USS G-2 (SS-27) was a G-class submarine of the United States Navy. While the four G-boats were nominally all of a class, they differed enough in significant details that they are sometimes considered to be four unique boats, each in a class by herself. G-2 was named Tuna when her keel was laid down on 20 October 1909 by the Lake Torpedo Boat Company in Bridgeport, Connecticut, making her the first ship of the United States Navy to be named for the tuna, a large, vigorous, spiny-finned fish highly esteemed for sport and food. She was renamed G-2 on 17 November 1911, launched on 10 January 1912 sponsored by Ms. Marjorie F. Miller, towed to the New York Navy Yard after the termination of the Lake contract on 7 November 1913 where she was completed, and commissioned on 1 December 1913.
SM U-151 or SM Unterseeboot 151 was a World War I U-boat of the Imperial German Navy, constructed by Reiherstieg Schiffswerfte & Maschinenfabrik at Hamburg and launched on 4 April 1917. From 1917 until the Armistice in November 1918 she was part of the U-Kreuzer Flotilla, and was responsible for 34 ships sunk (88,395 GRT) and 7 ships damaged.
USS Winchester (SP-156) was an armed yacht that served in the United States Navy as a patrol vessel from 1917 to 1919. Prior to and following World War I, Winchester was a private yacht, later renamed Renard. In World War II, Renard was requisitioned for use in the Royal Canadian Navy as a patrol vessel, keeping her name. She was returned to her owners in 1944.
HMS Sickle was a third-batch S-class submarine built for the Royal Navy during World War II. Completed in 1942, she made her initial war patrol off the Norwegian coast. Sickle then sailed to Gibraltar, from where she conducted one patrol, then to Algiers, French North Africa. From 10 May to 10 October, the boat patrolled the Gulf of Genoa five times and sank a German submarine as well as three minesweepers and an escort ship. She then moved to Beirut, French Lebanon, and conducted two patrols in the Aegean Sea, sinking three caïques and a merchant ship, in addition to landing resistance operatives in Greece.
HMS Sportsman was a third-batch S-class submarine built for the Royal Navy during World War II. Completed in 1942, she spent most of the war serving in the Mediterranean Sea. After an initial patrol off Norway, she sank the heavy transport Général Bonaparte in the Mediterranean in 1943 and missed a French oil tanker. She was heavily damaged after a mistaken attack by an Allied bomber, and was sent east after repairs to participate in operations in the Black Sea. After the operation was cancelled, Sportsman patrolled the Aegean Sea, sending several Greek and German ships to the bottom. She sank the German transport SS Petrella in early 1944 despite it being clearly marked as a prisoner-of-war ship, killing 2,670 out of 3,173 Italians aboard. Sportsman sank several more ships, and suffered minor damage when she was detected and sighted while attempting to attack a convoy.
An armed yacht was a yacht that was armed with weapons and was typically in the service of a navy. The word "yacht" was originally applied to small, fast and agile naval vessels suited to piracy and to employment by navies and coast guards against smugglers and pirates. Vessels of this type were adapted to racing by wealthy owners. The origin of civilian yachts as naval vessels, with their speed and maneuverability, made them useful for adaptation to their original function as patrol vessels. In the United States Navy armed yachts were typically private yachts expropriated for government use in times of war. Armed yachts served as patrol vessels during the Spanish–American War and the World Wars. In the latter conflicts, armed yachts were used as patrol vessels, convoy escorts, and in anti-submarine duties. In the United States, yachts were purchased from their owners with the owners given an option to repurchase their yacht at the close of hostilities.
USS Wakiva II (SP-160), often referred to as USS Wakiva, was an armed yacht that served in the United States Navy from 1917 to 1918 and saw combat in World War I. She was originally the yacht SS Wakiva II built for Lamon V. Harkness in Scotland.
SM U-31 or U-XXXI was a U-27 class U-boat or submarine for the Austro-Hungarian Navy. U-31, built by the Hungarian firm of Ganz Danubius at Fiume, was launched in March 1917 and commissioned in April.
The Viola is a steam trawler built in 1906 at Hull. She is the oldest surviving steam trawler in the world. During her long career, she was known as HMTViola, Kapduen, and Dias. She is currently beached at Grytviken in South Georgia, though there are currently plans afoot to return her to Hull.
USS Remlik (SP-157) was a yacht acquired by the U.S. Navy during World War I. She was converted into an armed patrol craft and assigned to protect ships from German submarines in the North Atlantic Ocean. Post-war she was decommissioned, stripped of naval ordnance and sold in Norfolk, Virginia.
The Atlantic U-boat campaign of World War I was the prolonged naval conflict between German submarines and the Allied navies in Atlantic waters—the seas around the British Isles, the North Sea and the coast of France.
SM U-33 was a German Type U 31 U-boat of the Imperial German Navy.
The first USS Sabalo (SP-225) was a United States Navy patrol vessel in commission from 1917 to 1919. Following World War I, Sabalo was sold to private interests before returning to service as a patrol vessel in World War II, this time with the Royal Canadian Navy, renamed Cougar. Returning to private ownership following the war, the vessel sank in a hurricane in 1950.
SM U-109 was a Type U 93 submarine of the Imperial German Navy in World War I, taking part in the First Battle of the Atlantic. The building contract was confirmed 5 May 1916, and was awarded to Germaniawerft, Kiel. A Type 93 boat, she was launched 25 September 1917 and commissioned 7 November. She was under the command of Otto Ney. On 28 January 1918, she was sunk in the English Channel, possibly by a mine, while diving to avoid ships from the Dover Patrol. She sank no ships.
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.
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.
HMS Pargust was a Royal Navy warship that was active during World War I. She was a Special Service Vessel used by the RN in anti-submarine warfare. Pargust was active in this role during the last two years of the war, and was successful on one occasion, destroying the U-boat UC-29.
The SY Hildegarde and the SY Hiawatha were steam yachts chartered by the Ministry of Agriculture, Fisheries and Food - Directorate of Fisheries, now known as the Centre for Environment, Fisheries and Aquaculture Science (Cefas) between 1912 and 1914 to carry out fishery investigations.
HMCS Lynx was an armed yacht in service with the Royal Canadian Navy (RCN) during World War II. The vessel was built at Newport News Shipbuilding as the yacht Dolphin in 1922. The yacht was sold in 1929, becoming Ramona. In 1940, the RCN acquired the vessel as part of the effort to bolster its patrol forces, armed and renamed the vessel Lynx. However, the vessel suffered a series of mechanical issues and was taken out of service in 1943 and sold for commercial service. Renamed Elena and then Samana Queen the ship was used in the banana boat trade, taking on its final name Rican Star in 1952. The vessel was converted to a fishing trawler in 1959 before sinking on 25 May 1960 off Hummocky Island, Queensland.
HMCS Otter was an armed yacht in service with the Royal Canadian Navy during World War II. Launched in 1921, the vessel was constructed as Nourmahal for Vincent Astor of New York as a pleasure yacht. He sold the vessel in the late 1920s and it was renamed Conseco. The Royal Canadian Navy, finding a lack of suitable vessels in Canadian ownership to be taken into naval service, sent Canadian yacht owners south to the United States to find those vessels. Conseco was acquired and brought north to Halifax, Nova Scotia where the vessel was converted to an armed yacht in 1940. Renamed Otter the ship participated in the Battle of the Atlantic, escorting convoys and patrolling the Canadian coast. On 26 March 1941, Otter suffered a catastrophic fire aboard that sank the armed yacht. Two officers and seventeen ratings died in the incident.
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