When new submarine design concepts are tested, a proof of concept or prototype is fabricated and used in testing the design. The various components, subsystems, sensors, and mission-related systems may be tested and developed for the new design. When radial-hull submarine designs were developed, the first step was a submarine like ALBACORE which today sits ashore as a museum near Portsmouth, NH. ALBACORE resulted in the construction of the BARBEL Class of SSKs. Germany started with small diesel-electric submarines which were derived from the wartime Type XXIII designs and then progressed through the Type 201, Type 205, Type 206/206A, and the world-renowned Type 209 series, leading to the Type 212 and 214 submarines.
