sentences:  Second Ostend Raid
  
  The Second Ostend Raid (officially known as Operation VS) was the later of two failed attempts made during the spring of 1918 by the United Kingdom's Royal Navy to block the channels leading to the Belgian port of Ostend as a part of its conflict with the German Empire during World War I.Due to the significant strategic advantages conferred by the Belgian ports, the Imperial German Navy had used Ostend as a base for their U-boat activities during the Battle of the Atlantic since 1915.