Own the water column.
Leave no cable behind.
SepcoTech fields Hydromea — the Swiss developer of ExRay, the wireless underwater inspection drone, and LUMA optical wireless communications. Built for navies, coast guards, marine police and the operators guarding submerged critical infrastructure: a man-portable drone that flies free of a tether over a light link, and a comms family whose optical signal carries no acoustic signature to give the operation away.
The threat moved underwater. Surveillance has to follow it.
Since the Nord Stream explosions of 2022 and the run of severed Baltic cables and pipelines that followed, protecting critical undersea infrastructure has become a front-rank NATO and allied priority — and the seabed is exactly where sensors, divers and conventional ROVs struggle most.
Cables & Pipelines Exposed
The power, data and gas that nations run on cross the seabed largely unwatched. A single cut or emplaced device can disrupt a region — and attribution is hard once the vessel has sailed.
Threats Ride the Hull
A limpet mine, a contraband package or a tracking device clamped below the waterline is invisible from the deck and slow to find by diver — on a warship, a merchant vessel or a suspect boarding.
The Comms Gap
Down at the seabed, radio does not travel and acoustic links are slow and easy to detect. Uncrewed vehicles lose the high-bandwidth, hard-to-intercept link they need to be useful.
NATO stood up Baltic Sentry in January 2025 to step up patrols and safeguard critical undersea infrastructure, committing uncrewed systems to watch the seabed across the Baltic.
— NATO Allied Maritime Command, Baltic Sentry announcement, January 2025Baltic Sentry, Task Force X and NATO's REPMUS / Dynamic Messenger experiments are cited here as the operational context our customers work in. They are not Hydromea programmes and no Hydromea participation is implied. Hydromea's verified defence link is the 2026 AUKUS Maritime Innovation Challenge project described under Proof & Record.
Get eyes on the target. Keep the link off the acoustic band.
Hydromea answers the underwater problem with two complementary technologies. ExRay is a wireless inspection drone whose detachable FLYOUT works free of a cable of its own, flying a hull or a subsea structure where a trailing umbilical snags, fouls and signals the surface. LUMA carries the control, telemetry and live HD video on a beam of light — a directional, low-power, encryptable optical link that radiates no acoustic signature for a sonar to hear. Together they give a single operator underwater domain awareness that a tethered, acoustically-noisy system cannot.
One platform. The full underwater-security mission.
The same wireless ExRay vehicle and LUMA link, configured for the threat at hand — from naval hull search to the surveillance of subsea critical infrastructure, to covert undersea communications.
ExRay for Defence
Covert hull search for limpet mines, contraband and tampering; harbour and anchorage security; confined-space inspection inside ships and infrastructure. No tether means no snag risk, no surface signature and access to spaces divers cannot safely reach.
Explore ExRay Defence →
ExRay for Infrastructure Security
Routine and on-alert inspection of pipelines, subsea cables, offshore energy platforms and port structures — detecting damage, interference and emplaced threats before they become incidents. Repeatable, wireless inspection of the assets that matter most.
Explore Infrastructure Security →
LUMA Optical Comms
High-bandwidth wireless data between divers, AUVs and seabed sensors on a beam of light — directional, low-power and inherently low-probability-of-intercept, with an encryption option. The optical technology selected for a 2026 AUKUS undersea-comms project.
See LUMA covert comms →Built for the people who work the waterline
ExRay and LUMA are matched to the operators whose mission runs below the surface — selected for the task, not adapted from consumer kit.
Hydromea markets ExRay and LUMA for the inspection of military vessels, submarines and underwater infrastructure and for the security of ports and submerged critical assets. Coast-guard, police, EOD, interdiction and search-and-recovery tasks are shown as representative applications the platform is suited to — matched to your requirement on request.
A free-flying drone, talking through light
In flyout mode, control, telemetry and live video travel over the LUMA optical underwater modem — the light-based technology that lets ExRay work wirelessly, up to about 30 m beyond its relay ROV.
Deploy
One operator hand-launches the sub-10 kg vehicle from a quay, RHIB or shoreline — no crane, no winch, no heavy umbilical spread to manage.
Fly
Six degrees of freedom let ExRay hover, hold station and manoeuvre into confined voids and tight structure that rule out conventional ROVs.
Link
The LUMA optical modem streams full-HD video and commands wirelessly between the flyout and its relay ROV at low latency — light, not a trailing cable.
Document
The NAVIA interface logs geo-tagged points of interest and FHD video with 4K stills, producing a structured inspection record on the spot.
Why the missing cable changes everything
A tether is the single biggest limitation on where an inspection vehicle can go and how quietly it can work. Detach the flyout and the vehicle moves freely around a hull, into a flooded compartment or along a pipeline without snagging, fouling thrusters or telegraphing the operation from the surface.
ExRay's wireless FLYOUT links to its relay ROV over the LUMA optical light link, reaching up to about 30 m beyond the tether. Control and live video run on light, so the operator keeps a real-time picture while the flyout works free of any cable of its own.
See defence missions →Move the data on light — not on a signal the enemy can hear
Acoustic modems are the default for underwater comms, but every ping is an omnidirectional emission a hostile sensor can detect, classify and localise. LUMA moves the data on a directional beam of blue-green light instead: low-power, line-of-sight, and inherently low probability of intercept, with an encryption option for the link itself.
That makes LUMA the natural high-bandwidth layer for tactical undersea work — passing HD video and sensor data between divers, AUVs and seabed nodes at short range without lighting up the acoustic band. Six models span a simple serial link replacement (LUMA 100 / 250LP / 500ER) through 10 Mbit/s Ethernet with mesh networking (LUMA X / X-UV) to the compact LUMA flex — all rated to 6,000 m depth.
See the AUKUS project →
Carried in one hand. In the water in minutes.
At just under 10 kg and only 13.4 cm wide, ExRay travels in a case and launches by hand — a single operator can survey a hull or a harbour without a vessel, crane or dive team standing by.
Credentials that stand up to scrutiny
Every claim below is sourced and stated as it stands — no invented contracts, no borrowed programmes.
AUKUS Maritime Innovation Challenge — 2026
Hydromea's LUMA optical-comms technology was selected as the optical layer in a ~US$1M AUKUS Maritime Innovation Challenge project, led by Florida Atlantic University and backed by the US Defense Innovation Unit (DIU), UK DASA and Australia's ASCA — building a hybrid acoustic-plus-optical system for command-and-control in contested and congested undersea environments.
Sources: FAU College of Engineering; Marine Technology News; startupticker.ch (June 2026). Award to FAU with Hydromea as technology partner.DNV Class Approval — ExRay, 2023
ExRay holds DNV class approval for the Visual Remote Inspection Technique (RIT), enabling certified inspection of flooded spaces on offshore floating structures such as FPSO ballast-water tanks — secured via Hydromea's partner Air Control Entech (ACE) in June 2023.
Sources: Hydromea; ECO Magazine; Sea Technology (June 2023). An offshore-energy class approval for visual/NDT inspection — not a defence certification.Swiss-Engineered · EPFL Spin-Off
Hydromea SA is a Swiss company and EPFL spin-off, designing and building ExRay and the LUMA optical-modem family in Renens, near Lausanne. The technology is developed and manufactured in Switzerland.
Sources: Hydromea SA (hydromea.com); Swiss commercial register (CHE-475.622.854).SepcoTech does not claim any named navy, coast-guard or police procurement contract for Hydromea; none is published. The AUKUS project is a research-and-demonstration award with Hydromea as technology partner, not an operational contract. Specifications are stated to Hydromea's own published figures.
From ship hulls to the seabed grid
Representative applications across naval, coast-guard, policing and infrastructure-security tasks.
Ship-Hull Inspection
Covert search of hulls, niches and sea chests for limpet mines, contraband and tampering — without putting a diver in the water first.
ExRay Defence →
Interdiction & Boarding Support
Applications such as searching a suspect vessel's hull for concealed contraband or a hull-mounted device during a coast-guard or customs boarding.
ExRay Defence →
Search & Evidence Recovery
Applications such as locating and recording submerged objects or evidence with geo-tagged FHD video — reducing diver exposure in cold, dark or contaminated water.
ExRay Defence →Critical Infrastructure
Inspection and surveillance of pipelines, cables, offshore energy structures and port assets against damage and interference.
Infrastructure Security →ExRay and LUMA, underwater
Footage published by Hydromea — the EXRAY wireless inspection drone and LUMA optical communication in operation.
A safe pair of hands for defence at sea
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