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23973Re: Aerated Power Boat Bottoms /Sneakeasy

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  • tom28571
    Sep 30, 2002
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      --- In bolger@y..., "dbaldnz" <oink@p...> 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
      > going sailing trimaran called Maui. It sailed 306 miles in 24
      > 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
      > pressurized by a battery driven fan, causing a carpet of bubbles
      > 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
      > the time, but I have seen nothing like it since. Perhaps others
      > tried the idea, and I wondered whether it may be applicable to the
      > fast powerboats being discussed in this Group.
      > DonB


      Many powerboat designers and experimenters have tried aeriating the
      hull bottom but usually with step bottoms. Some have used air
      inlets to augment the air that gets in the normal way through the
      chine area and a few have closed off the chine at the step and
      supplied all the air from the deck by power fans. Some have routed
      the engine exhaust through the bottom. I have not heard of it being
      done on a sailboat as you speak of though.

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