PRE WW 2
30 July 1919 S 27 3 killed – After decommissioning on 2 April 1919, S 27 was selected as a target for depth charge testing. During a pre-test inspection on 30 July the boat unexpectedly flooded at sank at it’s mooring near Niantic Bay. Three of the six-person inspection team died in the dinking. At a depth of 13 1/2 fathoms the SS 27 was too deep for salvage and was struck from the Navy List.
WW 2
31 July 1942 SS 216 Grunion 70 killed all hands lost, USS Grunion (SS-216) vanished during her first patrol in July 1942, after firing at the freighter Kano Maru near kiska. Grunion was armed with the then, later modified, faulty Mark 14 torpedo. After discovering the wreck of Grunion damage analysis and Japanese records suggest one torpedo probably circled back and struck her periscope shears and crippled her control surfaces fatally wounding Grunion. Her rediscovery 64 years later by her captain’s sons closed one of the last unsolved U.S. submarine mysteries of World War II.
11 July 1943 SS 275 Runner departed Midway on her third War Patrol to the Kuril islands off Northen Japan on 27 May. Runner was never heard from again. Japanese records reviewed after the war indicate she most likely sank a cargo ship near Hokkaido on 11 June and was then under attack on 22 June 78 Killed. The exact date of Runners loss is uncertain because off conflicting entries in Japanese records.
4 July 1944 SS 133 49 killed all hands lost off the island of Oahu while conducting training exercises with the Coast Guard Cutter Reliance. No cause of sinking was determined and the depth was too great for recovery.
26 July 1944 SS 273 Robalo was lost after radioing that she had sighted the Japanese battleship Fuso. No further messages were received. There were 77 killed and 4 taken prisoner, none survived as POWs
(pictured: USS Robalo SS 273 )