"Sculpin" returned to San Diego on 13 November 1971 and began preparing for a secret deployment to track gun smuggling trawlers in the South China Sea. The deployment began on 5 January 1972 and on 10 April 1972 "Sculpin" lay in wait south of the Chinese island of Hainan. After having spotted its target the "Sculpin" followed the smugglers for 2,500 miles to the Southern coasts of South Vietnam, where on 24 April a South Vietnamese destroyer escort under the direction of "Sculpin" sank the Chinese trawler. With its mission a success the "Sculpin" returned to port on 24 July.