P. 508, right column: for section “Navigation and position plotting”:
Much of the information in this section has been drawn with permission from the website of Dave Gittins at: http://users.senet.com.au/~gittins/navigation.html.

P. 511, from top of right column up to the section on “Sextant”: text should read:
incorporated into its movement to compensate for changes of temperature, humidity and other factors which would cause an ordinary timepiece to gain or lose time. The chronometer on British ships was kept by the Master and was used to record the time of celestial observations.

The foremost problem of navigation for centuries had been how to find longitude. There were simple tables to ascertain latitude, but not longitude. It was possible for a navigator to find his local time, but he was unable to determine his exact longitude because he did not know the time at the zero meridian. (For many years the zero meridian varied according to the user’s nation. By 1912, it was agreed to be the meridian of the Royal Naval Observatory at Greenwich.)

Many inventors worked to create a device to overcome these problems, but it was not until the late 18th century that the first accurate chronometer was produced. From about 1830 the standard marine chronometer was contained in a brass-bound mahogany box, with a lid on it that swung open so the time could be read through a glass pane. A key would be used to open a second lid that gave access to the mechanism, which swung on two sets of gimbals to maintain its level accurately in spite of the movement of the ship. By the 1830s most good ships had proper chronometers, although there remained mariners who preferred to obtain Greenwich Mean Time by observations of the moon relative to other celestial bodies (the Lunar Distance method).

The common chronometer was wound every twenty-four hours, though most could run for five days. They were never reset by physically moving the hands. If a chronometer ran down, it was not restarted until the time indicated on the dial was exact with Greenwich Mean Time (GMT). Titanic was fitted with two chronometers, a useful arrangement in case one of them became irregular. The chronometers were kept in a special cabinet in the Chart Room. While in port the chronometers were removed and sent to an optician⁹ such as the Kelvin company for calibration. The supplier of these expensive timepieces for Titanic is unknown; however, the firm of J. Sewill manufactured a chronometer raised from the wreck of the White Star Line’s Arabic sunk during the First World War.

Comments: The reference to obtaining longitude by timing noon has been removed as this method was not sufficiently accurate. The reference to obtaining latitude by using tables has also been corrected.

P. 512, text from top left of page up to italicized quotation: text should read:
distant objects. It was the most convenient and accurate instrument devised for use where the observer had a very unstable support, as on board ship, and was in common use by navigators and surveyors.

At sea, it was used to determine the altitude above the horizon of celestial bodies. Inshore, it was held horizontally to measure the angles between known landmarks. In conjunction with an instrument called a station pointer, this gave a position without the need for compass bearings. By measuring the angular altitude of a landmark whose height was known, the sextant determined the ship’s distance from it.

Titanic’s Captain and Senior Officers utilized sextants to verify the ship’s position and daily run. Fourth Officer Boxhall gave a good description of the use of a sextant aboard Titanic in his testimony on the Titanic sinking for the United States Senate hearing:

Comments: The reference to Lunar Distance has been removed as it did not apply to Titanic’s navigation. The reference for using the sextant to check the compass has also been removed; the compass was checked by taking azimuths of celestial objects, using the standard compass.

P. 522, right column, near bottom of paragraph:
The last two sentences should read: A pair of binoculars was issued to each Senior Officer, and when the officer was on duty could be stowed in a teak box located on the bulwark of either Bridge wing. An additional pair of binoculars was provided to the Bridge; these were commonly referred to as “Pilot glasses.”

Comments: The reference to stowage of binoculars on the Bridge Wings has been changed. Binoculars could be stowed there but not necessarily at all times; for example in inclement weather they would not be. The reference to binoculars in the Crow’s Nest has been removed; lookouts were not normally issued them and any use of them in the Crow’s Nest would have been primarily by the 2nd Officer while in pilotage waters.

P 498, Fig. 21-37, and P 515, Fig 22-26: Both images should be credited to: Campbell McCutcheon collection.

P 225 – Fig. 11-41 – Photos within caption are referenced incorrectly.  Caption should read as follows:
At upper right, an example of a Harland & Wolff skylight on the raised roof of Britannic’s  Boat Deck, port side.  This skylight has two panes per side.  The horizontal protection bars over the glass give the appearance of four panes per side, but this effect is caused by a central vertical strengthening bar.  The upper left image is an enlarged detail of a starboard-side photograph of Titanic, showing the skylight over the Marconi Operating Room.  At lower right, an enlarged detail of the skylight on the roof of the Officers’ Quarters deckhouse over the Officers’ Lavatory.  This skylight, shown in the raised position, had two sashes per side.

P 370 – Endnote #3 – the figure of 1,500 tons per hour in the last sentence needs to be corrected to 1,700 tons per hour. (This figure includes the 5 ballast pumps and 3 bilge pumps, but not the ash ejector pumps.  It also does not include the condenser circulating pumps, which could be made to draw from the engine room bilges but not the bilges further forward that were in the flooded areas.)

P 384 - Fig. 17-22 Last sentence should read “Titanic’s  after masthead light, if one was present, was almost certainly an oil lamp hoisted up a stay.”
(The existence of this lamp, though possible, has never been proven and no hard evidence has been found to support it.)

P 417 -  In Figs. 18-12 and 18-13, the captions have been reversed.

P 512 – col 2, para 2, first sentence, should read as follows, with the indicated text deleted:
Titanic’s Captain and Senior Officers utilized a sextant for compass deviation and   to verify the ship’s position and daily run.

P 515 – Fig 22-27 – in the caption text, “water barrel” should instead read  “water breaker”.