A new type of uncrewed vessel, identified by the MarineTraffic reporting system as ‘USV Catbus’ has been sighted in San Diego harbor. It seems to be a previously unseen U.S. Navy project, similar to the mysterious Wave Glider craft that have washed up in Scotland and elsewhere, but with one big difference: it’s fast.
Twitter user @cjr1321 is a photographer who takes pictures of shipping in San Diego. Having spotted the unusual craft from a distance on Sept. 13, they decided to get a closer look.
“I drove over to the pier the other day to see whether I could get better photographs and I ended up having a brief conversation with a guy (assume engineer) working on the USV,” the photographer told me. “Here is what I learned. They are from Raytheon and the vessel is a prototype using a converted racing catamaran.”
We also know the craft is about 18-feet long, and powered by an array of solar cells. According to the engineer it can withstand waves of about 3 feet, so it is not intended for operations in rough seas, and the vessel can be packed into a shipping container for rapid transfer anywhere in the world. The engineer said the USV Catbus will tow a small acoustic array and travels at up to 13 knots, or 15 mph.
The U.S. Navy has already demonstrated a system called SHARC (Sensor Hosting Autonomous Remote Craft) that combines the Wave Glider with Boeing
“Its previous location was near Raytheon defense in Rhode Island and it is now in San Diego,” says @cjr1321. “So I may assume that it has something to do with the U.S. Navy. They did sea trials yesterday and were directly off of San Clemente Island which is U.S. Navy controlled.”
It is its speed which marks the Catbus out from previous USVs. The Wave Glider, made by Liquid Robotics, is a 10-foot-long craft resembling a surfboard with solar cells to power mission systems, but propulsion comes from an underwater arrangement which taps into wave energy. This gives it effectively unlimited endurance – in 2012 a Wave Glider crossed the Pacific Ocean — but it typically sails at just 1.5 knots / 2 mph. The U.S. Navy has operated a fleet of Wave Gliders for intelligence gathering and other missions since 2016.
Saildrone is a similar robot craft used for hurricane research — it’s a robust vessel with a rigid, high-tech sail that can achieve speeds of 2 to 6 knots, according to the makers. Australian company Ocius has developed an unmanned vessel called Bluebottle that combines wind, wave and solar power for a typical speed of 5 knots and which is being acquired by the Australian government for extended patrols off the coast.
The USV Catbus is likely an experimental craft rather than a prototype, and it appears to have been designed for speed. MarineTraffic clocked it moving at over 17 knots/20 mph on Sept. 14 , even faster than originally claimed. This speed is likely related to the racing hull, which offers less drag than previous designs. Solar cells may not drive the USV Catbus at high speed continuously, but could recharge batteries to provide a sprint capability where needed.
It is not clear from the images if the Catbus has hydrofoils to ‘fly’ above the water, a feature of modern racing yachts, which can skim along with minimal friction at speeds as low as 8 knots. Hydrofoiling allows a small vessel to reach good speeds with minimal energy expenditure.
Until the design can cope with the sort of heavy seas that other small uncrewed vessels can weather, the USV Catbus will only have limited value, but this will probably follow once it has been optimized for speed. Looking ahead, large numbers of small naval drones will be able to cover a wide area, with the potential to one day create an inescapable net for submarines. That might give pause to anyone about to spend tens of billions on a new submarine fleet.