Russia’s Black Sea Fleet is in trouble. In the 20 months since Russia widened its war on Ukraine, Ukrainian forces have bled the fleet with ballistic missiles, cruise missiles and explosives-laden drone boats.
And the fleet’s problems are about to get a lot worse. In late August, a Ukrainian company revealed the country’s first one-way drone submarine: an 18-foot-long, torpedo-like robot that could haul hundreds of pounds of explosives over a distance of up to 600 miles and strike Russian warships where they’re most vulnerable: below the waterline.
While the Black Sea Fleet has defenses against missiles and boats, albeit imperfect ones, it doesn’t have many good ways of countering a tiny explosive submarine. If Ukraine can solve a few key technical problems – in particular, how to guide its new drone subs – it could escalate its assault on the Black Sea Fleet, and send many more of its ships to the bottom.
And in so doing, the Ukrainians might just introduce a whole new kind of naval warfare.
The Black Sea Fleet labours under a significant disadvantage. There’s just one route from the world’s oceans into the Black Sea: the Bosphorus Strait. Turkey controls the strait, and has not allowed any warships to pass through since Russia escalated its war on Ukraine starting in February 2022.
So the Black Sea Fleet cannot receive reinforcements from the rest of the Russian navy. It has to win the war with the ships it has – or lose. And the ships it has, which originally included one missile cruiser, a handful of missile frigates and several dozen smaller missile corvettes plus a dozen or so amphibious assault ships, aren’t well-equipped for anti-submarine warfare.
Submarines weren’t a problem for the Russians, at first. The Ukrainian navy’s only submarine, the 1970-vintage Zaporizhzhia, was hopelessly obsolete and dangerously unsafe for her crew when she finally decommissioned in 2014. With no undersea threat, the Black Sea Fleet armed itself to control the sea’s surface and attack targets on land.
The Russian fleet initially succeeded in doing both. The Ukrainian fleet went to war with just two large warships, the frigate Hetman Sahaidachny plus an aging amphibious ship. Ukrainian sailors quickly scuttled Hetman Sahaidachny in her home port of Odesa. The amphibious ship sailed into hiding somewhere near the mouth of the Dnipro River.
By March 2022, the Ukrainian navy was a ship-less navy. When the Ukrainians fought back against the Black Sea Fleet, they initially did so with land-based ballistic missiles. Then they added land-based cruise missiles – both locally-produced and American-donated examples. And in late 2022, Kyiv’s forces sent their new $250,000 robotic boats into battle for the first time, in an assault on the Black Sea Fleet at its main base in Sevastopol, in Russian-occupied Crimea.
Between the drone boats and the missiles, the Russians have lost their cruiser, three amphibious ships, a submarine, a supply ship and several patrol boats and landing craft. Other vessels have suffered heavy damage. Most recently, a swarm of Ukraine’s drone boats – guided by GPS – chased down at least three of the Black Sea Fleet’s smaller vessels, and apparently damaged two of them.
That was around Sept. 13, just two weeks after Ukrainian firm Ammo Ukraine launched Marichka, a prototype unmanned undersea vehicle, or UUV.
For the Kremlin, it was an ominous debut. The Black Sea Fleet has plenty of guns and missiles for shooting down missiles and blowing up drone boats. Its defenses against underwater threats – ship- and helicopter-mounted sonars and torpedoes – are minimal.
“By operating below the waterline, UUVs have an obvious advantage in terms of stealth,” wrote Scott Savitz, a senior engineer at the nonprofit RAND Corporation in California. “Moreover, striking below the waterline can be especially damaging.”
Before the undersea assault can begin, the Ukrainians must accomplish two things: scale up production of the $430,000 drone sub – and also figure out how to navigate the subs the 100 miles between Odesa and Sevastopol, then steer them to successful strikes while underwater.
Drone subs “lose access to the electromagnetic spectrum below the waterline, limiting their ability to communicate and to accurately navigate,” Savitz wrote. GPS isn’t an option unless the sub periodically surfaces to catch a satellite signal.
The alternative is inertial guidance, where a drone knows its starting point and keeps track of its speed and direction in order to plot a course the traditional way. But that can be imprecise. Marichka and her fellow UUVs have enormous destructive potential. But they’re unproven.
Count on the Ukrainians to prove them, just like they’ve proved other new ways of waging war against much more powerful foes. The Black Sea Fleet was already losing its war on the essentially ship-less Ukrainian fleet. Once those drone subs join the fight, the Russian fleet might lose even faster.