61 we’re offering, we are receiving interest from people who need USVs but didn’t even know they existed before us.” The watercraft has hence become a cost-effective choice among both budget-constrained and wealthy organisations, with 30 units in service as of writing. The 3 m-long, 1 m-wide, electric monohull boat is built from composites and solar panels to hit key mechanical and power capacities for persistent endurance. If pressed, Seasats can construct upwards of 20 units in a month. The Lightfish Looking down at the Lightfish, one sees square solar panels covering much of the top deck, flat down the centre, and angled on the port and starboard sides to better capture sunlight, as well as a mid-frontal mast and rear mast for mounting instruments such as antennas, lights and video cameras. Beneath the deck hatch, Seasats installs a lithium-ion battery with up to 4 kWh of energy at the centre of buoyancy, a cold combustion generator that serves as a range extender in front (in addition to the solar cells above), and payload electronics behind. Further across the boat, one finds a single electric motor propeller and rudder combo installed at the rear, enabling up to 4.5 knots of speed, with control electronics, including an independent backup GNSS tracker, inside the bow. A retractable keel for added stability is integrated underneath. Up to 50 kg of payload mass can be installed, with up to 200 W over 5-28 V that can be allocated to powering them, including EO/IR cameras, SIGINT systems and EW devices on deck, and active and passive sonars below deck. Depending on how much payload (and added battery) mass is installed, the Lightfish typically weighs 132-192 kg. “We have made sure Lightfish only needs four to six people to pick it up on their shoulders and walk it down a beach for launching into the waves. We’ve seen too many ocean platforms that are trailer-only, so their points of entry and recovery are limited to where you can find slipways,” Rodriguez says. “And if you do have a crane or slipway then one person is enough to do it all.” Journey’s preparations Seasats has previously managed a journey from San Diego to Hawaii in summer 2024, before reaching just past 2300 miles (3700 km) across the remaining Pacific – roughly halfway between Japan and Hawaii – before being scuppered by a typhoon. “We lost the boat, but streamed all the telemetry. Admittedly it was exciting watching 80 knots of wind battering the USV at certain moments, and watching the sea state go up through IMU readings, though with a recovery being impossible, we didn’t get to do a full autopsy,” Kramers notes. “We found the likely problem was an intake to one of our air-breathing generators; then tested it in various ways. Although we can’t go into too much detail, we corrected that potential issue, and changed a few more things around to sense and take precautions of other Seasats Lightfish USV | In operation Uncrewed Systems Technology | April/May 2025 The bow of the Lightfish contains its control electronics, including an independent backup GNSS tracker
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