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    Dated Chart Datum
    From: Bruce Hamilton
    Date: 2008 Nov 03, 21:51 -0800

    I still remember going over the charts when I made my first trip around
    Newfoundland and seeing that the charts were annotated with, "as
    surveyed by James Cook, 1775". There was no indication of any updates.
    The waters were deep enough that we slept well at night, but the Mate
    told us of meeting with an unmarked sea mount on one arctic trip.
    Apparently shoring up a steel hull with wood and canvas still does the
    The work that Cook accomplished is quite amazing especially considering
    the equipment of the day.  I just realized that I used to know the
    markings of the lead line, but have forgotten them completely. Was seven
    fathoms red bunting?
      I wonder how many of the world's charts are still quite out of date. I
    read once of a volunteer program in the UK where mariners submit the
    soundings from their own GPS linked sounders, and the chart makers use
    that data to help improve the systems. Is that really happening or was
    it just a plan?
    Oh, a little note on situational awareness.  In the early eighty's, some
    genius in our nation's capital decided that nautical charts should be
    metric and for a while you could have charts with soundings in meters
    and feet/fathoms, as they were not replaced all at one time. We never
    had any groundings, but we certainly had a few unkind words to say about
    our chart makers as we jumped back and forth from metric to nautical
    soundings.  I used to do the chart updates from the Notice to Mariner's
    and burn all the old charts when they were finally replaced.  I wish I
    had kept them all. I could have quite a collection, and I still love
    paper charts!
    Keep a good watch.
    Bruce Hamilton
    Navigation List archive: www.fer3.com/arc
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