15 April 1959 – The third submarine named Skipjack (SSN 585) was commissioned. The first single shaft and screw nuclear submarine. Auxiliary propulsion in event the reactor became inoperable, was by an electric propulsion motor which could run off either the diesel or battery. As a backup to that, the Skipjack was also the first to have a secondary propulsion motor (sometimes referred to as the outboard motor) it was lowered from a well that under normal conditions did not interfere with the streamline shape of the hull. Skipjack was also the first nuclear submarine to enter the Mediterranean, which was by way of the strait of Gibraltar