Bouncing over choppy waters, the Ukrainian sea drones fanned out and sped toward the Russian warship in a swarming tactic that military experts say has proved lethal and effective against what had been a dominant naval power on the Black Sea.
From the safety of a room hundreds of miles away, the drones’ pilots pushed forward joysticks to accelerate, steer and swivel deck-mounted cameras, keeping their target in sight. Russian sailors opened fire with heavy machine guns.
A brief sea battle between men and drones erupted over several minutes, according to an account from the Ukrainian drone operators. One drone sped so close to its target, they said, that when bullets struck the 500-pound warhead it was carrying, the explosion breached the hull of the Russian corvette patrol ship, the Sergey Kotov.
“When we hit the target, the whole team, of course, was filled with emotion,” said the operator of the drone. The pilot asked to be identified only by a nickname, Thirteen, while describing the battle at sea on Sept. 14, one of dozens of such engagements over the past year, according to the Ukrainian military, using drones built by Ukraine.
Such attacks have been a rare bright spot in a disappointing year for Ukraine with no frontline breakthrough on the ground.
“We were screaming and congratulating one another,” the pilot said, describing the mood among the drone operators in September. (Russia’s Defense Ministry said at the time that the Sergey Kotov had thwarted an attack by five maritime drones.)
The use of the sea drones highlights a path forward for Ukraine in its fight with Russia that has been promoted by the White House and embraced by the Ukrainian leadership. The idea is to supplement weaponry provided by Western partners with armaments produced domestically by Ukraine, including innovative systems like the sea drone fleet.
Ukraine will have to rely heavily on military aid for the foreseeable future in a lopsided war against Russia, a far more populous and enemy with a far greater industrial capacity. Much of that assistance is now in doubt as the U.S. Congress has delayed a vote on military aid.
Faced with such obstacles, the Biden administration is promoting joint ventures between U.S. and Ukrainian arms makers. President Volodymyr Zelensky of Ukraine, who has promoted Ukraine as a “hub” for weapons manufacture and battlefield testing, met with chief executives of U.S. military contractors during a visit to Washington last week.
Some in the U.S. military want Ukraine to pursue a “hold-and-build” strategy — to focus on holding the territory it has now and building an ability to produce its own weapons over 2024.
With a Ukrainian offensive now stalled, and little chance for advancing on land, the goal would be to create enough of a credible threat with long-range drones and missiles that there would be an opportunity for meaningful negotiations with Russia at the end of next year or in 2025.
The White House said in a statement after convening a conference this month on Ukraine’s domestic defense industry that the goal was to “advance a robust and self-reliant Ukrainian defense industrial base that captures Ukraine’s innovative culture and provides material for urgent military needs.” The State Department would send an adviser to Ukraine’s ministry of defense to oversee cooperation, the statement said.
Sprawling military factories in Ukraine once formed a cornerstone of the Soviet military industry, building aircraft and intercontinental ballistic missiles. Many fell into obsolescence at the end of the Cold War and as Ukraine won its independence from the Soviet Union.
Still, domestic arms makers have provided about 20 percent of the Ukrainian Army’s needs since Russia’s invasion in February 2022, according to Serhiy Hrabsky, a military analyst who was a colonel in the army.
Ukraine makes armored vehicles and tanks, a self-propelled howitzer, artillery shells and laser-guided anti-tank missiles. Its greatest potential, however, is seen in battle testing innovative systems that might leapfrog older military gear, military experts say.
Exploding sea drones, a new class of naval weapons, were first deployed in combat in defending against Russia’s assault on Ukraine. Kyiv operates two manufacturing programs, one under the military intelligence agency, with the other run by the domestic intelligence agency.
The Ukrainian military made a pilot available for an interview this month and allowed a viewing of a drone workshop and storage site with a requirement that its location not be disclosed. The intent, the military intelligence agency said, was to demonstrate Ukrainian self-reliance even as Congress considers whether to provide more military aid to Ukraine.
In the year since they set sail in the Black Sea, the drones have damaged and sunk dozens of Russian ships, according to the Ukrainian Navy, and played a role, alongside Western-provided missiles, in forcing Russia to relocate vessels from Sevastopol harbor, the home port of one of Moscow’s four naval fleets. The drones helped clear a shipping channel for the export of grain, a critical commodity for Ukraine’s economy. And they pushed Russian missile carriers to launch farther from Ukrainian shores, giving more warning of strikes to air defense forces. Ukraine does not disclose the size of its drone fleet.
“Nobody has the experience using sea drones as we do,” said Thirteen, the drone pilot, who turned up for the interview wearing a ski mask, for security reasons. “There are no instructors, no textbooks. We are writing these books now.”
In a darkened warehouse, dozens of speedboats painted gray and black, making them harder to spot at sea and at night, rested on dollies in various stages of assembly.
Some were rigged only with cameras, for reconnaissance, some built with mechanisms to drop mines into the path of Russian ships. Most were equipped with triggers on their noses — three small rubber balls on springs — to detonate high explosives.
Using satellite connections, the pilots in the war room use consoles to steer the drones, which are designed to attack in swarms of six or so, boosting chances of penetrating defenses, such as deck-mounted machine guns, toward the hulls of Russian ships.
The latest successful sea drone strike for the defense intelligence agency was Nov. 10, when a swarm struck two Russian landing ships moored in a Crimean bay, sinking both, the program’s operators said in interviews.
Russia has responded with electronic jamming, and by placing booms across the mouths of harbors, mounting machine guns on its warships and sailing out of range for the drones. “With every new operation, we are learning and they are learning,” said Thirteen.
Scholars of naval warfare say the Ukrainian models have demonstrated how smaller militaries can defend coastal waters with drones.
The drones will not replace large surface ships anytime soon, according to Sidharth Kaushal, a research fellow and expert on sea power at the Royal United Services Institute in London.
But “the ability to harass and significantly damage disproportionately priced vessels is an impressive return on investment,” Mr. Kaushal said in a telephone interview.
Ukrainian sea drones, said Thirteen, the pilot who helped cripple the Sergey Kotov, have cleared a swath out to 200 or so miles from the Ukrainian coast. “It’s possible to push them back,” he said. “Russia’s reign on the Black Sea is over.”
Maria Varenikova contributed reporting.