Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Type VII U- boats were the workhorses of the German World War II U-boot-waffe. Type VII was based on earlier German submarine designs going back to the World War I Type UB III, designed through the Dutch dummy company Ingenieurskantoor voor Scheepsbouw den Haag (set up by Germany after World War I in order to maintain and develop German submarine know-how and to circumvent the limitations set by the Treaty of Versailles) and built by shipyards around the world. The Finnish Vetehinen class and Spanish Type E-1 also provided some of the basis for the Type VII design.