[August]

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. Work began on 11 July and by the first of December the repairs were completed. It took thousands of man-hours, much new equipment and considerable money. Once again the USNS CARD proudly sailed the seas again

http://www.usscard.org/history.asp

Google is your friend...