An Admiralty film depicting the functionality and uses of the submarine including an underwater attack on an "Hun" convoy and a surface attack on an U-boat.
An interesting wartime information film that uses a diagram to illustrate who does what and where on a tightly packed diesel-electric submarine where electricity is always at a premium. It has a propaganda element as it uses actuality to demonstrate an attack on a Nazi convoy and the successful destruction of a surfaced U-boat. It's well enough put together with one clear, morale-boosting, purpose.