# Was mine bigger than yours?? i.e. GPS



## les.edgecumbe (Dec 24, 2007)

*st "La Loma" 1973*
One of the original, if not prototype, GPS navigators.
Consisted of Magnavox Receiver (top panel of racks), a Hewlett Packard PC with 8*KILO*byte of RAM, and the 'readout' was a converted teleprinter, sitting on top of the racks.
Failure rate about 75%. Magnavox even flew their man out to Capetown who reckoned to "fix it in a couple of hours", but when he looked up the Old Man was at Full Ahead for Europoort!! Didn't sort it, and spent 2 weeks drunk as a skunk!!


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## Varley (Oct 1, 2006)

Les,

Are you sure this wasn't Transit rather than GPS?

Had something similar Conoco Europe 3 or 4 years later. Programmed with cassette tape - didn't work.

David V


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## Ron Stringer (Mar 15, 2005)

You are correct David. GPS did not come into initial operation for the US military until about 1974 (full operation 1994) but Transit was operational from about 1964 until the early 1980s. 

The machine pictured was one of the early quasi-military/commercial Transit models marketed by Magnavox. They were not only huge, but hugely expensive and proved to be less than reliable on commercial vessels.


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## Tai Pan (Mar 24, 2006)

we had a thing called a sextant, no problems there.


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## John Cassels (Sep 29, 2005)

Tai Pan said:


> we had a thing called a sextant, no problems there.


Except when you couldn't see the horizon , ship rolling heavily, etc.
ltlle bit of mist , overcast etc.....................

The sextant , the most useless form of navigation tools.


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## Varley (Oct 1, 2006)

John,

Coming ashore when you did I am surprised you dismiss the one tool of your trade so lightly (rib-rib).

Satnav did affect the weather badly, so that overcast around noon increased from the mid sixties on, but as for the horizon John Dunipace would have had you taking your sights from the maindeck to 'bring it in'. Maybe he did?

I cannot lay rolling at the door of 'progress' but Satnav of the size Les exampled yesterday may have had some effect on GM!

David V


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## Tai Pan (Mar 24, 2006)

Tell that to Nelson Hi.


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## YankeeAirPirate (Oct 26, 2011)

*Transit: The New Tiki God*

I remember an early Transit Navigator Unit on a Lykes Lines ship in 81. Must have been a Magnavox. It was about the size of a stereo amplifier. I was surprised the company actually spent the money for it as they were too cheap to buy something really useful (like Loran C or decent ice cream). Lykes lines has been raked over the coals about being notoriously cheap and a poor feeder in other forums. But I still remember uncertain US landfalls without Loran C and those cheap little pots of ice milk (never decent ice cream) with the wooden paddle spoons coming aboard in New Orleans. They looked bad when they arrived from the ship chandlers and got worse as the voyage progressed. But, back to navigation, in any case:

Every few hours the Transit box would spit out that little piece of paper that looked like a sales slip telling you where you were. 

We thought it a miracle at first. Of course only the Captain could go over and tear off the little slip of paper and examine it. Then the 2nd Mate was held to scrutiny and his star sights gone over with a wire brush. The poor cadet had to stand up his figuring to the damned thing as well because we all know the cadet is always wrong. That's why we have cadets aboard ship, right? So's we have someone to blame...I digress again.

It got so that Sparky and the Old Man would plan their morning coffee time visits to the wheelhouse so they could be there when the fix (magically) came in. Frankly, I was busy working sun lines and star sights and never paid too much attention to it. If a sunline was not quite right, you could always plot another one and check yourself. What else was there to do on the bridge for four hours? They send you up there to navigate so navigate I did!

I have said this before, but I consider the hours I spent with a sextant in my hand as golden. It was a thoroughly reliable piece of gear as was the number 2 pencil and sight reduction tables that went with it. No batteries required for the dividers or triangle either.

I was very happy in my work in those days....


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## John Cassels (Sep 29, 2005)

David and Tai Pan; I've made many a post over the years on this subject.

And Yes , I sailed with Capt.Dunipace ( Dunkyle I believe) but I took my own
sights from the maindeck without any extorsion from him.

The sextant may have been fine for Nelson- but this nowadays is lost on me.

If you managed to get a decent morning sun sight , assuming you could see
the horizon and the sun, assuming you could do this from a bridge wing that
was perhaps heaving a great deal ( what height of eye correction would you
use ) , all this gave you was a single position line to be run up ( at an estimated
course and speed) and crossed with a noon sight.

Not an accurate navigation system , known best for the "Mystique"that the
name brings.

I was always thankful if I got a position within 3 nm of where the ship
actually was.


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## Baulkham Hills (Jul 11, 2008)

I remember on a greek ship I was on, the only one who took a sight was the old man and considering the 2nd mate had been ashore for seven years and before that a bosun maybe it was wiser he did it himself.

In the late eighties I sailed on a few vessels with a prototype Racal Decca integrated positioning system that worked on Loran, Omega, Decca and Satnav and compared positions from at least 2 systems. 
It was not a bulky piece of equipment but you always knew it was there because it was always in constant alarm. In the area we sailed in only Omega was available and when it received a position from a transit satellite it would compare the position with the Omega and of course there was always a difference because the Omega system was not very accurate compared to Satnav. There was no way to just operate in Satnav mode. 
Constant audible alarms which could not be silenced for more than a few minutes at a time. Another case of what seemed like a good idea turning into a nuisance. 

The first gps I sailed with was at the start of the first gulf war. I had installed it when Ice bound in the Gulf of St. Lawrence. After installation the position was correct to about 20 metres, which seemed pretty accurate to me. A few days later still in the Gulf of St. Lawrence the mate said that he had checked the accuracy visually and the error had reduced to virtually zero. I knew that the civilian version of the gps was deliberated downgraded the accuracy compared with the military users. I read afterwards that because of the Gulf war and the sudden demand for gps in the military they installed commercial gps in their equipment and then upgraded everyone to the military accuracy.
Maybe it was just a coincidence but it seemed strange at the time.


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## Varley (Oct 1, 2006)

John,

Wiki suggests you were not quite at the peak of your game with 3 NM but surely the point is that we slept soundly in our bunks because you were aware of your shortcomings (which were, perhaps, not quite as many as other departments would have you accept!). I hear some would even do so without a nightcap.

Since selective availability was switched off (the deliberate downgrading technique of GPS positioning) GPS has been accurate enough to put a cruise missile at its destination with an accuracy that a conventional merchant ship should never need to make a precise landfall. It has, however, been impossible to prevent "operator interests" from inserting differential GPS requirements into specifications and vetting requirements. How can it be a good idea for the accuracy to be variable (as one moves in and out of differential coverage), albeit it between two adequately accurate standards?

If your navigational safety is dependent on achieving such precision then no-one on board should be sleeping soundly at anytime (especially in those nice comfy cockpit seats that have been adopted!).

It is quite a long time since the GPS constellation allowed for continuous universal coverage (since 1995?) and had, anyway, been superior to Transit for some years before this. So why do sets universally include a dead reckonning feature. If you are using DR then the receiver(s)/processing is not working properly so reliance is being placed on a certainly defective equipment as it was when Royal Majesty grounded in 1995 (IMO now requires status alarms for GPS which was not, I think, the case then). Had the position simply blanked out the most indolent of watches would have been alerted. 

Ships are only one lightning strike away from reliance on the ham bone again. Many will find this a struggle, even to achieve 3 NM!

I do realise there are other benefits of accuracy. Fuel consumption is an obvious citation however the association of frequent fixes with frequent course corrections might have the reverse effect.

"Know the kit, know the risk".


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## Criffh (Feb 27, 2006)

Several T&J Harrison ships had Redifon Transit satellite navigation equipment fitted in the 1970's. These were rather large metal boxes, which sat on the chartroom table. The readout consisted of a row of 7 segment LED numeric displays. Also on the front panel were a numeric keypad, a panel meter which 'tracked' the satellite being received across the sky, and a punched paper tape reader, through which the device was, with luck, programmed. Besides the navigation program, Redifon also supplied some additional game tapes, a particular favourite amongst the mates (when the old man wasn't around!) being 'Lunar Lander'. 
On one occasion a power supply failed, and two boffins from Redifon attended the vessel upon arrival at a UK port. They had great pleasure in pointing out to me some rather novel 'hidden' acronyms in the operators' manual. Only one survives in my memory, and that was the Wholly Accessible Numerical Keyboard Entry Routine.


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## Vital Sparks (Sep 19, 2007)

The device on the left of this image is a Magnavox Transit SatNav from around 1978. BP fitted these as standard but a few had to be replaced after being commandeered by the RN during the Falklands war.


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## Varley (Oct 1, 2006)

Norcontrol DB4 was also programmed with high speed paper tape but did not formally do gaming (a la Redifon in #12). However "golden shot" was pretty popular with the player using a radar hood over the daylight PPI and "Bernie the bolt" using the joystick of the "DataRadar" target acquisition device. David V


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## Dave Woods (Apr 9, 2006)

Criffh said:


> Several T&J Harrison ships had Redifon Transit satellite navigation equipment fitted in the 1970's. These were rather large metal boxes, which sat on the chartroom table. The readout consisted of a row of 7 segment LED numeric displays. Also on the front panel were a numeric keypad, a panel meter which 'tracked' the satellite being received across the sky, and a punched paper tape reader, through which the device was, with luck, programmed. Besides the navigation program, Redifon also supplied some additional game tapes, a particular favourite amongst the mates (when the old man wasn't around!) being 'Lunar Lander'.
> On one occasion a power supply failed, and two boffins from Redifon attended the vessel upon arrival at a UK port. They had great pleasure in pointing out to me some rather novel 'hidden' acronyms in the operators' manual. Only one survives in my memory, and that was the Wholly Accessible Numerical Keyboard Entry Routine.


The first one was fitted on the Wayfarer in London on the 23rd October 1973. We sailed for the Great Lakes and Redifon sent a Technician and his wife for the trip across the pond. It worked very well while they were on board, but the following trip I finished up feeding that tape at least once a day.


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