 The plan of attack was for the British raiding force to sink two obsolete cruisers in the canal mouth at Ostend and three at Zeebrugge , thus preventing raiding ships leaving Bruges . The Ostend canal was the smaller and narrower of the two channels giving access to Bruges and so was considered a secondary target behind the Zeebrugge Raid . Consequently , fewer resources were provided to the force assaulting Ostend . While the attack at Zeebrugge garnered some limited success , the assault on Ostend was a complete failure . The German marines who defended the port had taken careful preparations and drove the British assault ships astray , forcing the abortion of the operation at the final stage . 
