In the last 50 years of military, political and economic fields of the Ottoman Empire, Germany and the Germans have been very important. Part of the German officers, who started to come to the Ottoman lands from 1882 onwards at the invitation of Abdul Hamid II, made efforts for the improvement of the Ottoman army, while others wanted to equip the Ottoman army with only German weapons and gain personal benefit from it. One of the German officers who had acted in this way, the retired Marine Major Heinrich Mayer's offer to arm the Ottoman army during the Tripoli War was rejected by the Ottoman authorities. Mayer took the American ambassador to Berlin and came to Istanbul many times before and explained to him that he wanted to share his intelligence with the Ottoman army about the fortifications of the Straits. In this respect, Mayer convinced the Italian government to make two operations with the fleet to the Dardanelles and to make the Ottoman government dictate the peace by dictating the Italian government, which is in a difficult position both for its own and world public opinion, because it could not obtain the victory expected in the Tripoli War soon. has provided guidance. In this work, for the first time, two Dardanelles operations under the guidance of Mayer were explained.