After the invasion of the Netherlands in 1940, three older Dutch cruisers and armored ships were converted into floating AA batteries. The armored cruiser Gelderland
was launched in 1898 and first used as a training ship for cadets and midshipmen after World War I, but because of its ancient age and bad condition, the ship was not used by the Dutch navy anymore.
After taken over by the Germany in 1941, the ship was renamed to Niobe
and converted into a floating AA battery between 1941 and 1944. Work started at the Dutch harbor of Krinpen and was completed in Elbing on 01.03.1944. Unlike other floating AA batteries, the Niobe kept its steam engine and therefore was still able to sail by its own power.
After only three months of service in the German Kriegsmarine, the ship was sunk off Finland near Kotka at 60°28'N/26°57'E during a large air attack with over 130 aircraft by Soviet naval aviation on 16.06.1944. The wreck was raised in 1953 and scrapped after that.