Naval operations Submarine World War, 1939-1945 29 History 19 Naval operations, American 17 Military operations, Naval 16 Sea control 15 more ... World War, 1914-1918 14 Campaigns 13 Naval operations, German 11 American 9 Submarines (Ships) 9 Military campaigns 6 Shipwrecks 5 Officers 4 Submarine warfare 4 Secret service 3 Anti-submarine warfare 2 Armed Forces 2 Engineers 2 Freedom of the seas 2 German 2 Histoire 2 Mechanical engineers 2 Merchant marine 2 Military operations, Aerial 2 Motion pictures in propaganda 2 Naval operations, Canadian 2 Naval operations, Japanese 2 Pearl industry and trade 2 less ...