With the benefit of hindsight, I think that the German U boat fleet was probably the most cost effective element of the German war effort. They had great success until 1943, when the allies developed radar technology to enable aircraft to catch subs on the surface. The German subs had to travel on the surface because they were simply too slow under the water. Instead of getting their new, faster underwater designs into production, they carried on building the same subs they had started the war with. The design of these U boats was virtually unchanged from those that put to sea in WW1, which I find amazing. :confused:
These creaky old tubs managed to sink ships faster than the UK and USA could build them for a while, and the UK's strategic reserves were shrinking by the month. A real missed opportunity for the Germans. I dont intend to make the same mistake. Invest, invest, invest!