Ukraine has released footage of the incident, the Russian warship Ivanovets had a crew of 40, with 5 officers. All were lost as the ship sank so quickly, getting hit by three sea drones. The Ivanovets missile corvette was supposed to be out of range off the coast of Crimea. It wasn't. The ship had its hull punctured, sinking like the Titanic.

Those types of ships cost around USD 60 million to produce. Ukraine claims they can produce their long-range sea drones for around $250,000 each, and were possibly crowdsourced. Such drones are usually made with "off-the-shelf" components normally for commercial - rather than military - use. (Think AliExpress and the like.) The little country with no navy is in effect destroying the Russian navy with their ingenuity.

Source: Moscow Times

Ukraine’s Military Intelligence Directorate (GRU) said Thursday that its special forces had destroyed a Russian warship off the coast of annexed Crimea using a group of waterborne drones.

“The enemy ship was patrolling the Black Sea near Lake Donuzlav in occupied Crimea,” the GRU said in a statement.

Ukrainian military officials identified the vessel as the Ivanovets missile corvette.

“As a result of a number of direct hits to the hull, the Russian ship suffered damage incompatible with further movement,” the GRU’s statement read, adding that the operation took place overnight Wednesday.

“The Ivanovets rolled to the stern and sank.”

A video accompanying Thursday’s statement showed what appeared to be several waterborne drones striking into both the sides and the stern of the warship.

The Moscow Times could not independently verify the video.

Ukraine’s GRU claimed that Russian search and rescue operations for the ship and its crew were “not successful,” but it did not specify further, nor did it mention if there were any casualties from the purported attack.