‘Civilian’ ships could soon carry carrier-crippling drone swarms. A new age of warfare is coming
Hero loitering munitions
The German defence contractor Rheinmetall is pitching a new form of weapon: a standard shipping container concealing 126 separate attack drone silos. If one company is publicly discussing the idea, you can bet others are considering it too. And the implications for maritime warfare could be significant.
It’s worth noting at the top that whilst drones are anything but new, they are now unambiguously the direction of travel for militaries around the world. Everyone is investing in uncrewed systems in the air, surface and subsurface domains for tasks ranging from logistics resupply to surveillance to jamming to strike. This isn’t necessarily because they are better than the alternatives, but because they are cheaper. With most Nato defence budgets under pressure, this is important.
Having to defend against swarm attacks is also old hat. Nato navies have spent decades in the Gulf learning how to defend against an Iranian fast attack craft swarm which could number in the hundreds. That isn’t to say doing so is easy, and each ship has a number above which it needs either assistance or layered defence in place to defeat it, but it’s not entirely untested ground.
However, whilst drones and swarms are not new, having a containerised way to deploy both is. Defending against this would cause issues, the most obvious of which is that 126 is frequently above the number you could cope with. Modern radars would have no difficulty tracking all of them but many defence systems would quickly run out of missiles and bullets. Some currently under development such as the UK’s Dragonfire laser would provide a great way for doing so, but even one of these could only account for so many. Microwave weapons that blast a cone of energy taking out loads in one go might be the best solution and are being explored in the US with vigour. In the meantime, however, there is a real risk that immediate defences could be overloaded.
This means shifting defence forward a layer. For on overt enemy to be in a position to attack you this way, a number of things have to be in place, many of which are detectable. Intelligence agencies these days are good at spotting small things like new aerials being fitted. A warship with a container strapped to the back is going to be noticed, and by the time one is range you are likely to know the threat is and how to adjust.
The bigger problem is the concealed threat. Take the risk of fire from points on shore. A container moving around in Western Yemen might be detectable, but one in a busy port would not. It wouldn’t need to engage in much targeting, either, because unlike missiles these systems need not be pinpoint accurate. They could launch in the rough direction and the swarm would self-target on route.
A good attack option would be to launch a swarm that jams your systems whilst providing targeting data back to the firing unit which then follows up with anti-ship missiles. This is how the Black Sea flag ship the Moskva was sunk. Although that was done with “just” a single drone and two missiles (which a competent ship would have defeated), make that 126 drones and a salvo of ballistic missiles, all with a simultaneous time on top and you have a problem.
A merchant vessel firing at you is perhaps the most interesting scenario. With two ships at sea, range is an issue. These drones will be small and have short legs, meaning the MV needs to know roughly where you are and unless they’re lucky and you happen to be passing, close your position. Merchant vessels tend to operate in a predictable way. If one is loitering out at sea, altering course regularly or manoeuvring to close you, then clues will emerge and your shields will go up.
If they do manage this and launch a drone swarm, they have just given themselves away. This swarm will paint clearly on radar and the point of origin will be immediately obvious. Having said that, sending a couple of missiles back their way whilst tempting, might not be legal. Bloodthirsty types look away now, but international maritime law and the Rules of Engagement that come from it can be restrictive this way. What if they were “just” surveillance drones? You might think they are not, but can you prove it in the subsequent tribunal when you’ve just killed a bunch of civilian sailors? If you’re at war and the gloves are off, this is less of an issue. If you’re not, and this is a surprise attack, then it is not always that simple.
If a handful of drones do get through your defences and hit you, they probably won’t sink you but they don’t really need to. One drone into, say, a Type 45 destroyer’s Sampson radar would render that system inoperable and the ship unable to conduct its primary duty. A mission kill lacks the drama of a sinking but in warfighting terms can be just as effective.
If defending against this is hard then we should consider buying them for our own offensive purposes. As ever, fitting one to a ship comes with complications.
A warship is a web of sensors and data, all of which are integrated through the command system. The captain, sitting at the centre of this web, is being fed information via the 30 or so people sitting in the operations room with them who in turn are being fed from 100s of sensors and inputs around the ship and elsewhere. It happens fast and forms the basis of their decision-making. Anything that sits outside this network is going to cause command and control issues. These are surmountable, but not ideal. It’s not hard to imagine drones being deployable from something like a Mk 41 Vertical Launch System in due course, at which point, these integration issues go away.
Ships go to great lengths to minimise their radar signature. The last thing you want is a right-angled metal container on the upper deck acting as a radar magnet for enemy ships and their missile seeker heads. You could paint, cover or even make it from radar-absorbent materials but then your cheap solution quickly becomes not-so-cheap.
Another practical consideration is managing munitions on the upper deck in high temperatures, such as those found in The Gulf in the summer. We would go to great lengths to ensure that the temperatures of ammunition stowed in direct sunlight were kept within limits. Best case, the life of the munition is reduced. Worst case, it can cook off causing fires or worse. An aircraft carrier or a Royal Fleet Auxiliary ship with one of these stowed inside to be wheeled out when needed would overcome many of these issues. It’s also safe to assume that if the aim is for this system to be cheap, the individual drone warheads will not be “insensitive”; i.e, they would explode rather than burn if struck. In other words, you could have just strapped a bomb to your upper deck.
Defensively, systems like this pose many questions for which intelligence tracking, improved defensive weapons and cast-iron rules of engagement all need to be in sync if you are to avoid being surprised and then overwhelmed. Whilst the drones might not kill you, they could render you “mission ineffective” which is the same thing. Offensively, they therefore make perfect sense to pursue, noting the caveats above.
In the eternal game of warfare cat and mouse, too many of the basics are still required for this to work for it to be a game changer. But defensively it causes a headache, so the Royal Navy should look closely at how to return the favour. Maybe we should even consider putting one on a merchant vessel of our own. I can immediately hear lawyers sharpening their quills but we do need to get better at operating in our own “grey zone”. This would be a perfect way to begin.
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