 McClellan did not believe his army was ready for a battle , and hoped that Lee would not give them one . Nonetheless , he left his troops at Malvern Hill and traveled downstream aboard the ironclad USS Galena to inspect his army 's future resting place at Harrison 's Landing . McClellan did not delegate an interim commander ; Porter , who was in command during the initial attack , became the de facto leader on the Union side of the battle . 
