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Old 07-08-2013, 15:24   #1
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GPS as the Sole Means of Navigation.

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The National Geospatial-Intelligence Agency misplaced a reef in the Philippine Islands by eight miles on its digital nautical charts, which helped cause the USS Guardian to run aground Jan. 17, destroying the ship.

NGA director Letitia Long told Chief of Naval Operations Adm. Jonathan Greenert that the digital nautical chart display of the Tubbataha Reef in the Sulu Sea was wrong due to erroneous commercial satellite imagery. Long made the assertion in letters obtained by the watchdog website Government Attic.

That error was compounded by “exclusive reliance” of the USS Guardian crew on GPS as a “single source of navigation.” The crew did not pay heed to lighthouses on the reef, according to a 160-page post-wreck investigation report by Adm. Cecil D. Haney, commander of U.S. Pacific Fleet.
How a Misplaced Reef on a Digital Chart Helped Destroy a Navy Minesweeper - Nextgov.com

The Canadian Coast Guard has this on their chartplotters.

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Old 07-08-2013, 15:31   #2
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Re: GPS as the sole means of navigation.

Every chartplotter I have ever used displays an initial splash screen that states it is not to be used as a sole source of navigation.

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Old 07-08-2013, 16:07   #3
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Re: GPS as the sole means of navigation.

I've been thinking about this a bit lately - the last couple of trips up the coast i did, i was a little lazy - i didnt do ANY navigating - i was even embarrassed when i had to do a sched update and could only give my position as 'off the 3rd big headland down from barrenjoey' cos i couldnt be bothered getting the gps out. As a matter of habit i had the chart out and had a look at it now and then. Thing is - even at night i 'navigate' by knowing where i am, knowing where i'm going and using my eyes and occasionally my binoculars (which i inherited from my dad and were used by him sailing all around the pacific in the 60,70s). I wonder how many of you who are, like me, of the vintage that didnt habitually use electronics, really rely on all the aids that much? Even getting off the coast i tend to be a bit relaxed because - well if you cant see the coast here you know its somewhere to the west, and the only things you're going to bump into are lord howe or middleton...or nz if you really fell asleep.
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Old 07-08-2013, 17:01   #4
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Re: GPS as the sole means of navigation.

This.

and iirc most say dont use as primary navigation tool

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Originally Posted by colemj View Post
Every chartplotter I have ever used displays an initial splash screen that states it is not to be used as a sole source of navigation.

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Old 07-08-2013, 17:28   #5
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Shouldn't the lesson in this case be 'don't trust charts' instead of 'don't trust GPS' ?
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Old 07-08-2013, 19:06   #6
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Originally Posted by conachair View Post
Shouldn't the lesson in this case be 'don't trust charts' instead of 'don't trust GPS' ?
Use you eyes!
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Old 07-08-2013, 19:38   #7
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Re: GPS as the sole means of navigation.

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Originally Posted by colemj View Post
Every chartplotter I have ever used displays an initial splash screen that states it is not to be used as a sole source of navigation.

Mark
And I'm sure everyone reads the End User License Agreements when they install software.

Turn off the GPS satellites and see how many boats with chartplotters could get anywhere.
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Old 07-08-2013, 19:52   #8
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Re: GPS as the sole means of navigation.

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Originally Posted by rebel heart View Post
And I'm sure everyone reads the End User License Agreements when they install software.

Turn off the GPS satellites and see how many boats with chartplotters could get anywhere.
what a great day that would be for delivery skippers who can navigate in real time.....bring it on ....in days past you earnt the right to be called a captain/navigator by how succesfull your landfalls were
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Old 08-08-2013, 04:06   #9
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Re: GPS as the sole means of navigation.

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Originally Posted by conachair View Post
Shouldn't the lesson in this case be 'don't trust charts' instead of 'don't trust GPS' ?
I would say the answer is YES! I bet their GPS told them exactly where they were, but that doesn't help you if a reef is recorded in the wrong position.

That only excuses some of the error in this case as it sounds there is a lighthouse that they should have been questioning the position on.
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Old 08-08-2013, 04:16   #10
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Re: GPS as the sole means of navigation.

Are the paper chart of the area wrong as well?
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Old 08-08-2013, 04:16   #11
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Re: GPS as the sole means of navigation.

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Originally Posted by charliehows View Post
I've been thinking about this a bit lately - the last couple of trips up the coast i did, i was a little lazy - i didnt do ANY navigating - i was even embarrassed when i had to do a sched update and could only give my position as 'off the 3rd big headland down from barrenjoey' cos i couldnt be bothered getting the gps out. As a matter of habit i had the chart out and had a look at it now and then. Thing is - even at night i 'navigate' by knowing where i am, knowing where i'm going and using my eyes and occasionally my binoculars (which i inherited from my dad and were used by him sailing all around the pacific in the 60,70s).
Not sure if you were being ironic - but to me all that sounds like Navigating . Of course if you had also got a pencil out it would have been "proper" navigating .

If "you" know where you are not then IMO no great need to know exactly where you are (let alone to the last inch). In ye olden days (pre GPS!), less precise locations actually fitted in very well with prudent navigation (if you can't navigate to the last inch, then likely won't hit something which is 6 inches to the left of where it is meant to be. Or the GPS thinks it is, because Capt Cook had a WAG on a Friday , using a leadline).
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Old 08-08-2013, 04:22   #12
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Re: GPS as the sole means of navigation.

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Originally Posted by noelex 77 View Post
Is the paper chart of the area wrong as well?
Could well be the case. Paper and Digital maps are produced based on the same sources after all.

It is of course also possible that however integrated the original data in the product this particular vessel used made a mistake.
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Old 08-08-2013, 04:23   #13
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Re: GPS as the sole means of navigation.

What was the bridge crew doing? Was anybody looking were they were going? Did the depth gauge not show the depth shallowing out? There was a lighthouse on the reef, so surely there was other buoyage as well?

I might reprimand the map-maker, but I would certainly beach the bridge crew.

[edit: I just noticed the link above the picture - apparently lookouts saw the lighthouse and the crew ignored their reports.]
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Old 08-08-2013, 04:35   #14
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Re: GPS as the sole means of navigation.

Likely reason was either that someone changed the scale of the chart on the Chartplotter (where is here & japan?!) so the reef "disappeared" or that different people were using the Chartplotter (some people just can't stop fiddling with buttons) which means that no one had an easy visual way of spotting when something was odd or different (with a quick glance) - because the chart was always different (in size, orientation - or screen, oh look it has how many inches it is to the North pole!).
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Old 08-08-2013, 05:10   #15
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Re: GPS as the Sole Means of Navigation.

I do much of that "Charliehows" navigation. I think that is legitimate form of navigation,- you look out at the coastline, see the familiar features and rely on your local knowledge. At other times, with less familiarity, I might use the GPS in addition. If I'm in a new place I would use more navigation tools. 'depends on the situation.
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