Unmanned Anti Submarine Warfare


I know promotional videos tend to concentrate on the positives and completely ignore the negatives but this concept from Leidos (formely SAIC) looks interesting.


In response to a contract from DARPA Leidos released this press release

An autonomous unmanned vessel designed to track quiet diesel-electric submarines spanning miles of ocean depths for months at a time with minimal human input is now under construction and is expected to set sail for testing in 2015. Leidos (NYSE: LDOS), a national security, health and engineering solutions company, has begun construction on ACTUV (Autonomous Continuous Trail Unmanned Vessel) under a Defense Advanced Research Project Agency (DARPA) program for the design, development, and construction of a vessel originally conceived for an anti-submarine warfare mission.

“ACTUV’s advanced sensor technology should allow for continuous surveillance which, combined with the vessel architecture and design, is expected to provide autonomous safe navigation supporting Navy missions around the world,” said Leidos Group President, John Fratamico.

ACTUV carries other sensors and mission packages designed to allow it to conduct a variety of Intelligence, Surveillance and Reconnaissance and other alternate missions. With situational sensors that can ensure safe navigation, the ACTUV trimaran has electro optics, long range and short range radar.

“A cross-disciplinary Leidos team leveraged insights and innovation from across the organization to develop the concept of the autonomous unmanned vessel. It would help keep our troops out of harm’s way and provide capability in more harsh environmental conditions for a longer period of time,” added Fratamico.

Maritime and hydrodynamic engineers designed the platform, and scientists and experts designed autonomy for safe navigation, status and health reporting, and sensor control and processing. Analytics experts programmed the logic for identifying other vessels and predicting their behavior.

Leidos received direction to start construction of the ACTUV from DARPA Program Manager Scott Littlefield at the conclusion of a Production Readiness Review held in February. Christensen Shipyard, Ltd. (CSL), is constructing ACTUV in Vancouver, Washington using non-traditional composite structures and modular construction techniques under supervision of Leidos and Oregon Iron Works (Clackamas, Oregon). CSL employs a lean manufacturing process with parallel work flow to complete ACTUV construction in approximately 15 months. ACTUV is scheduled to be launched on the Columbia River in 2015.

Rather than concentrating expensive sensors into increasingly rare high end surface and airborne platforms this would seem to offer the prospect of an alternative, distributing cheaper sensors across cheaper and numerous platforms netted together so the whole becomes more than the sum of its parts.

I doubt it would actually be all that cheap, these things never are, but an interesting alternative approach nonetheless and one worth bearing in mind as we move into Type 26 and Nimrod replacement territory.

The times they are a changin.




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Chris Werb

As it’s unmanned, what in international maritime law is to stop someone just turning up and “salvaging” it, or interfering with it – or even outright sinking it?


Isn’t this a repeat? Think they had something similar 2 years back, which also went nowhere.

Not a Boffin

As it’s unmanned iit’s non-compliant with International Law in any case as it cannot comply with IRPCS.

As soon as it starts Tx or even recording data in anyone’s territorial waters (useful if you’re going to pick up boats) then it ain’t compliant with UNCLOS either and you can indeed “interfere” with it from disabling offending systems to outright destruction.

Interesting concept though.


There is no need to make such things unmanned. Men have sailed around the world non-stop in tiny sailing yachts. A crew of 3-5 is easily possible in such a boat, and don’t require much space or weight. Their crew module could even be an unsinkable rescue boat, capable of reattaching without aid.
I think the “unmanned” is merely fashion.

Such unmanned ASW concepts pop up again and again, and every time they are suspiciously devoid of information about ASW sensor applied. I suppose it’s multistatic LF sonar (receiver).


Agreed its a option we should be looking at, and posted a link a few months back. The unmanned aspect is possibly a step too far at the moment but even a small crew as S O mentions could make it workable. I’ve never really understood why we chase SSNs to stop them getting close to HVUs in a HVU (a.k.a. T23, T26 etc).


Seems like this could make a good sub chaser for protecting SSBN routes.

Free up T23/26s to nose around the Black Sea and other areas of interest…


Incredible. They have rewritten the laws of physics! Well done – ought to bump up their share price a little!

El Sid

It’s the same programme as before, it was little more than Powerpoint last time it hit the news and it’s still a technology demonstrator now. A big part of it is getting sufficient autonomy to respect IRPCS etc. If ASTRAEA can fly a Jetstream unmanned at 200mph in 3 dimensions, doing collision avoidance at 20mph in 2 dimensions should be doable, even if it’s new to naval engineering.

Sensor-wise, think something like a helicopter fit. But a helicopter with 80 days endurance and good for 6,200km. There’s been open-source mention of “onboard acoustic, electro-optical, radar and lidar sensors” :


The whole point is that other platforms do the hard job of finding the submarine, then hand over to ACTUV for the mundane task of tracking it (which needs far less sensor technology). Imagine picking up Iranian subs moving into the Gulf of Oman, or North Korean subs into the SCS.


El Sid, really not sure on all this. The old USV fad died off a few years back with not much to show for it.

And I was wondering why the shipform looked so familiar. Took me a while to remember.


Burnt down totally due to the fact that there was no damage control crew on board to contain the fire. Extrapolate this to USVs?

A Different Gareth

If maritime law required such a vehicle was manned I assume heavy weather would be tiring for a small crew in a relatively small ship and slow them down too, while the sub to be tracked would be unimpeded.

If it had to be manned would a small submarine be better? Something designed to go deep enough to avoid weather but not much further. Could operate from a mothership disguised as a tanker…

El Sid

@A Different Gareth
Problem there is the physics of small submarines, which militate against any kind of range, particularly since you need to be significantly faster than your target to allow for the odd misdirection. Think of the biggest torpedo, a Russian Type 65 – 5 tonnes, but only has a range of 60 miles at 30 knots. Submarines are also much more expensive than surface vessels, particularly if you want them to be manned.

It wasn’t so much a fad, as this programme shows there were lots of things just kept going in the background. Part of it was a greater appreciation of the degree of autonomy required, which just needed a few years of software development that could bounce off related developments in other fields – and sequestration didn’t help, the way it worked hit development programmes particularly hard.

Another way to look at the Indonesian fire was that it was started when human beings came on board to do maintenance… And things like galleys are good fire hazards that aren’t needed on unmanned vessels.

In reality – obviously unmanned systems have a higher loss rate, we’ve seen that with Predator/Reaper. You have to compare that with the cost of the manned version. The reason Predator/Reaper loss rates are a problem is that they’re not that much cheaper than a manned aircraft like an A-10. The comparison for ACTUV is a $450m LCS with $50m module. If they hit their target of $20m/ACTUV, then you can afford to lose over 90% of them and still have more submarine-tailing capability than one LCS (although the LCS can obviously be used for other things). So you don’t care so much about losing the odd one here or there. And from a recruitment POV, 8-hour shifts from the family home are bound to be more acceptable than 6-month tours away (and possibly being permanently stationed forward).


ElSid – I have been impressed by gliding UUVs – those that use changes in buoyancy to glide down or up at shallow gradients to propel themselves forward – if I understand correctly one of the US devices has been out on its own for over 6 months without the need for fuel or recharging. Very long endurance. And very quiet not having a propeller or propulsor, just some plumbing, low power electric valves and a winged enclosure. The early ones were slow, but rummaging in googlespace brought this: http://www.evologics.de/en/products/glider/index.html – good eh?

Not a Boffin

“A big part of it is getting sufficient autonomy to respect IRPCS etc. If ASTRAEA can fly a Jetstream unmanned at 200mph in 3 dimensions, doing collision avoidance at 20mph in 2 dimensions should be doable, even if it’s new to naval engineering.”

Except ASTRAEA was operating in managed airspace with unlimited LoS comms. That doesn’t invalidate the feasibility of IRPCS compliance form a ship, its just a different approach and a different set of international regs to change. Looked at another way, ASTRAEA di what it did. EuroHawk found it all a bit difficult (and expensive!)


This may have been covered already but how do these underwater craft know where they are and how do you send signals to them if they’re not on a command wire ore near the surface.

El Sid

@Chris There’s all sorts of fun things in that area, they’re undoubtedly going to change all sorts of sectors like hydrography – but 5-10km/h top speed is still a long way from being able to keep up with a sub.

Eurohawk isn’t the last word on this kind of thing, and think about where ASTRAEA might be in 5-10 years time rather than where it was last year. The fact remains, this is fundamentally a Moore’s-Law-type problem rather than a physics problem like battery life, and there’s enough incentive for the basics to be worked out in the civilian field that it’s going to happen. Perhaps driverless cars are a better analogy – this is where we are today :

Can’t help feeling that it’s a great way to deliver car bombs, but that’s another matter…

Not a Boffin

Absolutely agree – in most cases (standfast UW connectivity and energy storage) it’s not about the physics. It’s all about getting a regulatory regime that will work agreed (time consuming, not necessarily difficult) and more importantly, demonstrating that your autonomous system can and will comply with it (needs both systems assurance and software assurance).


Sid, think the reason why I get the impression that is was a fad was because we got into the game a lot earlier than you guys, since the time of the Spartan scout (about 2001), then the Protector in service for Coalition patrols in Iraq. After that, nothing. That was about 10 years ago. Hell, we even had a USV mothership deployment concept where an OPV would release 4 USVs from the side, still went nowhere. No word at all, but the fact that they no longer use USVs probably means that there is still some bugs in the concept.

El Sid

Fair enough – and you guys have your own reasons for wanting to minimise manpower. Rafael have continued to plug away with the Protector, although it seems to be more about defensive CG-y use protecting point targets like oil rigs rather than the watery Robocops of 10-15 years ago. I suspect that the reason the military have failed to be enthused is partly because RHIB-type solutions just don’t have much range or endurance, the RQ-170 takedown made people nervous of remote-control for something likely to be used around Iran, particularly with weapons, and insufficient autonomy. This new generation of things like ACTUV have range, no weapons, and much more autonomy. Even then it’s still a tech demonstrator, and will remain so for a few years yet.

A Different Gareth

El Sid said: “Problem there is the physics of small submarines, which militate against any kind of range, particularly since you need to be significantly faster than your target to allow for the odd misdirection. ”

Would something like the Juliet Marine Ghost boat (youtube) be suitable? It is supposed to be a gas turbine powered, super cavitating, SWATH boat but that would presumably be far too noisy. A more conventionally propelled one could be quieter.

El Sid

You don’t need to keep up with Alfas, just fast enough to keep up with SSK’s in the first instance. Which pootle around at 5-10 knots, but can do 20-22 in a short sprint (measured in minutes unless they have AIP). Ghost is fun, but it’s more of an anti-swarm and ninja delivery boat – and if its range is less than Aden-Socotra, that’s not much more than 100 miles. So more Usain Bolt than Mo Farah.

A Different Gareth

Range of the Ghost is claimed here to be 900 nautical miles.

El Sid

Here’s an overview of what some people are doing with UUVs, from an underwater K-Max equivalent for commercial transport companies to DARPA’s latest toys like Hydra and :

The Blue Wolf program will develop and demonstrate an integrated underwater vehicle capable of operating at speed-range combinations previously unachievable in fixed-size platforms, while retaining traditional volume and weight fractions for payloads and electronics.”

The program — which is under the agency’s tactical technology office — aims to develop ways to reduce drag on the UUV,


That sounds like supercavitation or a variation thereof. The Chinese are also on the case :

the team’s innovative approach meant they could now create the complicated air “bubble” required for rapid underwater travel….Once in the water, the team’s supercavitation vessel would constantly “shower” a special liquid membrane on its own surface. Although this membrane would be worn off by water, in the meantime it could significantly reduce the water drag on the vessel at low speed.

After its speed had reached 75km/h or more the vessel would enter the supercavitation state. The man-made liquid membrane on the vessel surface could help with steering because, with precise control, different levels of friction could be created on different parts of the vessel.

“Our method is different from any other approach, such as vector propulsion,” or thrust created by an engine, Li said. “By combining liquid-membrane technology with supercavitation, we can significantly reduce the launch challenges and make cruising control easier.”

However, Li said many problems still needed to be solved before supersonic submarine travel became feasible. Besides the control issue, a powerful underwater rocket engine still had to be developed to give the vessel a longer range. The effective range of the Russian supercavitation torpedoes, for example, was only between 11 km and 15 km.