August 1915. The German flotilla, which was under the command of Hipper, also included the battlecruisers , , and , several light cruisers, 32 destroyers and 13 minesweepers. The plan called for channels in Russian minefields to be swept so that the Russian naval presence, which included the pre-dreadnought battleship , could be eliminated. The Germans would then lay minefields of their own to prevent Russian ships from returning to the gulf. Helgoland and the majority of the other big ships of the High Seas Fleet remained outside the gulf for the entirety of the operation. The dreadnoughts and Posen were detached on 16 August to escort the minesweepers and to destroy Slava, though they failed to sink the old battleship. After three days, the Russian minefields had been cleared, and the flotilla entered the gulf on 19 August, but reports of Allied submarines in the area prompted a German withdrawal from the gulf the following day. Battle of Jutland Under the command of Captain von Kameke, Helgoland fought at the Battle of Jutland, alongside her sister ships in I Battle Squadron. For the majority of the battle, I Battle Squadron formed the center of the line of battle, behind Rear Admiral Behncke's III Battle Squadron, and followed by Rear Admiral Mauve's elderly pre-dreadnoughts of II Battle Squadron. Helgoland and her sisters first entered direct combat shortly after 18:00. The German line was steaming northward and encountered the destroyers and , which had been disabled earlier in the battle. Nomad, which had been attacked by the ships at the head of the line, exploded and sank at 18:30, followed five minutes later by the Nestor, sunk by main and secondary gunfire from Helgoland, Thüringen and several other German battleships. At 19:20, Helgoland and several other battleships began firing on , which, along with the other s of the 5th Battle Squadron, had been pursuing the German battlecruiser force. The shooting stopped quickly though, as the Germans lost sight of their target; Helgoland had fired only about 20 shells from her main guns. At 20:15, during the third Gefechtskehrtwendung, Helgoland was struck by a armor-piercing (AP) shell, from either or , in the forward part of the ship. The shell hit the armored belt about 0.8 m (32 in) above the waterline, where the armor was only 15 cm thick. The 15-inch shell broke up on impact, but it still managed