Nearly a month ago, we reported on a uniquely configured vessel that was far along in its construction at Hudong-Zhonghua Shipyard on Changxing Island in Shanghai. The intentions behind this design appeared to be as an uncrewed underwater vehicle (UUV) mothership, capable of deploying a handful of very large vehicles or many more smaller ones via its stern garage door and well deck. Its large pylons would be used to lift the vessels up and down out of the water and to different levels in the ship. Now it appears China has not just one, but two of these vessels nearly complete.

Make sure to read our initial report on this vessel configuration for full context by clicking here.

The new image was taken in Guangzhou and the vessel has a near identical shape, but with smaller proportions and minor changes to its overall moldline, compared to the larger one in Shanghai. This new vessel appears to be about a third smaller overall than its counterpart. The lift towers number six in total instead of six larger ones and six smaller ones on the Shanghai vessel. Regardless, the major design features are all there, including the flight deck and hangar behind the forward superstructure, the location of the smokestacks, and so on.

While two of these assets could still be considered largely intended for experimental use, a growing fleet would have increasing tactical and even strategic importance. Being able to easily launch and recover large numbers of UUVs, or a few very large ones, far from Chinese shores would provide an asymmetric capability. A fleet of ships that is dedicated to deploying, recovering, and tending to these systems, some of which can remain on patrol for very long periods, would be a major indication of how important China sees UUV operations as part of its future strategy.

There have been rumors that these vessels are part of a larger overall program that will see more ships with similar capabilities constructed. Once again, this would be a strong indication that these vessels’ utility will go beyond testing and limited operational use cases. The launch and recovery of large UUVs remains a conceptual work in progress for the U.S., with nothing similar in the U.S. Navy’s inventory, as we discussed in our original post.

Large long-range UUVs can be used for many tasks, from mapping the sea floor to hunting submarines and ships to searching for mines to launching cruise missiles and drones to being turned into immensely destructive weapons in their own right that can circumvent traditional strategic defenses. For China, providing a credible threat to America’s outposts deep in the Pacific and even the U.S. seaboard would be on the table.

There is speculation online as to where exactly this vessel was built. The first place that came to mind is Guangzhou Shipyard International’s (GSI) facilities on Longxue Island, just southeast of the city of Guangzhou. GSI is a subsidiary of the China State Shipbuilding Corporation (CSSC). It is here that many of China’s most unique vessels are born. These include drone test ships of various kinds, massive beach landing barges, and giant supply ships. Upon closer review of archival satellite imagery, we can say for certain that GSI did build this ship. An image from October 2nd shows it peeking out of a covered graving yard area at the facility prior to launch.

The emergence of two of these large UUV tenders in such a short period of time underscores China’s major bet on the technologies they will support. If more ships are added to the currently known fleet of two, a clearer picture of the People’s Liberation Army Navy’s large UUV plans, and its expeditionary potential, will come into focus.

Contact the author: Tyler@twz.com

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For the past six months or so, a curious-looking vessel with a very boxy superstructure has been taking shape at a shipyard in the Chinese city of Shanghai. A new satellite image lends credence to an earlier assessment that this is a mothership to support China’s growing fleets of ever-larger submersible drones, though it could also have other roles.

TWZ obtained the image of the ship in question, which was taken on September 10, from Vantor. Since then, it has also received an overall coat of gray paint, pointing to future service with the People’s Liberation Army Navy (PLAN). It is some 669 feet (204 meters) long and around 98 feet (30 meters) at its widest. In terms of basic length and width, the vessel being built now is very roughly comparable to China’s Type 071 amphibious warfare ship. However, it appears to be much taller overall than the Type 071.

The new ship has been under construction at the Hudong-Zhonghua Shipyard on Changxing Island in Shanghai since at least April. This yard produces a variety of naval vessels, including surface combatants and amphibious assault ships, as well as commercial designs.

The September 10 image, which shows the ship from the stern, is interesting for a number of reasons. It notably confirms that the design not only has a well deck, but that it is sized around what looks to be a large cradle-like platform visible in the shot. The very roughly 164-feet (50-meter) long rectangular platform has an arch-shaped structure at one end and two teardrop-shaped ones at the other, as well as six pillars, three on each side, in between. The teardrop-shaped structures, in particular, point to the platform being at least a semi-submersible, as they would help with stability and otherwise guide the flow of water while being pulled along.

The satellite image also clearly shows six large struts extending from the top of the stern end of the superstructure, each one which is paired with a shorter strut, for a total of 12. Earlier this month, independent naval analyst H.I. Sutton, who tracks undersea warfare developments in particular, posited that these struts could be used to lower a platform or some other similar structure below the hull of the ship. He also assessed that they could be used as part of a larger system capable of moving payloads between decks internally. This would help account for the configuration of the core superstructure, especially how high it is all the way from the front to the back. Overall, signs point to the inside of the superstructure being largely hangars and other open work spaces, allowing for multiple large UUVs to be carried and supported. Individual UUVs would be launched and recovered, one at a time, via the cradle.

In making his assessment, Sutton drew specific attention to a previously shown rendering of a proposed Chinese scientific research vessel with a roughly similar strut-based system at the stern for deploying submersibles and other large payloads. However, on that design, the system was entirely exposed rather than contained with an extended superstructure.

The platform seen immediately behind the ship being built at the Hudong-Zhonghua Shipyard aligns with Sutton’s assessment about the purpose of the struts. At the same time, launches and recoveries could also be conducted in a more traditional manner via the well deck. The design of the cradle-like platform would seem to suggest the latter option is at least part of the plan.

The general idea of launching and recovering payloads through the bottom of the hull of a ship, including through moon pools, is hardly new. As another point here, Russia is known to have highly specialized mothership submarines that can carry crewed midget submarines and large uncrewed submersibles attached underneath their hulls, and that are also capable of launching ultra-long-range nuclear-powered and nuclear-armed torpedoes. The idea of deploying and retrieving large UUVs via well decks using cradle-like systems is something being explored by other navies globally, including in the United States. All that being said, a large specialized ship built for the purpose of launching and recovering very large underwater vehicles in an operational capacity is unique.

The image from September 10, as well as other recent views of the ship, highlight other features that are now taking shape. This includes a large opening on the starboard side, which could be for launching and/or recovering lifeboats or other watercraft, or moving payloads to and from the pier while docked, as well as a multi-pronged mast on top of the bridge. An additional part of the ship’s superstructure extends behind the bridge area, and there is what looks to be a hangar inside. There is no attached helipad present now, but one could well be added later on somewhere on top of the superstructure. Many naval auxiliaries, as well as commercial ships designed for offshore support and other specialized tasks, have open helipads on raised frames attached to different parts of the superstructures.

Though there is growing clarity about the ship’s design, many questions do remain about the full breadth of its intended purpose. In Sutton’s view, the PLAN has a need, just in general, for a dedicated mothership to support its growing uncrewed underwater vehicle (UUV) fleets. The PLAN is pursuing various tiers of UUVs to perform a host of different missions, including intelligence, surveillance, and reconnaissance (ISR), as well as mine-laying, special operations support, and even launching direct attacks on enemy vessels. Larger and larger UUV designs have been steadily emerging in China, which could require more specialized launch and recovery options to be feasibly employed operationally, especially from other vessels at sea. Deployment and retrieval at sea could, in turn, support very long duration missions far from China’s own shores.

“With smaller UUVs, even up to 20 meters like the AJX-002 and HSU-100 paraded in Beijing last year, they are road mobile. Truck mounted cranes should be sufficient for getting them in and out of the water making operations much simpler. With these latest, much larger XXLUUVs [extra-extra large uncrewed underwater vehicles] however, China will start to need dedicated port facilities,” Sutton wrote previously on his website. “Until now China has been using floating docks to house the two XXLUUV prototypes being tested on Hainan. One of these docks was purpose built while the other may have been taken up from general use.”

China's naval unmanned systems.

Consisting of (in order), AI enabled unmanned submersible (HSU-100), used for detection and attack.

Unmanned patrol boat.

Unmanned mine-laying/attack submersible (AJX-002), this was previously mistaken for a nuclear powered torpedo.
Because the… pic.twitter.com/Mlj55XLNBH

— Zhao DaShuai 东北进修 (@zhao_dashuai) September 3, 2025

“This arrangement also has a significant drawback: each floating dock can only carry a single XXLUUV,” Sutton added. “Or if more than one, then they both need to be placed in the water at the same time. Because the whole dock floods, there cannot be one undergoing maintenance while another is being launched or recovered.”

A mothership vessel able to discreetly deploy and recover large uncrewed and crewed submersibles and other large payloads underwater could be tasked with more specialized missions, including cutting cables, retrieving objects from the seabed, and other kinds of undersea espionage. There is overlap here with more benign roles, such as submarine rescue, salvage, and even deep-sea scientific research. There is also the matter of servicing an expanding array of Chinese underwater infrastructure, including sensor and communications networks. As something of a corollary, Russia’s spy ship Yantar is officially described as an oceanic research vessel. In China, the line between military and non-military assets and capabilities, including ships, is often very blurry, to begin with, as TWZ regularly highlights. This dichotomy was observed right at the Hudong-Zhonghua Shipyard around the end of last year after pictures of a commercial cargo ship being used to showcase a new family of containerized weapons, sensors, and other systems went viral online.

It is also worth pointing out that the boxy and largely enclosed design of the ship now being built at Hudong-Zhonghua Shipyard will inherently make it difficult to observe any activities onboard. This will have the additional knock-on effect of helping keep any payloads, as well as the crew, shielded from the elements. This could be valuable for operations in harsher locales, including waters in and around the Arctic, an ever-more strategic part of the world where China is working to be more engaged.

We also do not know if the apparent mothership vessel is intended to be a one-off or part of a larger class. It could be a stepping stone to broader plans or be part of an already extensive fleet of bespoke naval auxiliaries, as well as unique ostensibly commercial vessels, in service in China today. The PLAN’s aforementioned UUV ambitions will bring along significant test and evaluation requirements, as well as the need to support actual future operations.

If nothing else, evidence is only growing that the new ship under construction at the Hudong-Zhonghua Shipyard is intended to serve, at least in part, as a mothership for large submersible drones.

Contact the author: joe@twz.com

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A British Excalibur uncrewed underwater vehicle (UUV) has fired a U.S. Mk 48 heavyweight torpedo in what is said to be a first-of-its-kind test for both countries. Though just a proof-of-concept so far, this is a significant new step for the United States and the United Kingdom toward future operational fleets of armed UUVs.

The U.S. Navy and the Royal Navy conducted the armed UUV test at the British Underwater Test & Evaluation Center (BUTEC), a maritime test range in Scotland, on September 13. Personnel from the Pentagon’s Defense Innovation Unit (DIU) and the Naval Undersea Warfare Center Keyport Division (NUWC Keyport), as well as unspecified industry partners, also took part, per a U.S. Navy press release.

U.S. NAVY UPDATE: U.S. Navy and Royal Navy Successfully Test Fire Torpedo from Unmanned Undersea Vehicle

WASHINGTON – On September 13, 2026, the U.S. Navy and the Royal Navy successfully conducted the proof-of-concept launch of an exercise U.S. Mk 48 Heavyweight Torpedo… pic.twitter.com/lVB4wYSwC0

— Office of the Chief of Naval Operations (@USNavyCNO) September 22, 2026

The test was also carried out under the umbrella of Pillar 2 of the trilateral Australia-United Kingdom-United States (AUKUS) defense cooperation agreement, which was first announced in 2021. AUKUS’ Pillar 2 covers a wide range of advanced technology cooperation, with particular focus on uncrewed platforms and autonomy. Pillar 1 of the agreement centers on support for Australia’s establishment of a nuclear submarine force.

For the September 13 test, the Mk 48 torpedo was slung under the Excalibur UUV. The nearly 40-foot (12-meter) long, 19-metric-ton submersible drone has a large internal payload bay, but it is reportedly not large enough to accommodate the Mk 48, which is the standard heavyweight torpedo in U.S. Navy service today. The 19-foot-long, 21-inch-diameter weapon has been successively upgraded over the years to expand its capabilities and improve its resistance to enemy countermeasures.

The Royal Navy officially unveiled Excalibur, which was developed by U.K.-based MSubs under Project Cetus, last year. The external torpedo launch capability was the result of two additional efforts, called Project Broadsword and Trial Iron, according to the U.S. Navy release.

The September 13 test “successfully validated the mechanical, electrical, and software integration of a U.S. kinetic payload onto an allied autonomous vessel, proving that allied forces can rapidly achieve weapon interchangeability,” the Navy’s release adds. “Approved in February 2026 by the Department of the Navy Rapid Capabilities Office (DONRCO), the project was executed in less than seven months.”

How the Excalibur UUV was controlled during the test and whether the torpedo was launched at a test target of some kind are unknown. TWZ has reached out for more information.

“BROADSWORD is a great example of how AUKUS Pillar II drives interoperability in across the alliance. Demonstrating the launch of a US torpedo from a UK extra-large unmanned underwater vehicle (XLUUV) is an important early step in developing lethality in our undersea autonomous systems,” U.S. Navy Vice Adm. Robert Gaucher, Director of Submarine Programs, did say in a statement. “We look forward to continuing to leverage the AUKUS partnership to keep pushing the potential warfighting advantages of unmanned undersea systems.”

“This successful test marks a historic first for allied undersea warfare,” U.S. Navy Adm. Daryl Caudle, Chief of Naval Operations, also said in a statement. “Proving that we can seamlessly launch a U.S. heavyweight torpedo from a Royal Navy autonomous underwater vehicle validates our shared vision for true interchangeability.

“This is a really important moment in our journey towards building a hybrid navy, which is where the Royal Navy will sail with crewed ships and submarines alongside uncrewed and autonomous vessels,” Luke Pollard, U.K. Minister of State for Defence Readiness and Industry, separately said in an interview with LBC radio. “It is a substantial increase in our lethality, to show that torpedoes can be fired not just by the Astute class hunter-killer submarines that we have in the Royal Navy, but also now by our uncrewed systems.”

The U.S. Navy and the Royal Navy employ various tiers of UUVs operationally today, but primarily for mine-sweeping and reconnaissance and surveillance missions. Future fleets of submersible drones capable of carrying out attacks on other vessels will create entirely new operational possibilities. Operated closely together with crewed surface warships and submarines, torpedo-toting UUVs could be sent ahead into riskier environments and offer an immediate option for engaging any threats they might find. Even a bigger UUV like Excalibur would also be more challenging for opponents to spot and track than a traditional attack submarine.

Excalibur is also in a category of larger and more capable submersible drones that offer significant endurance and higher degrees of autonomy. Adding in the ability to launch torpedoes, in turn, then opens the door to new concepts for employing these UUVs in groups more independently of crewed companions. In the future, for instance, armed Excaliburs or similar UUVs might be deployed to a particular maritime choke point to not just monitor for enemy movements, but actively hold them at risk.

In addition, in general, UUVs offer a way to expand total undersea warfare capacity in a more cost-effective manner compared to acquiring and fielding more traditional submarines. The ability to have more presence below the waves at a lower price point also translates to more persistence across large areas, something that could be especially valuable across the broad expanses of the Pacific, as well as other bodies of water globally. This presents additional targeting challenges and uncertainty for opponents.

“In securing the North Atlantic, especially against those nations that wish to do us harm, like Russia, the ability for us to now say it’s not just where our submarines are that you need to worry about – it is about how we create greater deterrence and question marks in the eyes of our adversary, with uncrewed systems there as well,” U.K. Minister Pollard said in speaking with LBC.

Pollard’s remarks here speak to particular considerations the British government is faced with just in its backyard. This includes the so-called Greenland-Iceland-United Kingdom (GIUK) Gap, which is the main path through which Russian Navy submarines transit to and from bases in the northwestern end of that country and the Atlantic proper. There is also the English Channel and the nearby Baltic Sea. The Royal Navy has limited capacity with its crewed submarines to monitor this and other critical regional chokepoints. UUVs could then help take pressure off its fleet of just five (of a planned seven) Astute class submarines, helping free those boats up for the myriad other missions they are tasked with, including carrier escort and special operations support.

“By converting commercial and allied uncrewed undersea hulls into high-end strike assets, the partnership drastically alters the cost-exchange ratio in contested maritime environments,” the U.S. Navy’s press release today notes, as well.

There are still many questions still to be answered about future larger UUV operations, including just how they will be deployed and recovered. Video the U.S. Navy released today shows that the torpedo-armed Excalibur was launched into the water in Scotland using a commercial truck-mounted crane. U.S. shipbuilders Huntington Ingalls Industries (HII) and General Dynamics National Steel and Shipbuilding Company (NASSCO), among others, have been working on new options for launching and retrieving larger drone submersibles from surface warships. External carriage on the hulls of ships and/or submarines might also be an option in the future.

Additional torpedo and other munition options for UUVs beyond the full-size Mk 48 could also be on the horizon. The U.S. Navy has invested heavily in compact and lightweight torpedo designs that could be well suited for employment from underwater drones like Excalibur.

The U.S. Navy says it is working with its international partners on another similar UUV capability demonstration, but this time involving an Anduril Dive-XL, under what is dubbed Project Cutlass. This effort “will tackle advanced payload integration data, command and control architectures, and tactical employment scenarios to further mature uncrewed undersea capabilities,” according to the U.S. Navy’s release.

The Royal Australian Navy is already in the process of acquiring and fielding a militarized version of the Dive-XL, called Ghost Shark. It’s also worth noting that the Dive-XL evolved from the earlier Dive-LD design. The Dive-LD is in at least limited operational U.S. Navy service now, a fact that was revealed by Iran’s capture of one of these submersible drones earlier this month, as you can read more about here.

The U.S. Navy is also continuing to push ahead with plans to field a force of Orca XLUUVs from Boeing. In August, the service announced that an Orca had conducted a 1,000-nautical-mile transit in the Pacific the preceding month as part of the ongoing development of that design.

Other countries are pursuing larger UUVs, as well. China has been making strides in this regard and is in some ways ahead of other competitors globally.

Excalibur’s ability to launch a standard Mk 48 heavyweight torpedo is already an important show of progress now toward a shared goal of a future underwater ecosystem that includes submersible drones that are able to attack other vessels.

Contact the author: joe@twz.com

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