This company wants to stop underwater drones and even submarines with a whole new form of sonar technology

• August 24, 2026

• Ultra Maritime pairs its Sea Spear passive sonar array with the AN/SSQ-125B active sonobuoy at the US Navy’s Lanternfish 2026 exercise in a bid to detect underwater drones
• While neither sonar type is new, the distributed architecture that links both to Anduril’s Seabed Sentry and the Navy’s command systems generates usable, precise readings for unmanned underwater vehicles
• The chain detects and then alerts operators to the presence of potential hostile naval assets in the vicinity of sensors that work in tandem to generate more reliable information

The threat that keeps modern navies awake at night is no longer a single, quiet submarine that gave regular defenses the slip, but a plethora of cheap drones that come in all shapes and sizes and could target anything from a pier to an undersea cable or a pipeline, for example.

While modern navies use sonar to track larger submarines, small drones are much harder to track reliably, even as Ultra Maritime, a defense tech company, says it has an answer.

The company showed that a pairing of its Sea Spear, a deployable passive sonar array, with the AN/SSQ-125B, its active sonobuoy offering, could, when working in tandem, track unmanned underwater vehicles (UUVs) better.

Existing tech, paired, repurposed and integrated to deliver results

It is important to know that neither of the hardware solutions used, passive sonar arrays or active sonobuoys, is a new creation; they have been deployed for years by the US Navy and many of its counterparts across the world since World War II to detect and track submarines.

The underlying approaches are even older: Passive listening and active pinging are two of the oldest techniques in the business, and both have existed since the First World War.

The intriguing part is the integration at play here and why it is tactically sound: Passive sonar is quiet, and it gives up nothing for the information it collects, including the listener’s position, but it does get a bearing on any potential craft it does detect. Active sonar can then be used to determine range and location; however, for modern naval units, it is a double-edged sword, as it essentially announces one’s presence in the region.

The tech essentially figures out whether anything is worth detecting by leveraging the first, then turns to the second to determine its specific location when needed. The company’s Ocean of Things concept extends that to a mesh of autonomous sensors seeded from crewed and uncrewed platforms.

Ultramarine’s approach allowed it to detect and classify UUVs of various sizes and sophistication in the US Navy’s 2026 Lanternfish exercise. It has also announced that its Sea Spear is working with Anduril’s Seabed Sentry to detect the same.

The timing is excellent for its buyer: defense contractor Lockheed Martin recently agreed to purchase Ultra Maritime from its private equity owner Advent for $3.45 billion, essentially adding it to the former’s Rotary and Mission Systems division.

With navies struggling to identify and stop underwater drones that pose a persistent threat to their operations and defensive capabilities, Ultra Maritime’s two-pronged approach seems like an interesting play to adopt. It combines already-existing scalable seabed infrastructure with a mesh of cheap listening arrays and expendable pinging buoys to get the job done.

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Ultra Maritime pairs its Sea Spear passive sonar array with the AN/SSQ-125B active sonobuoy at the US Navy’s Lanternfish 2026 exercise in a bid to detect underwater drones While neither sonar type is new, the distributed architecture that links both to Anduril’s Seabed Sentry and the Navy’s command systems generates…