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One tyre rotation was just about what my legs did round his port fwd wheelarch after he hit me. I think a shorter drive might well have been the luckier length, Bill, although then he was coming up it.
 

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Is it, then, that I do nothing well? Oh, woe! (but thank you, I have a few friends and were their number enough for a quorum I fear you would loose the vote).
 

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Can the 'market' for a super accurate system with universal coverage be so large that it brings the cost of maintaining at least one satellite network (two actual and a third almost there) down to that of maintaining a terrestrial hyperbolic system or systems? Does the conventional cargo ship pay less in light dues because it does not need the precision of GPS (which for DGPS shares some terrestrial infrastructure)? How much of the overall maritime contribution to maintaining the satellite systems goes then on providing 'time' to almost every gadget imaginable?

Or is it the other way round? The marine industry is paying for the satellite systems only through their national taxes used for support of the military and no specific contribution is made. If we choose to parasitise instead of maintaining a more appropriate set of aids for 'ourselves' we will have to live with any consequences.
 

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Navigating in the 1950's

How the hell did I sail on tramps going round the world -out East and back West, twice before I was 18 and continue to trade the world on a magnetic compass and sextant ???
 

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Just a lighthearted look at all the comments above. During the early 70s I was on the Berkshire as Purser sailing through the Inland Sea of Japan, and on the bridge with the old man looking at all the lovely islands, we had a Japanese PPilot andHong Kong Chinese helmsman, listening to the pilots orders the old man said who is speaking what? Sounds like the pilot knows Contonese, so asks thePilot who was speaking what? Ah says the pilot we both speak engerish
 

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You may find eLoran making a prompt return?

I have just disembarked a bulker in Kalamaki, Greece after a short 2.5 day passage from Haifa, Israel. About 8 hours out of Haifa, when 75 nml south of Cyprus, the vessel suffered severe jamming of all GNSS/GPS signals for a period of 3.5 hours over a distance of about 50 nml. The navigators were prepared for it, as the ship had similar problems a fortnight earlier on the way to Haifa. As a chartless/full ECDIS vessel the system reverted to DR' positions so didn't pose a problem.

This is just one of five GNSS/GPS jamming episodes in various locations that I am aware of over the recent past. A fortnight ago I had experience of false signals on a vessel in the Southern Red Sea/Gulf of Aden over an extended period, there are reports from many vessels of jamming in the Black Sea off the coast of Crimea, off the east coast of Korea and strangely, off the east coast of UK.
Seems that this is a growing problem? Just wait for the mess when signals over the land are jammed!
Cheers. Chris
 

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I can remember going up the Gulf during the Iran/Iraq war and the Decca Navigator system was unusable because at least one transmitting station had been switched off for military purposes.

Likewise in the event of any future war no radio wave based navigation system is likely to be relied upon as it can be jammed, put into a strictly military encoding system or simply switched off.

Best keep those sextants lubed and polished.
 

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You may find eLoran making a prompt return?

I have just disembarked a bulker in Kalamaki, Greece after a short 2.5 day passage from Haifa, Israel. About 8 hours out of Haifa, when 75 nml south of Cyprus, the vessel suffered severe jamming of all GNSS/GPS signals for a period of 3.5 hours over a distance of about 50 nml. The navigators were prepared for it, as the ship had similar problems a fortnight earlier on the way to Haifa. As a chartless/full ECDIS vessel the system reverted to DR' positions so didn't pose a problem.

This is just one of five GNSS/GPS jamming episodes in various locations that I am aware of over the recent past. A fortnight ago I had experience of false signals on a vessel in the Southern Red Sea/Gulf of Aden over an extended period, there are reports from many vessels of jamming in the Black Sea off the coast of Crimea, off the east coast of Korea and strangely, off the east coast of UK.
Seems that this is a growing problem? Just wait for the mess when signals over the land are jammed!
Cheers. Chris
Big NATO annual exercise on off west coast of Scotland just now, "Ocean Warrior" with GPS jammed.
 

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I was wondering if the sextant I was presented as Cadet Captain at the Boulevard Nautical School was now obsolete. I know we had Loran and Decca and the Echo sounder, for crossing the fathom lines on the charts along with radar if making a landfall. but sun and star sights were always taken where possible. The brown trousers always came in handy if you were navigating in Fog.
 

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With you expert navigator decrying the use of hambones and other paraphernalia of celestial navigation I am pleased to hear one of you, at least, is not suggesting that navigating in fog is best done FAOP in order to get through it quickly (or is that why you had the extra laundry on standby!)
 

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Apologies for returning to the thread subject, but some of you may have noted the following which recently appeared in the Master Mariner forum on LinkedIn:-
Openquote:-Korea institute KRISO awards UrsaNav an eLoran test bed contract.
The Korea Research Institute of Ships and Oceans Engineering (KRISO) has awarded UrsaNav a contract to supply an eLoran Transmitter Test Bed System in the Republic of Korea. UrsaNav, the exclusive, worldwide distributor of Nautel’s NL Series transmitters, will provide eLoran transmitter technology, as well as timing and control equipment.
The contract, awarded through UrsaNav’s agent Dong Kang M-Tech, represents the first phase in a broader program to upgrade Korea’s Loran-C stations to be the foundation of a sovereign Enhanced Loran (eLoran) positioning, navigation and timing (PNT) service. The Republic of Korea recognizes the challenges associated with relying solely on space-based signals (GNSS), the relative ease with which those signals can be jammed or spoofed, and the necessity to provide trusted time and position to its citizens and critical national infrastructure, UrsaNav said in a press release.
"eLoran is exceptionally difficult to spoof or jam, and it is nearly impossible to do so at a distance. Just as equipment required to spoof and jam GNSS must mimic relatively low powered GNSS transmissions, spoofing and jamming eLoran requires very high powered transmissions. Equipment needs alone to disrupt eLoran over a significant area would be almost prohibitive for any actor other than a nation state engaged in open conflict".
UrsaNav is the world’s leading supplier of eLoran technology. Have developed comprehensive solutions for the General Lighthouse Authorities of the United Kingdom and Ireland (GLAs) which include a complete set of nine Differential Loran (Dloran) Reference Station sites and two Monitor and Control System (MCS) sites as part of an Initial Operating Capability (IOC) level Dloran System.Endquote.
So now there are others that see the need?
Cheers, Chris
 

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Good,.

Discounting GPS spoofing, which is presently a miniscule risk (and easily detected on commercial tonnage I would claim), I am sure jamming is a reality although I think still more likely at state level than the pirate.

I am surprised that eLoran is considered jam resistant. It would require a lot of power to do it at the same distance as a loran station but I don't think so if closer up.
 

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Good,.

Discounting GPS spoofing, which is presently a miniscule risk (and easily detected on commercial tonnage I would claim), I am sure jamming is a reality although I think still more likely at state level than the pirate.

I am surprised that eLoran is considered jam resistant. It would require a lot of power to do it at the same distance as a loran station but I don't think so if closer up.
My experience earlier this year on a trip from Haifa to Greece was a period of severe GPS jamming for about 3.5 hours when around 75 nmiles south of Cyprus. Also had spurious and fast moving unknown radar targets throughout. Vessel had experienced similar two weeks earlier on the inward passage to Haifa. Considering the current military activity in Eastern Med I guess they were the perpetrators?
 

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As good a guess as any. Anyone not wanting cruise missile to land on them might be at it. An earlier problem reported (although not experienced) was the aerial being zapped by military radar in the PG.
 

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Memories of sailing up to Kharg Island during the Iran/Iraq war. Ship all blacked out even the nav lights.
Two things I always thought were a bit daft.
1. The 3cm radar was on !
2. The phosphorescence started at the bow and was still glowing ten miles astern in a big VEE.
Money was good though.
 

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I was on a supply vessel during the Iran/Iraq conflict, working for the Iranians, I certainly saw close up vessels being hit by missiles......they hit a Chemical Tanker close to Rakksh(R1) Oilfield and they had me up all night plotting it to make sure it cleared the Oilfields. Going back to GPS..when I worked on UCNW Research Vessel we used DGPS forget how much it cost...but I believe there are various similar systems Worldwide now WAAS.EGNOS to name a few
 
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