NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: sextant without paper charts
From: Lu Abel
Date: 2008 Nov 03, 16:47 -0800
From: Lu Abel
Date: 2008 Nov 03, 16:47 -0800
Peter Fogg wrote: > Lu continues: > Consider then the crudeness of our charting capabilities. Satellites > can't spot stuff below the water like they can above the water. Side > scan sonar is great -- if you've got the time and money to scan the > ocean a few hundred yards at a swath. Bottom line: we really don't > know what's out there in the great oceans. > > Response: > Although this is changing, at least in our waters. Australia claims a > vast swathe of underwater territory (in the guise of 'economic > interest') and has set about charting this realm in a systematic way. > All sorts of interesting things are bobbing to the surface .. of our > understanding. There's more than that, too. It's one thing to slash the bottom of the QE II, quite another to do it to the bottom of an oil tanker or to an LNG tanker. On more and more charts, I'm seeing symbols for channels where commercial ships operate having been swept for obstacles by drags, rather than merely having been scanned with sonar. It's interesting to look at the chart for that particular region -- whilst there's one tiny region where surveys date back a century, most of the shallower areas transited by commercial ships have been charted with side-scan sonar since the QE II incident. If anyone wants to take a look for him/herself, here's the image of the chart: http://www.charts.noaa.gov/OnLineViewer/13218.shtml There are a westward running string of islands eminating in the northeastern corner of the chart, off the western tip of the westernmost island is Sow and Pigs Reef, the QE II was sailing just south of that and I rather suspect some of the shallower rocks are recent discoveries. We have people from all around the world on this list and since I gave a weblink above, I'd like to mention that all charts of the US are available for on-line viewing. Starting point is http://www.nauticalcharts.noaa.gov/mcd/OnLineViewer.html --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---