 Complete the following phrase:  Following the outbreak of World War I, Hannover was tasked with guard duty in the Altenbruch roadstead at the mouth of the Elbe River during the period of mobilization for the rest of the fleet. In late October, the ships were sent to Kiel to have modifications made to their underwater protection systems to make them more resistant to torpedoes and mines. Hannover then joined the battleship support for the battlecruisers that 