Footage of German U-boats - captured German film.
Radar is used to find and blast U-boats in South Africa.
U-boats seen under construction and cruising at sea.
Captured German film showing U-boat pack returning to port.
American planes blast German U-boats in the Atlantic.
Mr Charles Jarman explains how to fight U-boats.
A German submarine attacked by depth charges from a Polish destroyer protecting a convoy.
Good material of German submarines being built and being used in action.
German U-boats, aircraft carrier and cruiser being attacked by RAF planes.
Convoy resists U-boat attack in the Atlantic.