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    Re: ratios,wind + current
    From: George Huxtable
    Date: 2003 Apr 22, 20:02 +0100

    Doug Royer said-
    
    >This subject of harbor or slip manouvering is a good subject for further
    >discussion both in theory and practical applications.What about discussions
    >on propeller charactoristics,hull shapes, fluid dynamics or just boat
    >handling in tight spots or in adverse conditions?Do you guys consider the
    >above as on subject or off?Maybe someone out there never operated a single
    >wheel vessel and might wonder about it or gain some insight from someone on
    >list that has the experiance etc.
    
    ====================
    
    George rises to the bait-
    
    Well, the causes and effects of prop-walk are, I think, often
    misunderstood, and that could make a fruitful thread.
    
    Why does the stern kick sideways? Does yours, like mine, do so much more
    strongly when the vessel has no way on, or is in reverse, or with the
    propellor back-pedalling to slow the vessel down, than it does when driving
    forward? If so, why? Why does it kick in the direction it does? Do
    single-screw merchant vessels show the same behaviour?
    
    I have heard all sorts of explanations, some quite ludicrous, on this
    topic, but never anything that seems fully satisfactory. I have developed
    my own ideas, which satisfy me if nobody else, and will be happy to debate
    them if any interest is shown.
    
    Has anyone found a satisfactory publication about prop-walk?
    
    George Huxtable.
    
    PS. I sent this posting a few minutes ago under a different thread-name,
    but have now renamed the thread "prop-walk", just in case it takes off.
    
    ================================================================
    contact George Huxtable by email at george---.u-net.com, by phone at
    01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
    Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    ================================================================
    
    
    

       
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