The navy learned several valuable lessons from the loss of both submarines, even though the exact cause of both losses is unknown. After the loss of the Thresher, the navy established the SUBSAFE program, where all seawater valves, and all critical parts and equipment, have strict quality control standards, and are fastidiously tracked within the supply system. As a storekeeper I ordered, inventoried, and stored all manor of SUBSAFE parts.
The loss of the Scorpion caused the navy to review, and revise it's overhaul standards. The Scorpion was one of several boats that the navy made to rush through,or skip entirely, scheduled overhaul periods, including periods in dry dock, as a cost saving measure . I understand that the Scorpion was a very unhappy boat, with constant equipment failures, and low crew moral. The generally accepted cause of her loss, is a battery explosion. I believe this explanation totally, because submarine batteries are prone to spectacular failures. If the Soviets sank her, that would be and act of war that could have easily led to WWIII, and the Soviets knew it! The Russians are a lot of things, but stupid isn't one of them.