Welcome to the NavList Message Boards.

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
       
    Reply
    Re: The shipwreck of Admiral Shovell
    From: George Huxtable
    Date: 2007 Aug 27, 10:19 +0100

    Frank wrote-
    
    | Here's a link to the file George provided:
    | http://fer3.com/arc/img/Clowdisley_Shovel_1707_JIN_1960.pdf
    |
    | For convenience, I also inserted a direct link at the end of the archive
    | copy of the previous message.
    |
    | Is this article under copyright? If so, please let me know in a couple of
    | weeks.
    
    =========================
    
    from George-
    
    Thank you Frank.
    
    I hope readers will take a serious look at it. It's a salutary tale of the
    dreadful state of Royal Navy navigation, in 1707. How things had changed by
    Cook's day, half a century later!
    
    Not entirely their own fault, of course. The concept of longitude, as a
    quantity that could be specified for locations around the world, with some
    common reference-point (perhaps at Greenwich), hadn't really sunk in then.
    Instead, mariners thought about changes in longitude, with reference to
    their starting point, derived from their dead-reckoning.
    
    But what I find so surprising are the discrepancies in latitude, in a fleet
    that was sailing together as a convoy. As long as the Sun shone at noon (and
    it had been doing so, reasonably often) latitude should have been clear-cut.
    Well, limited by the precision of their backstaffs, to perhaps 15 minutes or
    so.
    
    And not helped by the scandalous errors in charts, in the days when these
    were commercial ventures, before the Admiralty Chart existed. How many ships
    were lost because the Scillies, and Lizard, were plotted on the chart nearly
    10 miles North of their true position, I wonder?
    
    There's a decent gap, enshrined in the words of the old song, "Twixt Ushant
    and Scilly is thirty-five leagues ...", or 105 nautical miles. That was what
    mariners had to find their way between, and without even lighthouses, in
    early days. In the days before longitude could be measured, they had to do
    it by latitude sailing, taking deep soundings to establish how close in to
    the Western channel they had got. In thick weather, even latitudes were
    unavailable. That situation remained true, until radio aids became available
    (in the 1930s ?). I wonder if Henry Halboth can recall approaches made
    without even radio DF help, and how ships then managed, in prolonged thick
    weather?
    
    ================================
    
    Frank asked about copyright-
    
    Yes, that paper is only 47 years old, so I suppose that copyright
    restrictions apply, strictly speaking, and I should really have pointed that
    out. Readers should respect that. It has here been made available for the
    purpose of academic discussion, but should not be disseminated further, and
    it might be wise for Frank to make it unavailable again after it's had time
    to serve its purpose.
    
    George.
    
    contact George Huxtable at george---.u-net.com
    or at +44 1865 820222 (from UK, 01865 820222)
    or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    
    
    
    
    
    --~--~---------~--~----~------------~-------~--~----~
    To post to this group, send email to NavList@fer3.com
    To unsubscribe, send email to NavList-unsubscribe@fer3.com
    -~----------~----~----~----~------~----~------~--~---
    
    

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.
    Email:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site