(Editor's note: this story was updated on May 24 to clarify the comparison between the DDG-51 and FFG-62 costs estimates.) The Navy estimates the cost to develop and procure a fleet of 20 new guided-missile frigates is $24.7 billion, setting the average cost for each new FFG-62 Constellation-class warship at about $1.2 billion. The service reported the figure to Congress in an initial Selected Acquisition Report to Congress, according to a Navy spokeswoman. "The Navy confirms that . ...