'Uncertain of position'

[LadyInBed]

I recall rounding Cape Wrath in the Decca days in a small boat with almost no visibility in thick fog and no wind. You could hear Duslic rock breaking. We knew where the Cape was (from the radio beacon) but not how far off we were. For a terrifying 20 mins we headed straight for it to get a visual fix,

One of the readouts on my DECCA was Lat & Long!

 

[Supertramp]

One of the readouts on my DECCA was Lat & Long!

It wasn't a Decca, it was a Seafix and I think you looked for the null or point where the sound tone faded. All you got was a bearing. Different ranges for different beacons, and not always in good positions to plot from, especially if only two were available. Still much better than nothing on a long coastal trip in the dark or poor visibility.

It is true that we (now) take GPS for granted and there are some passages I would plan very differently if I was not certain of my position - Irish Sea banks for one.

 

[LadyInBed]

It wasn't a Decca, it was a Seafix

When you said

I recall rounding Cape Wrath in the Decca days

I assumed you were using Decca. It just goes to show that you can't make any assumptions when reading what people post!
Seafix was RDF. Yes, you 'swung' for a null point.
PS you could have done a running fix without closing the coast in fog.

 

[Praxinoscope]

When you said

I assumed you were using Decca. It just goes to show that you can't make any assumptions when reading what people post!
Seafix was RDF. Yes, you 'swung' for a null point.
PS you could have done a running fix without closing the coast in fog.

And of course you had to read Morse as if I recall each station transmitted a different sequence of Morse . Trying to find the null on an Seafix RDF in a Leisure 17 bouncing up an down in the middle of the Channel could be ‘fun’.

 

[LadyInBed]

And of course you had to read Morse as if I recall each station transmitted a different sequence of Morse

Yes, the Station Identifier, eg PB for Portland, then a tuning signal which you swang on.

 

[capnsensible]

				And of course you had to read Morse as if I recall each station transmitted a different sequence of Morse . Trying to find the null on an Seafix RDF in a Leisure 17 bouncing up an down in the middle of the Channel could be ‘fun’. Even on Joint Services Nicholson 55's it was often called the 'sick box'..... I inherited one on our liveaboard yacht. Didn't ever use it for fixing but it was really good for listening to long wave radio especially Christmas songs on Antigua radio stations. Which was kina weird in a brilliant blue ocean with sunshine and a few trade-in puffy clouds...

 

[GHA]

Never takes too long for a thread to go.............
?

 

[zoidberg]

.....a tuning signal which you swang on.

Interesting, if quite original, variant.

 

[zoidberg]

Navigation ain't as easy, on occasion, as some RYA Instructors would have you believe.

Discuss.....

 

[johnalison]

Navigation is the art of knowing what to do when you don’t know where you are.

 

[LadyInBed]

Interesting, if quite original, variant.

It didn't feel right when I typed it ?

 

[zoidberg]

It didn't feel right when I typed it ?

That's OK. It's one way to get peeps to read your comment twice, or thrice.....

 

[AntarcticPilot]

Navigation is the art of knowing what to do when you don’t know where you are.

I always try to know which direction to go to reach safe water. And pre GPS on the West Coast of Scotland, I usually had a set of clearing lines to avoid danger in my mind after examining the chart - usually a set of transits (I'm OK if I keep Sgeir Dubh to starboard of Glas Eilan" sort of thing). And on the East Coast, it's appropriate to note that John followed Jim Brading's advice about the direction to safe water in "We Didn't Mean to Go to Sea"

 

[AntarcticPilot]

I always try to know which direction to go to reach safe water. And pre GPS on the West Coast of Scotland, I usually had a set of clearing lines to avoid danger in my mind after examining the chart - usually a set of transits (I'm OK if I keep Sgeir Dubh to starboard of Glas Eilan" sort of thing). And on the East Coast, it's appropriate to note that John followed Jim Brading's advice about the direction to safe water in "We Didn't Mean to Go to Sea"

Should say, don't try using the example I gave - there are millions of Sgeir Dubh and Glas Eilans!

 

[AngusMcDoon]

Should say, don't try using the example I gave - there are millions of Sgeir Dubh and Glas Eilans!

Is that the one just off Tarbert?

 

[AntarcticPilot]

Is that the one just off Tarbert?

For the poor, benighted people who don't know the West Coast, Tarbert is nearly as common a placename as Sgeir Dubh!

 

[Spirit (of Glenans)]

It wasn't a Decca, it was a Seafix and I think you looked for the null or point where the sound tone faded. All you got was a bearing. Different ranges for different beacons, and not always in good positions to plot from, especially if only two were available. Still much better than nothing on a long coastal trip in the dark or poor visibility.

It is true that we (now) take GPS for granted and there are some passages I would plan very differently if I was not certain of my position - Irish Sea banks for one.

"Inside the banks" ... depth sounder and distance off. The Arklow Bank Windfarm is a good visual indicator of your course relative to the shoals.
Keeping your eye on the depth is well advised if you are steering towards the Blackwater Bank light and haven't realised that it's been moved. Don't ask how I know that, but luckily the skipper sensed something and came up from his bunk to advise the watch that the water was getting shallower?

 

[LONG_KEELER]

I do think that electronic navigation has enabled a sailor to perhaps go sailing where before you might not have done.

Although machine has no brain or imagination and no mental kinks but can't experience the satisfaction that of a job well done. I don't thinks it's spoilt sailing though as the emphasis is just shifted somewhere else to enjoy.

 

[Graham376]

I do think that electronic navigation has enabled a sailor to perhaps go sailing where before you might not have done.

Although machine has no brain or imagination and no mental kinks but can't experience the satisfaction that of a job well done. I don't thinks it's spoilt sailing though as the emphasis is just shifted somewhere else to enjoy.

When we started sailing in the early '90s we didn't have gps so everything was chartwork. These days, I still prefer to use charts to plan passages, then put destinations and waypoints into the gps. Quite often with hardly any cross tide to worry about here, just let the gps into autohelm get on with it. Positions still noted on chart from time to time, particularly if we're out of sight of land.

 

[LONG_KEELER]

There used to be charts with printed silhouettes of approaches and headlands etc.

I remember a few times hearing an anxious boater on the VHF to the Coastguard asking where he might be. The Coastguard would say " Tell me what you can see " . I expect they got it right most of the time.