Philadelphia Reflections

Loss of USS Thresher

Front Cover

Although there has been much speculation as to the cause of the Thresher loss, the committee must conclude from its own study of the facts developed that the specific cause is not known. It was important, therefore, that all aspects of the Thresher's design, construction, and operation be reviewed to uncover whatever weaknesses may have existed at the time, whether or not they were the proximate cause of the accident. Investigations revealed that in parts of the ship, practices, conditions, and standards existing at the time were short of those required to ensure safe operation of the Thresher. Basically, the ship was built to two standards. the standards of design and construction for the nuclear powerplant were more stringent than the rest of the ship. Of particular note is that the technical specification requirements were not greatly different, but that adherence to them was far more strict for the nuclear powerplant than for the rest of the ship. It is also obvious that while nuclear power was revolutionizing the submarine as a weapons system during the past ten years, the more conventional aspects of the submarine and its safety devices were not keeping pace with the more stringent performance requirements of greater endurance, higher speed, and deeper submergence. For example, the design and limited blowing capability of the deballasting system which might have been adequate for the World War II, and postwar conventional submarines were inadequate as an emergency system for the larger, deeper diving, higher performance nuclear submarines. Similarly, the use of the less costly method of joining metal piping systems by brazing is questionable for hazardous saltwater lines subject to the tremendous pressures of deep depth as compared to welding which is a more expensive and time-consuming method. Corrective action is now being taken by the Department of the Navy in both of these areas.

Originally published: Friday, March 18, 2011; most-recently modified: Thursday, May 23, 2019