The German naval staff hoped all these changes could be accomplished by April 1943, with the carrier's first sea trials taking place in August that year. Towards that end, Chief Engineer Wilhelm Hadeler was reassigned to oversee "Graf Zeppelin"s completion. Hadeler planned on getting the two inner shafts and their respective propulsion systems operational first, giving the ship an initial speed of 25–26 knots, fast enough for sea trials to commence and for conducting air training exercises. By the winter of 1943–1944 she was expected to be combat-ready.