Is Russian Black Sea Fleet trully trapped or reinforced in Black Sea?

Defense Express explains the situation in the Black Sea.

While most Russian ships in the Black Sea can no longer rely on their primary base in still-occupied Sevastopol, they have largely relocated to Novorossiysk. Russia has even announced the establishment of a new permanent base in de facto occupied Abkhazia.

It might appear that all Russian Black Sea Fleet vessels are confined to the region until the Bosphorus is accessible to warships again, which can only occur after the conflict's resolution. However, in reality, Russia has the capacity to withdraw and strengthen a specific category of ships, particularly small missile ships designed for the possibility of inter-fleet river crossings. Some of these vessels were constructed near Kazan at the Zelenodolsk Shipyard on the banks of the Volga River.

These ships include Project 21631 Buyan-M, Project 22800 Karakurt, Project 1239 Syvuch, patrol ships of Project 22160 Vasily Bykov, as well as smaller class vessels, including Molniya-1 missile boats, with a draft of up to 4-4.5 meters.

From a navigational perspective, Russia can utilize the crossing from the Azov Sea to the Don River, then through the Don-Volga Canal to the Volga River, which is already connected to the Baltic and White Seas via a canal network. However, the feasibility of replenishing ships in the Baltic Sea is questionable, as Russia has experimented with relocating some ships from the Baltic to Lake Ladoga.

This implies that, in theory, Russia can withdraw a significant portion of the Black Sea Fleet through river routes. Nevertheless, without access to the Bosphorus, submarines like the Varshavianka project, frigates like Admiral Grigorovich project 11356P, and patrol ships such as Burevestnik project 1135 will remain in the Black Sea.

Moreover, the option for inter-fleet river crossings works in both directions. Thus, Russia has the potential to reinforce the Black Sea Fleet by deploying small missile ships from the Baltic or the Caspian Sea. For instance, up to three Buyan-Ms from the Caspian Sea, and three more Buyan-Ms and three Karakurt from the Baltic Sea.

However, this opportunity will remain viable until the Ukrainian Armed Forces reach the Azov Sea coast, at which point the entire water area will be within the firing range of coastal anti-ship systems and, in the case of access to Taganrog Bay, even artillery.