Confined channel wave resistance effects - narrowboats

Discussion in 'Hydrodynamics and Aerodynamics' started by dpaws, Mar 8, 2016.

  1. dpaws
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    dpaws Junior Member

    Thank you David, sound advice! I've already stepped on a couple of those minefields, sometimes it's two forward, one back - but the learning process is always a pleasure.
     
  2. dpaws
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    dpaws Junior Member

    Thanks Jurgen - I've sketched similar myself. For the refined model the aft swim profile is more open which must be beneficial for the propellor, and the Cb is lower due to the finer profile so the squat will be reduced - both positive it seems.

    With reference only to the wave characteristics that have been discussed, would the second hull form be superior to the first, and in lay terms, why? (assuming all other things being equal)
     
  3. Leo Lazauskas
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    Leo Lazauskas Senior Member

    Attached Files:

  4. dpaws
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    dpaws Junior Member

    Thanks Leo, the PhD level is a little intimidating, but I'll give it a go :)
     
  5. Leo Lazauskas
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    Leo Lazauskas Senior Member

    My advice is to skip the maths (which is quite daunting in places!)
    and focus more on the discussion and observations. Hopefully you
    will get some insights. Good luck!
     
  6. dpaws
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    dpaws Junior Member

    Thank you Leo - that's amazingly good advice! Unfortunately you have to comprehend the maths first, then you see how chaotic the environment is ie the confined channel with continuously varying dimensions, and only then you understand that maths is wasted!

    I've been lucky to discuss the project with some amazing people. My impression now is very much do what you can that you know will help, on paper - I mean like fining the swims, thus lowering the Cp/Cb, lowering the squat - keep the flows smooth and then just hope for the best and enjoy the ride - at least if we sink the centre channel's only a metre deep!!
     

  7. SukiSolo
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    SukiSolo Senior Member

    There has been some significant discussion on UK canal boat design on this Forum. You might like to check these threads out.

    http://www.boatdesign.net/forums/me...arrow-boat-project-plate-thickness-49002.html

    http://www.boatdesign.net/forums/me...-narrow-boat-project-bilge-ballast-49009.html


    Out of interest, in the early 1970s' I can vouch for the fact that some canals still had some commercial traffic, at least just off the Thames. However the small size of the canals (compared to Europe), the value of waterside property for housing along with the loss of UK manufacturing etc etc resulted in a lack of maintenance, so presumably the dredging cost was er er 'lost'. Not forgetting that in the 80s' political changes meant that the obligation to keep waterways open to traffic was often transferred to other bodies who ignored it or the clause(s) were dropped anyway.
     
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