ZeroUSV The latest Oceanus 12 in Plymouth.
What it takes to keep pace in the race for commercially viable autonomous vessels
“This one is painted in something called Dazzle,” says Matthew Ratsey, managing director of ZeroUSV in the U.K. “It’s a throwback to World War I, when they painted the frigates in dazzle camouflage effect to confuse attacking U-boats. We thought it’d be a bit of fun, and that it might appeal to our defense customers.”
We are standing on the quay at Turnchapel Wharf in Plymouth, Devon. The tide is out, and we are gazing at a strange-looking vessel moored alongside the floating dock. With her long, lean hull, she could be a sailboat or perhaps an electric launch, but her rugged finish and hard-chine hull suggest another story. This is clearly a working boat of some description.
But perhaps the strangest thing about her is how little clutter there is on deck. There are a few cleats, some hatches, but apart from an A-frame mast festooned with aerials and radar domes, there’s very little else. Not even a wheel or tiller or any engine controls.
I’m slightly nonplussed, or possibly dazzled, as we stroll down the gangplank toward the boat. It’s only when I’m on board and I look down one of the open hatches that I fully understand the nature of the beast. The whole front half of the boat is packed full of machinery. The bow section houses two rows of computers, with all the associated fuses and cabling, while the middle section has two identical power-generating systems. Aft of the main bulkhead, the two 21-kWh battery packs and two 40-kW electric outboards are hidden under the checker plate metal floors. Ratsey later tells me there are about 350 cables snaking around the inside of the boat, like so many veins in the body.
ZeroUSV The interior reveals accommodations for the 350 cables that snake through the hull connecting generators, batteries, sensors, communications components, computers, and actuators, but no crew.
When we arrive, four people are crawling around the boat, two of them with spanners (wrenches) in their hands, the other two with laptops at their fingertips. All play an equally important role in the running of this highly specialized piece of equipment.
This is the Oceanus 12, an autonomous vessel designed to go to sea for up to 25 days, potentially without any human contact. Given that it will be out in all weather with no recourse to quick fixes, all the systems must be protected from the elements as much as possible. Even the outboards, I notice, are fitted under bolted-down plates instead of easy-access hatches. If access is required, that will probably mean the end of the mission.
Ratsey learned this lesson the hard way, while working on a previous project: the 50′ (15.2m) Mayflower Autonomous Ship (MAS400), which sailed from Plymouth, U.K., to Plymouth, Massachusetts, to celebrate the 400th anniversary of the original Mayflower. The boat’s first attempted Atlantic crossing in 2021 was abandoned due to mechanical failure, and even when the mission succeeded the following year, it had to pull in twice for repairs.
“The thing about USVs [unmanned surface vessels] is that a small engineering problem becomes a massive deal because you haven’t got someone with a spanner on board,” says Ratsey. “So, we had a raw-water impeller which broke. That’s game over. The generator can’t run; you can’t charge the batteries. Now, ordinarily on a boat, that would take you 20 minutes to change.
“So, that is why, in the Oceanus 12, we’ve gone for two generators. We’ve got rid of the raw-water pump, so we don’t have an external raw-water feed and have gone to skin-tank cooling. We’ve got a closed-loop glycol cooling system, which isn’t going to get blocked—no krill, no prawns, no plastic bags. The impeller in the pump is stainless steel, et cetera, et cetera. So, you learn from these things.”
Ratsey learned all about the destructive power of the sea early in his career. After studying naval architecture at Southampton University, he got a job with Chay Blyth, the man who famously sailed singlehanded “the wrong way” (east to west) around the world in the 1970s. Blyth went on to found the Global Challenge, in which a fleet of 10 67′ (20.4m) boats with amateur crews raced around the world by the same route.
By the time Ratsey joined the project, it was being upgraded to a fleet of 72-footers (21.9m) designed by Rob Humphreys and built from flat-pack laser-cut steel panels. Ratsey acted as the interface or project manager between the designer and the boatyards (10 boats were built in Plymouth and two in China). He then stayed on for another 10 years to help run the fleet, learning all about reliability and resilience of maritime systems.
After Global Challenge shut down in 2006, Ratsey worked for a Chinese sail-making company, outsourcing digital sail designs long before that became the norm in the industry. Next, he joined MSubs (also based in Plymouth) building submarines for, among others, the U.S. Navy Seals. The company is owned by the U.S.-based Submergence Group. MSubs’ most recent contract was a £21.5 million ($29 million) autonomous submarine for the Royal Navy, the biggest unmanned submersible operated by any navy in Europe.
ZeroUSV The Oceanus 12’s narrow, long lines borrow from sailboat design to create an easily driven hull for maximum fuel efficiency and long distance capability.
So far, so high-tech, and Ratsey’s career was to continue on that trajectory. His next appointment was as managing director of MarineAI, another Plymouth-based company, which designs software for commercial and naval vessels, including the U.S. Navy. Sister company of MSubs, MarineAI provided the software for the MAS400 project, which in 2022 resulted in the first crossing of the Atlantic by a full-size (50’) unmanned vessel. As well as pushing the limits of what is possible with USVs, the ship was fitted with a range of sensors and scientific instruments that provided valuable data for research into climate change and marine biodiversity. It was the perfect steppingstone to setting up a company purely focused on USVs.
A Hot Market
Unmanned surface vessels are one of the biggest growth areas in maritime industries for multiple reasons, not least the improvements in technology that make the reality of unmanned vessels so much more viable. There’s also been a push for greater defense capability, while at the same time a desire to reduce risks to human life. A USV can perform potentially dangerous tasks without endangering personnel. Additionally, those propelled by electric or hybrid systems are virtually silent—invaluable on a reconnaissance mission.
Environmental factors have also contributed to this surge of interest, with USVs providing an ideal way of conducting detailed ocean surveys, often in remote and inhospitable regions, without involving numerous human crewmembers working around the clock in challenging conditions. Quite simply, despite the large upfront costs, a USV is usually cheaper to operate than a manned vessel.
The possibilities, it seems, are endless. Ratsey cites conversations with potential clients from across the spectrum.
“We’ve had approaches from large fishing fleets which want a vessel which can go out and locate where the fish might be,” he says. “That way, they keep their boats, which are expensive to run, in harbor and only deploy them when the USV has found fish. Simple as that. Ten of these vessels could completely cover the English Channel and give a much better situational awareness picture. You could also load them with canister-launching systems for life rafts, so if there was a problem with a nearby manned vessel, you could launch one.
“We’ve had a demo recently for some people who potentially want to use our vessels to deliver spares and post [mail] to oil rigs. They’re currently using a helicopter, which is very expensive. The price of crude is down to about $65 a barrel, so there’s pressure on margins and they’re being told to find another solution; so, how about using an autonomous vessel?
“Fire safety boats are another possible use. Why on earth, in this day and age, would you have a fire safety boat run by people? Why put lives at risk? At minimum, you want that to be remote controlled.”
ZeroUSV Belowdecks, the Oceanus 12 is 100% business—every system designed to operate autonomously.
Much of the USV development has been driven by navies—the U.S. Navy in particu-lar—with the result that many USVs on the market are for military applications. Companies such as L3Harris Technologies and Textron Systems in the U.S. and Exail Technologies in France are building high-powered military USVs with attack capabilities. In 2016, the U.S. launched Sea Hunter, a 132′ (39.6m) unmanned trimaran with a range of 10,000 nautical miles (nm), which could ultimately be fitted with weapons.
There’s absolutely no doubt that we are at the start of a new era in remote, sea-based warfare already being played out in the Black Sea.
One of the first companies to see the potential of USVs for maritime survey use was Saildrone, founded in Alameda, California, in 2012 (for more on Saildrone, see Dieter Loibner’s Rovings article in Professional BoatBuilder No. 210, page 15). This company builds USVs in three sizes—23′ (7m), 33′ (10.1m), and 65′ (19.8m)—powered by small, solid sails and solar panels, allowing them to operate autonomously for up to a year. They’ve been used by the National Aeronautics and Space Administration (NASA), the U.S. Navy, the U.S. Coast Guard, and numerous research organizations around the world, with around 100 vessels launched as of 2024. Their main limitation, of course, is that they are wind-driven and, therefore, subject to local conditions, making it difficult to hold to a reliable schedule.
Close on their heels, a Norwegian company launched its own sail-driven 2m (6.6′) USV Sailbuoy, which in 2018 became the first unmanned vessel to cross the Atlantic, sailing from Newfoundland to Ireland in 28 days.
In such a crowded marketplace, ZeroUSV was launched with a very particular vision. Ratsey’s idea was to create multifunctional boats that could be chartered to different entities in the defense and commercial sectors to perform a variety of tasks. This would give companies that can’t afford to build their own USVs access to the fast-developing technology.
“Unmanned vessels are no longer the stuff of sci-fi,” he says. “We have the technology here now. We’re past the point of thinking how clever it is. It’s not about whether to have a USV, because lots of people have them. It’s about whether you’ve got the ability to quickly change that configuration, to put on specific payloads that are useful for defense, so you can use it for listening or whatever it is you might be doing, and you can then reconfigure the boat quickly and easily so that you can run it in hydrographic mode. That’s what we believe we’ve come up with in our design of vessel.”
Efficient by Design
Looking at some of the companies now building USVs, there’s a bewildering variety of designs available, from what look like typical speedboats with a box of tricks bolted onto them to full-fledged submersible robots. So, what exactly are the design parameters for such a particular type of craft, and why does the Oceanus 12 look like it could quite happily be fitted with a mast and sails?
“Well, because one of the most efficient hull forms is long and narrow, and that is generally what a lot of sailboats were like, before the modern trend for wide transoms,” Ratsey says. “We went for a long narrow boat for two reasons. One, we wanted to be very fuel efficient. Two, we wanted to fit in a 40-foot container, which meant we were obviously restricted on beam and length. So, we’ve got a length of 11.55m (37.8′) overall and a 2.35m (7.7′) beam. That gives a beam-to-length ratio of about 1:4.5, which is really quite high compared to a typical modern yacht, which might be around 1:3.2.”
ZeroUSV Figure 1. Cutaway profile of Oceanus 12
Another key factor in the boat’s design is its power source: a pair of 40-kW RAD electric outboards, powered by two 21-kWh battery packs charged by two 22-kW three-phase generators (plus two token solar panels). With long-distance capability a key issue, an efficient, easily driven hull shape was an essential part of the brief.
“Up to six knots, the boat uses very little power at all. That’s obviously the sweet spot,” says Ratsey. “At that point, the curve is more or less flat, but as you go faster, it’s exponential because all you’re doing is digging a hole in the water. The boat can sprint at 12 knots, but the optimum cruising speed is six. We wanted a very efficient hullform to ensure the boat uses the minimum amount of power to get the maximum amount of duration at sea.”
Getting to the nitty-gritty, the Oceanus 12’s generators each consume three liters (0.8 gallons) of diesel per hour. To power the boat along at six knots, the generators alternate, each running a total of six to eight hours per day. Between them, they consume about 48 liters (12.7 gallons) of fuel per day. Given the boat carries 1,200 liters (317 gallons) of fuel, that gives you 25 days at sea—more if you go a bit slower, less if you go faster.
As for the solar panels fitted to the two most recent boats, it seems they are there largely for decorative purposes—and to give the company’s lead engineer Henry Person a break.
“We got so bored with people saying, ‘Has it got solar?’ [that] we decided it would be simpler just to fit them and say yes,” says Person. “It works out cheaper, if you add up all the time we had to spend explaining why we didn’t have solar panels.”
More seriously, the panels do offer some extreme scenario redundancy. If both generators failed, there would be enough power to charge the emergency battery and send the vessel’s position back to base.
ZeroUSV The keel of the Oceanus 12 is largely for holding the skin cooling tanks for the boat’s generators.
Another surprising (and sailboat-like) feature of the Oceanus 12 is that it has a keel, though its main purpose is to hold the skin cooling tanks—one for the port generator and one for the starboard. It also has a plate on the bottom so payloads, such as multibeam sensors for underwater surveying, can be attached quickly and easily. Fixed standpipes that run through the boat allow cables to be run from whatever device is fixed onto the keel straight into the boat without having to take it out of the water.
As for the boat’s brains, all the Oceanus 12s are operated by the GuardianAI program developed by ZeroUSV’s sister company MarineAI. Crucially, this allows the boat to embark on complex missions not simply as an unmanned vessel but with complete autonomy, as in, no ongoing human input. In theory, once the boat is programmed to perform the required tasks, it can disappear over the horizon, returning 25 days later once its mission has been completed. All the while, the boat’s home base can harvest real-time data and closely monitor its progress.
Construction of the vessel was farmed out to Manor Marine in Portland, Dorset, U.K., using pre-cut aluminum panels from a specialist company in the Netherlands.
ZeroUSV A Netherlands company pre-cuts the aluminum panels from which the hulls are assembled in Dorset.
Despite ZeroUSV’s initial intention of chartering the fleet, their second boat was sold within weeks of being built to a Canadian company that leases survey ships. Leeway Marine has a fleet of seven vessels, ranging from a 37m (121.4′) aluminum oceanographic research ship to a 7m (23′) open workboat, which it hires out to a variety of clients, including the Canadian Navy. The Oceanus 12 is its first USV and, painted all black, has been renamed Viper as part of its new Serpent Class.
Leeway Marine’s list of mission capabilities for its new boat is instructive and remarkably wide ranging: hydrographic and geophysical surveys; environmental and oceanographic monitoring; port and coastal infrastructure inspection; offshore wind and subsea cable surveys; Arctic ice observation and navigation; fisheries research; and intelligence, surveillance, and reconnaissance. The advertised range for Viper is 2,500 nm at 7 knots or 3,400 nm at 3.5 knots.
ZeroUSV Leeway Marine in Nova Scotia, Canada, bought the second Oceanus 12 for its fleet of charterable research and service vessels. Listed missions range from fisheries research to surveillance.
In September 2025, ZeroUSV took part in the REPMUS (Robotic Experimentation and Prototyping with Maritime Unmanned Systems) exercises off Portugal, under the aegis of the Royal Navy. The annual event is organized by NATO to test and develop the latest unmanned systems, involving 3,700 personnel from 24 countries over a period of nearly three weeks.
ZeroUSV and Oceanus 12 were tasked with two main missions. One was to deploy and recover a 150m (492′) towed hydrophone autonomously, meaning the boat was programmed to do the job rather than being remotely controlled by a human operator. The other was to develop a sonar buoy launching system and launch the device autonomously. According to Ratsey, both were “world firsts,” and both were achieved successfully.
It’s an impressive timeline, from the company being created in January 2024, taking on its first employee in October 2024, having its first two boats launched in March 2025, and selling its first boat in June 2025. By the time I visited its offices in January, the company was employing 10 people, its fourth boat had just been launched (though it was still at the boatyard in Dorset receiving its finishing touches), and it was well into the construction of its next, much bigger boat: a 17m (55.8′) USV capable of at least 50 days at sea. Not bad for a startup of just two years, and more proof, if it was needed, of the strength in this market sector.
The Next Wave
Back at the ZeroUSV office on Turnchapel Wharf, Ratsey and the company’s CAD engineer, Nathaniel Serpell-Stevens, walked me through the drawings for the new boat. The design process was rather unusual and apparently falls under the category of what is currently known as “spiral development.”
“We used oversized engines on the Oceanus 12,” says Ratsey. “They are 40 kW, when we only really needed 20 kW. So, this time we’ve taken exactly the same package and thought, ‘What’s the largest vessel we can wrap around that?’ The answer was pretty close to 17m [55.8′]. That allowed us to concentrate on getting the design done and getting to market that much quicker, because having to design the whole thing from scratch would have taken another year. The only change is that we’ve gone for the 60-kWh battery pack, as the engines are going to be working harder because it’s a bigger, heavier boat.”
This time, there’s no question of trying to fit the boat into a container. Instead, they’ve gone for the maximum size you can fit on a trailer and tow onto a ro-ro ferry—which is what they ended up doing in practice with the Oceanus 12 anyway.
The result is a boat almost identical in shape to its predecessor, while being slightly narrower proportionally. Most of the extra length is in the longer payload area, which is now big enough to fit a 20′ (6.1m) container—not that they expect the boat to carry an actual container, but it might be required to carry one’s contents.
The new boat carries 3,000 liters (792.5 gallons) of fuel, which according to their calculations should double the range of the smaller boat, while carrying a much bigger payload of 4 tons (8,960 lbs)—more than five times the Oceanus 12’s capacity of 750 kilograms (1,653 lbs). It’s no coincidence that this payload more than matches the requirement of the larger systems regularly used by the Royal Navy. The boat also has a bow thruster, partly for positioning but also to maneuver out of tight spots.
It’s a measure of how fast this company moves that the aluminum panels for the Oceanus 17 were cut at the end of December 2025, and the boat was expected to launch in June 2026, ready to be shown at the Seawork commercial boat show at Southampton in June 2026. That’s less than a year from gestation to operation.
Wally Wallace | Professional BoatBuilder Magazine As part of its test mission at the REPMUS exercises off Portugal, this Oceanus 12 was fitted with a winch to deploy and recover a hydrophone.
It’s not all sunshine and rainbows, however. British regulations mean that unlicensed USVs are only allowed to be deployed in “categorized waters,” which in Plymouth’s case are two small areas on either side of Plymouth Sound, usually frequented by large numbers of pleasure boats—not ideal for serious USV testing. Getting a license is a complicated process, which so far has involved submitting 400 pages of documentation, even though the hull structure itself has already been signed off by the relevant authority. By contrast, the company had to submit just 50 pages of drawings and information to the Canadian authorities, and within three months, Leeway Marine’s boat was licensed to work up to 200 miles offshore.
Likewise, when ZeroUSV took part in the REPMUS exercise off Portugal, they were given free rein and used that time to their advantage.
“We achieved more and learned more being there for three weeks than we had in four months in Plymouth,” says Ratsey. “The reality is that we have, I believe, a small technical advantage here in the U.K. with our product development. But if we are not allowed or not able to carry on developing that at the pace we need to develop to meet the aspirations of the world, we will be left behind in short order. And the reality is that other countries are pouring hundreds of millions of dollars into companies like ours, right now, this second. They are moving very rapidly to catch up with us, and they will overtake us if we don’t carry on developing.”
The clock is ticking, and Ratsey and his team are determined to remain at the forefront of this brave new world that is emerging as we speak. They are in a strong position to continue to dazzle the marine sector with their on-water performance and retro paint jobs, provided they don’t get tangled in red tape.
About the Author: Nic Compton is a freelance writer/photographer based in Devon, U.K. He lived on boats in the Mediterranean until the age of 15 and worked as a boatbuilder for many years before swapping his chisel for a pen and his router for a computer. He sails a Rhode Island–built Freedom 33, currently based in Greece.
