Barbel-class

The last diesel-electric combat submarines ever built by the United States Navy. Their revolutionary Albacore-derived teardrop hull became the template for every American submarine that followed. First class to combine the control room, attack center, and conning tower into a single space - built with HY-80 high-yield steel and capable of 25 knots submerged. When USS Blueback decommissioned in 1990, the U.S. Navy became an all-nuclear submarine fleet.