US Naval Air Station Patuxent River "Submarine Simulator". The simulator was used as an ASW training device "find the snorkel and kill the submarine". It used captured German submarine snorkel for the topside portion.
Emil Hymowitz, electrical engineer & head of one of the search radar units at Patuxent, rides a bicycle seat on the Snorkel Simulator & operates it manually. This photo was run in the December 1956 issue of Popular Mechanics.
USN photo, 1 June 1956, from the files of the Vallejo Naval & Historical Museum via Darryl L. Baker.