# New nav aids



## Ken Wood (Sep 6, 2006)

I remember when I first sailed with satnav. The machine was the size of a double wardrobe, the front being a wall of flashing lights and plastic buttons, even better than Docotor Who. 

You might only get a satellite above the horizon every 3 or 4 hours, more the further from the equator you were, which we were not. But we were supplied with tables and could calculate when the next satellite would appear, a bit like stars really. Occasionally the equipment would throw a wobbler and would need to be re-programmed. Out would come the phone book manual, and the procedure could take an hour or two.

For some reason we never learned to trust the results, and used to marvel if we got a sat position that was anywhere near our star sight results! Changed days now when you can get a satnav that sits in your pocket and can find your golf ball for you. (Thumb)


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## Chris Isaac (Jul 29, 2006)

Voltaire obviously owned a deep fat fryer then.


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## trotterdotpom (Apr 29, 2005)

I thought this thread was about some deadly disease lurking in Public Toilets in Chelsea, but no, it's about Nav Aids.

I remember those early days of Satnav. The Mates would produce a "cocked hat" that could be cut out of the chart and used as a kite and say: "That Satnav's a load of crap, the sextant's here to stay." Sad but wrong.

Voltaire was a pretty witty character, but he wouldn't want to ask an Australian female if she had a "deep fat fryer" - not at closing time anyway.

John T


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## Ken Wood (Sep 6, 2006)

An aids, bit of finger trouble! The deep fat fryer, what a boon to Scottish culture. Pity about the weather, we could have had a solar powered fryer!


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## Ron Stringer (Mar 15, 2005)

Ken Wood said:


> You might only get a satellite above the horizon every 3 or 4 hours, more the further from the equator you were, .....


Wrong way round, Ken. The Transit satnav system used satellites in low polar orbit. So if you were near the pole, there was a satellite in view very frequently. At the equator, the tracks of the satellite were at their widest distance apart and you could go several hours before getting a 'pass' that was usable. Think of the satellite tracks as similar to lines of longitude - converging at the poles and furthest apart at the equator.


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## Ken Wood (Sep 6, 2006)

Ron, that's what I meant, more satellites nearer the pole, not the time between sats above the horizon. A grammatical misunderstanding. (Read)


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## Clanline (Dec 19, 2007)

I had no idea they were massive machines!

When I was with B & C I don't think any of our ships had Sat Nav, too mean to spend any money!

I must admit I thought they were so accurate then that you did not need a sextant any more and interesting to read otherwise.

Sat Navs nowadays must be great for the second mate not having to get up for sights!


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## Ken Wood (Sep 6, 2006)

They could be accurate, but these were early days and the system had not been proven sufficiently for us to have confidence in it. In fact there were so many mistakes and errors at that time that astro was still the best.
Satnav was still useful, eg coming through Palawan Passage in monsoon/ poor visibility, that is if a satellite came over the horizon!


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## Varley (Oct 1, 2006)

I think Ken's memory if frozen at the very dawn of Transit. On the first ship I sailed with something that could be described us 'production' they had already affected the global climate. The number of days on which either sun or horizon was too obscured had climbed dramatically from the days when conscientious masters would have their staff on deck to get a clearer horizon.


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## Interalia (Aug 9, 2007)

In mid seventies I did a delivery of a seismic vessel from Singapore to Persian Gulf. The vessel, I was told, was owned by Litton Industries, who were building and designing satellites and navigational systems. During the trip, a new sat-nav was being installed but not yet working, complete in it's own airconditioned compartment and with it's own dedicated generator to provide smooth power, and a doppler system to up date the fixes when in soundings.

One evening while taking star sights I had one of the seismic crew watching over my shoulder my every move; and intrigued with the frequent references to Nories Tables. Fortunately my sights came out good and I plotted the position on the chart and said " That's where we were half an hour ago". The seismic bloke then made the comment " Our sat-nav system can do it much faster"
"Yes" I replied " but I can do this by candle-light!"

Interalia


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## Sailtie (Jan 23, 2008)

I've just done a Channel Crossing Fowey to Chenal du Four and back in my yacht which is now fitted with AIS.
What a boon!
You really do know which ships are on collision courses, which are fishermen etc. Far fewer dramatic course alterations, just in case. Stress levels way down.
Back when I started the Company only put radar aboard when you were coastal, ditto Decca later on. Now, I've got all the toys. GPS, Chartplotter, HD Radar, AIS, GMDSS radios and all linked up.
Still got a sextant, tables and log but find I leave them at home unless I want to play with them.
Swing the lamp there, Jack


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## Ken Wood (Sep 6, 2006)

What about Loran C, or was it A, probably both. Always seemed a bit unreal to me until they automated the readings, but by then I never trusted it. Not like Decca, which was brilliant, especially close to the coast in thick weather. Except for vessels which would sail down a Decca line approaching harbour!


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## Hugh Wilson (Aug 18, 2005)

Ken,

I may be mistake, but I seem to recall you were assistant OIM on the Brent Bravo in the late 70s. I was one of the R/Os there 1975-80.

Hugh


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## 5036 (Jan 23, 2006)

trotterdotpom said:


> I thought this thread was about some deadly disease lurking in Public Toilets in Chelsea, but no, it's about Nav Aids.


I've never had aids, new or otherwise.


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## trotterdotpom (Apr 29, 2005)

There was a typo in the original thread title, but, hey, thanks for clearing that up.

John T


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## Ken Wood (Sep 6, 2006)

Who changed my spelling. Now looks as common as muck! Hugh, I worked for Shell but was Marine dept., never platform based. My brother Dave was OIS, perhaps it was him you remember.


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