LOST WITH aLL HANDS - 20 JUN 1941

Lost on 20 JUN 1941 with the loss of 33 officers and men when it sank off Isle of Shoals, fifteen miles from Portsmouth, NH.

USS O-9 submerged at 0738 to conduct deep submergence tests and the boat did not surface thereafter but was crushed by the pressure of the water at a depth of 402 feet.