Power cat unlikely performance?

Discussion in 'Hydrodynamics and Aerodynamics' started by Bostjak, Mar 19, 2020.

  1. Mr Efficiency
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    Mr Efficiency Senior Member

    When old Captain Cook went to Hawaii, he and his crew were astonished at the speed of little catamarans zipping around, it seems in 250 years the lesson really hasn't sunk in that you can go fast without power-hungry planing boats, but you can't stray too far from the basic principles of slender hulls and weight control. As far as I'm concerned, the boat the OP speaks of, has left that straight and narrow. I would say you have to forget about having habitable space inside the hulls, or be damned. I would also say single skin GRP would be out, too much weight because of the sheer surface area involved in a catamaran hull. Keep it light ( you get the bonus weight saving of lighter engines with that) and keep it slim, I can't remember who said you can't be too thin or too rich (speaking of people), but if you don't go "thin" with those hulls, you better be rich to pay for it.
     
  2. DogCavalry
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    DogCavalry Senior Member

    At vast expense and maintenance costs.
     
  3. BlueBell
    Joined: May 2017
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    BlueBell . . . _ _ _ . . . _ _ _

    I have no idea where in Canada the OP is but anywhere on the west coast it's a real challenge to keep hydrofoils attached.
    Big tides, big currents and big objects floating awash.
    Although the hull incorporated foils look much more promising.
     
  4. DogCavalry
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    DogCavalry Senior Member

    It's even worse on the East coast.
     
  5. Yellowjacket
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    Yellowjacket Senior Member

    The forward foils are within the two hulls and the aft foils stick out from the inside edges of the hull on a Hysucat. The aft foils tend to be shaped like smaller delta wings so they tend ride over things they hit. I agree that the forward foil could hit things, but it is indeed a lot more protected than a typical foil. Another advantage is that it's supported on both ends as well as the middle, so it can be pretty stout.
     
  6. DogCavalry
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    DogCavalry Senior Member

    At what speed range do they become advantageous?
     
  7. fallguy
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    fallguy Senior Member

    How did the thread morph from a clandestine review of the Leopard 53 to talking foils?

    jus sayin
     
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  8. gonzo
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    gonzo Senior Member

    Thanks for foiling the thread hi-jackers.
     
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  9. DogCavalry
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    DogCavalry Senior Member

    Lol!

    Although the OP seems to have left the building.

    Leopard 53? Let me look.
     
  10. DogCavalry
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    DogCavalry Senior Member

    Holy crap! That's not Homer Simpson fat, that's Peter Griffin fat!
     
  11. brian eiland
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    brian eiland Senior Member

    How about 26 knots under sail, without hydrofoils
    And don't get turned off to the complicated LOOKING rig, it might just turn out a lot easier than you think

     
  12. brian eiland
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    brian eiland Senior Member

    Look back thru the logs of this vessel, and you will get REAL figures on fuel consumption and speeds. I knew the owners back a few years ago,...marvelous couple. I offered this possible consideration of adding a sailing rig to it to turn it into a motorsailer.
    Future Sportfisherman Looks like the Past?
     
  13. jehardiman
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    jehardiman Senior Member

    LoL, Yes, many people miss the fact the Captain Cook "found" Hawaii, rather than the Polynesians finding England, in a tubby, slow, collier. No matter how well a hull form may excel in limited scope, it most certainly sucks at other things, some equally or more important.
     

  14. Mcarthur
    Joined: Mar 2012
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    Mcarthur Junior Member

    How about twin stub masts, say 20', half way down each side of the boat that run a square headsail (astern or at 45 degrees astern) or twin triangular "jibs" side-by-side up from 45 astern to near abeam? May be easier than a kite.

    BTW, were their "real figures" better or worse than implied?
     
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