Conquer the Sea - (2) Underwater Weapon: 'The First Human Torpedo'

Italian Human Torpedo Maiale

British human torpedo Chariot,

[Dokgo Uk, Former Senior Researcher at the Defense Science Research Institute] Torpedoes have been the most threatening underwater weapons possessed by navies worldwide since World War I and II. Currently, countries that have independently developed torpedoes include the United States, the United Kingdom, Germany, France, Italy, Sweden, Russia, China, Japan, and Korea. Advanced nations have continuously conducted research and development to improve torpedo performance. Consequently, complex underwater weapon systems utilizing the characteristics of torpedoes have emerged. These underwater weapon systems have been developed to combine the primary functions of other weapon systems with those of torpedoes, enabling more powerful and effective strikes.

▲ Classification by Guidance and Propulsion Methods = Torpedoes can be classified by guidance method into straight-running torpedoes, acoustic homing torpedoes, and wire-guided torpedoes. Straight-running torpedoes travel directly toward the target along a preset trajectory based on the target’s direction and speed. Acoustic homing torpedoes track and attack targets by following sounds or wakes emitted from the target vessel. Wire-guided torpedoes communicate via a wire connecting the launching platform and the torpedo after launch, guiding and controlling the torpedo until it hits the target. Wire-guided torpedoes are mainly applied to submarine-launched torpedoes.

For a torpedo to effectively pursue and attack a target, its speed must be at least 1.5 times faster than the target’s speed. However, as speed increases, propulsion noise also increases, becoming the main noise source underwater and providing an opportunity for the target vessel to detect the torpedo early. Therefore, it is necessary to install propulsion devices that fit within the limited internal space of the torpedo, produce minimal vibration noise, and achieve high-speed propulsion. Such propulsion devices include electric propulsion torpedoes driven by battery-electric motors, engine propulsion torpedoes driven by fuel engines, and rocket propulsion torpedoes propelled by combustion gases of propellants. In Europe, electric propulsion torpedoes are mainly adopted, while the United States develops and operates engine propulsion torpedoes.

▲ Human Torpedoes Controlled Directly by Operators = The world’s first human torpedo, developed to enhance torpedo control performance, was the Maiale operated by the Italian Navy during World War II. At that time, acoustic homing torpedoes capable of detecting and tracking targets had not yet been developed, making it very difficult to directly hit targets with torpedoes. To overcome this, the Maiale, named after a special operation, involved a diver boarding the torpedo, approaching the target vessel, attaching a warhead, and then escaping. Subsequently, Europe developed and operated human torpedoes resembling small semi-submersibles, such as the British Chariot, German Neger and Marder, and Russian Siren.

In Japan, facing a disadvantage in 1944, the navy produced and deployed an extreme human torpedo called Kaiten (回天) to reverse the tide of war. The Kaiten increased hit probability by having a pilot directly steer the torpedo to collide with enemy ships, detonating the torpedo and pilot together. This method, conducted underwater, was similar to the Kamikaze (神風) suicide attacks and inflicted damage on enemy vessels.

▲ Supercavitating Rocket Torpedoes Flying Underwater Like Bullets = When an object moves underwater, it experiences fluid resistance nearly 1,000 times greater than in air. This imposes limits on high-speed propulsion of torpedoes underwater. To overcome this, a gas-filled cavity (supercavitation) is created between the torpedo surface and the fluid, drastically reducing drag and allowing the torpedo to travel as if flying through an air layer underwater. Torpedoes utilizing this supercavitation phenomenon are called high-speed rocket torpedoes or supercavitating rocket torpedoes. The world’s first supercavitating rocket torpedo was the Soviet VA-111 Shkval, deployed in 1977 and still in operation by Russia. This torpedo was designed for use by Russian nuclear submarines, with a diameter of 533 mm, length of 8.2 m, weight of 2,700 kg, range of 7?13 km, warhead of 210 kg, speed exceeding 200 knots (approximately 370 km/h), and is known to be capable of carrying a nuclear warhead.

Iran is reported to have reverse-engineered Russia’s Shkval to develop the high-speed rocket torpedo Hout, which successfully passed tests and has been deployed since 2014. Among Western countries, Germany is one of the leaders in supercavitating rocket torpedo development. Since 1988, Germany has conducted supercavitation research and is developing the Barracuda, a supercavitating rocket torpedo with a speed reaching an astonishing 800 km/h. This torpedo is expected to overcome the Shkval’s limitations in range, improve speed and hit accuracy, and become one of the world’s top high-speed rocket torpedoes.

This content was produced with the assistance of AI translation services.