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    Re: Sumner's Line (Navigation question)
    From: Chuck Taylor
    Date: 2006 Feb 2, 13:34 -0800

    Ken,
    
    Excellent questions.  I don't have good answers,
    but for those wanting to follow the discussion,
    there is a rough chart along with part of the
    narrative from Sumner himself on pages
    7 and 8 of this pdf file:
    
      http://www.i-DEADLINK-com/bowditch/pdf/chapt01.pdf
    
    I think that one significant factor may have
    been that the wind was from the SE, making
    Ireland a lee shore.
    
    Best regards,
    
    Chuck Taylor
    47d 55' N, 122d 11' W
    
    --- Ken Gebhart  wrote:
    
    > I am looking for help in understanding something
    > about Thomas Sumner's event during which he
    > discovered his line of position.  Space does not
    > permit recounting the details of his situation, nor
    > a drawing of the navigational plot of his attempt to
    > find Small's light.  However, this is covered in
    > detail in Bowditch and many other navigational
    > books.  At the very end of the recount it says" The
    > DR position was found to be in error by 8 min too
    > far south, giving a longitude of 31 min, 30 sec too
    > far west.  The result to the ship might have been
    > disasterous had this wrong position been adopted".
    > My question is howso?
    >
    >
    >
    > Can anyone tell me from historical insight of
    > navigational procedures what course Sumner would
    > have set had he not questioned his first position?
    > In other words would he have turned to go straight
    > through St. George's Channel, or would he have
    > turned to acquire Small's Light first? I can see
    > that the latter choice might have been more
    > dangerous because he would have gone south of
    > Small's light, and his eta would have been upwards
    > of 2 hours late, catching him off-guard when land
    > (or rocks) appeared. But there were the Saltees
    > Rocks light and the Tusker Rock light off the coast
    > of Ireland which would have given him some
    > protection had he opted to go straight for the
    > Channel.
    >
    >
    >
    > This is not just a pedantic question I have.  I talk
    > about this situation in my seminars to show how his
    > line of position was discovered, but thankfully no
    > one has questioned me about exactly how a disaster
    > was averted.  Any comments are welcomed.
    >
    > Ken
    
    
    
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