(SS-192: displacement: 1,450 (surface), 2,350 (submerged); 1ength: 310'6", beam: 27'1", draft: 13'8"; speed: 20 knots (surfaced), 8.75 knots (submerged); complement: 55; armament: 8 21" torpedo tubes, 1 3" gun, 2 .50 cal. machine guns; class: Sargo)
Squalus (SS-192) was laid down on 18 October 1937 by the Portsmouth Navy Yard, Portsmouth N.H.; launched on 14 September 1938, sponsored by Mrs. Caroline Brownson Hart, wife of Rear Admiral Thomas C. Hart; and commissioned on 1 March 1939, Lt. Oliver F. Naquin in command.
After fitting out at Portsmouth, the submarine began a series of test dives off the Isle of Shoals starting on 12 May. After successfully completing 18 dives, the boat made another trial dive on the morning of 23 May with a complement of 56 crew members and three civilian contractors. At 0740, just after the submarine submerged, the main engine air induction valve failed and water poured into the boat's after engine room. The submarine sank stern first to the bottom, coming to rest keel down in 40 fathoms (240 feet) of water.
During the disaster, 26 men were trapped and lost in the flooded after portion of the ship. This left 32 crew members and one civilian alive in the forward compartments of the submarine. The survivors sent up a marker buoy and then began releasing red smoke bombs to the surface in an attempt to signal their distress.
Sculpin (SS-191), sent to the area later that morning, spotted a smoke bomb at 1241 that afternoon and marked the spot with a buoy. She was joined later that day by tug Penacook (YT-6), tug Wandank (AT-26), and Coast Guard vessels No. 158, No. 409, and No. 991. Divers and submarine experts, including the Experimental Diving Unit from Washington, DC, also converged on the location. During this preparatory period, the 32 survivors below spent a cold night trapped inside Squalus and began to suffer from the effects of chlorine gas released from the battery compartment.
At 1014 the following morning, after the arrival of submarine rescue ship Falcon (ASR-2), a preliminary observation by a Navy diver determined a salvage operation was possible. At 1130, Falcon (ASR-2)