[Zer0 (OP)]

🚢

[paul cotter]

??

[alancalverd]

CQ ("seek you") was an early call sign requesting anyone to answer.

Still, I think, used by radio hams, particularly morse enthusiasts: C Q / D E / G 2 X Y Z ("seek you from G2XYZ") is an invitation for anyone who wants to communicate with a British shack.

Fortunately the nonstandard C Q D (D for distress), which can easily be mistaken for the "social"  C Q / D E was replaced by {SOS} (no gaps) as an international standard over 100 years ago, with "MAYDAY" adopted shortly afterwards for voice comms. 

[paul cotter]

I am familiar with "cq" having had an active interest in amateur radio ~55years ago. I basically lost interest with the move to shop bought equipment as opposed to home built gear. Still I never came across "cqd".

[alancalverd]

Still I never came across "cqd".

Just as well, since CQD was a Marconi company code, specific to ships equipped with their RT kit, and never became an accepted  universal standard, though I guess most non-Marconi operators would have been aware of it. CQ DE, however, was definitely in the ham books in the 1960s.