Loss of position

[escape]

Sailing in the Irish Sea this w/e we had alarms from the GPS on 2 occasions.This is the first time in 12 months of constant use that our fix was lost.
Did anybody else experience problems?Are the US adjusting the system?
Thanking you in advance.
Escape

 

[oldharry]

Were there any warships in the vicinity? Sailing around Portsmouth, we find it not unusual for GPS to fail in the vicinity of modern warships - particularly American ones which seem to have a GPS 'exclusion zone' of around half a mile. Something to do with the HF equipment they used apparently.

 

[Guest]

Hope you were keeping regular fixes/EP's!
It will all be better when the new European system Galileo is up and running. Damn Yankees!

 

[jollyjacktar]

Bermuda Triangle

How do you know you were in the Irish Sea? You may be in the Bermuda Triangle, in a time warp or something.

 

[Jeremy_W]

Re: Bermuda Triangle

No way, JJT. You know when you're sailing in the Irish Sea. It's cold!If you can see the coast it's about to rain. ?If you can't see the coast IT IS raining.
You know you're near Bermuda by the sound of cash registers spinning ominously.

 

[escape]

Not that we could see oldharry but there was a navy training vessel that was tied up to the new pontoons in holyhead.
Unfortunately she was on the windward side with NE gusts to 50 knts.all her fenders burst and the cadets spent all friday night trying to hold her off .
she was a 50'' fast patrol boat with slab sides so they failed.The swell lifted her stern onto a cleat on the pontoon and she was holed.Also holed along her sides.
I'd like to be a fly on the wall during that board of enquiry!!
We left asap and made for Pwllheli.

 

[cynthia]

We had a position 'jump' last year whilst sailing alongside Arklow banks. The ship jumped several miles on the screen, fortunately we had a backup plot on the sweet, old fashioned chart. Hasn't happened anywhere else, so we thought it might be a glitch in the software. A bit disconcerting at the time mind!

 

[claymore]

That used to happen a lot near Galloway - especially with Decca - but don't rule out something as simple as your connections - mine froze last year but it was because someone (me!) had fallen against it.

What care we - tho' white the Minch is,
What care we boys, for wind or weather?

 

[Piers]

If your GPS is not properly shielded, the large amount of RF emitted from powerful radars (typically from navy or large ships) can penetrate the GPS unit and stop them from working.

Some of the original GPS sets suffered from this, typically found to happen when crossing an active shipping lane, but nowadays it is rare.

Piers du Pré
MBM Cruising Club enthusiast
www.dupre.co.uk/fsPlaydeau.htm

 

[philmarks]

Happens to me very often. I have an old Garmin 75 (which I like). Last week en route to St Malo it dropped out for a couple of hours, not tracking the satellites or signals too weak on others. Been like this for 3 years since I had it. I've know it drop out for 6 hrs before now. I hauled out the Magellan backup and ran a comparison. it had similar problems with some of the Satellites but was tracking others with stronger signal levels. I cleaned the aerial connections on the Garmin and adjusted the orientation of the aerial on the pushpit (had been leaning to one side). Improved matters maybe 50%. Still liable to drop out and did so on several (but shorter duration) periods on the way back last weekend.

I can live with it - I always maintain a paper plot, and update EP if necessary. When I hear the alarm, I immediately plot the last position on paper. Sods Law though - it often goes on a first time night approach to a port. Keeps me sharp!

I can't put the experience down to shipping, but then I have a steel hull, so I assum the radar doesn't get to the set, tho could affect active antenna.

I used to have a Philips AP9, and had to replace the patch antenna as water had got in.