Quarantine Flag

The history of the quarantine flag was related by Bernard Dulou in Rose des Vents #106, 2004. Rose des Vents is the bulletin of the association ABB (Association Bateaux en Bouteille).

The yellow quarantine flag is universal (Q letter in the international signal alphabet). Following the establishment of quarantine in the Mediterranean ports in the 14th century, it seems that there was for centuries no proper quarantine flag or any other quarantine signal.

The first time and place of hoisting of a quarantine flag is hitherto unknown. This gap was highlighted in 1975 by Rupp, who was the first in the German naval literature to write on the quarantine flag. The oldest known information on the use of signal flags to indicate quarantine dates back to the 18th century. At the time, signals were also used to indicate the absence of contagious disease on board. The oldes known record is to be credited to Henningen, who writes: "Danish sources give information according to which, during the great plague of 1710-1711, ships placed in quarantine should hoist a white flag." Hennigen adds that the quarantine signal should be used as the jack when the ship was in quarantine, as it was the case in 1751 in Cadix for the Swedish "Prins Carl" on her way to the East Indies. However, this flag was also hoisted as the jack to indicate that there was no contagious disease on board, as it was the case in 1799 in Capetown for the Swedish "Kongen af Danmark" on her way to China. It seems also that the Danish corvette Galathee hoisted in 1846 in Hawaii harbour a white flag in order to indicate that the health situation was normal on board. The very same white flag was then used with two opposite meanings, either quarantine or absence of disease on board.

An extract of the health report of the port of Marseilles (Health Office), dated 1730, describes the quarantine rules with details comparable to modern practice: everything is written, every member of the health service has its duty well defined, but there is no mention of a quarantine flag.

All the ships were controlled on the port of the island of Pommègue, located five miles off Marseilles, where 35 ships could moor. The contaminated ships were sent to the islands of Frioul and Galiane. All the other ships were allowed to enter the port of Marseilles, provided they moored again near the St. Nicolas citadel for checking their bill of health. The small boats plying between the port and the suspect or quarantined ships flew a red pennant.

In Britain, the quarantine signals were introduced in the 18th century. Mullet writes that, as from 1 January 1789, every quarantined ship off the British coast should hoist a specific signal. The daily signal was a big yellow flag whereas the night signal was a light placed on top of the mainmast. The non-observance of the rule was fined 200 pounds.

According to Fergusson, the origin of the yellow flag has to be traced back to the Middle Ages, when the heretics had to wear yellow clothes, the yellow colour being considered as the symbol of the hell fire, of betrayal, of jealousy and treachery. This was indeed a negative colour. The meaning of the "Yellow Admiral", known in the 19th century, is probably related. A "Yellow Admiral" was an old or supernumerary Captain who, short before retirement, was appointed Rear Admiral without ever having hoisted their personal flag on a ship of either the red, yellow or blue squadron. The name of "Yellow jack" given by the British seamen to the yellow fever seems to be related, too. During the great plague epidemics, it was common to mark the houses of the infected houses with a yellow cross and to force their inhabitants to wear yellow clothes.

An English Decree dated 1799 prescribes the size of the quarantine flag as "six breadths of bunting", which means six times the size of an ordinary flag. The "London Gazette" from 6 April 1805 published a Decree prescribing in detail the quarantine moorage, limited by yellow buoys topped with a yellow flag. The Decree from 10 October 1806, however, prescribed an "eight breadths of bunting yellow and black flag".

In 1832, the Nautical Magazine published a Decree, similarly prescribing a flag with yellow and black squares, eight breadths of bunting in size, to be hoisted by the quarantined ships on the coasts of Britain. The signal had to be hoisted on top of the mainmast. The naive lacking the bill of health has to fly on day a big yellow flag with a black ring or a plain black disc in the middle. This flag was tow breadths of bunting in size.

In Germany, the oldest record of the use of a quarantine flag is found in a report by Janssen, the Chief Pilot of the port of Hamburg. For long, there was no choice between the green and pale yellow colours for the flag. It was claimed that those two monocolour flag would prevent confusion with any national ensign. Therefore, the green flag was used for long in Hamburg as the quarantine flag. In 1856, a Decree lists also toe yellow flag: "All the ships submitted to a quarantine inspection are allowed to sail up the river Elbe and to moor under the quarantine flag. The flag is a green flag, two ells in size, hoisted on the foremast. The ships not having such a flag shall used a yellow flag or the national ensign."

In the Health Inspection Decree of the ships of the port of Hamburg issued in 1883, only the yellow flag is prescribed. The international use therefore eventually prevailed. Denmark adopted the international use in 1887 by a Notice published on 20 June, recommending the use of a yellow flag to the Danish ships.

Today, the Q signal flag is included in the international signal code. Hoisted alone, it means: "My ship is healthy and I require the free practice." Indeed, it is mostly used to require the inspection by the customs authorities, but that use is not strictly the same everywhere. In Britain, every ship coming from abroad must hoist the Q flag on the port side and wait for the customers, who are also in charge of immigration and health control. In theory, the crew shall not be allowed to land before the completion of the inspection. The procedure is simpler in France, where only the ships transporting goods to be declared have to hoist the Q flag.

An illustration of the yellow flag can be seen on the painting "HMS Hazard flying yellow quarantine flag", by Sir Oswald Walter Brierly (1817-1894, painting made 20 September 1841), kept in the National Maritime Museum, London.