Microsoft co-founder Paul Allenís father served in the Navy during World War II. To honor his dad and as a service to history, the billionaire entrepreneur and philanthropist has funded several expeditions to find famous sunken naval vessels. He uses a 250-foot research vessel called R/V Petrel, retrofitted with state-of-the-art equipment capable of diving 3Ĺ miles. "As Americans, all of us owe a debt of gratitude to everyone who served and who continue to serve our country for their courage, persistence and sacrifice," Allen said. Here are three of the most notable discoveries.USS LEXINGTON, FOUND MARCH 2018. This U.S. aircraft carrier was discovered about 500 miles off the eastern coast of Australia, 2 miles below the surface of the Coral Sea. It played a key role in the May 1942 Battle of the Coral Sea, the first time in history that opposing warships fought without seeing each other, using only warplanes as their weapons. The fight was a draw, but the U.S. forces blunted a Japanese naval offensive that would have endangered shipping lanes to Australia. Known as "Lady Lex," the aircraft carrier was hit by several torpedoes and bombs before the commander ordered the ship abandoned. In all, 2,770 crewmen and officers were rescued, including the captain and his dog Wags, the shipís mascot. Friendly fire was used to send the ship to the bottom and keep it from possible recovery by the Japanese. The Battle of the Coral Sea diminished the Japanese forces enough to help the United States to win the famous Battle of Midway a month later, turning the tide of the Pacific War.USS WARD, FOUND DECEMBER 2017. This ship fired the first American shots of anger in World War II, just over an hour before the attack on Pearl Harbor. The destroyer had been patrolling the harbor entrance when the officer-of-the-deck spotted a midget submarine trailing a U.S. warship into the harbor. The Ward steamed toward the submarine, and its second shot hit the subís conning tower. "We have attacked, fired upon and dropped depth charges on a (Japanese) submarine operating in defensive sea areas," Lt. William Outerbridge reported. It was 6:45 a.m. on Sunday, Dec. 7, 1941. Japanese planes began their attack 70 minutes later, the "day of infamy" that brought the United States into World War II. The Ward itself was lost exactly three years later in a kamikaze attack near the Philippines.USS INDIANAPOLIS, FOUND AUGUST 2017. The cruiser had just completed a secret, high-speed mission from California to deliver components of "Little Boy," the first atomic weapon ever used, to Tinian Island in the Pacific. A B-29 dropped that bomb on Hiroshima on Aug. 6, 1945. Days before that, the Indy had already set sail for the Philippines, but it was torpedoed by a Japanese submarine. Although about 800 of the shipís 1,196 sailors and Marines survived the sinking, fatal communications errors and other mistakes meant the Indyís disappearance went unnoticed until a passing aircraft spotted survivors several days later. After days and nights adrift in shark-infested water, only 316 men survived. It was and remains the Navyís worst disaster at sea. The Indy was found in the Philippine Sea, nearly 3Ĺ miles below the surface. Because this is a war grave and property of the U.S. Navy, the specific location was provided only to the Navy for it to administer.