The USS Thresher was launched in 1960. The first ship of her class (nuclear powered attack), the leading edge of U.S. submarine technology, she was fast, quiet and deep-diving. On April 10, 1963, while engaged in a deep test dive 220 miles east of Cape Cod, Massachusetts, the USS Thresher, SSN 593, was lost at sea settling at a depth of 8,400 feet with all aboard. The crew of 112 Naval Officers and Enlisted personnel and 17 civilians died.