The Navy's nuclear powered ballistic missile submarine force had a unique relationship with Charleston, where these submarines operated alongside diesel powered and nuclear powered attack submarines and, with separate Blue and Gold crews, depended on the Charleston Naval Complex for the weapons, supplies, and training needed to sustain their repetitive 70 day submerged patrols in oceans around the world. The first of these submarines, USS George Washington (SSBN 598), sailed from Charleston with 16 Polaris missiles aboard in 1960. By 1967, forty sister ships were at sea, and until they were replaced by Trident submarines, these 41 SSBNs and their fleet ballistic missile tender mother ships USS Proteus (AS19), USS Hunley (AS31), USS Simon Lake (AS33), and USS Canopus (AS34), operating from Holy Loch, Scotland, Rota, Spain, Guam, Charleston, and Kings Bay, Georgia, formed the Navy's afloat strategic deterrent force during the tense years of the Cold War.