How to Signal SOS
SOS can be signaled using any method that produces distinguishable short and long signals. With a flashlight, flash three short bursts, three long bursts, then three short bursts. With sound, make three quick taps, three slow taps, then three quick taps using a whistle, horn, or any noise-making object. You can also write SOS on the ground using rocks, branches, or clothing for aerial search teams. The key timing rule is that a dash should last roughly three times as long as a dot, with equal gaps between each signal within the sequence.
Why Was SOS Chosen as the Distress Signal?
SOS was adopted at the International Radiotelegraphic Convention in Berlin in 1906, replacing the earlier CQD distress signal. The letters S-O-S were chosen not because they stand for anything — "Save Our Souls" and "Save Our Ship" are folk etymologies invented after the fact. The actual reason is purely practical: the pattern ··· ––– ··· is simple, distinctive, and nearly impossible to confuse with any other signal. Its symmetrical rhythm makes it easy to send and recognize even in noisy conditions or by untrained operators.
SOS and the Titanic
The most famous use of SOS occurred during the sinking of the RMS Titanic on April 15, 1912. Wireless operators Jack Phillips and Harold Bride initially sent the older CQD distress call but then switched to the newer SOS signal — one of the first major uses of SOS in a maritime disaster. The Carpathia received the signal and rescued 710 survivors. This event cemented SOS as the universal distress signal and led to major reforms in maritime radio regulations, including the requirement that ships maintain 24-hour radio watch.
Modern Uses of SOS
Although formal maritime radio distress procedures now use voice calls (MAYDAY) and the Global Maritime Distress and Safety System (GMDSS), SOS remains universally understood. Hikers and campers learn SOS as a survival skill. Many smartphones include an emergency SOS feature that uses repeated signals. The International Morse Code prosign for SOS is still officially recognized by the International Telecommunication Union (ITU) as a distress indication.