One would expect that Cold War "special ops" involving U.S. nuclear-powered submarines are shrouded in secrecy. Other American sub activities during that era, however, are also hidden, one for a very strange reason.
In 1971, after he had spent two and a half years of duty in the White House as naval aide to President Richard Nixon, Commander Chuck Larson was ready to go back to sea. He was ordered to be executive officer of the attack submarine Sculpin (SSN-590), under Commander Harry Mathis. For several months the boat went through workups off the coast of southern California to prepare for a deployment to the western Pacific. That deployment included active participation in the Vietnam War.