I understand there were other people (e.g. Grant who were culpable for the disaster at Ft. Donelson, but the Confederates won the first day and also shelled the hell out of the Union fleet. They could have left the fort and the field of battle and survived to fight another day with 10,000 troops. They could even have assaulted Ft. Donelson and won it back----maybe. That would have altered the war in the West much to the Confederates' advantage.