(NOVOROSSIYSK, RUSSIA) – Ukraine’s Security Service said it has carried out a naval operation that critically damaged a Russian diesel electric submarine at the Black Sea port of Novorossiysk, marking what Kyiv described as the first recorded strike of its kind using underwater drones.
According to a statement from the Security Service of Ukraine, known as the SBU, the operation involved Sub Sea Baby underwater drones targeting a Project 636.3 Varshavyanka class submarine, referred to by NATO as the Kilo class. The SBU said the explosion caused severe damage, effectively putting the vessel out of action.
Ukrainian officials said the submarine was carrying four Kalibr cruise missile launchers that Russia has used in strikes against Ukrainian territory. The operation was described as a joint effort between the SBU’s 13th Main Directorate of Military Counterintelligence and the Naval Forces of Ukraine.
The Varshavyanka class submarine is considered one of the quieter vessels in Russia’s fleet and is often nicknamed the Black Hole because of its sound absorbing hull design, which makes it harder to detect by sonar. Ukrainian officials said the submarine had been stationed in Novorossiysk after earlier Ukrainian Sea Baby surface drone operations forced Russian ships and submarines to leave Sevastopol Bay in Crimea, which is occupied by Russia.
Ukrainian sources estimated the value of the damaged submarine at about 400 million US dollars. They added that, due to international sanctions and rising production costs, building a comparable vessel today could cost as much as 500 million US dollars.
Estimated Cost of Varshavyanka Class Submarine
| Item | Estimated Cost |
|---|---|
| Original construction cost | USD 400 million |
| Estimated replacement cost under sanctions | USD 500 million |
The SBU said the operation formed part of a broader campaign targeting Russian military assets at sea. In recent months, Ukrainian drones have been credited with striking air defence systems and offshore energy infrastructure used by Russia, including oil platforms in the Caspian Sea.
Ukraine has increasingly relied on domestically developed drone technology to offset Russia’s numerical advantage at sea and to disrupt missile launch platforms used by Moscow. Russian authorities have not publicly confirmed the extent of the damage, and independent verification remains limited.
The strike adds to pressure on Russia’s Black Sea Fleet and comes as Ukraine continues to frame its maritime operations as defensive actions aimed at reducing the ability of the Russian dictator Vladimir Putin’s forces to launch attacks on Ukrainian cities and infrastructure.
