The naval battles of World War II were not inferior in their significance and drama to many land battles. However, their circumstances are still a mystery. How was the daring attack of the German submarine U-47 the famous Gunther Prin on the English base of the Scapa Flow Navy prepared and carried out in 1939, during which the battleship Royal Oak was sunk? What caused the death in 1943 of the leader "Kharkov" and two destroyers, "Merciless" and "Capable," and why, after this tragedy, Stalin forbade the use of ships of the Black Sea Fleet in military operations until the end of the war? Did American scientists really conduct a dangerous experiment with the crew of the destroyer Eldridge in 1943, after which some people lost their minds and the ship was decommissioned? These and other questions are answered in his new book by writer-journalist V. Shigin.