This is what Admiral Oliver is speaking about when he refers to the DEFCON status being elevated?
"That evening [the 9th of May, 1972] the division commander Contra-Admiral I.I. Vereniki called me to his office and said succinctly, 'Go to the South China Sea and support our Vietnamese brothers.' I also found out from him that behind us were going Echo I SSGN K-45 and Echo II SSGN K-57"
1. "Cold War Stories: Guardfish vs. K-184, Part"
"Details about American submarine special operations aren't very common.. . ."
"There are exceptions. There is a little bit of operational detail of one particularly tense, wartime operation at Guardfish.org, a website dedicated to the men who have served on board the USS Guardfish (SSN 612). Entitled The Saga of the 1972 Guardfish Patrol, it is a little bit of Commander David Minton's account of operations by the USS Guardfish that ranged from the Sea of Japan to the South China Sea in the late spring of 1972."
2. "Cold War Stories - Guardfish Vs. K-184, Part II"
"K-184 suffers a potentially significant casualty and Captain Minton sends a CRITIC"
A Soviet era nuclear class Echo II class submarine as it would have appeared on the surface preparing to fire missiles at an American aircraft carrier. Sub must surface, raise missiles, receive an over-the-horizon targeting location from a high flying Tu-95 naval aviation warplane, then fire those missiles with nuclear warhead.
3. "Cold War Stories - Guardfish Vs. K-184, Part III"
"K-184 continues her transit toward the Gulf of Tonkin. Damage control drills are conducted and hilarity ensues"
Soviet era warships responding to the American mining of Haiphong harbor during the Second Indo-China War. Three nuclear powered submarines deployed to counter the American aircraft carrier presence Yankee Station. Each of those submarines armed with anti-ship cruise missiles tipped with atomic warheads.
Soviet submarines shadowed and tracked by the USS Guardfish. They were "eyeball to eyeball" and as during the Cuban Missile Crisis the "other guy blinked"?
BUT not DEFCON ONE!