Armed merchantman

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HMS Alcantara and SMS Greif dueling at close range during the action of 29 February 1916 Alcantara 1916.jpg
HMS Alcantara and SMS Greif dueling at close range during the action of 29 February 1916

An armed merchantman is 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.


In more modern times, auxiliary cruisers were used offensively as merchant raiders to disrupt trade chiefly during both World War I and World War II, particularly by Germany.

While armed merchantmen are clearly inferior to purpose-built warships, sometimes they have scored successes in combat against them. Examples include East Indiamen mimicking ships of the line and chasing off regular French warships in the Battle of Pulo Aura in 1804, and the German auxiliary cruiser Kormoran sinking the Australian light cruiser HMAS Sydney in their battle in 1941, although Kormoran was also destroyed and had to be scuttled.

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 to 1865 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 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.

In 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. In 1892 Russia likewise built two more auxiliary cruisers.

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-inch (89 mm) guns, six 37-millimetre (1.46 in) guns, and two torpedo boats. [1]

20th century

In both World Wars, both Germany and the United Kingdom used auxiliary cruisers. While 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

RMS Carmania sinking SMS Cap Trafalgar near the Brazilian islands of Trindade, 14 September 1914 Sinking Cap Trafalgar.jpg
RMS Carmania sinking SMS Cap Trafalgar near the Brazilian islands of Trindade, 14 September 1914

The armed merchant cruisers (AMC) of the British Royal Navy were employed for convoy protection against enemy warships. They ultimately proved to have limited value and many, particularly ocean liners, were later converted into troopships, a role for which they were more suited. Documentary evidence quoted by the BBC researched from the early stages of the First World War suggests that the express liners had greater speed than most warships (few warships of the period could exceed 21 knots), which made them suitable as AMCs.[ 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.[ citation needed ] The ships were vulnerable to enemy fire because they lacked warship armour, and they used local control of guns rather than director fire-control systems, which reduced their effective fire power.

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 Trinidade in 1914. [2] By coincidence, Cap Trafalgar was disguised as Carmania. In World War II, HMS Jervis Bay, the sole escort for convoy HX 84 in November 1940, stood off the pocket battleship Admiral Scheer, when the German ship attacked the convoy. Though she and five vessels of the convoy were sunk, this enabled the rest of the convoy to escape. Her master, Acting Captain Edward Fegen was awarded the Victoria Cross posthumously for his actions. Another famous action involving an armed merchant cruiser was the November 1939 battle between HMS Rawalpindi and the German battlecruisers Scharnhorst and Gneisenau. Outgunned, the Rawalpindi was quickly sunk.

Auxiliary cruisers

The Spanish and United States Navies 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 scheme. 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 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. Kaiser Wilhelm der Grosse was a former passenger liner that sank two freighters in 1914 before being caught by HMS Highflyer. Her sister ship, 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 Seeadler, a sailing ship under the command of the legendary Count Felix von Luckner. However, both Wolf and Möwe were each much more successful than Seeadler.

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. They were refueled and provisioned from special supply ships, from Japanese island bases or from prizes they had taken.[ 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.

Kormoran in 1940. During a single ship action on 19 November 1941, off the coast of Western Australia the German auxiliary cruiser Kormoran sank HMAS Sydney before being scuttled. Bundesarchiv Bild 146-1985-117-02A, Hilfskreuzer Kormoran.jpg
Kormoran in 1940. During a single ship action on 19 November 1941, off the coast of Western Australia the German auxiliary cruiser Kormoran sank HMAS Sydney before being scuttled.

In one incident, the German Kormoran (ex-merchantman Steiermark) managed to surprise and sink the Australian light cruiser HMAS Sydney, which approached too close, though Kormoran 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. Kormoran's attack upon Sydney was motivated by desperation.[ citation needed ] She was not the most successful German raider of World War II (both Atlantis and Pinguin scored higher kill tonnages). Another, 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 Thor. This small vessel, which captured or sank 22 merchantmen, encountered three British AMCs in her career, defeating RMS Alcantara and HMS Carnarvon Castle and later sinking HMS Voltaire in the Action of 4 April 1941. During World War II, German auxiliary cruisers are believed to have either sunk or captured some 800,000 long tons (810,000 t) of Allied shipping. Compare to the Q-ship, which was a disguised merchantman for anti-submarine operations.


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".

21st century

Despite a rise in modern piracy, it was up until the early 2010s 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 notable exception to this were the ships of Pacific Nuclear Transport Limited, [3] which are used to transport spent nuclear fuel and reprocessed uranium on behalf of British Nuclear Fuels Limited. 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. [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. [6] Another exception were various ships of the Soviet Union's Merchant Marine (MORFLOT) during the Cold War (MORFLOT often operated as an adjunct to Soviet foreign and military policy, both overtly and otherwise).

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.

In April 2010, it was reported that a Russian company was offering a version of the 3M-54 Klub missile that could 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 was allegedly capable of disabling or even sinking an aircraft carrier, but "it's not known how many of them would have to hit a carrier to knock it out of action, much less sink it." [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.

In October 2011, British Prime Minister David Cameron announced that British merchant shipping passing through areas known for piracy were permitted to carry firearms. [8]

Ship list

Since the late 19th century various navies have used armed merchant ships in the role of auxiliary cruisers, also called armed merchant cruisers. Significant use of this type of ship was made by Britain and Germany in both World Wars.

Some of the ships used in this role include:

See also

Related Research Articles

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The Kriegsmarine was the navy of Germany from 1935 to 1945. It superseded the Imperial German Navy of the German Empire (1871–1918) and the inter-war Reichsmarine (1919–1935) of the Weimar Republic. The Kriegsmarine was one of three official branches, along with the Heer and the Luftwaffe, of the Wehrmacht, the German armed forces from 1935 to 1945.

<span class="mw-page-title-main">Q-ship</span> Heavily armed merchant ships with concealed weaponry

Q-ships, also known as Q-boats, decoy vessels, special service ships, or mystery ships, were heavily armed merchant ships with concealed weaponry, designed to lure submarines into making surface attacks. This gave Q-ships the chance to open fire and sink them. The use of Q-ships contributed to the abandonment of cruiser rules restricting attacks on unarmed merchant ships and to the shift to unrestricted submarine warfare in the 20th century.

<span class="mw-page-title-main">Battle of the Atlantic</span> Attempt by Germany during World War II to cut supply lines to Britain

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<span class="mw-page-title-main">Merchant raider</span> Warship type disguised as a non-combatant

Merchant raiders are armed commerce raiding ships that disguise themselves as non-combatant merchant vessels.

German auxiliary cruiser <i>Kormoran</i> Kriegsmarine merchant raider of World War II

The German auxiliary cruiser Kormoran (HSK-8) was a Kriegsmarine merchant raider of World War II. Originally the merchant vessel Steiermark ("Styria"), the ship was acquired by the navy following the outbreak of war for conversion into a raider. Administered under the designation Schiff 41, 'Ship 41', to the Allied navies she was known as "Raider G". The largest merchant raider operated by Germany during World War II, Kormoran ("cormorant") was responsible for the destruction of 10 merchant vessels and the capture of an 11th during her year-long career in the Atlantic and Indian oceans.

<span class="mw-page-title-main">Warship</span> Ship that is built and primarily intended for naval warfare

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<i>Leander</i>-class cruiser (1931) UK class of light cruisers

The Leander class was a class of eight light cruisers built for the Royal Navy in the early 1930s that saw service in World War II. They were named after mythological figures, and all ships were commissioned between 1933 and 1936. The three ships of the second group were sold to the Royal Australian Navy (RAN) before World War II and renamed after Australian cities.

<span class="mw-page-title-main">Commerce raiding</span> Form of naval warfare

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HMS <i>Jervis Bay</i> 20th-century British armed merchant ship

HMS Jervis Bay was a British liner later converted into an armed merchant cruiser, pennant F40. She was launched in 1922, and sunk in battle on 5 November 1940 by the German heavy cruiser Admiral Scheer in an action which earned her captain the Victoria Cross.

<span class="mw-page-title-main">Edward Fegen</span>

Captain Edward Stephen Fogarty Fegen, was a Royal Navy officer and a recipient of the Victoria Cross, the highest award for gallantry in the face of the enemy that can be awarded to British and Commonwealth forces.

HMAS <i>Sydney</i> (D48) Australian World War II warship

HMAS Sydney, named after the Australian city of Sydney, was one of three modified Leander-class light cruisers operated by the Royal Australian Navy (RAN). Ordered for the Royal Navy as HMS Phaeton, the cruiser was purchased by the Australian government and renamed prior to her 1934 launch.

<span class="mw-page-title-main">Operation Berlin (Atlantic)</span> German commerce raid during the naval battles of the Second World War

Operation Berlin was a raid conducted by the two German Scharnhorst-class battleships against Allied shipping in the North Atlantic between 22 January and 22 March 1941. It formed part of the Battle of the Atlantic during World War II. The Scharnhorst and Gneisenau sailed from Germany, operated across the North Atlantic, sank or captured 22 Allied merchant vessels, and finished their mission by docking in occupied France. The British military sought to locate and attack the German battleships, but failed to damage them.

<span class="mw-page-title-main">Japanese raiders in the Indian Ocean</span>

The Japanese raiders in the Indian Ocean were those vessels used by the Imperial Japanese Navy (IJN) during the Second World War to pursue its war on Allied commerce in that theatre. Possessing a powerful fleet of warships, prior to the start of World War II, the IJN had strategically planned to fight a war of fleet actions, and as a consequence delegated few resources to raiding merchant vessels. Nevertheless, in 1940, two passenger-cargo vessels – Aikoku Maru and Hōkoku Maru – of the Osaka Shipping Line were requisitioned for conversion to armed merchant cruisers (AMC)s, in anticipation of the likely thrust southward by the Japanese. These vessels were subsequently used as merchant raiders attacking Allied commercial shipping along vital sea lanes of communication between Australia and the Middle East. Using their comprehensive armament and speed to their advantage, the raiders experienced a brief period of success. Japanese raiding in the Indian Ocean largely ceased by the end of 1942 after an action with a Dutch vessel, the Ondina and a Royal Indian Navy corvette, HMIS Bengal in which the Hōkoku Maru was sunk.

HMS <i>Turbulent</i> (N98) Submarine of the Royal Navy

HMS Turbulent (N98) was a T-class submarine of the Royal Navy. She was laid down by Vickers Armstrong, Barrow and launched in May 1941.

<span class="mw-page-title-main">Action of 8 May 1941</span>

The action of 8 May 1941 was a single ship action fought during the Second World War by the British heavy cruiser HMS Cornwall and the Kriegsmarine auxiliary cruiser Pinguin/Schiff 33. The engagement took place in the Indian Ocean off the Seychelles archipelago, north of Madagascar. Pinguin caused slight damage to Cornwall, before its fire on Pinguin caused an explosion and sank it.

<span class="mw-page-title-main">Armed boarding steamer</span>

An armed boarding steamer was a merchantman that the British Royal Navy converted to a warship during the First World War. AB steamers or vessels had the role of enforcing wartime blockades by intercepting and boarding foreign vessels. The boarding party would inspect the foreign ship to determine whether to detain the ship and send it into port or permit it to go on its way.

<span class="mw-page-title-main">Action of 4 April 1941</span> Naval battle during the Second World War

The action of 4 April 1941 was a naval engagement fought during the Battle of the Atlantic during the Second World War. A German commerce raider, Thor, encountered the British armed merchant cruiser HMS Voltaire and sank it after a short engagement. The German crew rescued the British survivors, some of whom were repatriated and gave an account to the Admiralty. It was accepted that German commerce raiders were too well-armed for converted ocean liners equipped with obsolete guns but nothing else was available to the Royal Navy until later in the war.

<span class="mw-page-title-main">German commerce raiders in World War I</span>

The German commerce raiders of World War I were surface vessels used by the Imperial German Navy for its Handelskrieg, a campaign against Allied seaborne trade. The ships comprised warships, principally cruisers, stationed in the German colonial empire before the war began, express liners commissioned as auxiliary cruisers and later, freighters outfitted as merchant raiders. These vessels had a number of successes and had a significant effect on Allied naval strategy, particularly in the early months of the war.



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  2. "Carmania I". Archived from the original on 2006-10-20. Retrieved 2006-07-21.
  3. PNTL Fleet Archived 2011-06-14 at the Wayback Machine
  4. "Nuclear fuel ship docks in Japan". BBC . 27 September 1999. Retrieved 2008-08-27.
  5. Brown, Paul (20 January 1999). "Nuclear fuel ships to be armed with heavy guns". The Guardian . Retrieved 2008-08-27.
  6. "UK British nuclear fuel ships armed". BBC . 8 July 1999. Retrieved 2008-08-27.
  7. "Arming Container Ships With Anti-Ship Missiles". StrategyPage. April 14, 2010.
  8. "Somali piracy: Armed guards to protect UK ships". BBC News Online. 30 October 2011.


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