Opening Savannah: Federal efforts to clear obstructions to the port

Once ashore at Normandy on June 6, 1944, the Allies put effort towards establishing port facilities.  Artificial harbors and over-the-beach delivery were helpful but inefficient.  What the allies needed was a deep water port where those fine Liberty ships could dock and disgorge supplies.  Cherbourg, captured weeks after the initial landings, was supposed to be