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

quarantine A quarantine is a restriction on the movement of people, animals, and goods which is intended to prevent the spread of disease or pests. It is often used in connection to disease and illness, preventing the movement of those who may have bee ...

d (the flag represents the letter “Q”). A ship flying two Quebecs ("QQ"), or "Double Quebec", is signaling: "I require health clearance." In both cases, if and when free

pratique Pratique 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. The clearance granted is commonly referred to as ''free pratique''. A ship can s ...

is granted, the vessel may lower the Quebec(s), raise the national ensign of the port, and do business there. In the event that, for health reasons, the vessel is not granted free pratique, it continues to fly the Quebec, in effect indicating that it is in quarantine until such time as any health concern is resolved. In

international maritime signal flags International maritime signal flags are various flags used to communicate with ships. The principal system of flags and associated codes is the International Code of Signals. Various navies have flag systems with additional flags and codes, and ...

, plain yellow, green, and black flags have been used to symbolize disease in ships and ports. The color yellow has a longer history. It was used to mark houses of infection prior to its maritime use. Yellow jack also became a name for yellow fever.

Cholera Cholera () is an infection of the small intestine by some Strain (biology), strains of the Bacteria, bacterium ''Vibrio cholerae''. Symptoms may range from none, to mild, to severe. The classic symptom is large amounts of watery diarrhea last ...

-infected ships also used a yellow flag. The plain yellow flag ("Q" or "Quebec" in international maritime signal flags), may derive its letter symbol from its initial use in "quarantine". In some

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

n cities such as

Jakarta Jakarta (; , Betawi language, Betawi: ''Jakartè''), officially the Special Capital Region of Jakarta (; ''DKI Jakarta'') and formerly known as Batavia, Dutch East Indies, Batavia until 1949, is the capital and largest city of Indonesia and ...

, plain yellow flags are commonly used to mark a recent death, regardless of cause. They are placed in intersections leading to the home of the recently deceased as direction markers for mourners, and to mark the funeral convoy, so that it is given the

right of way A right of way (also right-of-way) is a specific route that people, animals, vehicles, watercraft, or utility lines travel, or the legal status that gives them the right to do so. Rights-of-way in the physical sense include controlled-access h ...

. The Yellow Jack was also used to signify the time of execution of 2 Royal Navy Sailors condemned by a Court Martial. On the 7 Aug 1800 Portsmouth, at nine o'clock, a gun was fired on board the Royal William, at Spithead, and the yellow flag hoisted as a signal for executing J. Watson and J. Allen, who were condemned by a Court Martial as being concerned in the mutiny on board the Hermione. The signal being repeated, the yellow flag was hoisted on board the Puissant at Spithead, and the Braakel in the harbour, on board which ships they were executed, boats from all the ships at Spithead, manned and armed with marines, attended the Puissant as those in the Harbour did the Braakel.

References

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External links

The Yellow Flag of Quarantine
International flags Maritime flags Quarantine facilities Signal flags Flag, yellow (contagion)