Heh, first some wanted to use CQD:
dash dot dash dot | dash dash dot dash | dash dot dot
This was a political process among the notable shipping nations of those times. At first they … provisionally agreed: CQD.
CQD, in Morse code: ▬ • ▬ • ▬ ▬ • ▬ ▬ • •


This reminds me of the wonderful British band Public Service Broadcasting, whose defining feature is repurposing audio recordings into songs. CQD is the name of one of their tracks on their Titanic-themed EP.

@spgreenhalgh Don’t know if you went ahead and listened to the podcast I linked. Apparently most of the world went with SOS but the British stuck with CQD until the Titanic sank. The operators there broadcast CQD at first then switched to SOS…