On 16/12, Russia's defense television channel released a video showing a Project 636.3 attack submarine docked at the Novorossiysk naval base. The submarine appeared to have no visible damage to its hull. Some concrete debris was neatly stacked nearby, apparently from the cleanup of damaged material at the pier.

Colonel Alexey Rulev, head of the Russian Black Sea Fleet's press service, denied reports that the submarine was destroyed or heavily damaged following an attack by Ukraine's Sub Sea Baby uncrewed underwater vehicle the previous day.

"The enemy's uncrewed underwater vehicle sabotage attempt failed. No Black Sea Fleet surface ships or submarines in Novorossiysk were damaged, nor were any sailors injured in the attack. All are performing their normal duties," he stated.

Commercial satellite imagery taken on 16/12 showed a large section of the pier was damaged in the attack. This damage corresponds to the location where the uncrewed underwater vehicle struck and detonated in a video released by Ukraine.

"The explosion occurred about 20 meters from the submarine's stern. There are no indications that the warship sustained damage in the attack. Satellite images also do not show measures typically undertaken when a submarine is heavily damaged, such as equipment to help the submarine surface or oil containment booms," observed Joseph Trevithick, an editor at the US military news site War Zone.

Two submarines anchored near the explosion site have since moved, while other warships remained in their positions. "Panoramic photos of the Novorossiysk naval base after the attack show four Project 636.3 submarines. There is no evidence that Russia replaced the attacked submarine with an identical one to conceal the extent of any damage," Trevithick noted.

The pier at Novorossiysk base, Russia, in photos taken on 11/12 and 15/12. *Photo: Vantor*

However, the open-source intelligence account Archer83Able on social media suggested that the Ukrainian uncrewed underwater vehicle could have at least impacted the Russian submarine's propeller. This is because the propeller is submerged and closer to the explosion's center than the visible stern.

Attacks by Ukrainian uncrewed surface vessels have forced the Russian Black Sea Fleet to relocate warships from their homeport in the Crimea peninsula to Novorossiysk, approximately 300 km to the east. Russia also constructed multiple layers of barriers using barges and floating buoys, and deployed patrol aircraft to protect its forces.

These defensive measures are primarily designed to counter uncrewed surface vessels and appear unsuitable for stopping uncrewed underwater vehicles.

"The attack is another example of the continuous adaptation between weapons and countermeasures, which has become a prominent feature of the Russia-Ukraine conflict. Russia will likely deploy new measures to counter uncrewed underwater vehicles, a capability Ukraine spent considerable time developing," Trevithick stated.

Nguyen Tien (According to WarZone, AFP, RIA Novosti, Zvezda)