From underwater boat to submarine – The development of the Swedish submarine service 1945-1960 The scope of this essay is the development of the Swedish submarine service during the period 1945-1960. The aim is to answer the following questions: - What kind of new technology did Sweden acquire when salvaging the German type XXI submarine off Gothenburg at the end of World War II? - In what respect did this technology differ from that of the Royal Swedish Navy and did it subsequently contribute to the tactical and operational development? - What tactical and operational development was accomplished between 1945-1960? The timeframe, 1945-1960, was chosen since this is when the analysis of the salvaged type XXI submarine and related effects was conducted. Furthermore, it is also during this time that the Swedish submarine service is beginning to evolve as a result of the new knowledge mentioned above and the experiences made by both the allies and the Germans during World War II. The theoretical framework primarily refers to the theories on naval warfare by Sir Julian Corbett. Here the “Fleet in being” and his methods for viewing command have been deemed to be of primary interest, also the definition of “basic capabilities” applied by the Swedish Armed Forces is referred to in order to simplify certain matters to the reader. In conclusion, the technology acquired from the Germans provided Sweden not only with new actual technology but also a preview of the coming modern submarine and underwater warfare. The new technology and the experiences were implemented into the submarine service contributed to the fact that the Swedish submarines over a period of ten years developed from being underwater boats to actual submarines and subsequently contributed to the Swedish naval warfare capability during the Cold War.