The Skate-class submarines were the United States Navy

United States Navy

The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

's first production run of nuclear powered submarines. They were an evolution of the Tang class

Tang class submarine

The Tang class submarines were a product of the Greater Underwater Propulsion Power Program , which incorporated German U-boat technology into the United States Navy's submarine design...

 in everything but their propulsion plants, which were based on the experimental . The four Skate class boats re-introduced stern torpedo tubes. Although among the smallest nuclear powered attack submarines ever built, the Skate class served for several decades, with the last being decommissioned in 1989. USS Skate was the first submarine to surface at the North Pole, on March 17, 1959.

Skate and Sargo were built with the S3W reactor

S3W reactor

The S3W reactor is a naval reactor used by the United States Navy to provide electricity generation and propulsion on warships. The S3W designation stands for:* S = Submarine platform* 3 = Third generation core designed by the contractor...

, Swordfish and Seadragon also had the S3W reactor in the S4W reactor plant (same machinery in an alternate arrangement).