 The First Ostend Raid ( part of Operation <unk> ) was the first of two attacks by the Royal Navy on the German @-@ held port of Ostend during the late spring of 1918 during the First World War . Ostend was attacked in conjunction with the neighbouring harbour of Zeebrugge on 23 April in order to block the vital strategic port of Bruges , situated 6 mi ( 5 @.@ 2 nmi ; 9 @.@ 7 km ) inland and ideally sited to conduct raiding operations on the British coastline and shipping lanes . Bruges and its satellite ports were a vital part of the German plans in their war on Allied commerce ( <unk> ) because Bruges was close to the troopship lanes across the English Channel and allowed much quicker access to the Western Approaches for the U @-@ boat fleet than their bases in Germany . 
