Sorry, but the USS Yorktown, CV-5, was sunk due to enemy action at the Battle of Midway. After having suffered Japanese air attacks that damaged her mightily, repair crews were trying to stem flooding when the Japanese submarine I-168 torpedoed "The Fighting Lady" while also breaking the back and sinking the Destroyer USS Hammann (DD-412) that was beside the Yorktown.
From http://www.geocities.com/Pentagon/Quarters/8791/cv5hist.html
The second attempt at salvage, however, would never be made. Throughout the night of the 6th and into the morning of the 7th, "The Fighting Lady" remained stubbornly afloat. By 0530 on the 7th, however, the men in the ships nearby noted that the carrier's list was rapidly increasing to port.
Realizing there was no hope to save her, all who were able, from the other ships watched. With respect, they removed their hats. Some cried. Many muttered "The old York's going down. The old York's going down". At 0701, as if tired, the valiant flattop turned over on her port side, gave a loud groan, and sank in 3,000 fathoms of water, her battle flags flying.