Armed merchantman
In the days of sail, piracy and privateers, many merchantmen would be routinely armed, especially those engaging in long distance and high value trade.
Russia purchased three ships in 1878 of 6,000 long tons (6,100 t) armed with 6-inch (150 mm) guns for use as auxiliary cruisers for a Russian Volunteer Fleet.
Germany and the United Kingdom responded to the precedent by asking their shipping companies to design fast steamers with provision for mounting guns in time of war.
[citation needed] The downside proved to be their high fuel consumption; using them in a purely AMC role would have burned through the Admiralty reserve supplies of steam coal in less than three months.
A famous AMC of World War I was the British RMS Carmania which, after a battle that caused heavy damage on both sides, sank the German auxiliary cruiser SMS Cap Trafalgar near the Brazilian island of Trindade in 1914.
Another famous action involving an armed merchant cruiser was the November 1939 battle between HMS Rawalpindi and the German battlecruisers Scharnhorst and Gneisenau.
In World War I, the Imperial German Navy initially used fast passenger ships, such as past holders of the Blue Riband for fastest North Atlantic crossings, but they made obvious and easy targets because of their very familiar silhouettes.
The most famous German commerce raider of World War I probably was Seeadler, a sailing ship under the command of the legendary Count Felix von Luckner.
In World War II, Nazi Germany's Kriegsmarine operated ten very successful auxiliary cruisers, ranging in tonnage from 3,860 to 9,400; typically these vessels were equipped with: To preserve their cover, these ships flew the flags of neutral or occasionally Allied nations.
[citation needed] To counter the effectiveness of these disguises, the Allies introduced the check-mate system in 1942 to identify individual ships on a one-by-one basis with the Admiralty in London.
[citation needed] She was not the most successful German raider of World War II (both Atlantis and Pinguin scored higher kill tonnages).
During World War II, German auxiliary cruisers are believed to have either sunk or captured some 800,000 long tons (812,838 t) of Allied shipping.
[4] Travelling together in convoy during these ships' intermittent voyages, they have an onboard escort of armed police from the UKAEAC and its successors[5] and are equipped with two or three 30 mm (1.18 in) autocannons.
In 2007, facing a chronic shortage of naval vessels the Cuban Navy placed into service the Rio Damuji class of frigates, which are large fishing trawlers converted into warships.
"[7] During the 2011 Libyan civil war, forces loyal to Gaddafi armed several merchant vessels and attempted to use them to blockade the port of Misrata.
