The sudden temperature change as the Titanic crossed from the warm waters of the Gulf Stream into the much colder waters of the Labrador Current was noticed by Titanic’s Second Officer, Charles Lightoller, in the following testimony he gave to the British Inquiry into the Titanic disaster in 1912, which reveals a sudden, sharp, four degree drop in temperature in the half hour between 7pm and 7.30pm and a 10 degree drop in temperature in the two hours between 7pm and 9pm, when the air approached freezing point:

13589. (The Commissioner.) And from 7 to half-past seven there was a fall of four degrees in the temperature?
       – Yes, My Lord.
13590. (The Solicitor-General.) Did you observe that at the time as something pretty sharp?
       – Yes, a pretty sharp drop. It had been going down previously to that before I left the deck.
13591. When did you notice the fall in the temperature beginning seriously?
       – Probably about half-past six.
13592. Very well; the fall in the temperature began at half-past six and a drop of four degrees between seven and half-past?
       – Yes.
13593. Did you notice what the actual temperature was a little later by the thermometer?
       – Yes, later on in the watch I think the Quartermaster two or three times told me what the temperature was in order that I might know when it got near to freezing point to send word to the engine room and the carpenter with regard to fresh water.
13594. Can you tell me what was the temperature which you were given and at what time?
       – When Mr. Murdoch mentioned it to me as far as I recollect it had fallen from 43 degrees to 39.
13595. This is Fahrenheit I suppose, is it not?
       – Yes; and then I sent word down to the carpenter about nine o’clock; it was then 33 degrees, and I sent word to the carpenter and to the engine room – for the carpenter to look after his fresh water; that is to say, he has to drain it off to prevent the pipes freezing – and to the engine room for them to take the necessary precautions for the winches.
13596. It is 33 degrees at nine o’clock. That is only one degree above freezing?
       – One degree, exactly.

The sharpness of the boundary between the warm waters of the Gulf Stream and the cold water of the Labrador Current and its proximity to Titanic’s wreck site was recorded after the disaster by the SS Minia who, whilst drifting and collecting bodies near Titanic’s wreck site, noted in her log: “Northern edge of Gulf Stream well defined. Water changed from 36 to 56 [degrees Fahrenheit] in half mile”:

Log extract from the SS Minia

The rescue ship Mackay Bennett, also recovering bodies in 1912, drew the following map of water temperatures at Titanic’s wreck site, which records this sharp boundary between the warm waters of the Gulf Stream and the cold waters of the Labrador current, and its proximity to Titanic’s wreck site:

Map showing location of Titanic bodies and sharp boundary of Gulf Stream and Labrador Current, drawn by the crew of the cable ship Mackay Bennett, whilst recovering bodies in 1912

© Nova Scotia Archives Museum

On May 4^th 1912 RMS Royal George recorded the sharp boundary between the Labrador Current and the Gulf Stream. Note the nine degrees Celsius “Temperature wall” where the sea temperature rises as the ship moves from the cold “Arctic Current”, into the much warmer waters of the Gulf Stream:

Contemporary plot of the temperature wall between the Labrador Current and the Gulf Stream, drawn from the records of RMS Royal George, May 4^th 1912

From all of this it is clear that Titanic sank near the boundary between the freezing waters of the Labrador Current and the warm waters of the Gulf Stream, and that this boundary was relatively sharp, as warm and cold water do not mix very well.

I hope by blogging chapters from my book, A Very Deceiving Night, it will contribute to the ongoing discussions regarding the atmospheric conditions on the night of the tragedy and the true causes of the disaster. At the moment, the book is only available as an e-book. If you wish to purchase it then you can do so in Amazon Kindle format here and other formats, including Apple, Kobo and Nook, here. Thank you.