According to Russian media reports, a Russian naval academy has developed a miniature unmanned boat, code-named "marlin". This micro unmanned boat adopts the tactic of "making big with small profits" and can effectively deal with the attacks of enemy light boats and suicide unmanned boats, becoming one of the emerging forces in ship defense operations in recent years.

  Two types of rivers and seas are studied together

  The core design concept of the "marlin" unmanned boat is "small, fast, accurate" and "consumable use". The official has not yet announced its specific performance parameters. According to relevant sources, the length of this type of unmanned boat is no more than 1 meter and the speed can reach dozens of knots. Referring to the classification standards of unmanned surface boats, the "marlin" unmanned boat belongs to the X-class unmanned boat (i.e., a non-standard unmanned boat with a length of less than 3 meters), and is a micro unmanned boat that is "smaller than small" and mainly achieves combat goals through suicide impacts and detonates the target. Due to its small size, a warship can usually carry multiple unmanned boats of this type. In addition, this micro unmanned boat may adopt the same "first-person perspective" remote remote control control method as the FPV drone, which is easy to operate and flexible to use.

  To meet different combat environments, the "marlin" unmanned boats are divided into two types: river type and ocean type. The inland "marlin" unmanned boats usually carry about 1.5 kilograms of explosives, which are mainly used to accurately strike enemy light ships and landing troops.

  The marine "marlin" unmanned boats carry about 2 kilograms of explosives, mainly responsible for surface protection tasks around the fleet, intercepting enemy suicide unmanned boats that threaten warships. By accurately hitting the target and detonating, it can effectively attack enemy unmanned boats and protect the safety of their own ships.

  Three-layer offensive and defensive tactics

  At present, the traditional near-defense gun and missile interception systems used by large and medium-sized ships have problems such as low interception efficiency and cost ratio when intercepting low-cost and clustered unmanned boats. If the three-layer offensive and defensive tactics of micro unmanned boats are used, the ship's safety factor can be greatly improved.

  First, actively intercept attacks. Micro unmanned boats can carry a small amount of explosives, and respond to enemy unmanned boats or floating tools through the "high-speed maneuver-precision impact-self-destruction" mode to quickly eliminate the approaching threat. This suicide attack combat method had already begun to emerge during World War II. On the Pacific battlefield of World War II, the Japanese army dispatched suicide motorboats to attack the US landing craft and destroyer that came to the beach to land. In the current asymmetric combat scenario, this tactic is still of practical value. For example, Turkey used a ULAQ KAMA suicide mini unmanned boat designed for anti-ship combat during the exercise, launching a "reconnaissance-strike-counter" operation against large and medium-sized unmanned boats attacked by the enemy, demonstrating the counterattack and attack combat capabilities of micro unmanned boats under complex sea conditions.

  The second is electronic interference camouflage. After the micro unmanned boat is equipped with an electronic warfare system, it can implement navigation spoofing and communication blocking on enemy unmanned boat clusters. For example, a British company uses unmanned submarines to conduct underwater electronic warfare testing. By simulating the acoustic characteristics of large ships, the unmanned submarine successfully tricked the enemy unmanned boats from the target. This combat method is also suitable for surface combat. The US military once used unmanned boat groups to build distributed electronic warfare networks to interfere with enemy attack formations by releasing false radar signals. The micro-unmanned boats that form an unmanned boat group can not only disrupt enemy operations, but also enable them to approach raids through camouflage, greatly improving tactical abruptness.

  The third is to clear underwater mines. Conventional minesweepers rely on detection tools such as sonar to detect mines and use lightning suppression tools to detonate mines, which takes a long time and poses certain risks. After the micro unmanned boat is equipped with explosives to approach the minefield, it can detonate the mines through impact, and can also use deception methods to attract intelligent mines to approach and detonate them. The combat efficiency and cost-effectiveness are far beyond that of conventional minesweepers. In addition, in mine laying operations, micro unmanned boats have obvious advantages due to their high maneuverability and high concealment. It can quickly and conceal the several mines it carries based on path planning, turn the waterway into a maneuverable minefield, and effectively delay the actions of enemy ships.

  Challenges and opportunities coexist

  Micro unmanned boats have significant advantages in ship defense operations, but their disadvantages are also obvious. Micro unmanned boats can only carry a small amount of explosives. When facing large enemy unmanned boats, they need to rely on precise impacts to achieve strike effects, and the actual combat tolerance rate is low. In addition, the control and communication links of micro unmanned boats have security risks and are easily affected by enemy electromagnetic interference. In a strong electromagnetic confrontation environment, how to ensure the stable control and command transmission of unmanned boats is a question worthy of attention. In addition, the combat adaptability of micro unmanned boats in harsh sea conditions also needs to be tested. Due to the light weight and limited power of the micro unmanned boat, strong winds or storms may affect its heading control accuracy and even lead to out-of-control drifting.

  In the future, micro unmanned boats will evolve towards intelligence, coordination and multifunctionality. First, artificial intelligence empowers independent decision-making. For example, the U.S. military’s “Sea Hunter” unmanned boat uses edge computing to identify and plan the target and path, reducing the delay caused by human intervention. The second is the coordinated operation of "boat-plane". The micro unmanned boats combined with FPV drones to form a cross-domain strike group may become a new tactic of the future battlefield. This matching mode may lead to a "low-fitting version of the mothership combat group" to further improve multi-dimensional attack combat capabilities. The third is modular task expansion. After the micro unmanned boat is equipped with reconnaissance and electronic warfare modules, its mission will no longer be limited to simple offense and defense, but will transform from a single offense and defense platform to a multi-function combat platform.

  It can be seen that the emergence of miniature unmanned boats such as "marlin" shows that ship defense is transforming from traditionally relying mainly on heavy weapons to "low-cost, high-density, and intelligence". In the future, whether micro unmanned boats can play an important role in ship defense combat missions is worthy of continued attention.

[Editor in charge: Gao Qiang]