 On 3 August 1915, several heavy units of the High Seas Fleet were transferred to the Baltic to participate in a planned foray into the Riga Gulf.The intention was to destroy the Russian naval forces in the area, including the pre-dreadnought , and to use the minelayer to block the entrance to Moon Sound with naval mines.The German forces, under the command of Vice Admiral Hipper, included the four "Nassau" and four "Helgoland"-class battleships, the battlecruisers , "Moltke", and , and a number of smaller craft.