The action of 4 May 1917 was a naval and air engagement of the First World War in the North Sea. The action took place between the German Zeppelin LZ 92 (tactical name: L.43), several German submarines and a naval force led by the Australian light cruiser . The action was inconclusive with no casualties on either side, concluding when the Zeppelin had dropped all of its bombs and the cruisers had expended all of their anti-aircraft ammunition.
Sydney was serving in British waters when on 4 May 1917, while part of an anti-submarine patrol from Rosyth, Scotland, the ship took part in a battle with a German Zeppelin, L.43, commanded by Kapitänleutnant Hermann Kraushaar. In concert with another cruiser, and four destroyers, , , and . Sydney, under the command of Commander John Dumaresq, the second-in-command of the 2nd Light Cruiser Squadron, had been patrolling between the Firth of Forth and River Humber, when lookouts spotted a vessel on the surface to the east of t