Armed merchantman

Armed merchantman is a term that has come to mean a merchant ship equipped with guns, usually for defensive purposes, either by design or after the fact. In the days of sail, piracy and privateers, many merchantmen would be routinely armed, especially those engaging in long distance and high value trade. The most famous of this type were the East Indiamen able to defeat regular warships in battle (see Battle of Pulo Aura). In more modern times, auxiliary cruisers were used offensively to disrupt trade chiefly during both World War I and World War II, particularly by Germany.

Pre-20th century
East Indiamen of various European countries were heavily armed for their long journeys to the Far East. In particularly dangerous times, such as when the home countries were at war, a convoy system would be used whereby the ships were escorted by a warship. However, many East Indiamen also travelled on their own, and therefore were heavily armed in order to defend themselves against pirates and privateers. They also defended themselves against warships, scoring signal victories at the Battle of Pulo Aura and the Action of 4 August 1800. The British Royal Navy purchased several that it converted to ships of the line.

===Development of auxiliary cruisers ===

In 1856, privateering (or seizure of a belligerent country's merchant ships as a private enterprise) lost international sanction under the Declaration of Paris. From 1861-65 European countries built high speed ships to run the Union Blockade during the American Civil War. Some of these were armed and served as Confederate States Navy raiders.

Russia purchased three ships in 1877 of 6000 LT armed with 6 in 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.
 * 1890 - German and British shipyards built new civilian ships designed for wartime conversion, and France, Italy, Japan, Austria-Hungary, and the United States made similar agreements with their shipyards.

Russia built two more auxiliary cruisers in 1892.

In 1895 the Imperial German Navy mobilized the provisional auxiliary cruiser Normannia for a 15-day trial armed with eight 6-inch guns, two 3.5 in guns, six 37 mm guns, and two torpedo boats.

20th century
In both World Wars both Germany and the United Kingdom used auxiliary cruisers.. Whilst the British used armed passenger liners defensively for protecting their shipping, the German approach was to use them offensively to attack enemy shipping.

Armed merchant cruisers
The Armed Merchant Cruisers (AMC) of the British Royal Navy were employed for convoy protection against enemy warships. They had limited value because they lacked warship armour and used local control of guns rather than director fire-control systems. Many were later converted into troopships.

One famous AMC of World War I was the British RMS Carmania (1905) which, after a heated battle that caused heavy damage on both sides, succeeded in sinking the German auxiliary cruiser SMS Cap Trafalgar near the Brazilian island of Trinidade in 1914. By coincidence, Cap Trafalgar was disguised as Carmania.

In World War II, HMS Jervis Bay (F40)—the sole escort for convoy HX 84 in November 1940— stood off the pocket battleship GERMAN CRUISER Admiral Scheer, when the German ship attacked the convoy. Though she was sunk, this enabled the convoy to escape. Her master, Acting Captain Edward Fegen was awarded the Victoria Cross (posthumous) for his actions. Another famous action involving an armed merchant cruiser was the November 1939 battle between HMS Rawalpindi and the German battlecruisers GERMAN BATTLESHIP Scharnhorst and GERMAN BATTLESHIP Gneisenau. Fighting against hopeless odds, the Rawalpindi was quickly sunk.

Auxiliary cruisers


Both the Spanish and United States Navy used auxiliary cruisers during the Spanish-American War of 1898. In World War I too, American auxiliary cruisers fought several engagements with German U-boats.

The German practice was to arm merchantmen with hidden weapons and use them as commerce raiders. An auxiliary cruiser—Hilfskreuzer or Handels-Stör-Kreuzer (HSK)—usually approached her target under a false flag with guns concealed, and sometimes with her appearance altered with fake funnels and masts and often a fake paint job. The victim was thus engaged at point-blank range and had no chance to escape. 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 Germans therefore soon moved on to using captured and refitted Allied vessels, but principally only modified transport ships. These were slower, but less recognizable. In both world wars, these ships were vulnerable to attack, and were withdrawn before the war ended. Many were sunk after being caught by regular warships—an unequal battle since auxiliary cruisers had poor fire control and no armor. There were, however, a few success stories. SS Kaiser Wilhelm der Grosse was a former passenger liner that sank two freighters in 1914 before being caught by HMS Highflyer (1898). Her sister ship, SS Kronprinz Wilhelm, had a legendary journey, sinking or capturing a total of 15 ships in 1914 and 1915, before finally running out of supplies and having to put into port in Virginia, where the Americans interned her and eventually converted her into the United States Navy troop transport USS Von Steuben. The most famous German commerce raider of World War I probably was SMS Seeadler (auxiliary cruiser), a sailing ship under the command of the legendary Count Felix von Luckner. However, both SMS Wolf (auxiliary cruiser) and SMS Möwe (auxiliary cruiser) were each much more successful than Seeadler.

In World War II, the German Navy operated ten very successful auxiliary cruisers which ranged in tonnage from 3,860-9,400; typically these vessels were equipped with:
 * Floatplanes
 * 6 in (15 cm) guns
 * Smaller armaments (typically hidden away behind specially designed and hinged bulwarks, or beneath fake deckhouses and/or skylights)
 * Torpedoes
 * Mines

To preserve their cover, these ships flew the flags of neutral or occasionally Allied nations. They re-fuelled and provisioned themselves from special supply ships, from Japanese island bases, or simply from prizes they had taken.

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.

In one incident, the German GERMAN AUXILIARY CRUISER Kormoran (ex-merchantman Steiermark) managed to surprise and sink the Australian light cruiser HMAS Sydney (1934), which approached too close, though Kormoran herself was also sunk in the engagement. This was the only occasion in history when an armed merchantman managed to sink a modern warship; in most cases, auxiliary cruiser raiders tried to avoid confrontation with warships. It should be noted that Kormoran's attack upon Sydney was motivated by desperation. However, she was not the most successful German raider of World War II (both GERMAN AUXILIARY CRUISER Atlantis and GERMAN AUXILIARY CRUISER Pinguin scored higher kill tonnages). Another, GERMAN AUXILIARY CRUISER Stier, was also sunk in a mutually destructive engagement with the American Liberty Ship SS Stephen Hopkins.

The only encounters between Allied and Axis auxiliary cruisers in World War II were all with the raider GERMAN AUXILIARY CRUISER Thor. This small vessel, which captured or sank 22 merchantmen, encountered three British AMCs in her career, defeating HMS Alcantara and HMS Carnarvon Castle and later sinking HMS Voltaire.

During World War II, German auxiliary cruisers are believed to have either sunk or captured some 800000 LT of Allied shipping.

Compare to the Q-ship, which was a disguised merchantman for anti-submarine operations.

Others
The CAM Ship (from catapult armed merchantman) was a British merchantman fitted with a catapult that could launch, but not recover, a single fighter aircraft.

The Merchant Aircraft Carrier or MAC was a British or Dutch cargo ship with a flight deck that could carry a small number of aircraft.

CAM and MAC ships remained as civilian ships operated by civilian crews, with Fleet Air Arm or Royal Netherlands Navy "air parties".

Russian merchant cruisers
Note: This listing is incomplete.

Spanish Civil War
The Spanish Nationalists, whose navy was substantially outnumbered by the Republicans, made an extensive use of auxiliary cruisers during the Spanish civil war, two of them on loan from Italy:

Allied merchant cruisers
The Armed merchant cruisers were made by requisitioning large ships and providing them with guns and other equipment. They ranged from 6000 - 22000 LT. The armament varied but six 6 in guns with 3 in guns as secondary was usual. From 1941, many served as troopships.

Royal Australian Navy

 * HMAS Manoora (1935)
 * HMAS Westralia (1939)

Royal New Zealand Navy

 * Monowai

Royal Canadian Navy

 * HMCS Prince David (F89)
 * HMCS Prince Henry (F70)
 * HMCS Prince Robert (F56)

French Navy (Marine Nationale)
French auxiliary cruisers were armed with 138 mm, 152 mm or 150 mm guns, 75 mm and 37 mm AA guns and 13.2 mm or 8 mm AA HMG


 * Aramis (X01)
 * Ville D'Alger (X03)
 * Cap des Palmes (X03)
 * Ville d'Oran (X05)
 * El Mansour (X06)
 * Victor Scoelcher (X07) (lost on 6 May 1942)
 * Colombie (X10)
 * Charles Plumier (X11)
 * Djenné (X13)
 * El Kantara (X16)
 * El Djezair (X17)
 * Eridan (X18)
 * Barfleur (X19)
 * Quercy (X20)
 * Esterel (X21)
 * Mexique (X22) (hit a mine and sunk on 19 June 1940)

German auxiliary cruiser raiders
At the outbreak of war, the German Navy (Kriegsmarine) requisitioned a number of fast merchantmen and immediately sent them into naval shipyards to be converted into offensive auxiliary cruisers. These ships had at the time of building been fitted with extra strong decks specifically to facilitate the installation of military equipment when required, but this was the only difference between them and other merchantmen of the period. No precise plans had been drawn up for the conversion of these ships into warships, and consequently the conversion process was painfully long. Compared to the diversity of British auxiliary cruisers, the Hilfskreuzer were standardized insofar as possible. The ships themselves averaged approximately 7000 LT. Armament usually consisted of six 6 in guns, two to six torpedo tubes, and an assortment of 40 mm, 37 mm, and 20 mm automatic weapons. Most of these merchant raiders carried an Arado Ar 196 floatplane for reconnaissance. GERMAN AUXILIARY CRUISER Kormoran, GERMAN AUXILIARY CRUISER Komet, and GERMAN AUXILIARY CRUISER Michel were also equipped with small motor torpedo boats. In addition to armament, increased fuel, water, and coal storage had to be provided for as well. Furthermore, the raiders could not abandon the crews of their captures, so space had to be provided for prisoners. The first Hilfskreuzer got under way in March 1940, shortly before the Norwegian campaign.


 * GERMAN AUXILIARY CRUISER Orion (HSK-1)
 * GERMAN AUXILIARY CRUISER Atlantis (HSK-2)
 * GERMAN AUXILIARY CRUISER Widder (HSK-3)
 * GERMAN AUXILIARY CRUISER Thor (HSK-4)
 * GERMAN AUXILIARY CRUISER Pinguin (HSK-5)
 * GERMAN AUXILIARY CRUISER Stier (HSK-6)
 * GERMAN AUXILIARY CRUISER Komet (HSK-7)
 * GERMAN AUXILIARY CRUISER Kormoran (HSK-8)
 * GERMAN AUXILIARY CRUISER Michel (HSK-9)
 * GERMAN AUXILIARY CRUISER Coronel (HSK-10)
 * GERMAN AUXILIARY CRUISER Hansa (HSK-11)

Japanese armed merchant cruisers
See also Japanese raiders in Indian Ocean Campaign and List of Japanese Auxiliary Cruiser Commerce Raiders.

Japan converted fourteen merchant ships to "armed merchant cruisers" but, by the end of 1943, five had been sunk and seven had been converted back to merchant ships.
 * Aikoku Maru
 * Akagi Maru
 * Asaka Maru
 * Awata Maru
 * Bangkok Maru
 * Gokoku Maru
 * Hokoku Maru
 * Kinryu Maru
 * Kiyozumi Maru
 * Kongō Maru
 * Noshiro Maru
 * Saigon Maru
 * Ukishima Maru

Italian armed merchant cruisers
Unlike the Germans and the Japanese, none of the armed merchant cruisers (or auxiliary cruisers) of the Italian Royal Navy (Regia Marina) were deployed to destroy or capture Allied merchant ships. All of them mounted two 4.7 in guns.


 * ITALIAN SHIP Ramb I - Lost on 27 February 1941 in battle with cruiser HMNZS Leander in the Indian Ocean.
 * ITALIAN SHIP Ramb II - Never active as an Italian armed merchant cruiser and, after being chartered by the Japanese as the Calitea II, lost on 12 January 1945
 * ITALIAN SHIP Ramb III - Converted into an escort vessel and never served as an armed merchant cruiser, she took part of the battle of Otranto
 * ITALIAN SHIP Ramb IV - Converted into a hospital ship and never served as an armed merchant cruiser

21st century
Despite a rise in modern piracy, it is very unusual for modern merchant ships to be armed, save for maybe a number of small arms and the use of the ship's fire hoses to repel boarders. One exception to this are the ships of Pacific Nuclear Transport Limited, which are used to transport spent nuclear fuel and reprocessed uranium on behalf of BNFL. Transporting enough fissile material between them to produce 50-60 nuclear weapons, these ships—beginning with the Pacific Pintail and Pacific Teal—became armed in 1999 to avoid the cost of a Royal Navy escort. Travelling together in convoy during these ships intermittent voyages, they have an onboard escort of armed police from the UKAEAC and its successors and are equipped with two or three 30 mm autocannons.

In April 2010, it was reported that a Russian company is offering a version of the 3M-54 Klub missile that can be disguised and launched from a shipping container, in theory enabling any cargo ship to be armed with an anti-ship missile. This type of missile is allegedly capable of disabling or even sinking an aircraft carrier.

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.

In October 2011, the British Prime Minister, David Cameron, announced that British merchant shipping passing through areas known for piracy, could carry firearms.