1September, 937, U-23 (the third captain of U-23), a type 2 U-boat, was transferred from U-35 submarine. Shortly after the outbreak of World War II, he commanded the U-23 to achieve its first success in the British North Sea near the Scottish coast. Later, he successfully laid nine mines in the heavily guarded Scottish Eel Bay. 1940 65438+1October 12 sank the Danish oil tanker "Denmark", which was his first major victory. 1 month later, sank the British destroyer Bold (1, 375 tons).
1940 In April, Otto left U-23 and was appointed as the captain of the new type 7 submarine U-99 in the same month. Two months later, U-99 left his training base in Kiel, Germany, and began his most brilliant "hunting and diving". In this attack, he made nine surface attacks on the allied escort fleet and sank several allied ships. In particular, three British auxiliary cruisers refitted from merchant ships were sunk: Laurentiak (18724 tons), Patroclus (1 1.3 14 tons) and Fofar (16402 tons). By 1940, 165438+ 10, he had sunk more than 46,000 tons of ships. Since then, "Silent Otto" has become the "king of tonnage" among many U-boat captains, and no one has surpassed it so far. He also has a famous saying-"A torpedo for a ship". His tactical point is to go deep into the middle of the escort fleet and fire torpedoes from the direction that is easy to attack at close range.
But his good fortune didn't last. 194 1 In March, he set sail for the last time. After sinking the allied ship 10, on 17, he and Joachim Spock's U- 100 were intercepted by the British destroyers "rambler" and "Wannock" when attacking the convoy of HX 120. After the "rambler" found the U-99, it immediately launched a pursuit to cast a deep-water bomb. After many attacks, the hull of U-99 was seriously damaged and forced to be captured from the water. Otto and 43 crew members got off the submarine (note: the chief engineer on board was dead) and were immediately captured by the British ship. Then the first mate of the U-99 submarine was sunk.