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The call came in by radio one evening last September, at around 9 p.m. On the line was the master of a tanker, approaching the end of a monthlong journey from the Port of South Louisiana and carrying more than 5,000 metric tons of ethanol. The message was urgent: The ship’s GPS signal had suddenly disappeared—leaving the crew to navigate Cyprus’s shoreline in the dark.
On the other end of the line was the pilots’ office at the Vasiliko oil terminal, whose staff oversees shipping traffic at Vasiliko’s harbor on Cyprus’s arid, palm-fringed southern coast. Stelios Christoforou, the pilot on duty, recognized the gravity of the situation right away. In daylight, an experienced ship captain can maneuver using paper maps, markers, and the coastline as guides. But at night, GPS becomes a critical tool in unfamiliar waters—especially near Cyprus, where NATO and Russian warships roam. And any accident could spill the tanker’s cargo across miles of coastline.
 

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I was not aboard, however, as I understand it the Captain performed a large circle course which allowed him go to port at first light.
 

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Whether it's daylight or night should make no difference to dealing with a GPS failure.
He still has his charts and can use either visual bearings or radar ranges/bearing to determine his position.
 

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Totally agree with James_C, if he couldn't navigate without GPS he/she should not be Master or Navigator of any vessel.

I experienced a similar GPS interuption 75 nm south of Cyprus on passage from Haifa to Greece in 2018 which lasted about 3.5 hours. This was whilst carrying out an independent Navigational Assessment on a Greek bulker which had a full Filippino crew. The navigators responded appropriately using their established GPS failure procedures, reverting to DR positions on the duel ECDIS which corresponded well to the actual position when the GPS signal restored. The small scale eastern Mediterranean chart in their "get me home folder" was produced on the chart table, but only used for situational awareness. At the same time the vessel experienced continuous disturbances on the radar with multiple high speed echoes tracking across the screens. Nothing obvious was heard or seen, but there was a lot of USN and Russian naval activity in the area which could be heard on VHF. The loss of GPS signals in this area was reported to the appropriate authorities (British Admiralty HO). Subsequently we learnt that these events were not uncommon in this area where GPS jamming is regularly experienced probably from both government and military sources!
The message is very clear, do not be totally reliant on GPS for postions, but continue terrestial and celestial navigational practices, whereever you are.
Cheers. Chris
 

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Panic when the GPS is not functioning!!
What a change in today's navigation to when we used the skills we were taught.
I think it has come to the stage we must rethink the qualifications to become a master( or person in charge of a vessel)
 

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Reminds me of my son whose car apparently has automatic braking when he gets too close to a vehicle in front.
He took his wife's "primitive" car to work one morning and ran into the back of another vehicle.
Progress is not always a "good" thing ?
 

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Was it fault on the ship's GPS?
Did it self restore?
Best guess based on information provided to me, it seems that GPS signals were jammed.
 

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Reminds me of my son whose car apparently has automatic braking when he gets too close to a vehicle in front.
He took his wife's "primitive" car to work one morning and ran into the back of another vehicle.
Progress is not always a "good" thing ?
My Nissan Murano has this feature and it is a thing you get used to and if you forget to turn it on can cause bum puckering experiences.
 

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Best guess based on information provided to me, it seems that GPS signals were jammed.
Yes I'm getting the drift of that now from other's replies.
Considering that GPS is basically a military system which the rest of us are allowed to use, it would make sense that military exercises would involve some form of interruption to the transmission. On the basis that it would happen in the scenario that the exercise represents.
 

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One of course assumes that there are adequate charts (or the USB with all the charts on) on the ship and the people can actually interpret them.
I'm not being sarcastic either.
Anything military will be an obvious target of an enemy ?
Sat Nav is nice (when I left in the mid 80's - amazing) but like the sun and the stars is not 100% reliable.
Interesting read in the UK Sunday paper this morning with an article on autonomous unmanned ships run by AI.
No more Hello Sailor more Bye Bye Sailor ?
 

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A full interruption may be unusual but in fact it is normal - and should be expected. The GPS system including all 24 satellites (plus a couple of spare ones) deployed is the sole property of US Department of Defense and they clearly state that in allowing free international use of it they reserve the right to disrupt it without notice and/or deliberately impair its accuracy and reliability in the version accessible to everyone except US Government entities. This is primarily a matter of their national defense, but also occurs during exercises or maintenance or during exchange of active satellites or orbital correction.
 

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I think the Clinton administration ordered 'Selective availability' (the deliberately made less accurate facility to which non-US Navy users were allowed access) to be discontinued in 2000.

Not even NATO partnership guaranteed access to the nominal accuracy feature.

There were ways to improve the accuracy of the Sub-nominal (Selective availability) feature. One of the equations that receiver must solve is time so that if the receiver can be fed a direct and accurate 'time signal' such as with a Caesium beam standard clock it has one very accurate parameter without having to calculate it from the satellite signals especially (?) as it is wobulation of the transmitted time that is what degrades the 'Selective availability' access. The conventional trading vessel should have been quite happy with the pre-2000 public service..
 

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I'm a retired engineer. Until a few yeas ago I worked for an engineering and surveying company. On the roof of our building there was a system base station, its position was very well defined by traditional surveying. When a surveyor out in the field used his GPS it sent a signal to the base station. Back in the office when the data was imported to Autocad, the system calculated an offset to be applied to the field readings. They had an accuracy of better than a foot.
 

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someone's taking the piss with this post. Do they not understand gps is only an aid to navigation.
I agree with respect to conventional cargo vessels but it is many other things to many other people (it is now used for DP, where high repeatability equating in this case to high accuracy). It is used to provide 'time' and, of course, one would not want one's cruise missile going through the wrong window. What surprised me was the number of navigators (principally) on this thread that were ditching the hambone and chronometer and relying only on GPS.

(I had cause to take the Astronomer Royal to task when I heard him on R4 declariing ;'we now rely on GPS'. Obviously a good egg, he interrupted his Christmas break to give me reply - agreeing that we should not give up the hambone).
 

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Know matter how you put it, the original post related to basic navigation and the good practice of seamen, not the undoubted improvements and accuracy of gps over spherical trigonometry, - it’s still just one of many aids to navigation.

Until that’s understood, any examiner would give you another 6 months sea time – to think it over.
 
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