19. The Yorktown search was the most difficult of all for Ballard’s research team
The waters which swallowed USS Yorktown are 16,650 feet deep, a mile deeper than those in which the wreck of Titanic was found in 1985. To find the wreck, an expedition was formed by the National Geographic Society, led by Dr. Ballard and supported by the US Navy, who assigned personnel to the team. The Navy’s participation provided valuable real-world training for operators of its underwater search vehicles and submarine rescue teams. Ballard used techniques developed during the Scorpion expedition and honed in other searches during the difficult search for the sunken aircraft carrier.
During the search for Titanic and even more so for the Bismarck wreckage, the technicians and researchers discovered that as a ship strikes the bottom it does not do so gently. Instead, it slams into the bottom, its velocity dependent on the depth it descended, and the violence displaces large amounts of mud and bottom debris. The mud is often displaced in a circular pattern around the wreck, with clots the size of huge boulders. Once a clot is sighted, additional clots are sought until the arc of the circle can be computed, allowing the search to then focus on the center, where the wreck is found.
