In preparation for the coming invasion, some old ships were collected and turned into aa batteries. One of these ship was the pre-dreadnought 'Braunschweig'.
The Braunschweig was withdrawn from active duty in 1917 but still in reserve until 1931, when the new 'Deutschland'-class approached. She stayed as barracks ship in Kiel until 1945, when the plans for 'Sealion' were finally fixed.
All guns were stripped and new aa weapons installed. The main turrets were replaced by two 'Taifun'-twin launchers (SAM). The outside secondaries kept their casemats as ammo stores for the above installed 3cm-twins. The three inside casemats were removed completely and the empty rooms filled with a pair of 'Foehn'-launchers each. The 'Foehn' is an unleaded rocket, launched in a set of 35 with a range of 1200 m and used against strafing attacks. Each rocket produces a shrapnell cloud with a diameter of 60 m. (I wonder why this thing didn't proove successful in reality).
Ammo for the launchers was stored in the magazines used before for the 17cm grenades. The 17cm-turrets were replaced by 3" aa twin turrets. The barbette was simply closed and the aa-turrets simply set above.
The 8,8cm guns were removed, the casemats closed.
The name 'Braunschweig' was to be taken over by a new P-class cruiser, so it was renamed 'Eimyria'. 'Eimyria' kept only one funnel, one screw and 6 oilfired boilers only. The outer funnels were cut and radar platforms for aa-guidance installed.
'Eimyria' sailed to Dunkerque in Feb. 1946 to protect the deployed and still incoming invasion armada. The ships was reconstructed that way, that the silhouette still nearly looked like an old 'Braunschweig'-class battleship to distract allied aircraft. That didn't work.
In the morning of June, 15. a squad of Beaufighters reached Dunkerque and torpedoed 'Eimyria'. She was hit astern, but kept up. The 'Foehn' rockets blasted some aircraft off but the second 'Foehn'-salvo blew 'Eimyria' skyhigh. Partisans had sabotaged the chambers behind the launchers so that the blast of the rockets reached the magazines and disrupted the old ship.