History,  News

Divers Seek Cannonballs In Waters Around Island

Photo by Hector Mosley, U.S. Army Corps of Engineers, New York District

The U.S. Army Corps of Engineers currently has divers seeking cannonballs and whatever else is in the waters around Governors Island. There are three acres of underwater areas that are being searched this month. We reported on a 2012 discovery that brought the NYPD to the Island. The report was shared this week by the public affairs office:

Story by JoAnne Castagna
U.S. Army Corps of Engineers, New York District

Here’s how the story goes …

Decades ago, there was an active U.S. Army post on Governors Island, in the heart of the New York Harbor in New York City.

Military families resided on the island and stories exist of children getting into mischief and rolling cannonballs down a hill. Some possibly making it all the way to the water’s edge and splashing into the harbor.
Cannonballs and other munitions or explosives of concern are believed to have wound up in the harbor in other ways as well.

“Our historical research indicates that besides the playing children, the cannonballs may have wound up in the water from past military operations or dumped or accidentally fell into the water off of vessels that were loading and unloading munitions at the piers,” said Erik Jarger, project manager, New York District, U.S. Army Corps of Engineers, New York District.

This fall, the Army Corps has teams of divers investigating the waters off of the island so that munitions, such as cannonballs, can be found and removed for public safety.

“This work is to ensure that the waters are safer for the public, boaters, and for potential future development around the island,” said Jarger.

The Army Corps is doing this work in collaboration with the New York State Department of Environmental Conservation, the Army Corps’ Baltimore District, New York State Department of Health, the Army Corp’s Contractor, HydroGeoLogic of Reston, Virginia, the Trust for Governors Island and the National Park Service.

The diving work is being performed under the Formerly Used Defense Sites Program, a Department of Defense program for environmental restoration or cleanup of properties that were formerly owned by, leased to, or otherwise possessed by the Federal Government to protect human health and the environment.

Governors Island is located in New York City in the New York Harbor, a half mile from the southern tip of Manhattan at the confluence of the Hudson River and the East River.

Visitors can take a ten minute ferry ride from Manhattan or Brooklyn to the 172-acre island that has become a popular recreational, educational and cultural destination.

A big part of the island’s attraction is its rich role in American history and the historical military buildings.

The island was formerly used as a U.S. Army post for almost 200 years. Fort Jay and Castle Williams were built centuries ago on the island to prevent enemies from seizing control of New York Harbor, such as the British during the War of 1812.

Castle Williams was part of a system of forts designed and constructed in the early 19th Century. It was designed and erected under the direction of Lieutenant Colonel Jonathan Williams, Chief Engineer of the Corps of Engineers and first Superintendent of the United States Military Academy at West Point, New York.

The army post once served as a recruitment center, supply depot, prison, and supply base where munitions, such as cannonballs, were stored, tested, transported, and used for training and coastal defense.

It was during this time that munitions ended up in the harbor. The Army Corps has teams of divers surveying the waters for them.

Photo by Hector Mosley, U.S. Army Corps of Engineers, New York District
They are investigating the locations of old, historically significant, piers and other areas around the perimeter of the island. Jarger said that for safety purposes, the dive operations are being coordinated around ferry traffic.

“The divers are looking for what we refer to as “metallic anomalies,” or essentially any metallic items of interest that have the potential to be considered munitions or explosives of concern,” said Jarger. “The munitions most likely to be found are cannonballs of various sizes, based on the historical knowledge of past island operations and munitions stored and used on the island.”

The dive teams are inspecting almost three acres of the harbor floor and going down as deep as 30 feet in some areas.

According to Douglas Schicho, project manager, Aptim, the Army Corps subcontractor performing the diving operation, “The dive team is laying down approximately 12,000 linear feet of rope across an area to be surveyed. The divers are tied off to the rope and use it to navigate. They use hand held magnetometers – metal detectors – and survey a five foot swath on each side of the rope.”

“Any metal found with the metal detector is inspected visually and by touch to determine whether or not it is a suspected munition,” said Schicho.

Items found will be marked with weighted buoys for vessel safety, and will be removed appropriately at a later date for proper disposal.

These cannonballs are being retrieved to make the waters off of Governor Island safer for boaters, vessel traffic, and potential future development on the island, such as the construction of new piers, bulkheads or seawalls.

How cannonballs may have entered the waters off of Governors Island years ago, will never be known for sure. What is known, is that by searching for them, Governors Island’s future is bright.


For more history and to learn the secrets of Governors Island, pick up the first and only guidebook: The Governors Island Explorer’s Guide (Globe Pequot Press).

Kevin C. Fitzpatrick has written and edited seven books with ties to New York history, including "The Governors Island Explorer's Guide" and "World War I New York: A Guide to the City’s Enduring Ties to the Great War." Kevin is a licensed sightseeing guide and has been leading walking tours since 1999. He resides in Manhattan.