On patrol over the North Sea, the German Navy Zeppelin L 9, commanded by Kapitänleutnant Heinrich Mathy, encounters four British submarines on the surface and attacks them while HMS E5 fires at her and the other three dive; L 9 tries to bomb E5 as E5 dives, but does no damage. L 9 later catches HMS E4 on the surface and attacks with bombs, but E4 dives and survives as well. L 9 later sights another surfaced submarine and moves in to attack while the submarine fires at her, but the submarine dives before L 9 can attack.