SDSTAFF Dex’s discussion of the SOS maritime distress signal (see omits the important fact that SOS no longer is an international maritime distress signal for most ships, and hasn’t been for almost two years. Modern alternatives have done it in.

See and/or and/or
The latter has lots of further references, including, which gives a detailed history of SOS with lots more info than the SD staff report. This last piece tells us that SOS was in use by the Germans prior to being adopted as an international standard. It also mentions that SSSS was used to transmit that a submarine has been sighted during WW2, but makes no mention of the SSS signal refered to by the SD advisory report.

I have fixed the links. – CKDH
[Edited by C K Dexter Haven on 01-12-2001 at 12:11 PM]

“San Francosico”?

I’m glad “SOS” was the standard, at least for many years. Can you imagine ABBA singing “So when you’re near me, darling, can’t you hear me? CQD”? It loses something.

I’m also glad “OSO” wasn’t used, as this could have been misinterpreted by Spanish speakers as a signal that a bear was aboard.

Dex’s claim that Samuel Morse picked “combinations of dots and dashes that he thought would be easy to memorize” is not entirely correct. The sequences were chosen to minimize message lengths for English text; Morse constructed his code by listing the letters of the alphabet by their frequency of usage in English, and arranging them in a table with two letters (E, T) on the first line, four (I, A, N, M) on the second, eight (S, U, R, W, D, K, G, O) on the third, and so forth. To find the Morse code for a letter, start at the top of the table and go down line by line, taking the shortest path to the letter you want, and writing a dot every time you go left and a dash every time you go right.

The soap pad is actually called “S.O.S” There is no period after the final “S”. I read they had to do it that way to get the name copyrighted.

I’d like to second TST’s recommendation of Neal McEwen’s ‘SOS,’ ‘CQD’ and the History of Maritime Distress Calls as a very good review of the history of distress calls.

Reviewing the Staff Report article:

In fact, SOS in not an acronym and it doesn’t represent anything at all.

It should also be stressed that, unlike CQD, the “SOS” distress signal really isn’t even three letters. From the beginning it has officially been …—… or three dots/three dashes/three dots all run together as a single entity. If you informally divide it into three equal parts it becomes “SOS” in Continental Morse code. However, in American Morse code, which was used by many U.S. ships through the first part of the twentieth century, stood for the numeral “5”, so in this case the international distress signal was informally referred to as “S5S”. (See Francis A. Collins’ 1912 Some Stirring Wireless Rescues for more details.)

In 1908, an international committee tried to come up with a distress signal that would be easy to remember during a crisis, and could be transmitted by an amateur with only rudimentary knowledge of Morse Code. They decided a simple combination of threes: three letters, each represented by three marks, since three is a universally favored number. Well, at least in Western cultures.

The “SOS” distress signal actually dates back to at least April 1, 1905, when it was adopted by a national German law. (See Regelung der Funkentelegraphie im Deutschen Reich and German Regulations for the Control of Spark Telegraphy). It was next adopted as the international standard by the Berlin International Wireless Telegraph Convention, which was signed on November 3, 1906, and became effective on July 1, 1908. (See 1906 International Wireless Telegraph Convention/Service Regulation XVI.)

In Morse Code, the only letters represented by three identical marks are O (three dashes) and S (three dots). The committee toyed with OSO, but dashes are longer electrical signals to transmit than dots. An urgent message needed to be broadcast as quickly as possible and use as little power as possible, and so SOS became international standard.

I don’t know where this “committee” story comes from, but the simplest explanation is that the Convention merely adopted the distress signal that had already been in use in Germany for the past year-and-a-half. I’ve never seen any references to “OSO” being considered. And amateur operators certainly weren’t a factor, as they essentially didn’t exist in 1905/1906, and anyway, according to the 1906 Convention the distress signal was adopted for use by “ships in distress”.

During WWII, the signal “SSS” was adopted when the source of the emergency was a submarine attack, presumably so that potential rescue ships would know there was an enemy sub in the area.

Strings of S’s (three dashes each) had also been used during World War One to warn of submarines. From Bette Clemon’s Wake of the Wirelessman, a biography of her father as a shipboard radio operator during WWI: “Dale sat back and proceeded as usual to scan the dial listening for marine traffic. His heart jumped. He heard ‘.-  -…  .-…  —.’ (ALLO) followed by a profusion of dashes in a triplet pattern, a warning as attention getting as SOS. He waited for the location. It came, ‘Cape Spartel.’ Dale phoned the bridge. ‘Submarine in our front yard, Cape Spartel.’”

DES–you are confusing the current, International Morse code which we now use with Morse’s original code scheme, the earlier mentioned “American Morse”. Morse’s original code had oddities such as inter-letter half-spaces, (O was dot/half space/dot) and a long-dash for L. The Morse code we now used is a European modification of Morse’s original code. The Original Morse Code Modified in Europe has a good review of the developments.

Douglips, thanks for catching the typo, which is being corrected.

Annie, I will try to confirm the soap pad periods next week, and edit if necessary.

Whiteho, thanks for all the additional comments. There is always the question in writing these Staff Reports of how much to include or exclude. We aim to make a short, readable, informative piece rather than a three-volume dissertation, and that always means some condensing.

I didn’t expect you to include eveything I wrote–it’s just that I had pointed out some errors in the original column, so I wanted to fully document my sources for the corrected information.

Anyway, nobody asked, but this is how I would have answered the question:

Although many people think the “SOS” distress signal stands for “Save Our Souls” or something similar, it actually isn’t an acronym. If fact, officially it isn’t even three letters: it’s the continuous Morse code string …—… (three dots/three dashes/three dots all run together). But, because three dots form the letter “S” in International Morse code, and three dashes are the letter “O”, for convenience the distress signal is commonly referred to as “SOS”.

Although Morse code telegraphy dates back to the 1830’s, there wasn’t a need for a distress signal as long as everything was on land. That changed in the early 1900s when radiotelegraph transmitters were set up aboard ships, and endangered vessels needed a way to attract attention and make sure other stations didn’t interfere with emergency transmissions. However, there was no international coordination at first, so different organizations came up with different distress signals, for example, the U.S. Navy adopted NC, Marconi operators used CQD, and, effective April 1, 1905, a German law mandated …—… (“SOS”)

Having multiple distress signals was of course confusing and potentially dangerous, so at the 1906 Berlin International Wireless Telegraph Convention, Germany’s …—… was officially chosen as the international distress signal.


Soap On Steel.

I thought everyone knew that.

Dr. Matt

In your discussion of SOS you say, “In fact, SOS in not an acronym and it doesn’t represent anything at all.”

What you say is true enough, but in the spirit of tediously getting things right (which is what this forum is all about), I must point out that this was never really in question. An acronym is an abbreviation that is pronounced as a word. I don’t think I’ve ever encountered anyone who didn’t pronounce the distress signal as “es oh es,” not “sos.” Thus, at best it might have been an abbreviation for “Save Our Souls,” but never an acronym.

I did once have a roommate who refered to the cleaning supply as “sos pads,” where the first part came out something like “sauce.” It got very confusing when he was cleaning the sauce pans.

By the way, why does this site need to set cookies that don’t expire until 2019?


davanden, you are technically correct. SOS wouldn’t be an acronym even if it did stand for “Save Our Ships” or whatever, because it is not pronounced as a word, but rather as a set of initials - that makes it an initialism. However, it has become commonly accepted to refer to any initialism as an acronym. Stretching perhaps the meaning of the word acronym, but retaining the essence - it is a “word” made of the first letters or parts of a string of words. The only difference being that in the new case, the “word” in question is pronounced “essoess”. :wink:

Initialism? What dictionary are you using? If SOS stood for a phrase, it would be an abbreviation. BTW, I think misuse of the word acronym is slovenly and should be corrected when encountered.

“SOS” is officially a prosign. Prosigns are long Morse code strings that are arbitrarily expressed as two or more well known Morse characters, so people know the correct order of dots and dashes to send. But when prosigns are transmitted, they are keyed as a continuous string of all the dots and dashes specified by the individual prosign letters.

The …–… distress signal is universally referred to as the “SOS” prosign but, as noted by Karl Baarslag in his 1935 SOS to the Rescue, “SOS […  —  …] was used, although the letters VTB […-  -  -…], IJS […  .—  …] , or SMB […  –  -…] sent as one signal would form the same …—… in the Morse code.”

There is a list of Morse prosigns commonly used by amateurs at: Prosigns

Derleth said:

alt-usage-english-faq: usage - “acronym”

(use your “find in page” function)

I didn’t make it up.