Rule the Sea - (4) Underwater Weapon 'Giroe'

The East Sea Fleet of the Chinese People's Liberation Army is loading PMK-2 propelled mines onto a Song-class diesel submarine at Qingdao Port.

[Dokgo Wook, Former Senior Researcher] Representative underwater weapons include torpedoes and naval mines. Torpedoes are offensive weapons and tactical underwater weapons, whereas naval mines have both offensive and defensive operational concepts, serving as tactical and strategic underwater weapons.

Naval mines, as conventional weapons, are relatively easy to deploy among underwater weapons possessed by navies, and their production and operational costs are comparatively low. At the same time, they possess excellent stealth and very powerful explosive force, making them difficult for enemy forces to counter. Therefore, naval mines have characteristics as the most economical and efficient weapon system for conducting maritime control operations in modern naval warfare. Many countries around the world possess various types of naval mines, and military powers are also focusing on securing mine countermeasure capabilities to respond to these mine threats.

▲Origin and War Cases of Naval Mines= Naval mines (Sea mine, Naval mine) are an abbreviation of mechanical naval mines (機械水雷) and can be defined as explosives laid on the seabed, underwater, or on the water surface that detonate upon contact or sensing of a ship, causing damage or sinking the vessel. In 1776, David Bushnell of the United States developed the Keg Mine, which was a wooden barrel filled with explosives designed to move underwater at a certain position following currents using a buoy on the surface and explode upon collision with enemy ships. This is considered the first naval mine closest to the current concept of naval mines. This mine was used against British naval vessels during the American Revolutionary War in 1777, causing significant damage.

During the 19th century, naval mines were not distinguished separately from torpedoes and were called Torpedo until Whitehead developed the self-propelled torpedo, after which the term naval mine (Sea Mine, Naval Mine) came into use. However, until the early 20th century, mines and torpedoes were often collectively called Torpedo. Naval mines began to prominently appear in warfare during the American Civil War (1861?1865). The Confederate Navy, which was inferior in naval power, used mines to sink Union ships that had superior naval strength. During the Civil War, about 30 ships were sunk by mines. Due to this influence, naval mines became a regular feature in major naval battles from the late 19th century onward.

In World War I, approximately 240,000 mines were used over four years. Among them, during the 1918 North Sea Mine Barrage operation, about 70,000 mines were laid over 100 nautical miles, resulting in the sinking of six German U-boats. It is estimated that about 700,000 mines were used in World War II, causing damage to 1,316 Axis ships and 1,118 Allied ships. In various wars after World Wars I and II (Korean War, Vietnam War, Iran/Gulf War, etc.), the number of damages sustained by U.S. Navy ships from mines, guided missiles, torpedoes, and combat aircraft shows that damage from mine attacks was the most frequent.

▲Classification and Types of Naval Mines= Naval mines can be classified according to deployment operations, deployment means, or deployment depth, and there are various types based on detonation and sensing methods. According to deployment operations, there are offensive mines laid in enemy harbors and protective or defensive mines laid in friendly harbors and international waterways. According to deployment means, there are mines for surface ships, submarines, and aircraft. According to deployment depth, there are moored mines connected by wires or chains designed to maintain a certain depth below the surface, bottom mines designed to be laid on the seabed, and drifting mines that move freely with waves and currents without maintaining a fixed depth or position after deployment. Based on detonation methods, there are contact mines that explode when the mine body or its attachments physically contact a ship, influence mines that detonate by sensing magnetic, acoustic, or pressure changes caused by ships without physical contact, and controlled mines that are detonated remotely by controlling the mine’s firing device.

Among these, bottom mines are the most widely operated, and most mines use influence detonation methods triggered by magnetic, acoustic, and pressure sensors. Influence mines, which have been the most commonly used type since World War II, detect changes in physical quantities such as magnetic, acoustic, and pressure fields around the target ship from a distance and detonate accordingly. These mines use one or a combination of these physical changes.

Magnetic influence mines detect changes in the magnetic field caused by ships, as all ships have a certain magnetic field that can alter the Earth's magnetic field direction or intensity. These mines detonate by sensing such magnetic field changes.

Acoustic influence mines detect underwater sounds generated by ships, such as mechanical noise from engines or propellers and fluid noise from water friction, and detonate accordingly. The noise varies greatly depending on the ship’s size, shape, propeller blade design and number, and speed. Acoustic mines analyze the rate of change and magnitude of specific underwater sounds received through hydrophones to determine the presence of a ship and detonate.

Pressure influence mines detect subtle changes in water pressure caused by the continuous flow of water when a ship moves. These changes, expressed as functions of speed and depth, are sensed by precise pressure sensors to trigger detonation. They are designed not to respond to large ocean waves or strong current changes that cause similar pressure variations. However, these mines are almost impossible to sweep, which can limit friendly mine clearance operations. Recently, most mines use a composite sensing method combining two or three sensors among magnetic, acoustic, and pressure sensors to make enemy mine clearance more difficult and improve operational reliability.

▲Development Direction of Naval Mines= Contact mines developed and operated before World War I evolved into influence mines with remote sensing capabilities during World War II, and today’s modern mines are becoming increasingly smart with rapid advances in electronic technology. Intelligent mines equipped with mine counter-countermeasure (MCCM) capabilities and advanced target identification, self-propelled mines launched from submarines to distant target points, gliding mines dropped from aircraft equipped with GPS Guided Bomb (GGB) technology, active homing mines (CAPTOR: enCAPsulated TORpedo) containing torpedoes that detect targets acoustically and pursue and destroy them, and improved versions such as Littoral Sea Mines (LSM) are emerging, showing a trend toward complex weapon systems.

From a technical perspective, development directions can be summarized as increasing deployment depth, diversifying and refining sensing signals to improve detection performance, applying rising warhead technology to increase destructive power, applying stealth technology to enhance MCCM capabilities, and expanding tactical operational concepts for mine and counter-mine warfare.

Although naval mines are not highly complex weapon systems technically, they continue to spread as asymmetric weapons with future potential and utility, and their importance as tactical and strategic weapon systems in naval forces cannot be overlooked.

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