The waters of the world teem with drones, creeping into every application for the maritime world. We see experimental devices everywhere; everyone testing new ideas to explore the world of drones. We need to understand their limits. Decide on where best to use them. So, what are the pros and cons of maritime drones?
It’s a brave new world, and the marine world overflows with unmanned drones. They go by many names: Autonomous Surface Vessels (ASV), Unmanned Surface Vessels (USV), Maritime Autonomous Surface Ships (MASS), or just drones for short. The waters of the world teem with drones, creeping into every application for the maritime world. We see experimental devices everywhere; everyone testing new ideas to explore the world of drones. We need to understand their limits. Decide on where best to use them. So, what are the pros and cons of drones?
The main advantage behind ASV’s lies in their low cost. Drones work best on simple, single purpose missions with a long timeline. A classic example is the Sea Hunter, used by the US Navy. (Figure 2‑1) It uses active sonar to detect enemy subs. This drone just trolls along, constantly pinging with active sonar. No other purpose. Just one job.
Figure 2‑1: Sea Hunter Drone [1]
Sound underwhelming? Remember the key part: this drone never stops. Naval submarines rely on stealth. Imagine a drone pinging you on the surface, following you across the ocean, constantly announcing your presence for anyone else to hear. You just rendered that submarine useless, using a drone that cost much less than the submarine.
Drones achieve more than just run sonar. They can measure water currents, collect water samples, perform visual reconnaissance, blow up destroyers (military applications), aid in aquaculture, and more. (Figure 2‑2) The common theme for all drones: we keep them small and simple. Ideally, the drone only performs a single mission at a time. This simplicity was the key to keeping drones cheap, and cheap is the main advantage behind a drone.
Figure 2‑2: Ukrainian Military USV (Unconfirmed) [2]
Humans are so annoying! You want oxygen, and relatively normal temperatures, and don’t get me started on how you turn into sacks of goo if we acceleration too quickly. All together, a very temperamental design. This is one area where drones offer a major advantage. No humans means no human limitations, which greatly simplifies the design:
But the biggest advantage is the lack of environmental support. Here are just some of the systems that we completely eliminate from a drone:
We eliminated practically everything in the superstructure of a normal ship. Plus half the equipment in the engine room. Without those demanding humans, a ship gets much smaller and cheaper.
Technically, drones are illegal. The international rules for shipping were developed assuming humans on the ship. One of the biggest hurdles to drones is Rule 5 of the collision regulations (COLREGS).
Rule 5:
Every vessel shall at all times maintain a proper look-out by sight and hearing as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and or the risk of collision.
By “proper look-out”, they mean a human. A real human person physically watching and listening to the ocean. As written right now, the international rules don’t allow autonomous systems. Does that mean every drone on the water is a criminal?
Not exactly. The people who make these rules, the International Maritime Organization (IMO) are currently working to create new rules for drones. (IMO calls them MASS, just to confuse you with another acronym). But don’t hold your breath. The IMO works by international agreement. Ever convince the majority of the countries on the planet to agree on anything? It takes years to decades for the IMO to create major rulesets. In the meantime, we have MSC Circular 1604: The Interim Guidelines for MASS [drone] Trials. Basically, the IMO wants us to experiment with drones. They need case studies to help guide their rules. Currently, it’s the wild west for design and operation of unmanned vessels. Largely free to do what you want, with a few limitations:
Technically, every drone at sea is a research experiment. (This includes the military drones. I guess they research faster ways to decommission enemy ships?)
When it comes to navigation, ASV’s do better than you think. The software programming requires some thought. But we don’t need to reinvent the rules of the road. Thanks to the international COLREGS, we already have a very clear and regimental set of procedures that describe how ships should behave to avoid collisions. Clear and precise instructions work great when programming a drone.
For drones, the biggest challenge really comes from identifying the other ships. But AIS makes that extremely easy. All modern commercial ships include the Automatic Identification System (AIS). Each big ship continuously broadcasts navigation details to all other ships in the region. Really easy to identify the big ships, since each ship tells us it’s exact position, course, speed, and a host of other details.
That handles the big ships, but what about the smaller ships? Or the rare case when a ship turns off their AIS system. In those cases, radar works surprisingly well. Navigating on water isn’t like a self-driving car. We aren’t trying to spot a pedestrian amongst a background of trees. The ocean is largely flat and featureless. Radar makes it easy to identify ships on the ocean: they are the only notable features out there.
Of course, radar isn’t perfect. Clouds, rain, and large waves all interfere with radar signals. Thankfully, modern radar already created ways to deal with these items. If that fails, drones employ cameras for visual identification. Between AIS, radar, and visual cameras, a modern drone compiles these together into a fairly redundant and reliable set of hardware for object avoidance.
The other advantage of ocean navigation is time. Radar and AIS both detect objects from miles away. That gives the drone 20 – 30 minutes of decision time before collision. Plenty of time for its digital brain to troubleshoot uncertain signals. And time to form a pattern. When humans watch a radar screen, we also use patterns to identify ships. Stare the intermittent blip on the screen. If it keeps coming back, it’s probably a ship. Drones apply the same logic, because they have the time to search for that pattern.
The technology for drone navigation is much further along than you might think. I still don’t trust a computer to operate a giant tanker. But we already have drones that work reliably 90% of the time. Currently, humans monitor back on shore and step in for that last 10%. But I fully expect to see completely autonomous drone navigation within the next 5 – 10 years, probably sooner.
The biggest challenge with drones comes from power. You can find plenty of drones on the market that get by with nothing but a battery and electric motor. That works fine for short-duration missions. The battery lasts for a few hours, maybe a day. But for long endurance drones, we need sufficient energy to last for weeks, or months even. In those cases, a battery doesn’t cut it.
We can’t just supersize the battery. It adds too much weight. Extra weight drives up the hull resistance, requiring more power for propulsion, which needs even larger batteries. When storing massive amounts of energy, we need to get more creative.
For long duration, we find two major solutions: engines or renewable energy. Engines offer the more predictable option. When it works, the engine always provides reliable power, matching all our needs. We see successful examples on the drones by Chance Maritime. (Figure 6‑1)
Figure 6‑1: Chance Maritime Drone
Example of Engine Powered Drone [3]
But engines also introduce a lot of complexity. Potential points of failure. Plus, engines require air inlets, exhaust outlets and cooling. Those all lead to thru-hulls (holes) in the drone hull. Every hole is a potential point of flooding. In short, engines work great when they work. But if anything goes wrong, we face limited troubleshooting options from back on land.
The second option is renewable energy. Harvest power from the environment as we go. This tempts with the possibility of unlimited power. But it adds a note of warning: the sea rarely cooperates with our power needs. Wind and solar are the most popular power sources. We wind most often as sail propulsion, with the Sail Drone being a prime example. (Figure 6‑2) Of course, sails only work when the wind blows.
Figure 6‑2: SailDrone
Example of Sail Powered Drone [4]
Finally, we come to solar power, favored for its mechanical simplicity. If your drone only operates near the equator, solar offers abundant sunlight and easy power. But in the northern latitudes, winter brings scant sunlight. In those scenarios, a solar panel only produces 20 – 30% of rated power (depending on environmental conditions). Our location on the planet dictates the viability of solar power.
There are no perfect solutions for drone power. Every option comes with a list of pros and cons. And renewable energy greatly depends on the local environment. Creating a reliable and lightweight power source can be the biggest challenge for drones.
In the world of AI, all this talk about drones and ASV’s leads to a natural question: Will drones replace human sailors? Never going to happen. Despite all the technology, sailors have one critical skill that no drone can match: adaptability. Sailors quickly size up new situations and solve the problem. They improvise, create backup plans, alternatives to the backup, creative work-arounds. No drone can do that.
Drones are only as smart as the programming. And programming depends on our ability to anticipate any possible scenario. But no programmer can think of everything. Even if we somehow create adaptive programming, that doesn’t solve the physical constraints. Think about something simple like mechanical maintenance. Imagine a drone that needs to open an electrical panel and switch out a fuse. But we forgot to install the right screw driver for that electrical panel. No program in the world will magically materialize the right tool.
Sure, proponents of automation argue for creative solutions. We can install 3D printers on the ship that make new tools. No doubt, it’s possible to create automation solutions for every problem. But at what cost? Creating robots that repair the ship with an infinitely adaptable set of tools. And then we need robots to fix the repair bots. Each robot requires millions of dollars in development and maintenance. At some point, humans become the more affordable option. And the maritime industry always follows the more cost-effective strategy. That strategy still includes humans.
However, I do expect to see a synthesis between automation and humans. The automated systems may take more responsibility over pedantic and repetitive tasks, like watch keeping. The computer is much better when it comes to endlessly staring at the horizon to locate navigation hazards. Humans are better at deciding what to do once we find a potential navigation hazard. Same thing with maintenance. I expect to see repair robots that handle the simple tasks, like painting the hull. But humans still handle the more complex tasks like engine maintenance. In the end, humans remain valuable because of their skill and adaptability.
Every new age brings new technology. It incurs period of adaptation as we understand the new technology and where best to use it. Automated ships join as the latest link in that chain. They perform simple missions, costing much less than manned vessels. Simple works great for some situations, but not every mission is simple. Automated ships struggle to adapt, handle complex maintenance. Powering becomes their biggest limitation for long duration missions. They aren’t perfect. But they have their place. So, the drones are here. That isn’t the end for humanity and not the end for merchant sailors. Just another chapter in the story of marine technology.
| [1] | J. Turner, “Sea Hunter: inside the US Navy’s autonomous submarine tracking vessel,” Naval Technology, 3 May 2018. [Online]. Available: https://www.naval-technology.com/features/sea-hunter-inside-us-navys-autonomous-submarine-tracking-vessel/?cf-view. [Accessed 22 Dec 2025]. |
| [2] | J. Guttman, “How Ukraine Turned a 12-Foot Boat Into a Floating Guided Missile,” HistoryNet, 04 Nov 2022. [Online]. Available: https://www.historynet.com/usv-weapon-ukraine-war/. [Accessed 22 Dec 2025]. |
| [3] | Chance Maritime, “Fleet,” Chance Maritime, 2025. [Online]. Available: https://chancemaritime.com/fleet/. [Accessed 01 Jan 2026]. |
| [4] | SailDrone, “Revolutionizing Cable Route Surveys with USV’s,” SailDrone, 2025. [Online]. Available: https://www.saildrone.com/missions/meta-cable-route-survey. [Accessed 01 Jan 2026]. |
| [5] | NOAA, “How much of the ocean has been explored?,” National Oceanic and Atmospheric Association, 01 Jun 2025. [Online]. Available: https://oceanexplorer.noaa.gov/ocean-fact/explored/. [Accessed 22 Dec 2025]. |
| [6] | Rafnar Maritime, “How Not to Capsize – Self-Righting Explained,” YouTube, 4 May 2021. [Online]. Available: https://www.youtube.com/watch?v=ggNx7G6i664. [Accessed 1 Jan 2026]. |
| [7] | Maritime Safety Committee, “Interim Guidelines for MASS Trials,” in MSC Circular, London, International Maritime Organization, 14 June 2019, p. MSC.1/Circ. 1604. |
