Defense tech firm Epirus has unveiled a new maritime-focused high-power microwave (HPM) weapon, dubbed Leonidas H2O, which was tested in a recent U.S. Navy exercise to assess its effectiveness against small boats and unmanned systems.
During the U.S. Navy’s Advanced Naval Technology Exercise – Coastal Trident (ANTX-CT), the prototype system was used to disable the engines of four commercially available outboard motors ranging from 40 to 90 horsepower. According to the company, the tests were conducted at “record ranges,” albeit at reduced power due to safety and range constraints.
Leonidas H2O is built on Epirus’ existing Leonidas platform, a scalable HPM system designed to disrupt or destroy electronic components using directed energy. Though originally developed with aerial threats in mind, the H2O variant is tailored for maritime environments, targeting small craft, unmanned surface vessels and unmanned aerial vehicles.
The live-fire demonstration was organized by the Naval Surface Warfare Center Port Hueneme Division. Despite operating at around half of its potential power output and with limited waveform configurations, the system was reportedly successful in disabling all test engines.
While Epirus described the event as a significant milestone, independent verification of the system’s performance was not provided. The use of HPM systems to stop vessels has long been an area of interest within the Department of Defense, which has spent considerable resources exploring non-kinetic options for maritime interdiction. However, operational deployment of such systems has remained elusive.
In a statement, Epirus CEO Andy Lowery framed Leonidas H2O as a potential solution to that capability gap.
“The Department of Defense has spent years developing non-kinetic vessel stop solutions, with no operational system deployed to date,” Lowery said. “With Leonidas H2O, we are bringing forth a proven technology with demonstrated effectiveness.”
Brendan Applegate, Principal Investigator for the Coastal Trident program, said the tests contribute to broader Navy efforts to assess and integrate new technologies.
“Epirus’ participation in these experiments helps to facilitate early eyes on leading-edge technologies that are key to enabling the Navy’s mission,” he said.
Leonidas systems rely on solid-state, software-defined architecture and emit non-ionizing radiation, which Epirus says is safe for personnel, fuel and ordnance when managed appropriately. The company has previously promoted the system’s utility in counter-drone operations, emphasizing its ability to engage multiple threats with a theoretically “unlimited magazine.”
