As the Vietnam conflict escalated the USNS Card served with the Military Sea Transport Service under charter to the U.S. Navy. Manned by a civilian crew,
she carried troops and aircraft to Vietnam. Early on the morning of May 2, 1964, as she was moored at a Saigon dock, a North Vietnamese frogman planted
a charge that blew a hole in her hull. The Card sank in about 20 feet of water, but 17 days later, the Card had been raised, pumped out and made ready
for towing to a repair facility by two Navy tug boats. First to Subic Bay, P.I. then on to Yokosuka, Japan where the major work was finally accomplished.