What does Unrestricted Submarine Warfare refer to?

Answer 1

Unrestricted Submarine Warfare (URSW) is a Naval doctrine in which a submarine will attack any vessel carrying a flag of its enemies, its enemies' allies, or others suspected of giving aid to an enemy, without warning or provocation. The doctrine applies to any vessel, whether it is civilian or military in nature, large or small.

HISTORY

Prior to WWI, belligerents observed "Prize" or "Cruiser" rules, which stated that the ship couldn't sink a passenger ship, only a merchant vessel of an enemy nation, and that the crew/passengers aboard any vessel must be clear and safe before it was sunk. These rules were from the days of sailing vessels, and with WWI and the advent of submarine warfare and modern weapons, it didn't take long to determine that those rules were obsolete. This was essentially the basis for Germany's initial submarine warfare policy.

Though Germany initially tried to comply with Prize Rules, as WWI submarine warfare progressed, it became apparent that those rules were outdated and even dangerous. With its practice of warning ships and allowing passengers and crew to leave prior to sinking, it meant that the attacking submarine would be a sitting duck to any enemy vessels or aircraft. The ship's crew only needed to summon military assistance by radio, and the passengers and crew could take their time to evacuate the ship, giving time for aid to arrive.

URSW & THE SINKING OF THE BRITISH PASSENGER LINER RMS LUSITANIA

On May 1, 1915, the British passenger liner RMS Lusitania departed New York for Britain. Just a few days earlier, Germany had released this notice via its embassy in Washington, D.C.:

Notice!Travelers intending to embark on the Atlantic voyage are reminded that a state of war exists between Germany and her allies and Great Britain and her allies; that the zone of war includes the waters adjacent to the British Isles; that, in accordance with formal notice given by the Imperial German Government, vessels flying the flag of Great Britain, or any of her allies, are liable to destruction in those waters and that travelers sailing in the war zone on the ships of Great Britain or her allies do so at their own risk.

Imperial German Embassy

Washington, D.C. 22nd April 1915

On May 6, 1915, the British passenger liner RMS Lusitania was torpedoed by the German U-boat U-20, just 11.5 miles off the coast of Ireland, sinking in 18 minutes. Of the 1198 passengers who died, almost 100 were children, and she also carried 139 Americans, 128 of which died in the sinking. Among the passengers were many American and British dignitaries and luminaries of the day.

The resulting world public backlash pressured the German leadership to revert to a policy of Restricted Submarine Warfare. They reverted back to URSW in 1917 to counter the British blockade of Germany, hoping to break the back of British shipping and to delay the U.S. entry into the war, but by then it was too late. Had they held fast and continued their policy of URSW after the Lusitania, WWI may have turned out much differently, as URSW and advancements in submarine warfare in general were relatively new during WWI. As a result, Anti-Submarine Warfare (ASW) techniques had not yet significantly progressed enough to deter a significant submarine threat if Germany had continued.

Their reversion back to a URSW policy was also one of the key elements leading to the entry of the United States into WWI.

UNRESTRICTED SUBMARINE WARFARE DURING WWII

Until the advent of the escorted convoy system and improved Anti-Submarine Warfare (ASW) techniques, German U-boats during WWII conducting URSW in the Battle of the Atlantic caused devastating losses for Allied shipping. However, contrary to Hollywood fiction and wartime Propaganda, it is well known that many U-Boat commanders would give aid (including food, water, and blankets) to survivors and point them toward the nearest land, despite official Nazi policy.

Following the Japanese attack on Pearl Harbor and its declaration of war on America, one of the first commands to deployed Pacific-fleet U.S. submarine commanders was to "Execute Unrestricted Submarine Warfare" against Japan. It was this policy that bought the U.S. enough time to repair the fleet at Pearl Harbor, and help reinforce the Carrier Groups that had survived to counter the Japanese expansion into the Pacific. Japan's failure to deal with the U.S. submarine threat helped speed her defeat in the Pacific Theatre.

LEGACY

Even today, the mere threat of URSW can tie up a fleet's resources. During the Falklands War in 1982, the sinking of the Argentine Navy Cruiser ARA General Belgrano by the British nuclear submarine HMS Conqueror, had a chilling effect on Argentine Naval operations. After the sinking, the entire Argentine Navy fleet retired back to port for the remainder of the war, save for their one remaining conventional DE submarine, the ARA San Luis.

The British, having captured and scuttled the only other Argentine submarine, remained on the defensive as a result of the San Luis' presence. Though the San Luis failed to successfully attack 2 British ships (some torpedoes missed, others were dealt with by torpedo countermeasures), the threat from the San Luis tied up one carrier, eleven destroyers, five nuclear-powered submarines, one diesel submarine, and over 25 helicopters.