The Russian Black Sea Fleet entered the Ukrainian war as the unchallenged master of that body of water. Ukraine's own fleet was small and less modern, and the opening weeks of the war were dominated by news of the Russian fleet launching missile attacks and threatening naval landings that pinned down Ukrainian forces in Odessa. But when the Moskva sank, the pattern of naval activity changed dramatically. Now, the Russian fleet stays mostly away from the Ukrainian cost, nervous of missile, drone, and air threats posed by an opponent whose own navy is mostly neutralised. In this episode I look at the evolving war in the Black Sea, the evolution and role of the Russian navy there, the sinking of the Moskva - and what if any lessons foreign observers might be taking from the war at sea so far.