RMS Titanic as it is leaving Southampton on 10 April 1912. The Titanic was the first ship to issue an SOS distress call. Black and white photograph of a large steamship with four funnels.
2 December 2021
The universal distress call SOS was chosen because it is easy to transmit via Morse code. It is not an acronym, and the letters do not stand for anything, but over the years many have interpreted it to mean save our souls or save our ship.
The call was adopted by the International Radiotelegraphic Convention of 1906, which went into effect in 1908. The relevant portion of the convention reads:
Ships in distress make use of the following signal:—
- - - — — — - - -
repeated at short intervals.
Morse code for <s> is three dots, and for <o> three dashes, so the signal can be read as SOS, but the convention text itself does not mention the letters.
The first published use of the term SOS, not the actual transmission of it as a distress call, that I have found was following the 23 January 1909 collision between the steamships Florida and Republic off Nantucket, Massachusetts that resulted in the Republic sinking. In this instance, the first time a wireless distress call had been sent by a ship at sea, the radio operator onboard the Republic used the older distress code CQD (the Florida had no wireless capability). Six lives were lost in the collision, but the radio distress call and timely response undoubtedly saved many lives.
This first use of the term SOS was in a letter published by the journal The Electrician on 5 February 1909. The letter was in response to an article in the 23 January issue that had contended that if the International Radiotelegraph Convention of 1906 had not been in force, there would have been much greater loss of life:
What the Radio telegraphic Convention had to do with incident is not evident. The Radio telegraphic Convention is not in force in the United States to begin with, and the operator Binns preferred to put his trust in the “C.Q.D.” of the Marconi organisation rather than employ the arbitrary and as yet unfamiliar, “S.O.S.” of the Convention.
Another early use of the term SOS was in the 1910 edition of J.A. Fleming’s The Principles of Electric Wave Telegraphy and Telephony. Fleming repeats the words of the 1906 convention and then adds this footnote:
This signal, S, O, S, has superseded the Marconi Company’s original high sea cry for help, which was C, Q, D.
This passage and footnote are not in the earlier 1906 or 1908 editions of the book.
The first time an SOS signal was sent by a ship in distress was famously by the RMS Titanic, which sank on 15 April 1912. The Titanic had broadcast a number of CQD messages, but in its final distress call the radio operator used the SOS call. This fact was reported in any number of newspapers throughout the English-speaking world. This one is from The Sacramento Bee on the day of the sinking:
The Titanic’s first “S.O.S.” message was received by the Allan liner Virginian, which, according to the position given by the Titanic’s operator was not more than 170 miles away.
[...]
Immediate inquiry by the Associated Press in an urgent dispatch to the Marconi Station at Cape Race was answered soon afterward in the following words:
“At 10:25 last night the steamer called “C.Q.D.” and reported having struck an iceberg. The steamer said that immediate aid was required. Half an hour afterwards another message came reporting they were sinking by the head, and that women were being put off in the lifeboats.”
The association of SOS with save our souls, and also CQD with come quickly danger, came in the wake of loss of the Titanic. The following exchange took place when Guglielmo Marconi gave testimony to the British Wreck Commissioner’s Court on 18 June 1912:
Commissioner: Who made the change?
Marconi: The International Convention on Wireless Telegraphy held at Berlin in 1906
Commissioner: They made the change?
Marconi: They made the change
Commissioner: Of CQD to SOS?
Marconi: Yes
Commissioner: What does SOS stand for, anything, or is it simply three letters?
Marconi: Simply three letters, my Lord
Commissioner: I understand that CQD stood for “Come quick, danger”?
Marconi: It can be interpreted that way
Attorney-General: It really is an easy way to remember it, and SOS is, I am told, “Save our souls” It is simply an easy way to remember it?
Marconi: That is so.
Note that Marconi is being very politic. He, of all people, knows the letters do not officially stand for anything, but he is not about to contradict the belief of the commissioner
Sources:
Fleming, J. A. The Principles of Electric Wave Telegraphy and Telephony, second edition. London: Longmans, Green, 1910, 882. HathiTrust Digital Archive.
“Mammoth Liner Hits an Iceberg on First Voyage.” Sacramento Bee (California), 15 April 1912, 1, 5. Readex: America’s Historical Newspapers.
Oxford English Dictionary, second edition, 1989, s.v. S.O.S., n.
Radiotelegraphic Convention. London: H.M. Stationery Office, 29 November 1906, 34. HathiTrust Digital Archive.
“Wireless Telegraphy on Board Ship” (letter). The Electrician, 5 February 1909, 835. HathiTrust Digital Archive.
Wreck Commissioner’s Court. Formal Investigation into the Loss of the S.S. “Titanic,” vol. 7. London: H.M. Stationery Office, 1912, 672. HathiTrust Digital Archive.
Photo credit: Francis Godolphin Osbourne Stuart, 1912. Public domain image.