ухищрение были для увлечения (чего)

для понятия сам контекст
In the naval sphere similar evasions were practiced. The Versailles Treaty allowed only a small naval force with a maximum strength of fifteen thousand men. Subterfuges were used to increase this total. Naval organizations were covertly incorporated into civil ministries. The Army coastal defences were not destroyed as prescribed by the Treaty, and soon they were taken over by German naval artillerymen. U-boats were illicitly built and their officers and men trained in other countries.