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Question For The Nav's Amongst Us!

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Question For The Nav's Amongst Us!

Old 27th Dec 2018, 03:16
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Question For The Nav's Amongst Us!

Is this possible?

The one thing they left out was which Time Zones they were in?

Also....would not the date have to be the 30th at one end of the ship and the 1st at the other end....with the 31st disappearing altogether?

As the Warrimoo was an Aussie ship....could this just be some odd sort of a prank?


Sea story!

The passenger steamer SS Warrimoo was quietly knifing its way through the waters of the mid-Pacific on its way from Vancouver to Australia. The navigator had just finished working out a star fix and brought Captain John DS. Phillips, the result. The Warrimoo's position was LAT 0 31' N and LONG 179 30' W. The date was 31 December 1899. "Know what this means?" First Mate Payton broke in, "We're only a few miles from the intersection of the Equator and the International Date Line". Captain Phillips was prankish enough to take full advantage of the opportunity for achieving the navigational freak of a lifetime. He called his navigators to the bridge to check & double check the ship's position. He changed course slightly so as to bear directly on his mark. Then he adjusted the engine speed. The calm weather & clear night worked in his favor. At mid-night the SS Warrimoo lay on the Equator at exactly the point where it crossed the International Date Line! The consequences of this bizarre position were many:
The forward part (bow) of the ship was in the Southern Hemisphere & in the middle of summer.
The rear (stern) was in the Northern Hemisphere & in the middle of winter.
The date in the aft part of the ship was 31 December 1899.
In the bow (forward) part it was 1 January 1900.
This ship was therefore not only in:
Two different days,
Two different months,
Two different years,
Two different seasons
But in two different centuries - all at the same time!

Last edited by SASless; 27th Dec 2018 at 04:04.
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Old 27th Dec 2018, 04:59
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The whole story is on Wikipedia. The keyword is allegedly.

Important caveat:
However, the last part of the final sentence is disputed because strictly speaking, the 20th century began with the year 1901, not 1900.
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Old 27th Dec 2018, 06:52
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Sam Clemens aka Mark Twain made a similar voyage on the Warrimoo and penned his thoughts about part of the issues brought up in my original. post.

https://quadriv.wordpress.com/2011/1...-s-s-warrimoo/
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Old 27th Dec 2018, 12:10
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If you think about it for a moment, the celestial navigation techniques available in 1900 were nowhere near accurate enough to position a ship within one nautical mile, let alone straddling two hemispheres. In addition, a position fix would only be valid at the time it was taken, and trying to steer an exact interception course via compass, in the face of wind and sea currents, is impossible.

Disclaimer, aviation related content: Exactly the same challenge was faced by bomber aircraft, until the advent of GPS guided weapons in the 1990s. The history of strategic bombing during WW2 indicates the enormous technical efforts put into place, with very limited effectiveness.

Personal note: My late father was a navigator seconded to the RAF during 1944-5. I'm sure he would have had stories to tell, but sadly did not live as long as Danny42C.
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Old 27th Dec 2018, 13:22
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Now that we have GPS, digital auto positioning, providing extremely accurrately placement of Oil Drill Rigs and dynamically positioning of ship mounted drill operations....I suggest it is possible t to position such a vessel over the spot within a meter ro two accuracy and maintain that position.

That gets us back to the original question.

If the RAF and USAF had GPS as t hey do today....WWII would have had a much different Strategic Bombing Campaign.

The Tirpitz would have gone down in a single mission, buildings would be targeted rather than whole cities, but that was not the case back then....but it is today.
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Old 27th Dec 2018, 15:22
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The Luftwaffe would have shot down a lot more too.
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Old 27th Dec 2018, 17:56
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Originally Posted by Fareastdriver View Post
The Luftwaffe would have shot down a lot more too.
Navigation is only relevant for stationary objects. Moving targets require tracking with radar, which is a very different technology, and was quite effective during WW2.
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Old 27th Dec 2018, 18:39
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The Luftwaffe would have shot down a lot more too.
Had the RAF and USAF launched a thousand airplanes each....day and night....to say three hundred targets scattered all over Germany.....how would the Luftwaffe have coped with such a wide area to defend?

The Flak Batteries would have to be spread out more, fighters would have further to go to reach the many bombers, and diversions would be much simpler to devise.

The idea of miles long streams of bombers flying the same route and to the same destination and fighters (day and night) being able to make like Orca's going after schools of Sardines would not have been possible.

But with GPS which could be pilot operated for navigation....who would serve up the Pies and Tea?

Bomb Aimers would be out business as well....but then who would wake up the Nav to have the inflight meal served.
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Old 27th Dec 2018, 18:52
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Had the RAF and USAF launched a thousand airplanes each....day and night....to say three hundred targets scattered all over Germany.....how would the Luftwaffe have coped with such a wide area to defend?
That assumes that the technology existed to detect, identify and locate the relevant targets. As we know this was frequently not the case.

YS
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Old 28th Dec 2018, 00:29
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If you think about it for a moment, the celestial navigation techniques available in 1900 were nowhere near accurate enough to position a ship within one nautical mile
Without the tankers these chaps would have been in the poo, and wishing they had someone with the celestial nav skills of Capt. Gordon Vette.

https://www.defenseindustrydaily.com...te-line-03087/

https://en.wikipedia.org/wiki/Cessna_188_Pacific_rescue
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Old 28th Dec 2018, 00:52
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It just reminds one of how thin the line can be between surviving and dying can be!
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Old 28th Dec 2018, 03:43
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Originally Posted by megan View Post
Without the tankers these chaps would have been in the poo, and wishing they had someone with the celestial nav skills of Capt. Gordon Vette.

https://www.defenseindustrydaily.com...te-line-03087/

https://en.wikipedia.org/wiki/Cessna_188_Pacific_rescue
Both the technology failure and rescue stories are remarkable in their own way, though I would emphasise the difference between being 'lost' with no idea where you are, and 'exact' navigation to within a ship's length, as implied by the original story at the start of this thread.

Another concept that comes to mind is the use of daylight tracking to geolocate lightweight animal tags (without GPS). Automatic measurements of length of day, and time of local noon (along with an on-board clock and some processing power), are generally sufficient to estimate latitude and longitude respectively, and track migrations over vast distances: Animal Migration Research, Jeff Kelly Lab

As one reference humorously states: It is difficult to persuade an animal to carry out a daily sextant observation!

Edit: This article implies that the claimed accuracy of Capt Vette's solar navigation and VHF 'boxing' was about as mythical as Mark Twain, though his role in the rescue was indeed honourable: http://www.navworld.com/navcerebrations/mayday.htm

Next Vette instructed Prochnow to determine the elevation angle of the Sun above the horizon using his partially outstretched arm and fingers as a sextant. Prochnow established the elevation of the Sun as four fingers as Vette measured the elevation of the Sun as two fingers. Vette estimated the Cessna was about 240-250 nmi (each finger was slightly more than 2 degrees with each degree worth 60 nmi) from the DC-10.

Last edited by GordonR_Cape; 28th Dec 2018 at 04:26.
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Old 28th Dec 2018, 08:06
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Originally Posted by SASless View Post

If the RAF and USAF had GPS as t hey do today....WWII would have had a much different Strategic Bombing Campaign.
But if the adoption of technology had followed the same patterns as in the 1930s, the German Air Force would have had superior GPS equipment, before the RAF or USAAF put it into service. As the crucial targets in 1940, like air fields and armaments plants, were mostly clearly located on the excellent Ordnance Survey maps, history might have gone differently well before the bomber offensives.
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Old 28th Dec 2018, 08:42
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The F-22 incident occurred at the time I was testing an in-flight AAR mission planning and management computer system. So I devised a plan which crossed both the equator and IDL at midnight GMT in the middle of an AAR refuelling bracket, knowing that the previous contractor's version was certainly date dependent...one of its many failings But the new version was fine and much to the relief of the supplier, no problems were encountered.

Regarding navigation in WW2, one aspect which should be recalled is that magnetic declination values were much greater than today - and there were no INS running on true in Lancasters! Everything was magnetic - with around 11 deg W declination at Waddington and 4 deg W over Berlin! Maintaining an accurate course whilst being harassed by night fighters cannot have been easy!
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Old 28th Dec 2018, 09:58
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Declination?

I think you mean variation, Beagle!
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Old 28th Dec 2018, 10:59
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Never mind WW2 - it wasn't much better in the 50s. On the navex flown to qualify for a BC Select rating, the requirement for a Canberra crew on the long 'limited aids' (ie astro) leg was to stay within 50 miles of the intended track - I don't remember what was called for on timing. It did make you realise what a godsend the introduction of Gee must have been.
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Old 28th Dec 2018, 11:20
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Even in the 80s you could have problems. In April 82 just after the Argentinians had invaded the Falkland Islands, and before the Victor tankers deployed to Ascension Island, there was an AAR trail for Harriers to Goose Bay. After taking on fuel in a Tanker/Tanker bracket at Stornoway we set off across the North Atlantic in company with 3 Harriers. Shortly thereafter the Doppler failed. The forecast wind was 270/40, so this what we had to use for DR. Fixing was not possible as although there were several Position Lines to give a Latitude check (Stavanger Consol, Faroes NDB and Sun Shots) there was nothing to give a Longitude check. The wind was actually 270/120!! Fortunately we had 3 INS equipped chicks with us to give us position updates until we could get a N/S Position line from Iceland. If we had been on our own we would have been 80 nm in error after an hour.

On the return leg, as first in the stream, in a different aircraft with working Doppler we transmitted the actual winds/positions to the following stream of Victors.
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Old 28th Dec 2018, 12:18
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Brian 48Nav:-

Declination?
I think you mean variation, Beagle!
Declination, Schmecklination...that might have been the cause of this slight whoopsie:-

Incidents and Accidents
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Old 28th Dec 2018, 13:31
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Brian 48Nav wrote:

Declination?

I think you mean variation, Beagle!
Probably - a lapse in terminology through having to consider 'station declination' and actual MagVar when considering Place/Bearing/Distance from various ground-based beacons which applied fixed declination values to transmitted radials rather than actual MagVar.

Trying to work out how to cope with an aircraft which didn't have a 'north sense' switch and which operated in northern Canada using magnetic values displayed on the instruments whilst the INUs worked in True was....interesting. Particularly without the benefit of a food-powered navigation system (in his case...lots) such as Tengah Type!

Originally, as it was only ever expected to fly on UK AARAs, the VC10K flew with Mag values displayed to the pilots. This could be changed to 'True' by turning an 'HSI' switch on the centre panel. Except that it wasn't really 'True', it was Mag minus whatever MagVar the navigator had set.... I only tried the switch once (with a very experienced navigator on the crew) over Canada - when turned it did so reluctantly and subsequently kept rotating! I managed to get it back into 'Mag' and vowed never to touch it again!

Things became much more logical after the VC10K was fitted with a GPS/LINS to augment the Carousel - and we also had the luxury of an autopilot 'NAV' mode. But the Mod was a typical cheap botch-up as the navigator didn't have a repeater display to see what the pilots could see - and the pilots (perhaps wisely) couldn't make any nav inputs (except verbal requests to the navigator!).
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Old 28th Dec 2018, 16:47
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You could also have a lot of fun with setting the Variation to whatever value was required. We often flew a" single heading " from Hong Kong to Singapore, despite a track change of 20 degrees as we passed Vietnam, by judicious use of the Variation Setting Control. Some pilots queried why some Navs called for a heading change but others did not. We never told them!

Flying Grid/Gyro also had its amusing times as the pilots tried to resolve the Grid heading with the Magnetic Heading. One month at Marham we flew on Grid for "Navigator Training" with a Grivation of 180 degrees,ie North is South. You departed Marham and flew "South West" to the North Sea. Watching the pilots turning in their seats to try to read the conflicting headings was great fun. After a month we were told to stop it.
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