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Re: Aerated Power Boat Bottoms /Sneakeasy

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  • John Cupp
    This concept is already in production by the US for their Seal Teams. They have a heavily modified, narrow beam, step chined boat that can cruise at 70 knots
    Message 1 of 11 , Oct 1, 2002
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      This concept is already in production by the US for their Seal
      Teams. They have a heavily modified, narrow beam, step chined boat
      that can cruise at 70 knots with an ultra smooth ride. Very Slender
      Vessel (VSV). The VSV is designed as a wave piercing craft; in lieu
      of the standard high speed boat, which produces an extremely
      uncomfortable ride over long, high-speed transits in higher sea
      states. The VSV is expected to deliver SEAL or other SOF operators to
      objective areas who are much more mission capable.
      Check out the photo's I put up at Bolger 2.

      http://groups.yahoo.com/group/Bolger2/files/Modified%20Sneakeasy/

      These boats are very fuel efficient but they give no details of the
      power supply's or how they induce the air under the hull be it fans
      or venturi effect. They are amazing craft and not to far from the
      Wyo/Sneakeasy profile. I also am adding a picture of an air assisted
      test bed catamaran. The 'Surface-effect-cat' concept is an air-
      assisted catamaran with wave-slicing fine-entry side hulls. Air is
      blown into the recesses in the side-hulls. This method of lift
      reduces power requirements to about 1/2 that of a conventional
      catamaran at cruise speed.

      I also took the liberty to use another designers concept boat as a
      modified Sneakeasy with reverse bow. It would not be hard to modify
      the Sneakeasy the same way. With a LWL at 38' a little air induction
      from a cyclone air bilge pump on the drive shaft and it would be a
      very sexy missile. The picture is in the same file, a sort of art-
      nouveau Sneakeasy. Looks cool anyway.

      John




      --- In bolger@y..., Chance Curtis <sneakeasy2002@y...> wrote:
      >
      > The bubbles might have more to do with turbulence. The US Navy did
      studies of this affect on fish with scales vs fishskin like sharks.
      Fish with scales are faster but fish with skin are quieter. The navy
      did develop subs producing bubbles and they were faster, but those
      Sonobouys could hear them coming miles away.
      > CCG
      > dbaldnz wrote:Not strictly a Bolger topic, but an addition to the
      current
      > Wyo/Sneakeasy bottom discussion.
      > During the 1960's, a modern pioneer multihull designer and
      > aerodynamics engineer, J.S. Taylor in Australia, built a 23ft ocean
      > going sailing trimaran called Maui. It sailed 306 miles in 24 hours
      > at sea, remarkable at that time for such a small sailing cruiser.
      > The boat had a low deadrise chine hull. The interesting innovation
      > however was the double bottom with air space between. Along the
      > bottom of the hull, running diagonally from keel to chine, were
      > close spaced narrow slits. The air in the bottom space was slightly
      > pressurized by a battery driven fan, causing a carpet of bubbles to
      > disperse right along the bottom of the hull. I don't know if the
      > bubbles acted like a carpet of ball bearings, or whether they
      > sheared and lessened resistance. Magazine articles were published
      at
      > the time, but I have seen nothing like it since. Perhaps others
      have
      > tried the idea, and I wondered whether it may be applicable to the
      > fast powerboats being discussed in this Group.
      > DonB
      >
      >
      >
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    • pvanderwaart
      I believe that Project Amazon, an around-the-world singlehander also had an aeration scheme. The boat was designed by Eric Sponberg, but as I recall, the
      Message 2 of 11 , Oct 1, 2002
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        I believe that Project Amazon, an around-the-world singlehander also
        had an aeration scheme. The boat was designed by Eric Sponberg, but
        as I recall, the aeration was the owners design. Sponberg's web site
        doesn't have details of the design anymore. Maybe someone out there
        knows more.

        http://www.sponbergyachtdesign.com/SailDesigns.htm

        Peter
      • John Bell
        I just heard from someone on the WB forum who s been around Hunter s Child and confirmed that it does in fact have the aeration system. She s going to ask
        Message 3 of 11 , Oct 1, 2002
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          I just heard from someone on the WB forum who's been around Hunter's Child
          and confirmed that it does in fact have the aeration system. She's going to
          ask Steve Pettingill how it worked for me.

          JB


          ----- Original Message -----
          From: "tom28571" <harbinger@...>
          | I still don't see how they could get enough pressure differential to
          | pull air through the hull at that point without introducing drag
          | that might be greater than the benefit, but what do I know? The
          | Laser tried that on the original models but it never worked as a
          | bailer until they put in the extended venturi.
          |
          |
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