Built by Electric Boat Company of Groton, Connecticut.
Laid down February 14, 1940. Launched December 23, 1940. Commissioned on May 23, 1941. Named "Grampus" for two members of the dolphin family (Delphinidae): Grampus griseus, also known as Risso's dolphin, and Orcinus orca, also known as the killer whale. Placed under the command of Lieutenant Commander Edward S. Hutchinson.
After shakedown in Long Island Sound, Grampus sailed to the Caribbean Sea with USS Grayback (SS-208) on September 8, to conduct a modified war patrol, returning to New London, Connecticut, on September 28. With USS Grayback (SS-208) departed for patrol duty in the Caribbean Sea and Chesapeake Bay, then to Portsmouth, New Hampshire for overhaul arriving November 30.
When the Pacific War began, Grampus was undergoing post-shakedown overhaul at Portsmouth, New Hampshire. Departed on December 22 via the Panama Canal and Mare Island reaching Pearl Harbor on February 1 , 1942.
Departed on February 8. Grampus sank an 8636-ton tanker, the only kill of her short career, and reconnoitered Kwajalein and Wotje. Patrol ended on April 4. This patrol was deems as successful.
Second & Third Patrol
Grampus's second and third patrols were marred by a heavy number of anti-submarine patrol craft off Truk with poor visibility as heavy rains were present along her path off the Luzon and Mindoro coasts. Both patrols terminated at Fremantle.
Grampus departed on October 2, 1942 for her fourth war patrol. Aboard were four coastwatchers, landed on Vella Lavella and Choiseul while conducting her patrol. During this patrol, she sighted a total of four enemy cruisers and 79 destroyers in five different convoys. Although she conducted a series of aggressive attacks on the Japanese ships, receiving 104 depth charges, Grampus was not credited with sinking any ships. On October 18, 1942 Grampus even scored a direct hit on Yura, but the torpedo failed to explode. Returned to Australia on November 23. This patrol was deems as successful.
Departed December 14, 1942, took her across access lanes frequented by Japanese submarines and other ships. Air and water patrol in this area was extremely heavy and although she conducted several attacks on the 41 contacts she sighted, Grampus was not credited with any ships sunk or damaged. Returned January 19, 1943. This patrol was deems as successful.
Departed Brisbane on February 11, 1943 with USS Grayback on a patrol of the central Solomons area.
Lost due to unknown circumstances between February 18 to March 5, likely in the Central Solomons. When repeated attempts failed to contact Grampus, the submarine was declared missing and presumed lost with all hands. Officially struck from the Naval vessel register on June 21, 1943. Grampus received three battle stars for World War II service.
The Japanese side reveals two possibilities for her sinking. One, being February 18, 1943 Japanese seaplanes reported sinking a submarine on February 18 in Grampus's patrol area, but USS Grayback reported seeing Grampus in that same area on March 4.
Another possibility, on March 5, 1943 when Japanese destroyers Minegumo and Murasame conducted an attack in the Battle of Blackett Strait near Kolombangara. A heavy oil slick was sighted there the following day, indicating that Grampus may have been lost there in a night attack or a gun battle against the destroyers, both sunk in a night action with U.S. cruisers and destroyers.
When repeated attempts failed to contact Grampus, the submarine was declared missing and presumed lost with all hands.
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May 22, 2017