Best boom I heard was when sailing from Brest to the Solent - probably early 90s? - when a (sadly French
) Concorde dropped a boom on us, presumably en route to S America.
Rattled the sails it did - very impressive. 'Twas a gin clear day and the crew - mostly aircrew nursing post-Brest nightstop duty free wine hangovers - saw the fast moving contrail a long time in advance and guessed exactly what it was.
A magical moment - completely (just) out of sight of land.....
