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.
USS Pensacola (CL/CA-24) was a cruiser of the United States Navy that was in service from 1929 to 1945. She was the lead ship of the Pensacola class, which the Navy classified as light cruisers in 1929, with the Pensacola herself originally designated as "CL-24." Under the terms of the Washington Naval Treaty, from 1931 on the class was re-classified as heavy cruisers, with the Pensacola being re-designated as "CA-24." The third Navy ship to be named after the city of Pensacola, Florida, she was nicknamed the "Grey Ghost" by Tokyo Rose. She received 13 battle stars for her service.
HMS Triumph, originally known as Libertad, was the second of the two Swiftsure-class pre-dreadnought battleships of the Royal Navy. The ship was ordered by the Chilean Navy, but she was purchased by the United Kingdom as part of ending the Argentine–Chilean naval arms race. Triumph was initially assigned to the Home Fleet and Channel Fleets before being transferred to the Mediterranean Fleet in 1909. The ship briefly rejoined the Home Fleet in 1912 before she was transferred abroad to the China Station in 1913. Triumph participated in the hunt for the German East Asia Squadron of Maximilian Graf von Spee and in the campaign against the German colony at Qingdao, China early in World War I. The ship was transferred to the Mediterranean in early 1915 to participate in the Dardanelles Campaign against the Ottoman Empire. She was torpedoed and sunk off Gaba Tepe by the German submarine U-21 on 25 May 1915.
SMS Moltke was the lead ship of the Moltke-class battlecruisers of the German Imperial Navy, named after the 19th-century German Field Marshal Helmuth von Moltke. Commissioned on 30 September 1911, the ship was the second battlecruiser of the Imperial Navy. Moltke, along with her sister ship Goeben, was an enlarged version of the previous German battlecruiser design, Von der Tann, with increased armor protection and two more main guns in an additional turret. Compared to her British rivals—the Indefatigable class—Moltke and her sister Goeben were significantly larger and better armored.
Thor was an auxiliary cruiser of Nazi Germany's Kriegsmarine in World War II, intended for service as a commerce raider. Also known to the Kriegsmarine as Schiff 10; to the Royal Navy she was Raider E. She was named after the Germanic deity Thor.
Naval warfare in the Mediterranean during World War I took place between the naval forces of the Entente and the Central Powers in the Mediterranean Sea between 1914 and 1918.
The Mark 12 5"/38-caliber gun was a United States dual-purpose naval gun, but also installed in single-purpose mounts on a handful of ships. The 38-caliber barrel was a mid-length compromise between the previous United States standard 5"/51 low-angle gun and 5"/25 anti-aircraft gun. United States naval gun terminology indicates the gun fired a projectile 5 inches (127 mm) in diameter, and the barrel was 38 calibers long. The increased barrel length provided greatly improved performance in both anti-aircraft and anti-surface roles compared to the 5"/25 gun. However, except for the barrel length and the use of semi-fixed ammunition, the 5"/38 gun was derived from the 5"/25 gun. Both weapons had power ramming, which enabled rapid fire at high angles against aircraft. The 5"/38 entered service on USS Farragut, commissioned in 1934, the first new destroyer design since the last Clemson was built in 1922. The base ring mount, which improved the effective rate of fire, entered service on USS Porter, commissioned in 1936.
The Raid on Scarborough, Hartlepool and Whitby on 16 December 1914 was an attack by the Imperial German Navy on the British ports of Scarborough, Hartlepool, West Hartlepool and Whitby. The bombardments caused hundreds of civilian casualties and resulted in public outrage in Britain against the German Navy for the raid and the Royal Navy for failing to prevent it.
The Thrasher incident, as it became known in US media, was a political and diplomatic incident in 1915, when the United States was still neutral in World War I. On 28 March 1915 the German U-boat U-28 sank the British steamship Falaba by torpedo, killing more than 100 people. One of the victims was a passenger from the US, Leon Chester Thrasher.
The Shelling of Newcastle was conducted by the Japanese submarine I-21 in the early hours of 8 June 1942. The bombardment followed the attack on Sydney Harbour on 31 May, and was conducted shortly after I-24 shelled the Eastern Suburbs of Sydney. During the attack I-21 fired 34 shells at Newcastle, including eight illumination rounds, but caused little damage. The Australian gunners at Fort Scratchley fired four shells at the submarine, but scored no hits.
Defensively equipped merchant ship (DEMS) was an Admiralty Trade Division programme established in June 1939, to arm 5,500 British merchant ships with an adequate defence against enemy submarines and aircraft. The acronym DEMS was used to describe the ships carrying the guns, the guns aboard the ships, the military personnel manning the guns, and the shore establishment supporting the system. This followed a similar World War I program of defensively armed merchant ships (DAMS).
SM U-21 was a U-boat built for the Imperial German Navy shortly before World War I. The third of four Type U-19-class submarines, these were the first U-boats in German service to be equipped with diesel engines. U-21 was built between 1911 and October 1913 at the Kaiserliche Werft in Danzig. She was armed with four torpedo tubes and a single deck gun; a second gun was added during her career.
The action of 29 February 1916 was a naval engagement fought during the First World War between the United Kingdom and the German Empire. SMS Greif, a German commerce raider, broke out into the North Sea and Admiral Sir John Jellicoe dispatched Royal Navy warships to intercept the raider. Four British vessels intercepted the commerce raider Greif. The armed merchant cruiser RMS Alcantara and Greif fought a brief engagement before British reinforcements arrived when both were severely damaged, both being sunk.
The bombardment of Cherbourg took place on June 25, 1944, during World War II, when ships from the United States Navy and the British Royal Navy attacked German fortifications in and near the city, firing in support of U.S. Army units that were engaged in the Battle of Cherbourg. In doing so, the Allied naval forces engaged in a series of duels with coastal batteries and provided close support to infantry as they fought to gain control of the city. The bombardment was initially scheduled to last just two hours but it was later extended by an hour to support army units attempting to break into Cherbourg's city streets. After the bombardment, German resistance lasted until June 29, when the port was captured by the Allies. Afterwards, the task of clearing the port for use lasted several weeks.
United States Navy operations during World War I began on April 6, 1917, after the formal declaration of war on the German Empire. The United States Navy focused on countering enemy U-boats in the Atlantic Ocean and the Mediterranean Sea while convoying men and supplies to France and Italy. Because of United States's late entry into the war, her capital ships never engaged the German fleet and few decisive submarine actions occurred.
HSwMS Hvalen was a submarine of the Swedish Navy. Constructed in Italy, the submarine sailed the entire way to Sweden for her commissioning unaccompanied. In October 1915 she became involved in a diplomatic incident between neutral Sweden, and Germany, which was then engaged in fighting Britain in the First World War. Following a series of sinkings of German cargo ships and naval vessels in the Baltic Sea by British submarines entering the Baltic through the (Swedish-controlled) Öresund straits, a German warship opened fire on Hvalen killing a crew-member. According to the captain of the Hvalen, she was flying the Swedish naval flag and in Swedish home waters at the time she was fired on. Compensation was later paid to the widow of the crew-member and an apology was issued.
HSwMS Nordenskjöld (12) was a destroyer in the Swedish Navy. Together with the sister ship HSwMS Ehrensköld, she constituted the Ehrensköld class, which, with its size and speed, was a major step in the Swedish destroyer fleet. The ship was launched on 19 June 1926. During the World War II, she participated in the neutrality watch and escorted merchant ships along the Swedish east coast. Especially the ore traffic from Luleå to Germany had to be protected. In the context of the neutrality watch, she therefore participated in the pursuit of Soviet submarines who broke out of the Gulf of Finland in search of merchant ships. Initially, Nordenskjöld had pennant number 12, which was later switched to 2. In 1951–1952, the ship was converted to frigate and then received the pennant number 72. She was decommissioned in 1963 and was sold for scrap the following year.
Soobrazitelny was one of 18 Storozhevoy-class destroyers built for the Soviet Navy during the late 1930s. Although she began construction as a Project 7 Gnevny-class destroyer, Soobrazitelny was completed in 1941 to the modified Project 7U design.
Vice Admiral Hans Viktor Simonsson was a senior Swedish Navy officer. He served as head of the Military Office of the Naval Defence (1933–1938) and as Commanding Admiral of the South Coast Naval District (1938–1942) and of the East Coast Naval District (1942–1945). Simonsson was one of the founders of the Swedish Submarine Service.
The Battle of the Bosporus was a naval engagement during World War I on 10 May [O.S. 27 April] 1915 between the Russian Black Sea Fleet and the German battlecruiser Goeben in the Black Sea, north of the Bosporus, resulting in a tactical victory for the Russians. The battle took place during the main operation of the Black Sea Fleet aimed at shelling the Bosporus fortifications. The action of the Goeben led to the interruption of the operation, but it did not manage to inflict significant damage to the Russian fleet, suffering only minor damage itself.
Sweden 
Germany 
HSwMS Hvalen 
German merchant navy