On 23 MAY 1939, USS SQUALUS suffered a catastrophic valve failure during a test dive off the Isle of Shoals. Partially flooded, the submarine sank to the bottom and came to rest keel down in 240 feet of water.
Commander Charles Momsen and Navy divers on USS FALCON (ASR 2) rescued thirty-three survivors use the diving bell he invented. Twenty-six men drowned in the after compartments.
Later USS SQUALUS was raised and recommissioned as USS SAILFISH. In an ironic turn of fate, USS SAILFISH sank the Japanese aircraft carrier carrying surviving crew members from USS SCULPIN, which had located USS SQUALUS after sinking in 1939.
USS SAILFISH was sold for scrapping to Luria Brothers of Philadelphia, PA.
Her conning tower stands as a memorial to the lost crew of USS SQUALUS at the Portsmouth Naval Shipyard in Kittery, ME.