A U.S. Navy Sikorsky SH-3A <i>Sea King</i> from Helicopter Anti-Submarine Squadron 4 (HS-4) "Black Knights" hovers over a submarine. The submarine appears to be a "fleet snorkel"-modernized <i>Balao</i>/<i>Tench</i>-class submarine. HS-4 was assigned to Carrier Anti-Submarine Air Group 55 (CVSG-55) aboard he aircraft carrier USS <i>Yorktown</i> (CVS-10) for a deployment to the Western Pacific and Vietnam from 28 December 1967 to 5 July 1968.
U.S. Navy
U.S. Navy photo <a rel="nofollow" class="external autonumber" href="http://www.navysite.de/cruisebooks/cv10-682/205.htm">[1]</a> from the <a rel="nofollow" class="external text" href="http://www.navysite.de/cruisebooks/cv10-682/index_021.htm">USS <i>Yorktown</i> (CVS-10) 1967-1968 cruise book</a> available at <a rel="nofollow" class="external text" href="http://navysite.de/cruisebooks/index.html">Navysite.de</a>