Three days after Ukraine’s drone blast, Russia’s missile sub still hasn’t moved

Three days after a Ukrainian drone submarine infiltrated the Russian Black Sea Fleet's base in Novorossiysk in southern Russia and exploded, the target—the Improved Kilo-class attack submarine B-271 Kolpino—still hasn't moved from her original moorings, just a few meters from where the Ukrainian Sub Sea Baby drone triggered a warhead weighing potentially hundreds of kilograms.

That's an ominous sign for the battered Black Sea Fleet, which, after steady losses to Ukrainian missiles and drones, may now have as few as eight warships, including potentially just two Improved Kilos, capable of launching Kalibr cruise missiles at Ukrainian cities.

Many of the other warships inside the protected basin in Novorossiysk as of Monday—including corvettes, frigates, and at least one additional Improved Kilo—quickly departed Novorossiysk in the immediate aftermath of the Ukrainian attack.

But not Kolpino. Satellite imagery from Tuesday and Wednesday confirms: the 74-m diesel-electric submarine was, as of Wednesday afternoon, still moored to the pier where the Ukrainian drone attacked it.

Why "near misses" can cripple submarines

It's worth asking why. That Kolpino hasn't budged "allows one to suggest it may not be able to move at this time," Radio Free Europe reporter Mark Krutov noted. If the sub is indeed immobilized, it may be due to damage sustained to external or internal systems along the vessel's stern as a result of the shock wave from the massive, and very close by, underwater explosion.

After all, "the most probable threat" to a sub "does not involve direct contact of a ship with a mine" or other underwater munition, "but has the mine exploding in the vicinity of the ship, launching a high-pressure wave into the liquid," the Massachusetts-based Mitre Corporation explained in a 2007 study.

"During World War II, it was discovered that although such 'near miss' explosions do not cause serious hull or superstructure damage, the vibrations associated with the blast nonetheless incapacitated the ship, by knocking out critical components," Mitre continued.

Hoping for a direct hit

The Ukrainian state security agency, the vaunted SBU, had clearly hoped for a direct hit when it steered the Sub Sea Baby drone through the narrow opening into the Novorossiysk basin and past other moored warships to strike at Kolpino. The nine-year-old Kolpino is one of just three Improved Kilos left in the Black Sea Fleet after a series of Ukrainian missile strikes destroyed another sub of that type in Sevastopol in occupied Crimea in 2023 and 2024.

The battered Black Sea Fleet, which has lost around a dozen warships to Ukrainian attacks since February 2022, can launch Kalibrs from a pair of frigates as well as a trio of corvettes, but the Improved Kilos are the most survivable Kalibr launchers owing to their ability to submerge.

The Russians can't reinforce the Black Sea Fleet because Türkiye has closed the Bosphorus Strait, the only sea route into the Black Sea, since Russia widened its war on Ukraine 46 months ago. The subs the fleet has are likely the only subs it'll ever have until the war ends.

That makes Kolpino very valuable. And it incentivizes the Kremlin to lie about the vessel's condition. “Not a single ship or submarine, as well as the crews of the Black Sea Fleet stationed in the bay of the Novorossiysk naval base, were damaged as a result of the sabotage,” the Kremlin stated Tuesday.

A video accompanying the statement pointedly did not show Kolpino's stern, however. And it's along the stern where damage is likeliest. Satellite imagery seems to confirm that the submerged stern of the sub was potentially just a few meters from the Sub Sea Baby's point of impact on the pier to which Kolpino is moored.

Analysts have scrutinized all available post-raid imagery in a desperate effort to understand whether Kolpino is damaged, and how badly. The official video seemed to include a glimpse of chains tethering Kolpino to the pier—a possible sign the sub was flooding and in danger of rolling over. In fact, it appears more likely that the chains secure rubber bumpers that prevent the sub from colliding with the concrete pier.

No safe harbor for repairs

If there's meaningful damage, it's likely under the waterline or strictly inside the sub. In other words, invisible for now. But every day Kolpino doesn't move from her original moorings will fuel intensifying speculation that she can't move at all.

Worse for the Black Sea Fleet, there are no major submarine repair facilities in Novorossiysk. The only place where the fleet might repair Kolpino without somehow transporting her out of the Black Sea is in Sevastopol.

But repairs in Sevastopol would be extremely dangerous. That Improved Kilo the Ukrainians hit with a missile in 2023? It was in Sevastopol’s drydock for overhaul at the time of the attack.