Military Embedded Systems

The worldwide market for unmanned naval vessels


February 29, 2024

Ray Alderman

VITA Standards Organization

Graphic courtesy U.S. Navy

WARFARE EVOLUTION BLOG. In our last escapade, we investigated the worldwide market for warships and submarines. Out of respect for the literary principle of subject matter continuity, we are forced to explore the worldwide market for UNVs (unmanned naval vessels) in this essay, since they are an extension of warships and submarines. UNVs break down into two basic groups: unmanned surface vessels (USV) and unmanned underwater vehicles (UUV). We will deal with naval unmanned aerial vehicles (NUAV) in another composition.

Let’s start with unmanned surface vessels (USV). The Navy has defined four basic categories: large (LUSVs) 200 to 300 feet in length displacing 1,000 to 2,000 tons, and medium (MUSVs) 45 to 190 feet in length displacing up to 500 tons. Then, there’s the common unmanned surface vessels (CUSV). They are about 40-50 feet long and displace less than 10 tons. Finally, we have small unmanned surface vessels (SUSVs). Those are basically speedboats about 20-40 feet long, weighing a few tons. All these unmanned surface vessels fit under the U.S. Navy's Ghost Fleet Overload program.

The Navy is about to issue contracts for nine LUSVs, the first being delivered in 2025. They will have 16 to 36 vertical launch system (VLS) missile tubes onboard and will become “missile barges” to support the carrier strike groups. These boats will cost about $250 million each.

Over four months in late 2023, the Navy conducted exercises in the Pacific involving four unmanned surface vessels: Mariner, Ranger, Sea Hawk, and Sea Hunter. Mariner and Ranger were built from boats used to resupply oil drilling platforms in the oceans (they have conventional hull designs). They are sister ships (194 feet long, displacing about 670 tons). That makes them MUSVs, if you fudge the numbers a little. Sea Hawk and Sea Hunter are sister ships that are 135 feet long and displace 145 tons when loaded. That makes them MUSVs too, just a bit smaller. However, they have trimaran hulls (a main hull with stabilizing outriggers) instead of conventional hulls.

To read more Warfare Evolution Blogs by Ray Alderman, click here.

There are four conventional-hull MUSVs operating today: Ranger, Mariner, Nomad, and Vanguard. These ships cost about $56 million each and are used as ISR (intelligence, surveillance, and reconnaissance) platforms. Recent deployments of small unmanned surface vessels in the Middle East waters show that they can do the ISR job better and cheaper, so the MUSV program has some problems. The only trimaran-hulled MUSVs operating today are Seahawk and Sea Hunter, and there are no plans for future orders.

Four CUSVs have been built, for use in mine sweeping operations. They are 39 feet long, displace 7.7 tons, and are undergoing testing with advanced magnetometers and sonar systems. Other mission modules are under testing: a 50 caliber machine gun for harbor patrol, and a small guided missile launcher system. After testing is complete, they will go into service.

That brings us to the small unmanned surface vessels (SUSVs). They are basically speedboats. In 2023, the Navy deployed the Devil Ray SUSV (38 feet long, 4,000-pound payload) in the Arabian Gulf as an ISR platform. And, we have seen what small fast boats loaded with explosives can do (kamikaze boats). Look at the Ukrainian Magura V5. These speedboats have sunk three Russian warships in the Black Sea.

There is a horribly mutated derivative of the SUSV class that you should know about. It has been used in the seas around the Middle East: the Saildrone. It is 23 feet long, weighs less than 1 ton, moves under power of the wind, uses solar panels to power the electronics, and can operate for 365 days without human intervention. This is an expendable ISR platform and appears to be a very expensive military version of a Ring doorbell duct-taped to the top of a surf board.

 In January, the Navy issued a request for information for small interceptor boats, made from commercial hulls with commercial engines, capable of carrying 1,000 pounds of gear, and traveling for 575 to 1150 miles as fast as 40 MPH in blue water. If you look at the Navy’s 2024 shipbuilding plan, they want 90 to 150 unmanned surface vessels for the fleet. A large portion of these will probably be SUSVs and CUSVs, since they can be built on commercially available fiberglass hulls with commercially available outboard engines. By 2050, the Navy wants 40% of their fleet to be unmanned boats.

As of this writing, the U.S., China, Canada, Italy, Portugal, and Norway are developing USVs. According to the latest report by MarketsandMarkets (a market research company), the worldwide market for USVs was $0.8 billion in 2023, growing to $1.2 Billion by 2028 (a compound annual growth rate of 10.3%). As you can see, there are some experiments going on with USVs worldwide but nothing to get excited about, unless you are selling fiberglass speedboat hulls or outboard engines.

Now it’s time to get wet and look at unmanned underwater vehicles (UUVs), so hold your breath while reading this section. The Navy breaks those down into categories so obscure, that it makes the tax code look simple. There are small (SUUV), medium (MUUV), large (LUUV), extra-large (XLUUV), and large displacement (LDUUVs). None of these are related to a definitive length, diameter, or displacement. They further break UUVs down by how they are operated. Remotely operated underwater vehicles (ROUV) are controlled by an operator through a cable tether. They are used to examine ship hulls for damage below the waterline, look for magnetic mines stuck to the hull of our warships by enemy frogmen while in port, or for rescue and salvage operations where they need real-time information. Autonomous underwater vehicles (AUV) operate independently, without a tether. So, let’s stick to AUVs and untangle this Gordian Knot.

First, we need a visual-reference baseline for mental comparison of the UUV classes, so I have chosen the MK-48 torpedo presently in service on our submarines. It is 19 feet long, 21 inches in diameter, and displaces about 1.8 tons. Now, get that visual image clearly in your mind before we go forward or you could easily drown in the following ocean of information.

Under SUUVs, there are a bunch of small (4 to 8 feet long) versions that are used in shallow water for mine hunting, bottom mapping, and intelligence collection. No need to go through them here. Just be aware they exist. Look at the Swordfish, which is now being replaced by the Lionfish (8 feet long, 12 inches in diameter, displacing 150 pounds).

Under MUUVs, we have the Kingfish (about 12 feet long, 24 inches in diameter, displacing about 600 pounds, depth range 5,000 feet); Iver (about 8 feet long, 9 inches in diameter, displacing about 230 pounds, depth 650 feet); and the Bluefin-21 (16 feet long, 21 inches in diameter, displacing 1,650 pounds, depth 15,000 feet).

Then, there’s Knifefish, a derivative of the Bluefin-21 (22 feet long, 21 inches in diameter, displacing 2,000 pounds), These are used for mine detecting, bottom mapping, ISR, and littoral battle space intelligence missions. What we are seeing is the Kingfish/Bluefin platforms merging into the Razorback MUUV platform. Then, that will merge into the Viperfish platform with more sensors and capabilities in 2024. The MUUV platforms are all merging into torpedoes (19 feet long, 21 inches in diameter). This segment is a bit confusing with all the mergers.

Under the LUUVs, we have the Snakehead (4 feet in diameter, about 10 feet long). That platform was cancelled back in 2023. There’s another one called Echo Ranger in this class (18 feet long, about 4 feet in diameter, displacing about 6 tons).The Seawolf (40 feet long, 5.5 feet diameter) uses  fuel cells for power and is under development in Australia. In early February, the Navy released contracts to three companies to develop new prototypes of LUUVs. Maybe they will be used for deploying "upward falling payloads" (UFP) near enemy harbors or in shipping lanes. We’ll get to UFPs in a minute.

At this point, we must change our visual-reference baseline. Forget about the MK-48 torpedo and now visualize the Virginia class attack submarine (about 400 feet long, 34 feet in diameter, displacing about 10,000 tons). Under the XLUUVs, we have the Cutthroat (111 feet long, 10 feet in diameter, displacing 205 tons). This is about 1/4 the size of a Virginia Class nuclear attack sub. It is being used to test different technologies for naval warfare.

Next comes the Orca (85 feet long, 8.5 feet in diameter, displacing about 50 tons). The Navy has one for testing and training now, and 5 more on order. They cost about $125 million each. Then, we have the Echo Voyager (51 feet long, 8.5 feet in diameter, 50 ton displacement). And there’s the Echo Seeker at 32 feet long. The Navy doesn’t talk much about it, but these platforms can carry weapons (mines, torpedoes).

Finally, under the LDUUV program, those platforms were to be 4 feet in diameter, about 7 to 8 feet long, and launched from submarine decks while submerged. When the latest Virginia class sub design removed the Virginia Payload Module, it also removed the LDUUV program with it. LDUUV and LUUV seem to be merging together.

Why are these UUV classes rattling around and confusing? I think there are two reasons. First, the Navy is trying to figure out which sizes, shapes, ranges, and depth capabilities are needed for different missions. But more importantly, it’s the surface ships and submarines that launch, maintain, refuel, and recover them that dictate the size, shape, missions, and depth capabilities. I think logistics are now a major concern.

That suggests that small UUVs (4 to 8 feet long, 8 to 12 inches in diameter) will be launched by sailors in small boats in shallow waters. Medium UUVs (19 feet long, 21 inches in diameter) are like torpedoes, and will be launched from submarines and bigger warships. Large and extra-large UUVs (up to 85 feet long, 8 feet in diameter) will be launched from docks in harbors. Ultimately, I think there are three classes of UUVs that will eventually eliminate our bewilderment: man-launched (SUUVs), submarine-launched and ship-launched (MUUVs), and dock-launched (LUUVs and XLUUVs). 

There might be a third reason for all this confusion, but it’s pure speculation on my part. Maybe the Navy is busy designing platforms instead of designing kill chains. The objective of USVs and UUVs is to connect distributed naval ISR systems to distributed naval weapons and hit enemy targets in seconds over a large area of water. Designing platforms is a bottom-up process. Designing kill chains is a top-down process. What I see with UUVs is mostly bottom-up.

According to Fortune Business Insights (a market research company), the worldwide market for unmanned underwater vehicles was $3.02 Billion in 2022, growing to $8.14 Billion by 2030 (a 13.5% CAGR). Obviously again, there’s more electronics content in these UUV platforms than on manned surface ships or submarines (more electronics per cubic foot of internal space). The U.S., United Kingdom (U.K.), Australia, China, Germany, France, and maybe a few other countries with ocean access have UUV programs ongoing.

There are other interesting things going on with UUVs. How can these vehicles communicate with each other (a swarm) or with manned surface ships and submarines? The Navy folks are working on gateways with acoustic modems, where a USV on the surface can receive data from RF or satellite sources, translate those signals into acoustic signals, and send the data through the water to submerged UUVs or manned subs. Or, they can translate acoustic signals from UUVs or subs underwater and send that data to surface ships, aircraft, and satellites. However, there are a host of problems with sending and receiving acoustic signals through the water (transmission delay, water temperature, salinity, background noise, etc). There are some interesting papers about underwater communications on the web worth reading.

Finally, there’s a concept called "upward falling payloads" (UFP) at DARPA. These could be ISR systems or weapons, so think of them as loitering munitions. One of the XLUUVs or LUUVs mentioned above could be loaded with these systems, secretly go into hostile zones (near enemy harbors or in littoral areas), scatter them around on the ocean floor, and then leave. When enemy ships come into that area, a nearby UUV with ISR systems onboard could send an acoustic signal to those systems sitting on the bottom. Those systems will then rise rapidly to the surface (upward falling) and attack the enemy ships with torpedoes and smart mines. Or, they could rise and send targeting data back to surface ships or aircraft (like tattletales), and those platforms will fire on the enemy. UFPs are minefields in the ocean, and UUVs are the vessels that put them on the bottom and wake them up at the proper time.

At this point, you should have a basic understanding about the markets for USVs and UUVs. I may have missed a few platforms here and there in my research, since this market is very fluid. From what I have learned, I don’t see more than a hundred of these UNVs being built over the next few years, and most of those will be small USVs and UUVs. The Navy’s plan is to experiment from 2024 to 2028, buy some specific UNVs in 2029 to 2033, and have an operational unmanned fleet after 2033.  It’s also clear that the Navy is very nervous about sending out hundreds of submerged autonomous weapons in a swarm, to attack enemy ships or submarines.

Next time, we will explore the markets for unmanned aerial vehicles (UAVs). If you think the classifications for USVs and UUVs is complicated, it gets worse with UAVs. So, give me some time to do the research and make sense of it. I have the feeling that writing the next article will be like taking a final exam in calculus after attending a keg party.

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