Complex sentence: Raeder served as Hipper's Chief of Staff during World War I as well as in combat posts, taking part in the Battle of Dogger Bank in 1915 and the Battle of Jutland in 1916.
Split into simpler sentences: Raeder served as Hipper's Chief of Staff during World War I, as well as in combat posts. He took part in the Battle of Dogger Bank in 1915 and in the Battle of Jutland in 1916.