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    Re: Modern celestial navigation: when and why?
    From: Bob Goethe
    Date: 2015 Mar 6, 12:11 -0800

    >>Welcome to Navlist Bob, perhaps you could expand on this a little.<<

    Thanks for the welcome.  This is quite a dynamic group, with a broad and passionate interest in navigation.  I am loving it.

    As for expanding on my perspective on British cartography, this was shaped by the preparation I did for my initial trip to the British Virgin Islands (BVIs).  The first thing you notice is that there are no British Admiralty charts of this region available for purchase...not at any price.  They are totally out of print.  So if you want something other than placemat-style, laminated, the-entire-Virgin-chain-on-one-piece-of-paper charts, you are left going to a German company called "NV Charts."

    NV produces top quality charts, thank goodness...but it seems odd that you get better BVI charts from almost-landlocked Germany than you do from the British themselves.

    If you purchase a copy of the NV chart pack for the Virgin Islands, they include a diagram which shows how up to date the soundings are in the areas covered by the chart pack.  Given that coral heads can grow up closer toward the surface of the water over time, knowing how current your charts are is pretty important.  (Of course, if the coral head dies, it will slowly disintegrate.  But having too MUCH water under your keel is not a concern when you are under way.)

    Now, I am working from memory here, but what I recall is that on the American side, most of the waters have been resurveyed in the last 20 years or so.  As soon as you hit the international border between the USVI and the BVI, the last survey date is "more than 100 years ago."

    Once you cross over into any territorial waters of the USA, not only are the charts up to date, but they are available at no charge by the Internet.  The American perspective is that the people paid taxes once to have the waters surveyed.  There is no need for them to pay a second time to get the results of those surveys.  So NOAA has taken their physically big charts and broken them down into PDF files that print out, booklet style, in 18 to 24 pages.  Download for free.

         You can still purchase a traditional, chart-table-sized charts, but what you
         are paying for is somebody to use their large-format printer to make
         you a nice chart.  You are not paying additional to the US gov't.

    The Canadians keep their charts up to date, like the Americans, on a month by month basis through a publication called "Notices to Mariners."  So if a buoy gets shoved off position by 50 yards by a storm, the Canadians will advised you of that in no more than 30 days.  You tell the gov't which charts you own, get yourself a purple pen, and can manually update your own charts as they send you the "Notices", with the data filtered specifically for your charts.

    The Americans don't just mark changes with purple ink, they actually update the downloadable charts themselves.  So what you download is deadly accurate, as of the day you download it.

    For all of the reputation Canada has of being more socialist than the USA, not only are we charged for initial surveys, but we are charged to purchase the charts as well.  Socialist by reputation; market economy in practice.

    The Americans GIVE away charts as service to the people and a way to enhance safety-at-sea.  Now THAT is a socialist impulse I can get behind.  May we Canadians someday emulate you.

    Where was I?  ...oh yes, the British and their charts.  They are simply not players in cartography, even when it comes to their own territorial posessions.  Presumably in home waters (other than the Scilly Isles!) they try to keep up to date, but not in this hemisphere.

    Bob

       
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