How to signal SOS?

SOS can be signaled using: Fire, mirrors, rocks, smoke, a phone, a flashlight, and anything that can be used to make a loud enough sound.

The reason why the distress signal is called SOS, is that each letter in the Acronym can be easily produced over and over again in Morse code. S is three individual long beats, O is 3 short beats. The pattern can be easily produced over and over again, which is why they chose the 3 letters. There is no deeper meaning behind any of the letters used in the distress signal. There are existing expressions like "Save our Ship" or "Save our Souls" which have been monikered to represent each letter in SOS, however these are not the official meanings. Since SOS is the universal distress signal shared by countries all over the world, the simplicity of the signal is more important than the meaning of the individual letters, especially since many countries do not use the English alphabet.

SOS using a Flashlight

The SOS signal became the official morse code distress signal in 1906 and was first used on June 10, 1909 off the coast of the Azores in the Atlantic. Three years later the Titanic also used SOS to signal for help after colliding with an iceberg, however their signal was via radio frequencies instead of a flashlight.