And for 4,644 people who stood in long lines, at times in the rain, it was a chance to tour one of the world's 84 warships equipped with the Aegis integrated weapons system, developed here over the last 30 years, first by RCA and now by Lockheed Martin Corp.
More than 5,000 people work on upgrading, testing and making key parts of the Aegis systems at Lockheed Martin's big Moorestown complex and at the adjacent Navy facility, which looks like a ship stranded in a cornfield.
The city's popularity among warships comes, in part, because Monica Santoro, who coordinates warship visits for the Penn's Landing Corp., works six months in advance lining up law enforcement for security and arranging things for sailors to do ashore.
She is aided by the Navy League, which remains active 106 years after it was founded by President Theodore Roosevelt, who wanted civilians to support sailors.
The 900-member Philadelphia chapter is on hand to welcome every Navy ship that arrives, whether under tow for storage at the Navy Yard or under its own power for display at Penn's Landing.
The league threw a welcome-to-Philadelphia party for the Carney crew at Finnigan's Wake, an Irish bar on Spring Garden Street; bought Phillies-Mets tickets; and donated $1,000 to the ship's morale and welfare fund. And it delivered armloads of pretzels.
Word is spreading about Philadelphia's hospitality.
"I get calls from commanding officers saying their crew heard about us from another crew and wants to come here," Santoro said. "Many sailors say they are planning to come back and spend vacations here."
Though crew members got their turns ashore while others escorted residents on tours, the 506-foot Arleigh Burke Class destroyer was fully armed and ready for battle.
Any threat would have had its its crew rushing guests ashore and manning the ship's complex array of radar, missiles, heavy artillery and other weapons.
Its Aegis system would have quickly been at the heart of the nation's response.
Aegis can detect distant threats, evaluate them, and launch missiles. If the enemy evades the missiles, Aegis switches to the ship's 5-inch big gun, which can rapidly fire 70-pound ammunition at targets eight miles away; two 1,500-round-a-minute Gatling guns; and other close-in weapons.
It can detect an array of threats simultaneously and launch responses from two 90-missile bays and other defenses against ships and low-flying cruise missiles.
"The Russian strategy used to be to fire 15 missiles at a ship and hope one got through," said Kyle A. Weiss, a fire control technician, standing in the "command-and-decision center," a dimly lit room full of computer consoles and big displays.
In recent tests, an Aegis-equipped ship has intercepted and destroyed missiles at every phase of flight, from arcing into outer space to the final seconds descending toward the target. In February, the system destroyed a defective spy satellite laden with toxic fuel before it could return to Earth.
"Aegis integrates everything into one picture to help us do our jobs. With missiles, inbound at a high rate of speed, everything happens in seconds," Weiss said.
The 12-year-old Carney does not yet have the newest version of Aegis, which can include data from other ships, aircraft, and stations on land in its decision-making. But its radar systems can detect multiple threats and guide missiles to the warheads, refusing to be distracted by decoys or pieces of the launch vehicle.
If things happen from more directions and faster than human responses can handle, said Lt. j.g. Brian Morris of Long Island, N.Y., the Carney's fire control officer, Aegis "can defend the ship on its own."
Contact staff writer Henry J. Holcomb at 215-854-2614 or firstname.lastname@example.org.