General Sverker Göransson, the Swedish chief of defense, is rather upset that a presumably Russian submarine can waltz into, and then out of, the Stockholm archipelago unchallenged. Before we complain about the previous government’s paying-off the Navy’s sub-hunting CH-46 helicopters before securing their NH-90 replacements, we should acknowledge the challenge of the task. The waters off the Swedish capital have some of the most complex hydrography for sub-hunting in the world. Even with its fleet of six corvettes pinging away for days with sonars, there was only so much that could be done. It’s not as though Swedish coastal waters are continuously patrolled.

 

First, a little background on the ACTUV. DARPA’s exploratory concept called for a semi-submersible of 157 tons, 19 meters long, and with a 27-knot top speed. Leidos proposed a more conventional trimaran with similar performance, and won. The whole point of the ACTUV is to trail a diesel submarine, pinging away with an active sonar to demoralize the crew, and to stick to the prey until she has to snorkel to recharge the batteries. With a twentieth the displacement of a frigate, and no on-board crew, an ACTUV would be a much more cost-effective way to follow a submerged contact. If the disagreement turns hot, and the submarine decides to fire, any loss of an ACTUV provides what navies call “a flaming datum” of the submarine’s last known location.

 

Thus, the ACTUV is what we used to call, quite literally, a sub-chaser. But the 2010 Industry Day presentation noted that the first ship could be just the “ASW configuration of a new class” of naval drones. The Q&A from that session noted that “design allocations for future weaponization are acceptable”—just as Leidos’s cross-town colleagues at General Atomics Aeronautical eventually did with with the Predator. The list of possibilities suggested is impressive: reconnaissance, surveillance, communications relay, littoral resupply, and drone launch. Assemble a flotilla of enough ACTUVs, and for the open ocean, the whole thing could approximate a SURTASS array. The company’s official video is pretty illuminating.

 

Swedish sensibilities might not permit drone warfare, where unmanned platforms release weapons on presumably manned submarines. But if that’s problematic, we might conceive of optionally-manned vessels, crewed for a hot fight. After all, how much space do a handful of people need for a week at sea? A small canteen with a food locker, a tiny gym, a few double staterooms, a head and shower might be enough. And without the crew, the patrols of such might quietly provide enough deterrence to make Russian submarine skippers think twice about penetrating too far into Swedish waters.

 

There is a final point for any navy. Long ago Sweden gave up cruisers for corvettes; with antiship missiles and the Air Force providing overwatch above the narrow Baltic, they were much more cost-effective means of sea control. Cruisers are also a challenging product to produce quickly in wartime. Hundred-ton robo-corvettes, on the other hand, may be the naval equivalent of MRAPs or Predator drones: militarily useful products that draw on commercial inputs, for which industrial surge capacity is relevant.