 Hannover put to sea during the Battle of Dogger Bank on 24 January 1915 to support the beleaguered German battlecruisers, but quickly returned to port. On 17 – 18 April, Hannover supported a minelaying operation off the Swarte Bank by the light cruisers of the II Reconnaissance Group. A fleet advance to the Dogger Bank followed on 21 – 22 April. On 16 May, Hannover was sent to Kiel to have one of her 28 cm guns replaced. The ship returned to Kiel on 28 June to have supplemental oil firing installed for her boilers; work lasted until 12 July. On 11 – 12 September, II Reconnaissance Group conducted another minelaying operation off the Swarte Bank with Hannover and the rest of II Squadron in support. This was followed by another resultless sweep by the fleet on 23 – 24 October. During the fleet advance of 5 – 7 March 1916, Hannover and the rest of II Squadron remained in the German Bight, ready to sail in support. They then rejoined the fleet during the operation to bombard Yarmouth and Lowestoft on 24 – 25 April. During this operation, the battlecruiser Seydlitz was damaged by a British mine and had to return to port prematurely. Visibility was poor, so the operation was quickly called off before the British fleet could intervene.
