Posted by TRUE. In 1912 ships’ clocks were set at midnight to correspond to the longitude of where the ship was expected to be at noon the following day, when the sun would be directly overhead, with adjustments made in the morning according to the speed of the ship. Titanic’s noon position on 14th April, 1912 was 43.02N 44.31W.
We know this because we know that Titanic was following the normal steamship route westwards along the south coast of Ireland from Daunt’s Rock Lightship at 51.43N 8.16W to Fastnet Light at 51.23N 9.36W, and from there she was following the Great Circle (or shortest) route westwards to a point in the Atlantic known as The Corner, at 42N 47W, where westbound steamships at that time of the year then turned due west to follow a Rhumb Line course to the approaches to New York harbour. The distance along this standardised westbound steamer route from Daunt’s Rock Lightship to The Corner was 1,675 miles and we know from Titanic’s daily ship’s run data provided by Third Officer Pitman that Titanic had run (484 + 519 + 546 =) 1,549 nautical miles along this route at noon on Sunday 14th April, 1912. (This means that at noon she had 1,675 – 1,549 = 126 miles to go to The Corner and this figure agrees with Titanic reaching The Corner at 5.50 p.m. or 350 minutes later, as we know she did, as 126/350 x 60 = 21.6 knots, which was about Titanic’s average speed that afternoon).
By plotting this point along that track we can see that Titanic was at longitude 44.31W at noon on Sunday 14th April 1912. This longitude is 30 degrees and 29 minutes of arc east of New York at 75W, because there are 60 minutes of arc in one degree of arc (so 75 degrees – 44 degrees and 31 minutes = 30 degrees and 29 minutes).
Given that the sun takes 24 hours to circle 360 degrees of arc around the globe, it travels (360/24=) 15 degrees of arc every hour, or (15×60=) 900 minutes of arc every hour, or (900/60=) 15 minutes of arc every one minute of time, or one minute of arc every (60/15=) four seconds. Therefore, the sun would take two hours, one minute and 56 seconds to travel the 30 degrees and 29 minutes of arc from Titanic’s noon position on 14th April to New York, whose time is measured from 75W ((2 hours x 15 degrees of arc = 30 degrees) + (1 minute of time x 15 minutes of arc = 15 minutes of arc) + (56 seconds/4 = 14 minutes of arc) = 30 degrees and 29 minutes).
Thus Titanic’s clocks were about two hours and two minutes ahead of New York time. This was confirmed by Harold Bride during the following testimony at the US Inquiry, though he did not go into the detail of the one minute and 56 seconds, content with correcting Senator Fletcher that the difference was not 1 hour and 55 minutes, but about 2 hours:
HSB709: ‘Did you have a watch or clock in your room?’
‘We had two clocks, sir.’
HSB710: ‘Were they both running?’
‘Yes, sir; one was keeping New York time and the other was keeping ship’s time.’
HSB711: (Senator Fletcher) ‘The difference was about 1 hour and 55 minutes?’
‘There was about two hours’ difference between the two.’
Now Titanic did not adjust her clocks again at midnight on Sunday night, as she would normally have done. This was because, in the words of Third Officer Pitman:
HJP643: ‘When were the ship’s clocks set; do you know?’
‘They are set at midnight every night.’
HJP645: ‘And were they set at midnight Sunday night?’
‘No; we had something else to think of.’
We also know that Titanic’s first distress signal was picked up by Cape Race and others at 10.25pm New York time. This was therefore 12.27 a.m. on Titanic, 47 minutes after her collision at 11.40 p.m.
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