USS Dace (SS-247), a Gato-class submarine, was the first submarine of the United States Navy to be named for any of several small North American fresh-water fishes of the carp family.
A midget submarine is any submarine under 150 tons, typically operated by a crew of one or two but sometimes up to 6 or 9, with little or no on-board living accommodation. They normally work with mother ships, from which they are launched and recovered and which provide living accommodation for the crew and support staff.
Human torpedoes or manned torpedoes are a type of diver propulsion vehicle on which the diver rides, generally in a seated position behind a fairing. They were used as secret naval weapons in World War II. The basic concept is still in use.
The X class was a World War II midget submarine class built for the Royal Navy during 1943–44. It was substantially larger than the original Chariot manned torpedo.
The Regia Marina was the navy of the Kingdom of Italy from 1861 to 1946. In 1946, with the birth of the Italian Republic, the Regia Marina changed its name to Marina Militare.
The Decima Flottiglia MAS was an Italian flotilla, with commando frogman unit, of the Regia Marina created during the Fascist regime.
Imperial Japanese Navy submarines originated with the purchase of five Holland type submarines from the United States in 1904. Japanese submarine forces progressively built up strength and expertise, becoming by the beginning of World War II one of the world's most varied and powerful submarine fleets.
The Nazario Sauro class are diesel-electric submarines operated by the Italian Navy. All boats were built by Fincantieri in Monfalcone.
A merchant submarine is a type of submarine intended for trade, and being without armaments, it is not considered a warship like most other types of submarines. The intended use would be blockade running, or to dive under Arctic ice.
Motoscafo armato silurante, commonly abbreviated as MAS was a class of fast torpedo-armed vessels used by the Regia Marina during World War I and World War II. Originally, "MAS" referred to motobarca armata SVAN (armed motorboat SVAN, Società Veneziana Automobili Navali.
The Marconi class was a class of six submarines built for the Royal Italian Navy. The submarines were all launched between 1939 and 1940, and all but one, Luigi Torelli, were lost in the Atlantic during the Second World War.
The Black Sea Campaigns were the operations of the Axis and Soviet naval forces in the Black Sea and its coastal regions during World War II between 1941 and 1944, including in support of the land forces.
Nisshin (日進) was a seaplane tender (AV) of the Imperial Japanese Navy during World War II.
The auxiliary ship Olterra was a 5,000 ton Italian tanker scuttled by her own crew at Algeciras in the Bay of Gibraltar on 10 June 1940, after the entry of Italy in World War II. She was recovered in 1942 by a special unit of the Decima Flottiglia MAS to be used as an undercover base for manned torpedoes in order to attack Allied shipping at Gibraltar.
The CB class was a group of midget submarines built for the Italian Navy during World War II. However, they were also used by several other navies, seeing action in the Mediterranean and in the Black Sea.
Leonardo da Vinci was a Marconi-class submarine of the Italian navy during World War II. It operated in the Atlantic from September 1940 until its loss in May 1943, and became the top scoring non-German submarine of the entire war.
The Italian submarine fleet of World War II was the largest in the world at the time, with 116 submarines. It saw action during the Second World War, serving mainly in the Mediterranean. During the conflict 88 submarines, some two-thirds of its total strength, were lost.
The explosive motorboat MT also known as barchino, was a series of small explosive motor boats developed by the Italian Royal Navy, which was based on its predecessors, the prototype boat MA and the MAT, an airborne prototype. Explosive motorboats were designed to make a silent approach to a moored warship, set a collision course and run into full gear until the last 200 or 100 yards to the target, when the pilot would eject after blocking the rudder. At impact, the hull would be broken amidships by a small explosive charge, sinking the boat and the warhead, which was fitted with a water-pressure fuse set to go off at a depth of one metre. By the end of September 1938 the Navy Department ordered six explosive boats. The one-pilot vessels were built by the companies Baglietto of Varazze and CABI of Milan, which was also to supply the engines. The small vessels were used by the Italian Navy in at least two major operations in the Mediterranean theatre during World War II.
The MTSM motor torpedo boat was a series of small motor torpedo boats developed by the Italian Royal Navy during World War II. The vessel was an improved version of its predecessor, the motor torpedo boat MTS. This was achieved through a larger sea-going hull with reinforced keel and a sharper stem. The MTSM were designed to be towed by larger motorboats into the target area. Once there, the MTSM could carry out a torpedo attack on moored or stationary ships. The boat could also been transported by land on trailers.
Enrico Tazzoli was one of three Calvi-class submarines built for the Regia Marina during the 1930s. Completed in 1936, she played a minor role in the Spanish Civil War of 1936–1939 supporting the Spanish Nationalists. She operated in the Atlantic during the Second World War and was second only to the submarine Leonardo da Vinci as the highest scoring Italian submarine of the conflict. Enrico Tazzoli was converted in 1943 to be a submarine transport for blockade-running between Europe and the Far East. She was lost on her first voyage in this role.
Regia Marina 
