How the Ukrainians – with no navy – defeated Russia’s Black Sea Fleet

Starting in the spring of 2022, with little external help, the Ukrainians began to design and build the world's first combat-deployed sea drone, known as the Magura-V5. This explosive-laden vehicle was designed to do what many thought impossible: travel long distances across stormy seas, undetected by radar, and deliver 500 to 700 pounds of explosives to distant targets....

https://theconversation.com/how-the-ukrainians-with-no-navy-defeated-russias-black-sea-fleet-234259