Today, 86 years ago, on 14 October 1939 (Calendar 2 September 1939), the British warships "Royal Oak Tree" were hit by the Royal Oak Tree as the latest victims of the submarine battle threatening merchant ships and battleships On 14 October 1939, the German Navy submarines drowned the British warships "Royal Oak Tree" with torpedoes, killing more than 800 soldiers. This shocked the British because they believed that the thickened body of the warships could resist the torpedo attacks, but the fact is the opposite, only 396 people survived. Two months later, the "Athenia" submarine was also sunk by the Nazi submarines, with 112 people killed.