In an interview with Naval News, Vice President for naval programs at Thales Defense & Security Inc. RADM Tony Lengerich (Ret.) and Vice President for strategy at Advanced Acoustic Concepts (ACC) Mark Bock, gave insights into the CAPTAS-4 Variable Depth Sonar (VDS) systems once destined for the now cancelled Constellation-class of frigates.
Ethan Grossrow story, additional reporting by Xavier Vavasseur
Presently, the first two CAPTAS-4 VDS systems have already been completely manufactured and assembled (with Naval News previously covering the sonar at Sea, Air, Space 2025), and are likely still destined to eventually be fitted to first two frigates, USS Constellation and USS Congress, making up a key part of their ASW systems.
Contacted by Naval News this week, ahead of Sea Air Space 2026, a Thales spokesperson confirmed:
“The 1st and 2nd sets have been delivered to the US, the 3rd and 4th sets are manufactured and ready to be delivered from France, and the production is currently paused to honor production of last 2 systems of the 6 ordered by the Navy”.
The U.S Navy can choose to take ownership over the first 3 set for immediate availability, with definitive conclusions still withheld. However, Thales has made it known that U.S Navy leaders have still expressed interest in variable depth sonars in some capacity during the SNA 2026 conference back in January, with uses in the U.S Navy still identified. Despite this, any possible uses on Navy warships specifically remain in limbo.
“The discussions I’ve had with Navy leadership about ASW suggests that a role for a variable depth sonar continues. How that gets implemented in the surface fleet, whether you think about a grey hull is still up to be determined.”
Vice President for Naval Programs at Thales Tony LengerichIn addition to outright mountings on warships, the system can be fully containerized, fitting completely into 2 40-foot shipping containers. This allows the system to be mounted on any available vessel with the requisite space, with the winch/sonar array fitted into one container, and a command center with 5 seats, waterfall displays, onboard processors, and capable of functioning in
inclement conditions.
Thales has also stated that the containerization of the CAPTAS-4 system can also be automated, allowing the system to be mounted on USVs, with particular interest given to the MUSV family (following the cancellation of the Modular Attack Surface Craft or MASC program) as a potential platform. Thales mounting on the USVs could be fully automated with depth control potentially transmitted to an operator in a different location.
Unmanned mounts presents as the probable route for Thales and ACC to pursue within the bounds of the U.S Navy, with a wide range of uses and platforms available in the unmanned realm.
Meanwhile, Thales’s CAPTAS-4 system continues to prove its worth, with French Navy FREMM frigate Aquitaine recently winning the U.S. Navy’s “Hook’em” award. This is the fourth time the U.S. 6th Fleet awards the price to a CAPTAS-4 VDS-equipped Aquitaine-class frigate for its ability to find and track submarines.
The Production Question
With the U.S. Navy still on contract for 6 systems and only 3 of them full produced and only 2 destined for installation on warships, the question around production of the other 3 systems still remains as their usefulness to the U.S Navy is uncertain. However, Naval News has been told by Thales that if interest once again increases, production can be restarted almost instantaneously, with the facility merely frozen, not fully shuttered.
The ACC facility responsible for production of the CAPTAS-4 sonar arrays in the U.S resides in Uniontown, Pennsylvania, with the facility fully completed and ready for both production and testing. As the cost has already been sunk and construction of the facility finalized, the production of additional CAPTAS systems retains vast potential for rapidly scalable manufacturing of proven sonar systems which could be distributed across many different platforms.
Thales and ACC also believe that the 6 CAPTAS systems under contract could be readily completed upon receiving order for a production restart. The time frame for the production and reception by the U.S Navy regarding these 6 systems is additionally thought to be in time to be delivered before any possible conflict with China.
