Submarine warfare 113 History 64 Naval operations 50 Submarine 45 Anti-submarine warfare 43 World War, 1939-1945 41 Submarines (Ships) 37 more ... World War, 1914-1918 21 Naval operations, German 19 Naval operations, American 9 Submarine forces 9 Submarine boats 8 Campaigns 7 Sea-power 7 Naval operations, British 6 Cold War 5 Communication systems 4 Espionage 4 Losses 4 Naval convoys 4 Naval hygiene 4 Physiology 4 Psychology, Military 4 Torpedoes 4 Aerial operations, American 3 Aviation 3 Fleet ballistic missile weapons systems 3 Military operations, Naval 3 Military policy 3 Naval strategy 3 less ...