 24 hours a day
    2.2 tonnes – hull weight equivalent to a whale calf
    1,185 m2 sail area equivalent to 6 x tennis courts
    4 m2 Living space on board equivalent to 4 m2
    -------------------
    Charal from astern:
    IMOCA Charal from astern.jpg
     
    Last edited: Sep 7, 2018
  4. Doug Lord
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    Doug Lord Flight Ready

    IMOCA sterns-compare with Charal above:

    IMOCA stern 1.jpg

    IMOCA Safran Stern.jpg

    IMOCA Hugo Boss stern.jpg
     
  5. philSweet
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    philSweet Senior Member

    Regarding Charal's transom shape - best guess is that managing the angle of attack of the foil now trumps maximizing the hull's form stability, particularly when you can't retract both foils. It will be interesting to see how this works on the final climb back up through the Atlantic. I expect the ballast tank arrangements are entirely different as well. I'd like to see the strut shortened up a foot or two with these boats.

    Oh, Coolest looks ever, nice job. But auto correct strikes again? From the first link - "worked hard during Almost 12 months in perfect osmosis." I'm pretty sure that's not what they meant to say.
     
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  6. Doug Lord
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    Doug Lord Flight Ready

    I don't know Phil--Definition 2 below would make sense:
    os·mo·sis
    äzˈmōsəs,äsˈmōsəs/
    noun

    1. BIOLOGYCHEMISTRY
      a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane.

    2. the process of gradual or unconscious assimilation of ideas, knowledge, etc.
      "what she knows of the blue-blood set she learned not through birthright, not even through wealth, but through osmosis"
     
  7. Dolfiman
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    Dolfiman Senior Member

    "En parfaite osmose" is a French common expression to describe the functioning of a team and I think the best translation is "in perfect harmony".
     
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  8. Doug Lord
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    Doug Lord Flight Ready

    Thanks , Dolfiman!
     
  9. Doug Lord
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    Doug Lord Flight Ready

    From the newsletter "Quest-France":
    https://www.ouest-france.fr/sport/v...itana-spithill-avec-gabart-beyou-fond-5942547


    Charal already full ball! (pardon the translation)

    Jérémie Beyou had some great sensations during the first trip aboard Charal, his new boat, launched less than a week ago. The VPLP - Beyou sailing team sailed in the bay of Lorient share a wind of fifteen knots, and obviously, the boat has already shown that it had in the belly. At the speedo, it has already reached the speed of 23 knots with 16 knots of wind in the sails! It promises !
     
  10. philSweet
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    philSweet Senior Member

    Erm, so what do the French attribute gelcoat blistering to? Really, someone ought to clue them in that osmosis has basically one literal meaning in English, and any metaphorical extensions are both informal and off the mark. Symbiosis has the metaphorical sense they want and isn't informal, but it still sounds a bit off, and isn't all that common either.
     
  11. Dolfiman
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    Dolfiman Senior Member

    I can confirm you that "osmose" is also the french name for osmosis as regard its first meaning. And osmosis of GRP hull is also a matter of concern, here is a complete overview of the subject by Gerard Boulant, a full time expert on this issue, you can click on each blue texts to have the pdf of all the chapters :
    Cahiers techniques (1) : l’osmose, de coques en cloques http://www.voilesetvoiliers.com/initiation-perfectionnement/parole-d-expert-gerard-boulant-cahiers-techniques-1-l-osmose-de-coques-en-cloques/
     
  12. Dolfiman
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    Dolfiman Senior Member

    Charal very first sailing , with a peak speed at 25 Knots at the end of the day :
     
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  13. CT249
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    CT249 Senior Member

    Down here in Oz we use osmosis in the French way.
     
  14. OzFred
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    OzFred Senior Member

    Another Charal video from the Le Défi Azimut. It looks fast in what must be very close to ideal conditions for a speed run, but it didn't seem to be significantly faster than other foilers. Early days yet, it looks very promising. Not having T foil rudders seems to limit how hard they can be pressed.

    Sylvain Hay https://www.facebook.com/sylvain.hay/videos/10216248237492107/

    However, it was clearly the fastest in the 1.5 mile (nm?) speed run in 20 to 25 kn before the start.

    Charal remporte les runs !

    "The long-awaited Charal was talking powder, perched on his huge foils. After a first unsuccessful attempt, the second was the good one. With a time of 4 minutes and 52 seconds, Jérémie Beyou crushed the competition. Samantha Davies on Initiatives-Cœur (5 minutes 31 seconds) and Paul Meilhat aboard SMA (5 minutes 37 seconds) finished 2nd and 3rd respectively."
    From French using Google Translate.​

    [​IMG]
     

  15. Doug Lord
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    Doug Lord Flight Ready

    I think Charal easily gets more air than any other foil assist IMOCA 60-and is probably faster. She would easily be full flying with rudder t-foils-shame about the rules holding everybody back:


    In this video she passes one of the other IMOCAS as if it were standing still:

     
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