Monday, 27 October 2014

Trans ocean navigation by satellite navigation in 1985

These  days a voyage with sat nav is forgotton, some ridiculed the idea even back then thirty years ago?

Notty and myself set sail from an island about sixty miles south of Rio in Brasil and bound for Cape Town in South Africa, we were expecting a voyage of about a month and that was what we got.


My old Walker 402 satellite Navigation system, it refuses to power up now, age has got the better of it? We used the later Walker 412 unit while crossing the South Atlantic Ocean.


An update, a few days left with 12v dc power on and the set started to accept programing, basic stuff like your lat and long plus a waypoint as well, the time it accepts needs to be GMT which is the old term now, plus the date, that will be the bother as its now 2014 and thirty two years ago the year 2000 was not allowed for.


The set on inspection has a round fuse holder, which was empty, page 4 of the user manual tells me that a 2 amp x 20mm fuse will be required. I found one in a Shipmate RS5910 GPS chart plotter. Running on 12 volts the set will accept 9v to 36v and draws only 0.7 amp which was very good in those days.
The set now powers up but as the 25 to 30 satellites were all turned off, thats as much as it will ever do?





This set was sold in France, Antibe by Harris Yachting to a boat named Anakena, the date was 18 / 08 / 1982 so here we are some thirty two years later and the unit still works, its a shame they switched off those satellites, mind you its showing one now and at one time showed it had located three but no fix.




Check the date, this was an interesting step back in time and a reminder of what were were able to buy and use some three decades back!


An email from Notty today.

Yep, it was 1985 indeed and I was 45, now 75 so almost 30-years depending on what month we left Rio, not sure of that. We did OK mate to do it back in 32 days............

My reply:

Captain and navigator,

I have just pulled out the log of Tal Gal, a loose page in the front is of your work sheet and dated 24/04/85 , it says DR  34 s 21 w, it was a noon shot as another is below and for 1pm. So we were still a good way off then, another sheet shows us to then be at 35s and 8 w, so about as far down as we went?


Yachts Elangani and Tal Gal ( ocean planet) both due to head back to South Africa later that month of April 1985.
We cleared the Ilha Grande channel at 1600 hrs and that was on April the 10th, for a while heading the wrong way you will remember!

On the next day and by 22.45pm we were down to three reefs in the main and number two staysail and still doing 6 plus knots, you then noted “bad Night,   we were busy right away it seems? We did 104 miles in the first 24 hrs, wind died and was 0 to 5 knots we then started the motor at 14.46pm this was by then the 11th of April.

The log ends: 12th May, North  Head sighted out of the fog, now entering outside channel, the time logged was 0800hrs!

This is actually a good read, we wrote lots down, I will have it copied and give it to Dion for you to re live the event?

Sat nav was fine by me, you were told when the next fix was due and normally it was on time, time may be some hours though, this was not an instant event, so your DR was an important part of working with a Sat Nav. To prove this we had started to pick up VHF traffic on what we knew was the South African West Coast, the only issue was fog and while we could see five fishing boats we could not see land.

I hailed Saldanha Port Control and asked that they find us on their radar, the reply was we can not see you and possibly you are not where you think you are?

A sobering thought?

Still having sailed for the entire distance from Brasil to South Africa we thought we were where we said we were, I asked could the radar see the four wooden fishing trawlers and large steel built factory ship?

The reply was a negative, so in we went in the fog and working only on our DR ploting.

When the fog did lift we were bang on and in the very center of the main shipping channel into the port of Saldanha!


A recent picture of Notty taken two years back and then in Hout Bay, South Africa.

Sat Nav worked for me just fine, it was a Walker 412, I still have one now, shame it can never work again.

Roy

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