When World War Two began, both Britain and Germany saw each others big ships as the main threat to her sea trade, It was intended that Germany's surface raiders would savage the merchant fleet on which Britain depended for much of her food, most of her raw material and all of her oil. Germany's U Boats were to operate in coastal waters, sweeping up anything left by the battleships. Both Britain and Germany were wrong, the real naval menace to Britain's survival was to be the U Boat. (Underseaboat)