thoughts on lack of hydrofoiled cats?

Discussion in 'Multihulls' started by ijason, Jan 23, 2009.

  1. ijason
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    ijason Junior Member

    greetings.

    i'm about as an uninformed boat enthusiast as you could find, but i'm struck by the apparent lack - or at least, lack of popularity - of catamarans using hydrofoils?

    the only thing i've seen on google is patents for systems to do this, and the occasional prototype racing boat... but nothing apparent for any blue-water or long-distance cruising cat. is this due to something intrinsic with the two-hulled design of catamarans?

    seems like a sailing/power combination boat would make great savings in fuel economy and handling by using foils.

    thoughts?
     
  2. pkoken
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    pkoken S/V Samadhi V

    It is no mean feat of engineering to produce a hydrofoil supported boat. Weight is even more of an issue than it is with a conventional hull. The cost of the foils for a large vessel will be huge.

    There are lots more reasons... I love hydrofoil boats, but I am not expecting a "cruising hydrofoil" anytime soon.
     
  3. ijason
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    ijason Junior Member

    so it's not actually a problem with doing it, or any lack of rewards for having it... it's more a problem of engineering and costing?

    i guess that explains why hydrofoils are almost exclusively in the realm of large passenger or military ships; deep pockets.

    thanks for replying!
     
  4. pkoken
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    pkoken S/V Samadhi V

    You could say that there is a "lack of rewards" in that standard planing hulls are more flexible than a foil supported hull, in addition to being a fraction of the cost.

    The US Navy stopped using hydrofoil boats, and the high speed ferries I see being built are almost invariably high speed cats.
     
  5. Doug Lord

    Doug Lord Guest

    Hydrofoils have been used experimentally on a number of sailing catamarans and are currently used on at least two types of production power cats.
    For sailboats ,the most recent foil application is on the SYZ cat from Switzerland-see the thread in this forum. Before that was the
    International C Class cat built by the Canadians-wasn't fast and the Chapmans' experimental boat as well as Icarus the flying Tornado years ago.
    For sailing -at this point at least-the fastest configurations are trimarans or monohulls equipped with foils.
    For power cats the Hysucat(sp?) and Corsair powercat use hydrofoils to improve handling,speed and full economy.
    Corsair:http://www.morrellimelvin.com/power/cruising/powerCRUISE.php?WEBYEP_DI=10
    Hysucat(Hydrospeed): http://www.hydrospeed.co.za/index2.html
     
    Last edited by a moderator: Jan 25, 2009
  6. Ad Hoc
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    Ad Hoc Naval Architect

    sailing yachts not many, but commercial vessels yes, there are quite a few foil assisted catamarans.

    A friend of mine also specialises in designing foil systems for catamarans
     
  7. Chris Ostlind

    Chris Ostlind Previous Member

    Perhaps, Ad Hoc, it wouldn't be too difficult to share with us the sizes, operating locations, designed purpose, etc., of a representative collection of these machines?

    Doug's references are purely experimental and in the case of the C-Class example, was a bust as far as showing anything like a competitive speed potential. It was lots of money and time that went into the project from some very smart and talented guys.
     
  8. pkoken
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    pkoken S/V Samadhi V

    Any time you post something about "Hydrofoils" you can expect Doug Lord to post glowing comments (putting it very mildly).
     
  9. ijason
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    ijason Junior Member

    interesting examples.

    i would be mostly interested in the benefits of hydrofoils in terms of increasing fuel-economy for a motor-sailing cat, and for increasing comfort for long trips... less rocking and jarring from the waves, etc.

    it seems almost all the smaller examples of foiled craft are designed for the speed advantages it offers more than extending range or better handling in rough seas.
     
  10. robherc
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    robherc Designer/Hobbyist

    I'm no expert in foil design, but doesn't it seem to anyone else like you could realize SOME efficiency benefits with even small/relatively inexpensive foils? Also, I know it's slightly less efficient hydrodynamically, but for cost-efficiency, it would seem that one option would be to use more, smaller foils.

    Just my two-cents, and there's no promise that it's worth any more than that...might be worth some experimentation though (I'll be experimenting on it myself...but it'll be several months before then probably).
     
  11. Ad Hoc
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    Ad Hoc Naval Architect

    Chris

    The ones i'm referring to are called "HYSUCAT"....there are generally smaller vessels dotted about here and there and if i recall there is the ECat down Gulf of Mexico way. I think that was built by Halter Marine...not 100% sure though.

    There are of course the Fjellstrand attempts too, but they use a different philosophy to the HYSUCAT method.
     
  12. Chris Ostlind

    Chris Ostlind Previous Member

    Thanks... I'll Google them up.
     
  13. Frosty

    Frosty Previous Member

    Anyone know the NACA number of a hydrofoil in general. I know they vary but there was one number that seemed to be most used.

    This number was also common on helecopter rotors.
     
  14. Ad Hoc
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    Ad Hoc Naval Architect

    Frosty

    Depends upon the whole 'design' of the vessel and the result required. The resistance of the hull, then the added resistance of the foil. So the lift/drag ratio needs to be assessed in its entirety with the hull and the power/propulsion requirements etc, not just stand alone.

    Otherwise it is a bit like saying which waterjet, or engine or propeller is best...depends on the whole design/SOR
     

  15. Doug Lord

    Doug Lord Guest

    ----------------
    63412-widely used on earlier Moths and many current monofoilers. Also Tom Speer's H105
    Huge foil database here: http://www.ae.uiuc.edu/m-selig/ads/coord_database.html
    And below the Selig 3010 used by Steve Killing on the Canadian C Class foiler:
     

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