'Uncertain of position'

[Daydream believer]

What's the Dutch for 'Care In The Community'...?

S.d off?
Works in a lot of places

 

[DanTribe]

My first North Sea crossing was 1976 in a Vivacity from Burnham to Ijmuiden. We had a Seafix but couldn't get it to work properly.
We reckoned if we kept heading East we were bound to hit Europe somewhere and could sail along the coast until we recognised a harbour. At dawn we could see planes landing and taking off so it must be Schiphol so headed for that. It was and we arrived at Ijmuiden spot on. Good job we didn't see Rotterdam airport.
The confidence of youth!

 

[Porthandbuoy]

I remember reading about a chap who sailed from California (??) to Hawaii and navigated by following the contrails of the aircraft heading that way. I've tried googling for info, without success. Could be an urban myth.

 

[Bilgediver]

Maybe someone could invent a system where three base stations at known locations could transmit a pulse at the same time and then the phase difference between the received signals could be compared to give a location. We might need some colourful lines overprinted on our charts but that would add to the fun. Perhaps a music company like Virgin would like to invent it and set up the system.

And could call it Dik Dak Decca to sound familiar to all generations.

 

[DanTribe]

I remember reading about a chap who sailed from California (??) to Hawaii and navigated by following the contrails of the aircraft heading that way. I've tried googling for info, without success. Could be an urban myth.

I think that might be from Nevil Shute, Trustee from the toolroom. I must read that again.

 

[Loopy]

There's a large community of boat users wholly dependent on e-technology for awareness of own position and the proximity of hazards.

I fall into this category. I have minimized the risk thus far by carrying multiple GPS receivers (the chartplotter, a couple of Garmin GLO units, and of course the cell phone) and keeping one device for GPS signal reception and navigation along with a small solar panel and battery in a small metal trash can that serves as a farady cage.

There's another, smaller and generally older community who have retained the simpler capability of determining position, etc. by self-contained means. That group includes merchant marine, RN and USN navigating officers encouraged by their professional bodies to have 'more than one string to their bow'..... and the bunch of entrants in the Golden Globe Race 22, currently heading down the South Atlantic towards Cape Town and beyond, using simple sextants and stars.
Implications for us?

While my strategy should protect me from having my electronics and electrical systems disabled by a lightning strike, I have started thinking about how to go about learning celestial navigation. But this would require carrying not only a sextant, but paper charts. If TPTB decide to limit access to GPS transmissions for geopolitical reasons, without these older tools you could be in a bad spot.

 

[lustyd]

Celestial navigation isn't the answer to complete failure of GPS. The normal solution is knowing which way land lies and how you'd get there. If you're mid Atlantic head west, if you're mid channel head either north or south depending how long ago you left and which way the favourable wind is. The liklihood of having suitable charts, almanacs, sextant, even pencils on board and making use of celestial is very low for most of us so it's now very much in the realm of hobby rather than genuine backup.

 

[Stemar]

I was looking for a blank CD in a box of stuff, and cane across a PDF of the American Practical Navigator. I offer the opening paragraph, which pretty much sums up my attitude to navigation, particularly the last sentence.

Marine navigation blends both science and art. A good navigator gathers information from every available source, evaluates this information, determines a fix, and compares that fix with his pre-determined “dead reckoning” position. A navigator constantly evaluates the ship’s position, anticipates dangerous situations well before they arise, and always keeps “ahead of the vessel.” The modern navigator must also understand the basic concepts of the many navigation systems used today, evaluate their output’s accuracy, and arrive at the best possible navigational decisions. Navigation methods and techniques vary with the type of vessel, the conditions, and the navigator’s experience. Navigating a pleasure craft, for example, differs from navigating a container ship. Both differ from navigating a naval vessel. The navigator uses the methods and techniques best suited to the vessel and conditions at hand. Some important elements of successful navigation cannot be acquired from any book or instructor. The science of navigation can be taught, but the art of navigation must be developed from experience.

 

[zoidberg]

I'll happily endorse what Stemar quotes from 'Bowditch', and aspire to most of it.

'Navigation happens between the ears, not on the chart table.'

 

[Baltika_no_9]

................. But this would require carrying not only a sextant, but paper charts...........................................................reasons, without these older tools you could be in a bad spot.

I do think I'd want paper charts if I were in this position but are they absolutely necessary? It would, in my experience at least, be uncommon to plot a fix from a series of celestial observations directly onto a chart. If doing say a sun-run-sun then the distance between GP, AP and ship's position may be considerable. I would only use a plotting sheet not a chart. Once you have your position then yes it is very convenient to transfer it to a chart be that either a paper chart or an electronic one. You can also of course locate your intended destination on the plotting sheet if you scale it correctly.

Edit to clarify the above. GP is not plotted of course if you're using AP3270 tables for example.

 

[zoidberg]

You can also of course locate your intended destination on the plotting sheet if you scale it correctly.

Edit to clarify the above. GP is not plotted of course if you're using AP3270 tables for example.

I'm reminded that the navigators ( 'Best Of Three') on the 'Black Buck' strike missions to Falkland Main/Stanley Airport used astro fixing there and back. They didn't plot Ground Position either, 'cos they were mostly 8 miles up.

 

[Baltika_no_9]

......................they didn't plot Ground Position either, 'cos they were mostly 8 miles up.

Well even in air navigation the aim is always to determine your "ground position", that is the point where an imaginary line from the aircraft to the centre of the earth cuts the earth's surface. As a navy man I must say I hold air navigators in very high regard. With my first experiences of offshore racing in the late 60s and onwards, we always felt lucky if the navigation was in the hands of a RAF bod. The speed at which they were able to work was very impressive.

 

[zoidberg]

As a navy man I must say I hold air navigators in very high regard. With my first experiences of offshore racing in the late 60s and onwards, we always felt lucky if the navigation was in the hands of a RAF bod. The speed at which they were able to work was very impressive.

You must be in a majority of one!

You've made an Ould Navigesstimater almost happy. Could I quote you?

 

[Baltika_no_9]

You've made an Ould Navigesstimater almost happy. Could I quote you?

I shall deny it of course!

 

[zoidberg]

As a navy man I must say.....

Which navy?

Shurely not Birmingham....

 

[Baltika_no_9]

Which navy?

Shurely not Birmingham....

Royal Navy, mostly as a submariner. I left in 1979 - so long ago!

 

[DanTribe]

A bit of thread drift but sort of relevant.
We were anchored in Pyefleet, River Colne late one night and overheard a boat on VHF asking Coastguard for assistance. He had left Bradwell and heading for Brightlingsea but had run aground.
I guessed he was on Mersea Flats or Cocum Hills.
The CG asked if he could see any features to identify his location, such as buoys, lights etc. [even a nuclear power station?].
After a while he came back with. "yes, the moon is exactly behind me"
Well that narrows it down a bit!

 

[Beneteau381]

I think that might be from Nevil Shute, Trustee from the toolroom. I must read that again.

I did, its now on my Kindle

 

[DownWest]

I did, its now on my Kindle

I read that many years ago, great book and finely written. Turning eggs on the lathe and explaining to the young niece that her parents had died.. Then setting off to recover the gems he knew might be still in the wreck...