The question is why were no US 16" battleships at Normandy. 16"/45 and 16"/50 naval guns could have made contributions firing either a 2700 pound armor piercing or 1900 pound bombardment round accurate at 20+ miles. The ships that could do this were not off Normandy, they were on the other side of the world off Saipan. I think all answers went to the grave with King, Marshall and Arnold. They were the ones determined what assets were available to theater commanders.