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- Newsgroups: rec.boats
- Path: sparky!uunet!gatech!paladin.american.edu!darwin.sura.net!ra!zielke
- From: zielke@hemlock.nrl.navy.mil (David Zielke)
- Subject: Re: GPS fix quality (was: Celestial vs. GPS )
- In-Reply-To: dudley@birch12.cray.com's message of 30 Dec 92 17:48:41 CST
- Message-ID: <ZIELKE.92Dec31113634@hemlock.nrl.navy.mil>
- Sender: usenet@ra.nrl.navy.mil
- Organization: Naval Research Laboratory
- References: <DUDLEY.92Dec30174839@birch12.cray.com>
- Date: Thu, 31 Dec 1992 16:36:34 GMT
- Lines: 23
-
- There is yet another problem with the 'precision' of the fixes given by GPS
- or even LORAN. While sailing from Norfolk to Cape May this summer I stopped
- in at Ocean City, MD. There was this guy single handing a 30' something or
- another sloop. He was convinced that he could make it into the inlet half
- way between Ocean City and Norfolk. The chart showed a 5.5' channel which
- was unmarked (because it moves with every major storm) and his draft was
- 5.25'. He told me 'I can get in there, my GPS is accurate to 15 meters and
- the channel is 30 meters wide' I hope I convinced him not to try... He was
- from Canada on the great lakes and simply did not believe that the bottom
- changed with time.
-
- This points out a real problem though. The charts themselves are often not
- as accurate as we would like to believe our GPS systems are. Differential
- GPS will make this even worse. I expect to see a lot of people aground
- because they try sailing full bore in the fog believing that they know
- EXACTLY where they are!!!
-
-
- David Zielke
- 'Botany Bay'
- Cal 35 Hull 006
-
- zielke@fozzie.nrl.navy.mil
-