When Russia invaded Ukraine in early 2022, the invaders also expected to reinforce and expand their control of the Black Sea. This included blocking Ukrainian grain exports, which would drive up prices for Russian grain exports. That financial goal was never met because Ukraine fought back and not only contested efforts to expand Russian control of the Black Sea but also disrupted Russian naval operations in the Black Sea and use of the Crimean Peninsula base for naval, air force and army operations. When the war began Russia had several warships in the Black Sea and these came under heavy attack by Ukrainian forces. This led to the destruction of the flagship of the Black Sea fleet and systematic attacks on the remaining Russian warships. Ukraine didn’t have any ships of their own for these attacks and had to improvise. Ukraine used armed UAVs (Unmanned Aerial Vehicles) and USVs (Unmanned seagoing vessels) for these attacks, as well as land-based guided missiles. This eventually forced Russia to abandon Crimean naval and air force bases. This included the major Crimean port and naval base of Sevastopol. The growing number of Ukrainian attacks on Crimea forced most of the Russian Black Sea Fleet to move. The UAVs and USVs carry explosive warheads to destroy military targets, including bases, ports, headquarters and airfields. While civilian targets are spared, the military facilities are a major source of employment. When these facilities are damaged, destroyed and shut down, the civilians begin to leave. Now Ukrainian forces are getting close to the narrow isthmus that connects Crimean to the mainland and the other access point, the Kerch Strait bridge in southeastern Crimea was also under constant attack. As the situation in Crimea deteriorates, corruption by local officials makes matters worse for the remaining civilians and persuades a growing number of them to leave.
In late 2023, advancing Ukrainian forces were close enough to the narrow isthmus connecting Crimean to the mainland that the only Russian rail line carrying supplies to occupied Crimea was within range of GMLRS missile attacks. These NATO supplied missiles were carried and launched from HIMARS vehicles. They had a range of 80 kilometers and were a constant threat to Russian supply lines, including ports and ships in the Black Sea.
Ukraine had already disabled the other rail supply route to Crimea, which used the Kerch Strait bridge. Ukraine used various types of UAVs, USVs and novel UUVs (unmanned underwater vessels) to do this, as well as destroy Russian air defenses in Crimea and drive the remaining ships of the Black Sea fleet to port on the east coast of the Black Sea. The largest of these eastern Black Sea ports is Novorossiysk, which had a small naval base facility added in 2012. Now it is being used to host the surviving remnants of the Black Sea Fleet. While Novorossiysk is mainly a commercial port, exporting oil and other goods produced in the area and handling most of the imports, most of that has been halted because of the Ukrainian unmanned weapons that now make the Black Sea a dangerous place for Russian ships of any type. Ukraine did this without a fleet of its own. The Russians were still able to launch missile attacks on Ukrainian ports using submarine launched cruise missiles as well as land-based missiles. These Russian attacks became less frequent as the Ukrainians advanced closer to the roads and railroads that supplied Crimea.