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June 23, 2025: A Chinese firm recently announced the UUV-300 series of Artificial Intelligence/AI controlled unmanned submarines. Described as a research vehicle, it is mainly used for purely military activities. The Chinese are trying to catch up with the Americans in this area. The American navy began developing and using underwater drones in the 1950s. These devices also had commercial applications and civilian versions were developed which found many eager customers. The Remus line of drones was particularly popular. China is trying to catch up in this area and do it quickly to support their new navy, which will be the largest on the planet by the end of the decade.

Meanwhile the U.S. Navy believes robotic subs carrying mobile mines would be an effective new ASW asset because the U.S. is already developing some of the new ASW technology needed for this. This includes Unmanned Underwater Vessels/UUVs and mobile mines. Over a decade ago the navy adopted civilian underwater UUVs used for monitoring the oceans and has been using them to do that as well as collect data useful for wartime submarine operations. With a growing number of civilian and military customers, American UUV developers and manufacturers have been coming up with new ocean research UUVs that also have military applications. The latest example of this is the new class of XLUUVs with the ability to go deeper, carry a cargo bay for other research gear to be stored and deployed from, and operate autonomously for up to six months. The first of these XLUUVs was the Echo Voyager, which Boeing developed from a research project and had the first one ready for testing in 2016. The tests were successful and have involved more complex and completely autonomous operations. In 2019 the navy ordered four militarized Orca versions of the Echo Voyager for $11 million each.

Both models are 16 meter long diesel-electric powered autonomous subs with a payload compartment 9.1 meters long and 2.6 meters in diameter wholly inside the pressure hull. Propulsion is by battery powered electric motors and diesel generators to recharge the batteries when on or near the surface. This XLUUV has no topside sail and can stay underwater for days at a time because there is no crew on board to sustain. While submerged these UUVs can move at 14 kilometers an hour and have sufficient generator fuel to travel 12,000 kilometers.

The main difference between Echo Voyager and Orca is that Echo Voyager is built to dive to 3,400 meter depths. Orca does without that but adds additional passive sensors and signal processing computers to detect other submarines or surface ships. There is also an underwater communications system for arming the dozen Hammerhead mobile mines Orca can place on the ocean floor in areas like the South China Sea. These Hammerhead bottom mines carry a Mk 54 lightweight torpedo which is normally carried by ASW helicopters and aircraft. Mk 54 has a range of ten kilometers and a guidance system that is regularly updated. Hammerhead is being used in a similar fashion to a larger version of this used during the Cold War that deployed a larger Mk 48 torpedo. Hammerhead is an encapsulated system equipped with passive sensors to detect and identify submarines and surface ships and attack specific types of targets, like diesel-electric subs larger than Orca.

China is seeking to augment its current submarine fleet with these automated unmanned submersibles. Fifteen years ago China had 62 submarines. There were 53 diesel-electric submarines, six nuclear submarines, and three nuclear ballistic missile submarines. Back then the U.S. had 72 submarines, all nuclear, including 18 ballistic missile submarines, each carrying 20 missiles.

Currently China has 60 more modern submarines with more on the way. The sub fleet includes six Type 094 nuclear powered SSBNs, with two more planned. This ballistic missile carrying boat is 135 meters long and 13 meters wide with a top speed of 54 kilometers an hour. Maximum operating depth is 400 meters and the crew of 140 can stay submerged for several months, or until food and other crew supplies run out. Each Type 094 carries twelve solid-fuel JL-2 or JL-3 ballistic missiles.

There are also six nuclear powered attack submarines similar to the American Virginias. Most Chinese subs are still diesel electric, with 48 of these currently in service. About half of them have been modified to include Air-Independent Propulsion/AIP that allows these boats to remain underwater for several weeks at a time.