Keywords: S2F-1 Tracker of VS-21 in flight in 1956.jpg A U S Navy Grumman S2F-1 Tracker of Anti-submarine Squadron VS-21 Lightning Bolts in flight with radar and MAD-sensor deployed VS-21 was assigned to the aircraft carrier USS Princeton CVS-37 for a deployment to the Western Pacific and the Indian Ocean from 5 January to April 1956 U S Navy photo http //www navysite de/cruisebooks/cv37-56/030 htm from the http //www navysite de/cruisebooks/cv37-56/index_002 htm USS Princeton CVS-37 1956 cruise book available at http //navysite de/cruisebooks/index html Navysite de 1956 USN PD-USGov-Military-Navy Grumman S-2 Tracker Sea Control Squadron 21 United States Navy Aerial photographs of military aircraft in flight |