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RE: [boatdesign] Re: Max. "Hull" Speed of No-Wake Hulls

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  • Kenneth Grome
    This is interesting because at 40 it would seem that the boat would be relatively light weight. Any chance of getting some pictures, drawings, dimensions,
    Message 1 of 188 , Apr 1, 2006
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      This is interesting because at 40' it would seem that the boat would be relatively light weight.

      Any chance of getting some pictures, drawings, dimensions, etc. so I can throw them into the simmering pot in the back of my mind ... and hope that something useful emerges one of these days?

      Kenneth Grome
      Bagacay Boat Works

      P.S. Sorry for the typo, I know your name is not Hohn ... :)




      On Sat, 1 Apr 2006 17:42:43 -0800, John Welsford wrote:
      > In broad principles yes, the one I'm working on course is only just over
      > half the length but yes, a lot like that.
      > JohnW
      >
      > -----Original Message-----
      > From: boatdesign@yahoogroups.com [mailto:boatdesign@yahoogroups.com]On
      > Behalf Of Kenneth Grome
      > Sent: Friday, 31 March 2006 8:27 p.m.
      > To: boatdesign@yahoogroups.com
      > Subject: RE: [boatdesign] Re: Max. "Hull" Speed of No-Wake Hulls
      >
      >
      > Hi Hohn,
      >
      > Here's one with a 70' length, Ilan Voyager, is this something like the one
      > you're talking about?
      >
      > http://tinyurl.com/7lk7z
      >
      > Kenneth Grome
      > Bagacay Boat Works
      >
      >
      >
      >
      >
      >
      > On Sat, 1 Apr 2006 10:46:08 -0800, John Welsford wrote:
      >> There are power catamarans and trimarans around which will run in
      >> displacement mode at a speed length ratio of up to up to 4 before drag
      > curve
      >> really starts to head upwards. Thats about 22 knots on a 30 footer. To
      > do
      >> this the beam to length ratio needs to be up around 12 to 1 or better and
      >> the displacement to length ratio needs to be relatively light.
      >>
      >> There is very little information on these hulls in the public domain as
      > yet,
      >> but there has been a great deal of research on them by commercial
      > designers
      >> and many passenger ferries are using this very slender hull form.
      >>
      >> I am currently involved in a project to develop a power trimaran of 40 ft
      >> waterline, powered by a single 120 hp fourstroke outboard motor, the speed
      > /
      >> range to be 1500 miles at 18 knots. The numbers work, the designs all
      > done
      >> and the boat is under construction . ( I am not the principle designer in
      >> this case, more like the client advocate in a team effort, really
      >> interesting stuff!)
      >>
      >> JohnW
      >>
      >>
      >>
      >> -----Original Message-----
      >> From: boatdesign@yahoogroups.com [mailto:boatdesign@yahoogroups.com]On
      >> Behalf Of Roger Dewhurst
      >> Sent: Thursday, 30 March 2006 1:21 p.m.
      >> To: boatdesign@yahoogroups.com
      >> Subject: Re: [boatdesign] Re: Max. "Hull" Speed of No-Wake Hulls
      >>
      >>
      >>
      >> ----- Original Message -----
      >> From: "Michael Casling" <casling@...>
      >> To: <boatdesign@yahoogroups.com>
      >> Sent: Friday, March 31, 2006 5:31 AM
      >> Subject: Re: [boatdesign] Re: Max. "Hull" Speed of No-Wake Hulls
      >>
      >>
      >> 1.34 is wave speed and you can not change that.
      >>
      >> Where we didn't get many answers, was my question about by how much
      >> the theoretical hull speed can be "cheated", i.e. how many percent
      >> more are possible/how much has been achieved already (without planing)?
      >>
      >> Gerr in The Nature of Boats has some graphs showing power requirement at
      >> different speeds. Basically, as I recall, resistance consists of friction
      >> which is partly due to boat shape and partly due to the surface finish
      > which
      >> generate turbulence, together with the wave making resistance. The former
      >> is linearly related to the speed while the latter is related to the square
      >> of the speed. The power requirement climbs rapidly as hull speed is
      >> approached but rises less rapidly thereafter. Of course it drops suddenly
      >> when a boat gets on the plane as anybody who has driven a fizz boat will
      > be
      >> aware.
      >>
      >> R
      >>
      >>
      >>
      >>
      >>
      >> Yahoo! Groups Links
      >>
      >>
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      >> Yahoo! Groups Links
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      > Yahoo! Groups Links
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    • John Welsford
      Traditionally the top of the wheel moves in the same direction as the tiller or whipstaff would have which makes sense when you think about it, thats why it
      Message 188 of 188 , Apr 5, 2006
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        Traditionally the top of the wheel moves in the same direction as the tiller
        or whipstaff would have which makes sense when you think about it, thats why
        it seems backward to someone educated in the function of steering wheels in
        a car.

        JohnW

        -----Original Message-----
        From: boatdesign@yahoogroups.com [mailto:boatdesign@yahoogroups.com]On
        Behalf Of Douglas Pollard
        Sent: Monday, 3 April 2006 7:06 p.m.
        To: boatdesign@yahoogroups.com
        Subject: Re: [boatdesign] Re: Max. "Hull" Speed of No-Wake Hulls


        Speaking of Tugs about 1963 I read a notice in the Baltimore Sun newspaper
        say that the Baltimore and Ohio railroad was taking its last steam tug out
        of service. They were giving free rides to all comers. I couldn't believe it
        I was the only person in all of Baltimore that was interested enough to go
        for a ride. Turned out to be great for me. The crew were bored setting at
        the dock. So we went out for several hours ride. They left a fellow at the
        dock with a radio in case someone came to go for a ride.
        The crew were some proud of that old tug and really disappointed that no
        one was interested. I have always been interest in steam engines and steam
        boats in particular. It's kind of strange that I mess with sailboats
        ,really love steam and am a machinist to boot. I should have built me a
        steam boat.
        I was amazed at the steering (they let me steer some) You turn the wheel
        to starboard and the boat goes to port. Tug boats steer backwards . At least
        that one did.

        Doug
        ----- Original Message -----
        From: Stefan Probst
        To: boatdesign@yahoogroups.com
        Sent: Monday, April 03, 2006 9:26 PM
        Subject: [boatdesign] Re: Max. "Hull" Speed of No-Wake Hulls


        --- "nutty_boats" <nutty_boats@...> wrote:
        > tugboats are optimized for other functions, hence that they throw up
        > a big wake is not important in their design.

        But even tugboats have different purposes:
        - the slow "movers and shakers" that work inside a harbour
        - the "fast" "search and rescue" that go outside
        to support ships that cannot manoeuvre anymore

        Stefan






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