On October 28th, Ukraine used a combined force of explosives-carrying UAVs and ASVs (autonomous surface vessel) bomb boats against three Russian frigates and several other ships docked at the Sevastopol naval base in Crimea. The night attack was detected and machine-guns and autocannon were seen firing on the attackers. One of the frigates and an amphibious ship were hit by the ASVs and damaged. This attack upset the Russians who responded by launching more attacks on Ukrainian civilians and ending its cooperation in allowing Ukraine to export grain that was needed in many Middle Eastern nations that get a lot of their imported food from Ukraine. The additional Russian attacks on Ukrainian cities led to higher than usual losses for the cruise missiles employed. Turkey had negotiated the grain export deal and responded to the Russian action by putting Turkish flags on the grain ships. Turkey is a member of NATO and an attack on the reflagged grain ships would be an attack on a NATO nation that would mean all NATO nations would be at war with Russia. This led Russia to quietly reinstate its cooperation with the grain export arrangement.
A week later Russia scored a rare naval victory of its own when it used one of its new (since 2019) Lancet Loitering Munitions to attack a stationary Ukrainian gunboat in a reservoir on the Dnieper River north of Kherson City. The small gunboat was damaged rather than sunk, largely because the Lancet carries only a small warhead containing two kg (4.4 pounds) of explosives. Lancets are regularly used on one-way reconnaissance missions or attacks on Ukrainian air defense systems and other unarmored targets. Before that Lancet was used several times in Syria.
What angered the Russians most about the Sevastopol attack was that it was another embarrassing (for the Russians) demonstration of Ukrainian ingenuity and improvisation. Bomb-boats are nothing new as they are the latest incarnation of centuries-old fire ship tactics and the use of small boats carrying explosives used in the 19th and 20th century. A month before the Sevastopol attack one of the Ukrainian ASVs, which was not carrying explosives, washed up on a Crimean beach. Russia did not release details but a photo did get it out and indicated that this was a rather sophisticated ASV that was equipped with optical sensors, water jet propulsion and the ability to be remotely controlled. This ASV was apparently on a reconnaissance mission when equipment failure disabled it. The only other group currently using bomb boats are the Shia rebels in Yemen who regularly send these boats, propelled by an outboard engine, at warships and cargo ships in the Red Sea. Most miss their targets but they are a threat These Shia rebels are backed by Iran with tech advisors and smuggled weapons.
The attack on Sevastopol was launched from nearly 300 kilometers away. The Ukrainians managed to get seven ASVs and nine UAVs across that distance at night and into Sevastopol harbor in a coordinated attack. This was unprecedented in naval warfare and it worked. Russia has to come up with some kind of defense against a form of naval warfare never encountered before. Russia has to do this with its Black Sea fleet, which includes amphibious ships, maritime infantry, a few maritime aircraft and even some submarines that have so far been a major disappointment. The Black Sea Fleet in general has been a disappointment, suffering several defeats but achieving little in the way of victories other than blocking cargo ships from exporting grain from Ukraine in an effort to deal with enormous food shortages caused by the Russian invasion that halted a major portion of the global grain exports. The grain ships are operating again, mainly because NATO member Turkey lets them fly the Turkish flag. Since the attack more of the warships based in Sevastopol have been moved to the port of Novorossiysk, which is in southern Russia, south of the Kerch Strait. If Ukraine attacks, or seems able to attack Sevastopol again, all the Black Sea fleet ships ships can be moved to Novorossiysk
Upgrading and reinforcing the Black Sea fleet is not an option as long as Russian ground forces are losing their battle against a month-long Ukrainian counter offensive that appears unstoppable. This situation does little for the reputation of the other Russian Baltic Sea, Northern and Pacific fleets. These fleets are still dangerous but unless they are somehow a lot more efficient than the Black Sea fleet, not as capable as they were once believed to be.