On May 14th, the website of the Russian newspaper "Shimbun" reported that we may be witnessing the birth of a new generation of underwater weapons. The large-scale promotion of ultra large (over 10 tons) unmanned underwater vehicles will enable the Navy to have sufficient military equipment to control vast waters in the future. Objectively speaking, they are much cheaper than existing submarines. At the same time, it can also free up submarines and crew to carry out more important tasks. The following is the development of unmanned underwater vehicles in various countries. The US Navy has ordered six Boeing developed "Tiger Whale" ultra large unmanned underwater vehicles with the following performance parameters: 26 meters in length, a displacement of about 80 tons, a range of about 6500 nautical miles, a maximum speed of 8 knots, and self-sustaining power for several months. The notable feature of this equipment is its modular payload, which can perform various tasks. That is to say, "killer whales" with different payloads can perform a series of tasks such as mine laying, anti submarine and anti ship operations, reconnaissance, and others. In the near future, they plan to use this unmanned underwater vehicle to practice group actions of robot systems. It is speculated that Northrop Grumman's "Devil Fish" unmanned submersible is also a modular equipment that can be paired with multiple payloads. The most famous ultra large unmanned underwater vehicle in Russia may be the Poseidon. The mission of this "apocalyptic weapon" is to reach US territory and carry out a nuclear attack. Poseidon weighs about 100 tons, is 25 meters long, has a maximum submergence depth of 1000 meters, and a speed of 60-70 knots. It is not difficult to speculate that it can carry different loads. The power device enables it to engage in long-term underwater combat. Another little-known unmanned underwater vehicle project is the "cephalopod class" suspected of being used to strike enemy submarines. In May of this year, China exhibited the UUV-300CB unmanned underwater vehicle at the Asian Defense Exhibition held in Malaysia. It is 11.5 meters long, 1.6 meters in diameter, weighs 50 tons, has a maximum speed of 12 knots, a maximum diving depth of 300 meters, and a range of 450 nautical miles. Another version equipped with torpedo tubes, the UUV-300CD, also appeared at the same time. South Korea showcased a combat unmanned underwater vehicle (with a displacement of 60 tons and a length of 23 meters) developed by Hanhua Marine Company at the 2023 Abu Dhabi International Maritime Defense Exhibition. It is equipped with an air propulsion system and lithium-ion battery that does not rely on it, and can operate underwater for a long time. Two torpedoes and shipborne sonar enable it to strike both surface and underwater enemies. In early May, the Japan Defense Equipment Agency and Mitsubishi Corporation showcased a 10 meter long endurance underwater vehicle. It is reported that this equipment can navigate underwater at a speed of 10 knots for a full week. In addition, North Korea, India, the United Kingdom, and Australia are also developing ultra large underwater unmanned equipment. (Lai Xin She)