Pratique /ˈprætɪk/ is the license given to a ship to enter a port, that indicates to local authorities (on assurance from the captain) that it is free from contagious disease.
[2] Since flying the Q flag involves a request for boarding by Port State Control,[3] it has also become an invitation to Customs to inspect a vessel for dutiable goods or contraband, as in the Rich Harvest case, where a yacht carrying a large quantity of alcohol flew the Q flag in order to seek exemption from having to pay duty during a temporary visit to port.
[4] The same vessel was also flying the Q flag when she was boarded in Cape Verde and found to be carrying more than one ton of cocaine.
However, although the captain had thereby invited the authorities to make an inspection (being, according to his claim, ignorant of the fact that the boat was carrying contraband), he and the crew were nevertheless arrested for trafficking.
[5] A question over who granted pratique arose with the COVID-19 incident involving the Ruby Princess cruise ship.