Tuned Hulls

Discussion in 'Boat Design' started by Lin Olen, Jan 25, 2008.

  1. Lin Olen
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    Lin Olen Junior Member

    Hello yipster. Interesting thought about area rule, I apply this to my aircraft designs to reduce fuselage cross section to compensate for progressive wing thickness, following the streamline form requirement.

    No, not my hull, but when looking at a so-called perfect displacement curve (part sine wave) my hull anticipates the rise of the curve, then reduces displacement to avoid the peak, again anticipating the loss of displacement as it passes.

    The curve of my hull is therefore mostly flat, reducing greatly the unwanted accelleration then decelleration of a mass of displaced fluid.

    Area ruling should be used when adding keels or fins to an efficient hull. Cheers, Lin.
     
  2. TollyWally
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    TollyWally Senior Member

    Wow, this is extremely interesting. I sure hope we can collectively figure out a way to get those pictures here. I'm staying "tuned".

    couldn't resist the pun :)
     
  3. tom28571
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    tom28571 Senior Member

    Lin,

    This sounds like the reduction in resistance would be greatly dependent on speed of the boat. Yes, No? What is the resistance like across the speed range?

    Yip, have you been away? I don't get here as often as I might but think you may have been on holiday.
     
  4. JonathanCole
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    JonathanCole imagineer

    All resonant systems are locked into certain specific operational parameters. The ringing referred to in an earlier post occurs under very narrowly defined conditions. A resonant generator I have worked with is very efficient, but only with a load of a certain size or current draw. In other words the load has to be matched with the resonant frequency. My guess is that in a boat using resonance as a means to efficiency, that the efficiency would be exhibited at a very particular speed.
     
  5. tom28571
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    tom28571 Senior Member

    Sure Jonathon, I am familiar with all that. Just trying to find out what Lin's boat is all about.
     
  6. yipster
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    yipster designer

  7. Lin Olen
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    Lin Olen Junior Member

    Tuned Hull. One frequency. Correct! Hull was initially tuned for resonance at 12 miles per hour, but the tuning was broad. What happened was that the expected drag was reduced as the speed increased, so no hump. My 11'7" prototype began to plane at about 10 MPH and was planing very freely at twelve MPH with the anti-cavitation plate modified 3 HP Seagull. This boat performed with a 5 HP Johnson much like a 12 ft tinny with a 10 HP Mercury. Cheers Lin.
     
  8. yipster
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    yipster designer

    on the frequency subject there is also the caravan effect
    not only between multi hulls but i've been reading that for inland ships
    hullform can be optimized for depth to minimise even cancel wave making.
    and eh.. apologies for the faint jokes.
     
  9. Lin Olen
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    Lin Olen Junior Member

    Re caravan effect... Walt Disney had these amazing ships exactly right.

    Hello yipster, I enjoyed the pix of your high aspect ratio tri-hulls but you are on a dead end course there. Increase velocity and you decrease pressure. The front of these craft are ok but the narrow aft sections will always suck down at speed. This is a major problem with seaplane floats as well. I think that I have worked out a solution with my tuned hull. I am still having trouble posting pix but have a post under rotary sails in the forum. Cheers, Lin
     
  10. yipster
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    yipster designer

    hello Lin, thanks for saying and the caravan effect i mentioned can somehow be compared with a tunnel or ground effect in aviation i guess?

    you refer to my ladybird study in above mail? did you see the sailplan pdf i started with and read on non planer wings?
    my objective is to design a 90/90 motor sailor, hulls (flying middle hull a la incat so not a tri)

    do you have thoughts on the lex and the flush strikable bi plane wingmasts with inflateble reverseble camber wingsails? stall warners?

    yes that ladybird needs r&d, but you yet have to convince me where you see a dead end, do appriciate comments tho
    please come again on that aspect ratio and your tuned hull, in a reply scroll down to manage attachments, no problem
     
  11. Lin Olen
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    Lin Olen Junior Member

    Tuned Hull Pix no go

    I have scanned tuned hull pix at 75 dpi and saved it to pix files and doc files but when I copy and try to paste I find my files become empty. I seem to get regular attacks of my files. Sometimes all written data vanishes from computer and takes a long time to fix. I have posted some copies. Serve me right for ? banking.??:mad:
     
  12. tom28571
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    tom28571 Senior Member

    Yipster, I like a little levity in the forum. We take life too seriously most of the time. Time will tell whether Obama brings a new Camelot or not. He has to win first.
     
  13. SeaSpark
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    SeaSpark -

    Lin, are you perhaps working on a mac? In that case the way of making the pictures smaller i posted won't work. Regardless of the operating system save pictures in jpg format.
     
  14. Lin Olen
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    Lin Olen Junior Member

    Thanks SeaSpark, No. I wont connect my beautiful Mac to the internet again. I have had too many computers ruined, in spite of expensive spyware. Macs are far less trouble than most PCs but I reman politically incorrect and am an open target. Visa has a back door. So do Boeings new airliners. Motors can be switched off remotely by a curious nut in a remote control room. Scary. Postal address to me may get info to you. Cheers
     

  15. Lin Olen
    Joined: Jan 2008
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    Lin Olen Junior Member

    Tuned Hull Update

    I was heaviy into human powered vehicles including planes. I trained to achieve a peak power output of one point one six horespower for thirty seconds then slow down to nought point five HP for long enough to fly the Henry Kramer figure eight with my smaller and much faster design. I could not get enough power with pedal cranks so I devised a linear propulsion arrangement, which raised efficiency from 56% to about 90%. Prop was edge mounted low aspect ratio small diameter high speed.

    As an untrained rower weighing eleven stone seven pounds I could easily row my tuned hull prototype at seven miles per hour, maitaining that speed. Pedal cranks would have given me over ten MPH. That was in 1957. My legs can still crank out 500 Watts but I am now 74 and weigh near 200 pounds. Still hoping, but I now realise what a screwball I must look to people when I zip past their bicycles on my Greenspeed Recumbent. Cheers, Lin.

    Want prints of Tuned Hull? Send Name and address to Lin Olen, PO Box 39, Wooli, Australia 2462 Appropriate postage would be appreciated.
     
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