Encyclopedia Titanica

The Sinking of S.S. TITANIC : A Chronology

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The Sinking of S.S. TITANIC :  A Chronology

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Timekeeping Aboard Titanic

Note: to avoid confusion, the word "watch" in this text refers only to either a four-hour period of duty, or to the men who worked during those four hours. The word "timepiece" refers to pocket watches used by gentlemen.

Timekeeping is based on the assumption that the earth turns exactly one revolution, or 360 degrees every 24 hours. This amounts to 15 degrees of longitude every hour. For the courthouse clock noon today day comes 24 hours after noon yesterday.

Unfortunately, the Earth does not rotate quite so precisely. Some days are longer or shorter by a small amount that can be ignored in daily life. The standard 24 hour day is known as "mean time." Navigators must apply a correction known as "the equation of time" when using the sun for navigation.

Things are not so neat for a ship like Titanic making a westbound passage. The courthouse never moves, but the ship steams some distance west between noon longitudes from day to day. This distance means that today's "high noon" comes a few minutes later than it did yesterday. (The reverse is true for an eastbound voyage. Here we will focus only on westerly trips because Titanic was going west.)

"High noon" on land is known to navigators at sea as "local apparent noon" (LAN). Both terms refer to the instant when the sun crosses the observer's meridian. This means the moment when the sun is at its zenith (highest point) for the day. Titanic used its LAN to establish shipboard time each day. At 22 knots Titanic moved west at the rate of not quite one degree of longitude (at 42º North latitude) every two hours. In 24 hours, it moved roughly 12 degrees which is equal to the rotation of the Earth in 8/10ths of an hour. On Sunday, April 14 the ship's westward movement worked to be 47 minutes. Those extra minutes were part of Sunday, so had to be "tacked on" to the end of the day. This meant the Sunday of Titanic's accident was to be 24 hours and 47 minutes long.

Navigators and astronomers use noon as the marker for the start of their "astronomical day" because the sun is visible in the sky. It was necessary to use noon to because prior to electronic navigation it was impossible to measure midnight. The familiar "civil day" starts at midnight 12 hours before the astronomical day. For example, 2 a.m. January 9 in civil time is the same as 2 p.m. January 8 in astronomical time. It would have been disconcerting to its guests if Titanic had changed day and date using the astronomical day. Passengers commonly used the civil day in their lives ashore, so thought of "midnight" as the start of the new day. In deference to passengers, Titanic adopted the civil day for ship's time.

By definition, "midnight" starts the new civil day. On shore it is no more than the tick of a clock. For Titanic, however, "midnight" was effectively a span of time rather than a single instant. This arose out of the need to set the ship's clocks back each night to match the ship's westward movement. Instead of a single tick, "midnight" was effectively became 47 minutes on the night of the disaster. This elongated "midnight" started at 12 hours after the ship crossed its noon longitude on Sunday, April 14th. It continued for those extra 47 minutes until civil midnight marking the start of Monday, April 15th.

While this may seem confusing, 47 minutes of midnight would not have been a problem for anyone except the ship's navigator if it were not for the need to share those extra minutes among the deck crew. Titanic's crew was divided into two "watches," the port and starboard. Each watch was to share about half of those extra 47 minutes. The starboard watch was to serve its time before and the port watch after the "midnight" change of watch. Second Officer Charles H. Lightoller confirmed this and explained that all clocks aboard Titanic were to be correct for April 15 noon at midnight. His statement meant that both the passenger and crew clocks would have been properly set back prior to civil midnight starting the new day.

It is obvious from Table A-1 why the “midnight” change of watch for the crew had to come 24 minutes after 12:00 o’clock in April 14th time or 23 minutes before 00:00 o'clock in April 15th hours. This required retarding crew clocks in two stages, each equal to the extra time served by its respective Watch. Hence the name “two-stage” for this method of time keeping..

Most sailors did not carry expensive and fragile pocket timepieces in 1912.  It would have been extremely confusing if the extra time was added after 8 bells. Men without pocket timepieces would not have been able to gauge 23 minutes while standing duty away from any of the ship's electric clocks.

Time Of Crew Change Of Watch

Time Of Crew
Change Of Watch

Starboard Watch Extra  Minutes

Port Watch Extra Minutes


12:00 p.m. April 14
Passenger Midnight



WRONG: Only Port Watch works extra.

12:24 p.m. April 14
Crew Midnight
(Correct Two-Stage Setback)



RIGHT: Both watches share extra time. 

12:47 p.m. April 14
Civil Midnight
0:00 April 15



WRONG: Only Starboard Watch works extra.

Table A-1

Table A-1 shows why the "midnight" change of watch had to take place midway between April 14th and April 15th civil time. This was the only way to split the 47 extra minutes equally between the port and starboard watches. However, this arrangement brought up the problem of ship's bells. Each watch started at 8 bells of the previous watch. One bell was then struck for every passing half hour. Two bells meant the first hour of the four had been worked. Four bells announced the halfway point. An immutable part of this timekeeping system was that 8 bells always marked the change of watch when the men on duty could go below for a few hours of rest. Table A-2 shows the traditional sequence of bells.

Ship's Bells


Time of





Ringing Pattern



(8 bells of previous watch)

























Table A-2

Note: Dog watches in Titanic followed British naval tradition. The first dog watch (4-6 p.m.) ended at "4 bells." The bell sequence for the second dog watch (6 to 8 p.m.) then re-started so that it also ended at "4 bells." This tradition eliminated "8 bells of the second dog watch," the infamous time of a mutiny during the Napoleonic wars.

However, adding those minutes within the schedule would not have been so confusing because of the way sailors really used their bell system. Hearing six bells did not tell a sailor he had served three out of his four hours on duty. Rather, he would have understood six bells as announcing one hour remained before change of watch.

White Star Line regulations allowed clock adjustments to start at 10 p.m. each night. Although this was late enough not to both passenger activities, the real reason for choosing that hour was convenience of the crew. Note that 10 p.m. is the midpoint of the 8 to 12 p.m. watch. Adding extra time in the middle of a watch would allow sailors to continue using ship's bells to measure their remaining time on duty. At 10 p.m. the crew's bridge clock was turned back to 9:36 p.m. This increased the normal 30 minute duration between four and five bells to 56 minutes. Even so, when 5 bells was struck, the crew knew it had an hour and a half remaining before the midnight change of watch. Table A-3 shows how adding the extra time at 10 p.m. would have allowed the starboard watch to serve its extra time and the ringing of 8 bells to mark the change of watch.


David G. Brown, USA


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Comment and discuss

  1. Samuel Halpern

    In Dave Brown’s latest contribution to ET, “Chronology — Sinking of S.S. Titanic,” he has a caution statement on the first page of the complete downloadable chronology which reads: “CAUTION: Times Presented In This Chronology Are Approximations Made To The Best Of The Author’s Ability.” Unfortunately, a more accurate caution statement would be that many of the times and some of the unsupported events presented in this chronology represent solely the author’s imaginative concept of reality and rationalization of events, and at times, completely disregards evidence which runs counter to those beliefs.

  2. Tad G. Fitch Tad G. Fitch

    Sam, One thing I would love to see is a comprehensive chronology of the sinking with all events and conclusions footnoted, so the original sources and eyewitness statements can be cross-referenced and examined for internal consistency, to ensure everything is being interpreted correctly and is not being taken out of context. This would be an enormous undertaking and in many cases, we couldn't pinpoint a specific time for each event, but it would be a very worthwhile resource, and something that is sorely lacking in the field of Titanic research in my opinion. There are dozens of timelines, but few, if any, are sourced. Dave, If you end up reading this thread, one thing I noticed that you may want to correct is that Steward Edward Brown was rescued in Collapsible A, not on Collapsible B as it says later in the chronology. I haven't had a chance to read your chronology in detail yet, but that was something that stood out to me when I scanned through it. Take care

  3. Samuel Halpern

    In the Brown Chronology, the author states: "This chronology reflects the general order of events surrounding the sinking of R.M.S. Titanic as based upon the sworn testimonies of survivors. All efforts have been made to insure the relative accuracy of events ..." But look at just some of the events described by the author which runs counter to the sworn testimonies of survivors, or has absolutely no foundation whatsoever: 22:04 (unadjusted time) "Hichens wakes up Murdoch." REALITY: Hichens said he went to call upon Murdoch at a quarter to ten. 22:24 (unadjusted time) "Murdoch relieves Lightoller as senior officer of the watch. Lightoller goes off duty. No bells struck as 4 bells have already sounded." REALITY: Lightoller said he relieved Murdoch at 10 PM. He also said that Boxhall had more than two hours remaining in his watch because the clocks were to be put back. Brown has Boxhall having only 2 hours remaining in his watch. Again a case of ignoring sworn testimony.

  4. Philip Hind

    I have moved the peer review section here.

  5. Bill Wormstedt Bill Wormstedt

    As previously mentioned by Tad and Sam, yes, a chronology or even article or book needs to be referenced so that the original sources can be examined by the readers/researchers. I've been caught by this way too many times. Also, many Titanic books have poor to non-existant indexes. Without this, how can a reader or researcher find anything?

  6. George Jacub George Jacub

    Forget what you think you know about the chronology of events on the Titanic. I'm rewriting the canon on my blog http://titanicsecrets.blogspot.com/ Start with "The First Boats. Cutting the Gordian Knot" and check back often.

  7. Dave Gittins

    "I accept that the difference between New York Time and Titanic time is one hour and 33 minutes. All wireless messages are referenced accordingly. There is much discussion on this point in various threads on Encyclopedia Titanica. As you will see, the 1:33 time difference accords with events on the ship as recounted by Titanic survivors." If you'll believe that. you'll believe anything!

  8. Paul Lee Paul Lee

    As I've said in http://www.paullee.com/titanic/time.php, the 1 hour 33 minute time difference is a totally random time that relates to nothing in the Titanic timeline. Seems that someone has been taking a certain Irish "researchers" findings too seriously.

  9. Bill Wormstedt Bill Wormstedt

    ""I accept that the difference between New York Time and Titanic time is one hour and 33 minutes." Why this one time, vs. a number of others? You give no reasoning for this. Have you read ET member Sam Halpern's article "The Mystery of Time", published in the Titanic Commutator #178 and 180?

  10. Samuel Halpern

    Since there are many people do not have access to the publication referenced by Bill, here is the relevant extract from my article dealing with the 1 hour 33 minute time difference. As you can see, there really was no mystery on how that came about. The bottom line is that it was wrong; just as wrong as the transmitted coordinates of where Titanic sank. [quote] There has never been agreement as to what was the difference between Titanic time and GMT or New York time (NYT). The American Inquiry settled on a value of 1 hour 33 minutes between Titanic ATS and NYT. The British Inquiry settled on a difference of 1 hour 50 minutes. At the Limitation of Liability Hearings in NY in 1913 a value of 1 hour and 39 minutes was implied by the White Star Line. So let us take a look at how these different times came about. 1 HOUR AND 33 MINUTES AHEAD — THE AMERICAN INQUIRY At 4 p.m. NYT, Monday, April 15, Capt Rostron of the Carpathia sent a wireless message to Capt Haddock on the

  11. Tad G. Fitch Tad G. Fitch

    Hi George, how are you? Thank you for posting the link to your Titanic blog. I am very interested to hear your theory on the alleged shooting incidents and who may have been shot. I am saying that honestly, even though we have many differences of opinion. I am also interested in hearing more about your placements of survivors in the lifeboats, as this is a mutual area of interest that we share. Regarding your blogs, first the bit on the launch times of the first boats, and timing of the rockets. In this blog, you wrote: "I accept that the difference between New York Time and Titanic time is one hour and 33 minutes...the 1:33 time difference accords with events on the ship as recounted by Titanic survivors." As already addressed above, your acceptance of this incorrect premise is a significant flaw, which leads to several incorrect conclusions in your timeline, particularly, having the launch time of the first boat too early, and the launch time of the first rocket too

  12. Tad G. Fitch Tad G. Fitch

    Hello again George, In regards to your second blog, about the aft port boats, you wrote: "The significance of this can’t be overstated. Boats 9 and 11 off the ship, Boat 13 lowered to A deck, Boats 16, 14, and 12 still on the davits, Boat 14 starting to load crewmen preparatory to being lowered." In previous discussions here on the ET message board, the flaws in your conclusions here were pointed out, but you have chosen to ignore them. You rely on Crowe's testimony that seems to place Murdoch at No. 14. While Crowe was sure the "senior officer" was present at that boat, he only guessed that it might have been Murdoch. Crowe was a member of the victualling department, and would have had little contact with the ship’s officers in the course of his day-to-day duties. In light of the other accounts from members of the deck department who knew the officers and who mention Wilde specifically by name as being at this boat, and considering that there is not a single other

  13. Samuel Halpern

    >>This is likely when he [Andrews] was racing to inform the Captain the ship was doomed, since Smith had only learned of 3 compartments flooding before the two separated.

  14. Mark Chirnside

    There is no disagreement from me regarding Smith's inspection and the comments from Tad and Sam. I know George Behe has done a great deal of work on that front, too, and I remember my discussions with him some years ago. He was very generous with his time and I learned a lot from him. Although I disagree with a number of George's findings, such as the time difference where Sam, Paul, Dave and others have worked wonders in clarifying matters, it is encouraging that there is at least some discussion of source material and conclusions drawn. As Sam said earlier, 'a comprehensive chronology of the sinking should have all events and conclusions referenced so original sources and eyewitness statements can be cross-referenced and examined to ensure everything is being interpreted correctly and not being taken out of context.' This enables us to see how and why some of the mistakes have occurred. In comparison with David's timeline, the difficulty with the 'Brown Chronology' is that

  15. David G. Brown

    Mark -- Once again you have wandered into personal criticism of me and my work that travels into the area of libel. -- David G. Brown

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Encyclopedia Titanica (2009) The Sinking of S.S. TITANIC : A Chronology (Titanica!, ref: #10843, published 13 June 2009, generated 27th May 2023 07:55:02 AM); URL : https://www.encyclopedia-titanica.org/chronology-sinking-of-ss-titanic.html