Cartel (ship)

Cartel ships, in international law in the 18th and the 19th centuries, were ships employed on humanitarian voyages, in particular, to carry prisoners for exchange between places agreed upon in the terms of the exchange. While serving as a cartel, a ship was not subject to capture. However, if it engaged in commerce or warlike acts such as carrying official dispatches or messengers, it lost its character of inviolability and would then be subject to capture. The cartel protection extended to the return voyage. Furthermore, the prisoners being taken for exchange were under an obligation not to engage in hostilities towards their captors. If they were to capture the cartel ship, they would have no rights to salvage, and the owner of the vessel, if it were a ship from their country, would have no right to reclaim the vessel.

During the War of 1812 the British Admiralty wrote to the United States Government that Great Britain would not accept as valid, cartel agreements made on the high seas. On 10 June 1813, USS President captured the outward-bound Falmouth packet Duke of Montrose, Captain Aaron Groub Blewett, which managed to throw her mails overboard before President could send a prize crew aboard. President made a cartel of Duke of Montrose, putting all of President's prisoners from three earlier captures, on board and then sending her and her now 79 passengers and crew into Falmouth under the command of an American officer. There the British government refused to recognize the cartel agreement that Blewett, his crew, and passengers had signed. Rather than turn Duke of Montrose over to the Agent for American Prisoners, the British government instructed Blewett to resume command of his ship and prepare her to sail again.

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