Submarine Warfare

The use of diving craft, usually armed with underwater weapons, in combat operations. Although initially ineffectual because of their primitive designs, submarines developed into highly effective combat vessels, capable of sinking the largest surface ships and causing severe strategic and economic disruption in modern war. Ironically, the submarine menace attracted a great deal of attention since World War II, but the end of the Cold War has returned submarines almost to an auxiliary role similar to the era of its origins.

Early Developments

The primitive submersible torpedo boats built at the beginning of the 20th century offered few portents for the future. Short ranged, unstable, blind, dangerous to operate, and pitifully under armed, these vessels nevertheless employed the new torpedo (torpedo first meant a sea mine) as main armament and thus could sink the grandest warship then afloat under certain circumstances.

Accordingly, the sole role assigned to these early submarines was the defense of harbors and coastlines against conventional blockades that navies had been using since the 16th century. Russian submarines kept the otherwise victorious Japanese navy clear of Vladivostok during the 1904–1905 Russo-Japanese War, for example. However, the threat of surface torpedo boats had already caused naval doctrine to change by then, introducing the distant blockade tactic, where fleets covered enemy coasts from hundreds of miles away, leaving coast defenses with little to accomplish.

The technical improvements to the submarine before 1914 sufficed to make it a formidable threat against warships on patrol and merchant ships, although their poor handling characteristics kept them out of fleet actions of the day. The submarines of World War I sank all classes of warships, driving blockading units far offshore, and the warfare potential of the submarine advanced it to the major naval problem of the day.

Initially, the submarine was expected to follow the rules for seizure of shipping established by the 1899 Hague Convention. Under such rules, a submarine was expected to stop a merchant vessel by surfacing to signal or fire a shot across its bow, after which the merchant ship would be seized as a prize of war or sunk after the crew had been ordered into lifeboats and safeguarded. Of course, submarines had minimal crews and accommodations, making the detachment of crews to take captured merchant ships or the embarking of their crews an absolute impossibility. The surfacing of a submarine before an unidentified merchant vessel also made it vulnerable to attack by ramming or concealed armament, not to mention nearby escorting warships and aircraft.

The tempting targets posed by Allied commerce—and the limited results offered under conventional attacks permitted by the rules of the Hague Convention—pressured the German navy to opt for unrestricted submarine warfare in World War I. The German government authorized this on two occasions—January 1915 to May 1916 and May 1917 to November 1918—the latter becoming the key cause of the U.S. declaration of war against Germany in April 1917. This calculated risk on the part of Germany almost brought Britain and Italy to economic collapse, but the improved weapons and detection equipment of [Page 688]antisubmarine craft and ships, and the use of convoys to pass more ships through the submarine zones under escort, resulted in the defeat of the German submarine campaign.

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