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A question for you experienced nautical people. During the time of Titanic with the navigational equipment they had and if they did everything right, just how accurate were their positional fixes and what was deemed accurate? I was reading some of the threads and was going blind looking at and trying to understand all the numbers. Was it a quarter mile...half mile or more? My economy model hand held GPS usually gets me within 10 to 20 feet. I know they couldn't be that accurate. But what was acceptable?
 

Jim Currie

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A question for you experienced nautical people. During the time of Titanic with the navigational equipment they had and if they did everything right, just how accurate were their positional fixes and what was deemed accurate? I was reading some of the threads and was going blind looking at and trying to understand all the numbers. Was it a quarter mile...half mile or more? My economy model hand held GPS usually gets me within 10 to 20 feet. I know they couldn't be that accurate. But what was acceptable?
They tried to get as close as possible, Steven.
I have seen numbers of half a mile quoted but that's nonsense. There was no need for any kind of pin-point accuracy on ocean passages. Near enough was good enough. The pinpoint accuracy came when in sight of a known position as in approaching land. Then geometry came into its own.
Position were never plotted with any accuracy on an ocean chart, A pencil mark would be more than half a mile thick.:eek:
 
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Thank You Mr. Currie. I kind of figured it was something like that. Yes I never even thought how much a pencil mark would cover on a chart. If they could get within a mile or 5 or even 10 back then that seems quite impressive considering how big the oceans are.
 

Jim Currie

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Thank You Mr. Currie. I kind of figured it was something like that. Yes I never even thought how much a pencil mark would cover on a chart. If they could get within a mile or 5 or even 10 back then that seems quite impressive considering how big the oceans are.
Leaving out the early attempts at electronic navigation, the method of navigation a ship across the oceans did not change from before 1912 right up until the 1980s when GPS systems began to replace the sextant. Believe me, the only thing that stopped spot-on navigation was weather and atmosphere. I have seen extremely, verifiably accurate, positions obtained using a sextant and multi celestial bodies.
 
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Aaron_2016

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A question for you experienced nautical people. During the time of Titanic with the navigational equipment they had and if they did everything right, just how accurate were their positional fixes and what was deemed accurate? I was reading some of the threads and was going blind looking at and trying to understand all the numbers. Was it a quarter mile...half mile or more? My economy model hand held GPS usually gets me within 10 to 20 feet. I know they couldn't be that accurate. But what was acceptable?

The SS Vestris listed over heavily and sank in 1928. She sent out an SOS distress call but her position was off by 37 miles. Over 100 lives were lost.

Photos taken as the ship went down.


vestris2.png



vestris1.png



.
 
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Julian Atkins

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A question for you experienced nautical people. During the time of Titanic with the navigational equipment they had and if they did everything right, just how accurate were their positional fixes and what was deemed accurate? I was reading some of the threads and was going blind looking at and trying to understand all the numbers. Was it a quarter mile...half mile or more? My economy model hand held GPS usually gets me within 10 to 20 feet. I know they couldn't be that accurate. But what was acceptable?
Hi Steven,

We know now that Boxhall mucked up his navigation calculations when calculating the CQD position of Titanic.

We also know now that Captain Rostron mucked up his navigation to the CQD position wrong and his speed.

It is also possible/probable that Captain Lord also made mistakes in his navigation? I know this is considered as 'heresy' by some, but it is merely a logical extrapolation or example of the possibilities knowing that Boxhall and Captain Rostron got their navigation wrong. There is no evidence that Captain Lord got a fix on his position at daybreak on 15th April compared to Captain Moore on the Mount Temple, and there is a considerable question mark over Stewart's 'Polar Star' sighting at 7.30pm the previous evening on the 14th April. His noon 15th April position by observations meant very little for the earlier positions due to the circuitous and vague movements of the Californian steaming around after 8.30 am on 15th April.

The only relevant evidence (which is off by 2 degrees with Stewart's alleged 'Polar Star sighting at 7.30pm) is the Dead Reckoning position given to the Antillian at 7.30pm on the 14th April in the ice warning message of 3 bergs seen, which differs from the Parisian position if the Parisian saw the same bergs - which it is generally accepted it did. We also have Evans' evidence that the Californian was on the same course as the Parisian, which I think has been overlooked!

To summarise, Boxhall and Rostron got their navigation wrong, and there is a lot of evidence that Captain Lord did not take advantage of potential observation opportunities to fix his position accurately, or if he did, he did log them in the Ships Log, and there is no testimony evidence to back up the gaps in the Californian's Ships Log.

Cheers,

Julian
 
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What does "right" or "wrong" mean with respect to this discussion? Remember, each ship had a horizon distance of about 8 to 11 miles. That a circle with a diameter of 16 to 22 miles within which objects like a sinking ship or lifeboat would theoretically be visible. Just how much accuracy was needed under the circumstances? In fact, today's "dead nuts" machines can actually confuse things because of the tendency to confuse LED screens and decimal points with useful information. What the brains of sand in electronic devices can't account for is the unknowable...like a wrong set of distress coordinates. The machine steers for the designated coordinates no matter how loudly the lookout screams, "Lifeboat to Port!"

-- David G. Brown
 
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Well if the distress sender is using GPS then there should be no error within 10 feet or so. Plus today with automatic satcomm distress signals (EPIRBs) everybody will know exactly where they are. And if the military decided to participate they could easily re-task one of their Keyhole birds and tell you within 6 inches where they are. Its a different world today. People now sit in an office in Nevada and kills bad guys in Afghanistan...remote drone pilots all done thru GPS and sats.
 

Jim Currie

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The SS Vestris listed over heavily and sank in 1928. She sent out an SOS distress call but her position was off by 37 miles. Over 100 lives were lost.

Photos taken as the ship went down.


View attachment 40849


View attachment 40850


.
Not really, Aaron. Be careful what you read in press reports. The following is from Page 10 of the UK Wreck Commissioner's report into the disaster. This was held in London in 1929 and presided over by oulr old friend, Butler-Aspinall.
2018-04-25 001 2018-04-25 001.jpg
 
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Aaron_2016

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Thanks, but wikipedia says:

'On 12 November, at 9:56 am, an SOS was sent out giving her position as latitude 37° 35' N. and longitude 71° 81' W., which was incorrect by about 37 miles. The SOS was repeated at 11:04 am.'

Is it possible that the official report was a whitewash to remove all acts of negligence i.e. sending an incorrect position?


.
 

Jim Currie

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Hi Steven,

We know now that Boxhall mucked up his navigation calculations when calculating the CQD position of Titanic.

We also know now that Captain Rostron mucked up his navigation to the CQD position wrong and his speed.

It is also possible/probable that Captain Lord also made mistakes in his navigation? I know this is considered as 'heresy' by some, but it is merely a logical extrapolation or example of the possibilities knowing that Boxhall and Captain Rostron got their navigation wrong. There is no evidence that Captain Lord got a fix on his position at daybreak on 15th April compared to Captain Moore on the Mount Temple, and there is a considerable question mark over Stewart's 'Polar Star' sighting at 7.30pm the previous evening on the 14th April. His noon 15th April position by observations meant very little for the earlier positions due to the circuitous and vague movements of the Californian steaming around after 8.30 am on 15th April.

The only relevant evidence (which is off by 2 degrees with Stewart's alleged 'Polar Star sighting at 7.30pm) is the Dead Reckoning position given to the Antillian at 7.30pm on the 14th April in the ice warning message of 3 bergs seen, which differs from the Parisian position if the Parisian saw the same bergs - which it is generally accepted it did. We also have Evans' evidence that the Californian was on the same course as the Parisian, which I think has been overlooked!

To summarise, Boxhall and Rostron got their navigation wrong, and there is a lot of evidence that Captain Lord did not take advantage of potential observation opportunities to fix his position accurately, or if he did, he did log them in the Ships Log, and there is no testimony evidence to back up the gaps in the Californian's Ships Log.

Cheers,

Julian
Hello Julian.

Boxhall did not make a mess of his navigation. He did what every navigator did...worked a Dead Reckoning position based on estimates of the ship's speed, her course made good and the time traveled since the previous occasion when he knew for sure where his ship was. Because he was not on the bridge at Midnight April 14, he did not know that Moody had already made the partial clock change due at that time, so he allowed for it in his work, thus making a double allowance. Additionally. he underestimated the speed of his new ship... a perfectly normal thing to do.
His anxiety ensured that he was not working under normal conditions, which was understandable, given the situation. in no way was he an incompetent navigator.

Captain Rostron or his navigator, Bisset, simply forgot that Carpathia had to cross the east-flowing North Atlantic Current on the way to the distress position. However, in my humble opinion, he compounded the felony by praising Boxall for the accuracy of the calculated distress position. It was a felony in that the moment Carpathia left the scene of the disaster, Bisset would have started a Day's Work Sheet... recording the courses and distances steamed from where they found the survivors up until the ship's position at Noon April 15. That Noon position would reveal the fact that the position given by Boxhall was rubbish. If it did not then these men were fakes.

I have seen it suggested that Stewart's pole Star latitude was wrong.
As I have pointed out on several occasions, the easiest and most reliable sextant observation is that of the Pole Star. Such an observation taken in perfect conditions would produce a very accurate latitude. The conditions were perfect that evening and the man taking the pole Star sights was an expert at the peak of his profession.

In fact, the ice report to Antillian giving a 42-03'North latitude and reporting 2 large bergs was sent at 6-30 pm ATS. The 3 berg sighting was at 7-15 pm, 45 minutes later. Shortly after that, Stewart obtained a proper latitude.
The ice reports filed with the US hydrographic office by Captain Lord have a revised latitude of 42-05'North. That is because after Stewart had taken his Pole Star sight he knew the true latitude of the ship at that time and would enter that value to the Scrap Log.
In fact, the SS Trautenfels probably saw the same bergs 14 hours earlier.

"April 14" "SS Trautenfels" "42.01 N 49.53 W" "5.05 am; sighted 2 bergs fully 200' long and 40' high;"

Note the latitude.

There is ample evidence to show that Captain Lord's navigation, albeit based on estimated positions, was remarkably accurate. That evidence comes from the masters of the Mount Temple and the Carpathia.
At 8 am on the morning of April 15, captain Rostron declared:

The first time that I saw the 'Californian' was at about eight o'clock on the morning of 15th April. She was then about five to six miles distant, bearing W.S.W. true, and steaming towards the 'Carpathia.'

Captain Rostron said the Carpathia was about 3 or 4 miles east of the pack ice. Because of this, we can plot the relative positions of Carpathia and the Californian at that time.
We also know from Captain Moore of the Mount Temple that Californian passed his ship at around 7-30 am that morning, heading southward along the west side of the ice. We can plot that too.
Captain Lord said his ship was making 13 knots, so let's do that.
Plotting Lord..jpg
 
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Jim Currie

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Thanks, but wikipedia says:

'On 12 November, at 9:56 am, an SOS was sent out giving her position as latitude 37° 35' N. and longitude 71° 81' W., which was incorrect by about 37 miles. The SOS was repeated at 11:04 am.'

Is it possible that the official report was a whitewash to remove all acts of negligence i.e. sending an incorrect position?


.
There is no such longitude as 71 81'West, Aaron. Unless they have found the wreck, there is no way to show an inaccurate distress position.
The Commissioner was aided and a betted by no less than 4 senior naval Navigatiors - Assessors. I doubt very much if they would have condoned any kind of coverup. In any case, there was no need to. The cause of the accident was not bad navigation but bad maintenance of a very old ship.
 

Harland Duzen

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Thanks, but Wikipedia says:
'On 12 November, at 9:56 am, an SOS was sent out giving her position as latitude 37° 35' N. and longitude 71° 81' W., which was incorrect by about 37 miles. The SOS was repeated at 11:04 am.'
That not the best way to state your case... :confused:

To be fair, this statement is given a footnote / source as having came from the this paper:

"United States District Court for the Southern District of New York (24 May 1932). "Vestris – Decision on the Merits". Retrieved May 14, 2015."

Whether the paper itself is accurate is another matter, but at least it wasn't conjured from air.
 

Doug Criner

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For a fix, a sextant was used to measure the angle of a star or other celestial body above the horizon. That angle and the exact time, along with a nautical almanac, would allow plotting a line of position. The intersection of several such LOPs would be the fix.
 

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