In Memoriam - USS Grampus (SS-207) - Lost 5 March 1943
Very little is known for certain about the demise of USS Grampus (SS-207).
On 2 March 1943, she and USS Grayback (SS-208) were ordered to sink enemy ships fleeing from American vessels approaching the Stanmore airstrip in the Solomon Islands. On the evening of 5 March, Grayback spotted a boat her crew believed to be Grampus; unfortunately, Grayback was unable to communicate with the other vessel. Since the two submarines were sister ships, the chance of mis-identification is slim.
Grampus did not respond to orders to report given on 7 and 8 March. She had been operating near USS Amberjack, which make piecing together records concerning her loss difficult to decipher, as both boats were lost within three weeks of each other. Enemy seaplanes reported having attacked a US submarine on 17 February near Grampus' position, and a large oil slick discovered by enemy patrol boats on the surface on 19 February seems to confirm a kill.
Grayback and Grampus had been warned that a pair of destroyers were making their way through the Blackett Strait on 05 March. Grayback never saw them. If Grampus did, she failed to, or was unable to, report it. The two enemy ships sailed on into Kula Gulf, where they were sunk by American warships. Survivors reported that their ships conducted an attack on an American submarine before their encounter with the American warships.
An oil slick was reported on 06 March in that area.
Therefore, the most likely explanation for the loss of USS Grampus is attack by Japanese destroyers on the night of 05 March.
Whatever the precise date of Grampus's sinking, she took with her all 71 members of her crew.