Posted by: "Adrian Stott" [EMAIL PROTECTED]
  Tue Aug 7, 2007 6:52 am (PST)
  "sean neill"
  <[EMAIL PROTECTED]> wrote:
>Of course the paddlewheel effect is much less potent in a diesel boat
  >than in a steamer.

  Why?

  I believe there is no correlation between the type of engine and this
  effect.

  However, I think there is a correlation between the effect and:

  - Propeller size (diameter and pitch)
  - Propeller speed of rotation

Adrian

I agree with Adrian that the engine itself has no direct effect - but my
statement reflected the fact that, de facto, current steam nbs have
direct-drive propellers with large diameter and pitch (there are some
steamboats with geared-up propellers) and most diesel nbs have
higher-revving smaller propellers - Bolinders and some other boats are
exceptions. I assume the nb in the original query was of the 'normal' 
type with relatively small-diameter / small-pitch propeller.

Sean


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