Much of what follows is based upon a long paper which I have not yet completed that focuses on the various "times" of Titanic. My plan is to publish this paper here with all deliberate haste. It will come with a chronology of about 600 separate events during the sinking.
Paul is getting close to what happened. The setback of the clocks was involved in the creation of the ship's CQD positions. Note that I wrote "positions" because there are two. One is the famous 41 46 N; 50 14 W of Boxhall. As it turns out, this is of lesser interest than the first CQD position of 41 44 N; 50 24 W. It is this first set of coordinates that holds the key to understanding why the wreck lies so far from Boxhall's "final position."
In simple, the "clock" was set back by 24 minutes between the time of rounding "The Corner" and the iceberg accident. Rowe said the corner rounding was at 5:45 p.m. The accident is generally agreed to have occurred at 11:40 p.m. It appears those two times are 5 hours 55 minutes apart, but that is wrong. Due to the 24 minute clock setback, they are 6 hours 19 minutes apart.
Using Boxhall's 22 knots as the ship's speed, at 11:40 p.m. on crew time simple dead reckoning puts Titanic 139 miles west of longitude 47 W, the longitude of "The Corner." On a plotting sheet, this puts the ship on 50 02 W longitude at the time of the accident. Hold that number for a moment.
Due to the clock setback, Titanic had three diffferent "midnights." The first came at "midnight" in April 14th hours. This was midnight for the passengers.
Midnight for the crew came 24 minutes later. The 24 minutes represented the extra minutes worked by the 8-to-12 watch that night. They should have gotten off duty at crew "midnight," which was the same time as when the 12-to-4 watch came on deck.
Titanic's third "midnight" would have come 23 minutes after the crew's midnight. This was when the ship should have crossed its geographic midnight meridian directly opposite from the noon meridian of the sun.
Because of the initial 24 minute setback, the crew was keeping what might be called April 14th-and-a-half time. The next setback of 23 minutes would have placed the crew on April 15th hours. This was the setback of the clocks Pitman said was not done.
The duration from the turning of "The Corner" to true geographic midnight was the 6 hours 15 minutes from 5:45 to midnight plus the total 47 minute setback of the clocks. For practical purposes that's 7 hours of run, which at 22 knots yields 154 miles.
If Titanic had avoided the iceberg and steamed 154 miles from "The Corner," it would have been on longitude 50 24 W at geographic midnight. That is the same as the longitude contained in the ship's initial CQD message. To confirm that this longitude is no fluke, a line drawn at 266.5 true (the ship's course) from longitude 47 W will pass through 50 24 W at latitude 41 44 N.
For all intents and purposes, Titanic's initial CQD coordinates are the predicted location of the ship at geographic midnight, or 0000 hours in April 15th time.
Titanic's accident took place at 11:40 p.m. using crew time. That was 20 minutes before crew midnight which, in turn, was 23 minutes before geographic midnight. That's a total of 43 minutes of time during which the ship could have steamed 15.8 miles. Going backward along the ship's track line that distance arrives at longitude 50 02 West.
Recall that we have been holding 50 02 West as the longitude achieved at 11:40 p.m. crew time based on turning "The Corner" at 5:45 p.m. in April 14th hours. We now have arrived at this same longitude by two different methods. For the record, the 266.5 track crosses this longitude at 41 44 N latitude.
Dead Reckoning of site of impact on the surface of the Atlantic: 41 44 N; 50 02 W.
Captain Smith gave the coordinates of geographic midnight to the wireless officers. Why would he have chosen geographic midnight when he knew the ship had not reached that location? The answer is that
Captain Smith seems to have understood that it was better to have ships heading his direction quickly than to wait to calculate a better fix.
Boxhall returned to the bridge just prior to the Captain departing for the wireless office. The fourth officer must have been a bit breathless after two trips into the bow. He had just accomplished the equivalent of climbing and descending a 12 story building. Smith, of course, was trying to digest the horrific truth that Titanic was sinking without enough lifeboats. The conditions of the two men were ripe for a miscommunication.
Smith must have instructed Boxhall to update the CQD coordinates. We do not know what he said, but he must have suggested that the initial numbers were for "midnight." Boxhall probably lost track of time during his double visits to the bow. He looked up, saw it was about midnight..crew midnight..on the clock and went to work.
Based on the initial coordinates, Boxhall simply "backed up" the track by 20 minutes of steaming. That gave him longitude 50 14 W. Then, he added 2 miles of northing to account for the time the ship steamed north after the accident. That produced latitude 41 46 N. He took those coordinates on a scrap of paper to the Marconi office.
Boxhall's coordinates are for where the ship would have been if the accident had occurred at 11:40 p.m. in April 15th hours. Curiously, had the accident not occurred, the crew would have been changing watch at their midnight as the ship crossed 50 14 W.
The dead reckoning position of the accident on the surface can now be used to determine the cumulative effect of currents experienced by Titanic both on the surface and on its way to the bottom. The process is a simple "tails" current vector using the center of the boiler field (41 43.5 N; 56.8 W) as the end of the vector. This produces a cumulative current of about 106 degrees at 0.8 knots.
Here may be another key to the accident. Boxhall testified that he rightly expected the ice to move east and north that night. In fact, the current appears to have been east and south. So, ice that should have been north of the ship's track was either south of it...or "right ahead."
A couple of loose ends-- Boxhall said he used 22 knots as the ship's speed for his calculations. Indeed, the reconstructed plot works properly with that speed even though Rowe's reading of the taffrail log indicated a speed of 22.3 knots. The log was probably more accurate, but this was unknown to the officer who created the projected geographic midnight fix, so is not reflected in that set of coordinates.
The location of geographic midnight was critical to the final clock adjustment. The 23 minute setback planned for the 12-to-4 watch was only an estimate. The actual amount would have been determined by the projected longitude of geographic midnight. The men might have worked 22 or 24 minutes depending upon whether the ship was ahead or behind where it was projected to be at the previous noon. So, it is not surprising that Captain Smith had the predicted geographic midnight coordinates handy when the time came to call for help.
Boxhall said he used
Lightoller's 7:30 p.m. star sights in calculating his CQD coordinates. This is true even though he probably "back figured" from the Captain's original midnight numbers. It was necessary to be as accurate as possible in predicting the midnight longitude, so Boxhall would have used
Lightoller's fix to improve the prediction made at noon on Sunday.
Boxhall said he thought the time of the accident was 11:46 p.m. Not so according to the two CQD positions.
Finally, the above reconstruction of the ship's track was done on a VP-OS plotting sheet produced by the U.S. Navy. I used ordinary plotting tools which do not yield the umpteen-digit answers that come from calculators. In this respect, my plot is closer to the fuzziness of real world dead reckoning than work done on a computer.
-- David G. Brown
