The Russian Navy is still larger and more powerful than the Ukrainians in the northern Black Sea. Despite the dominance on paper, the Russian Navy is in retreat after several successful attacks by small Ukrainian forces.
The October 29 attack on Sevastopol, in which unmanned surface ships (USVs) with unmanned aerial vehicles attacked the Russian Black Sea Fleet, seems to have pushed them further into the envelope of their naval bases. Their two Admiral Grigorovich-class frigates, the largest and most capable ships after the sinking of the Slava-class cruiser RTS Moscow (121), were mostly in port. One of them, flagship of the Black Sea Admiral Makarovreportedly suffered damage in the October attack.
Increased defenses after the September Discovery of a probably Ukrainian unmanned surface ship near Sevastopol do not seem to have succeeded. In the largest attack on October 29, several of the USVs entered the harbor. Footage of the drone’s eyes released shows them operating near warship docks deep within the base. Russian reports that drones reached Pivdenna Bay suggest they approached the submarines. Only one Kilo-class submarine was present at the time, according to USNI News.
Floating defenses around the main warship dock were pulled ahead of the line of warships, satellite imagery showed. The supply docks, deeper inside the port, also have floating booms deployed. The use of these barrages is still intermittent, but the Russians are deploying them more than before.
The evolution of exploitation patterns goes beyond frigates. Some coastal patrol areas, which have hitherto been under the jurisdiction of the Federal Security Service, or FSB, Border Guard, now appear to have Russian Navy vessels. Missile corvettes were seen patrolling where lighter FSB patrol ships used to patrol, ship spotters say
Sevastopol was the main base of the Russian Navy during the war and home to most of the Black Sea Fleet, its headquarters and flagship. Although this is still the case, some assets have also been transferred to Novorossiysk. This base, which has been expanded and improved in recent years, has been a hub for non-Black Sea Fleet warships brought in as part of the preparation for the invasion. The four upgraded Kilo-class submarines of the Black Sea Fleet are increasingly seen there rather than in Sevastopol. But Novorossiysk is much further from the action and Sevastopol remained the hub.
It is difficult to assess how long the heightened state of readiness in Sevastopol will last after the October 29 attack. The Russian Navy has so far been slow to adapt and has been operating continuously since the start of the invasion of Ukraine.
During the first months of the war, Sevastopol appeared inaccessible for the smaller Ukrainian navy, but the Russian forces implemented certain defensive measures. The Russians deployed fighting dolphins at the harbor entrance to guard against Ukrainian divers and reinforced their air defences. But overall the base appeared normal, almost complacent. High-value warships, including Moscow, continued to use their berths in peacetime. And the boom through the harbor entrance was mostly open.
That the USV could make it to Sevastopol, seemingly undetected, was a wake-up call for the Russian Navy. Damien Symon, a independent defense analyst, noted that the boom across the harbor entrance, normally open, was suddenly routinely closed. And, at the end of September, the Russians built a new barrage along the main berths for warships. This net, which appears to be aimed at submarine threats, protects the row of warships from a flanking attack. It can also extend to cover the front of the row of warships.
For a time, the number of dolphin enclosures at the entrance to the harbor was reduced from two to three. These do not defend against USVs, but would deter Ukrainian divers from attempting sabotage missions. A rotation of the animals or an increase in their patrols could explain the increase.