This is interesting footage. 'Deutschland' was the sistership of 'Bremen', which was the submarine I borrowed for RM5.
Both subs belonged to a curious type of submarine developed by Germany as clandestine merchant vessels (you can see how fat they were in the image above). They were designed to ship high value, exotic cargo's into Germany, circumventing the Royal Navy's blockade. Their limited cargo capacity however, and the fact that they just weren't that reliable meant they were later converted into 'U-cruisers'.