Trumpeter 1/144 German Type XXIII U-Boat Project type 05907The development of the Type XXIII was given very high priority. To reduce development time, Dr. Walter designed the new boat based on the previous Type XXII prototype. By June, 1943, the initial design was ready and construction began in parallel at several shipyards in Germany, France, Italy and German occupied USSR. The Type XXIII had an all welded hull design, and was the first submarine in the world to use a single hull design. For the power