The Yellow Jack ("Quebec") signal flag, is a plain yellow banner that was historically used to signify a vessel was, or might be, harboring a dangerous disease and needed to be quarantined (the flag represents the letter “Q”). Later the flag came to mean the opposite, signaling: "My vessel is healthy and I request free pratique".
The Yellow Jack ("Quebec") signal flag, is a plain yellow banner that was historically used to signify a vessel was, or might be, harboring a dangerous disease and needed to be quarantined (the flag represents the letter “Q”). Later the flag came to mean the opposite, signaling: "My vessel is healthy and I request free pratique".
https://en.wikipedia.org/wiki/Yellow_Jack_(flag)
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