William died in the White Ship tragedy of 25 November 1120. The Prince and his companions had been crossing the English Channel from Barfleur in the White Ship, the swiftest and most modern ship in the royal fleet. William and his party had remained drinking on the shore until after dark, confident that in a fast ship and on the still sea the delay would have no real effect. Consequently, it was the middle of the night when the drunken helmsman rammed the ship into a rock in the bay. The crew and passengers were unable to lever the ship off the rock, or prevent the ship from filling with water; however, William and several of his friends managed to launch a life-dinghy. At the last minute, William dashed back to rescue his illegitimate half-sister, the Countess of Perche; when they and several others threw themselves into the small dinghy, it, "overcharged by the multitude that leapt into her, capsized and sank and buried all indiscriminately in the deep."[4]
Henry of Huntingdon, speaking of the disaster, wrote that William, "instead of wearing embroidered robes...floated naked in the waves, and instead of ascending a lofty throne...found his grave at the bottom of the sea."[5]
William's wife was on another ship at the time of the wreck, and survived him to become a nun and eventually, Abbess of Fontevrault.