By Leslie Albrecht and Julie Shapiro
GOVERNORS ISLAND — A 450-pound cannonball that dates back to the Civil War was found on Governors Island Thursday morning, officials said.
The NYPD's bomb squad and the FDNY rushed onto ferries to the hard-to-reach site — which is closed to the public during the winter — to examine the cannonball and make sure it was not in danger of exploding.
They got some help from Mike Shaver, the National Park Service's chief ranger on Governors Island and an expert on 19th-century artillery.
Shaver told the bomb squad and 1st Precinct officers to take a close look at the 14-inch cannonball and see how many holes it had. Two small holes mean that the cannonball is solid iron (the holes were used to help soldiers lift it), while a third hole means that the cannonball is hollow and could hold gunpowder, Shaver said.
This cannonball had just two holes, so the emergency responders were able to relax.
"We all got a really cool education about Civil War-era cannonballs," Shaver said.
Workers uncovered the cannonball while doing construction on Soissons Dock, the main entry point for ferries to Governors Island, said Elizabeth Rapuano, spokeswoman for the Trust for Governors Island. The iron orb was resting in mud and water just behind the island's seawall, underneath a granite slab, Shaver and Rapuano said.
The cannonball was likely placed there in the early 1900s, as a piece of the dock's original foundation, Shaver said.
Governors Island was once awash in cannonballs identical to the one found on Thursday. They arrived during the Civil War, when Governors Island housed a key Union arsenal that received frequent shipments of cannons and ordnance, Shaver said.
If it had ever been fired, the solid iron cannonball, known as "shot," would have been used to punch a hole in an enemy ship.
After the war, hundreds of cannons and cannonballs remained on Governors Island, and even after the arsenal closed in 1920, much of the weaponry still stayed behind, Shaver said.
Cannonballs were so common on Governors Island in the early 20th century that people living on the base used the iron spheres to decorate their lawn, and cannons were sometimes found at crossroads, standing on their end like public art, Shaver said.
The cannonballs may also have been seen as useful building materials, which is how Shaver thinks it wound up near Soissons Dock.
"It was probably intentionally put there [during the dock's construction in the first half of the 20th century]," Shaver said. "It made a good solid foundation."
The cannonball is not the only one of its kind left, but Shaver said they are not very common, particularly not in such good condition.
"It was so clean," Shaver said, likely because it had been in the water for decades. "It didn't have a lot of rust on it, and it didn't have a lot of dents in it."