Bruges and its satellite ports were a vital part of the German plans in their war on Allied commerce ( `` Handelskrieg '' ) because Bruges was close to the troopship lanes across the English Channel and allowed Preventing_or_letting much quicker access Having_or_lacking_access to the Western Approaches for the U-boat fleet than their bases in Germany .

The Atlantic U-boat campaign Military_operation of World War Military_operation I ( sometimes called the `` First Battle Hostile_encounter of the Atlantic '' , in reference to the World War II campaign of that name ) was the prolonged naval conflict Hostile_encounter between German submarines and the Allied navies in Atlantic waters—the seas around the British Isles , the North Sea and the coast of France .

Initially the U-boat campaign Military_operation was directed Aiming against the British Grand Fleet .

Later U-boat fleet action was extended Expansion to include Cause_to_be_included action against the trade routes of the Allied powers .

To counter Attack the German submarines , the Allies moved Motion shipping into convoys guarded Defending by destroyers , blockades Besieging such as the Dover Barrage and minefields were laid , and aircraft patrols Patrolling monitored Scrutiny the U-boat bases .

The U-boat campaign Military_operation was not able to cut off Removing supplies Supply before the US entered the war in 1917 and in later 1918 , the U-boat bases were abandoned GiveUp in the face of the Allied advance .

The U-boat campaign Military_operation was not able to cut off Removing supplies Supply before the US entered the war in 1917 and in later 1918 , the U-boat bases were abandoned GiveUp in the face of the Allied advance .

The tactical successes and failures of the Atlantic U-boat Campaign Military_operation would later be used Using as a set of available tactics in World War II in a similar U-boat war Military_operation against the British Empire .

The tactical successes and failures of the Atlantic U-boat Campaign Military_operation would later be used Using as a set of available tactics in World War II in a similar U-boat war Military_operation against the British Empire .

British warships rescued Rescuing 111 survivors from `` Bismarck '' before being obliged to withdraw Escaping because of an apparent U-boat sighting , leaving Departing several hundred men to their fate .

The following morning , a U-boat and a German weathership rescued Rescuing five more survivors .

The ship was identified Check and torpedoed Destroying by the German U-boat and sank in 18 minutes , and also took on a heavy starboard list .

The U-boat Campaign Military_operation from 1915 to 1918 was the World War I naval campaign fought Hostile_encounter by German U-boats against the trade routes of the Allies .

The defeat Conquering of the U-boat threat was a prerequisite for pushing Motion back the Axis .