The MysteryCannon
In 1841 the twin towers of the Navesink Light Station were refitted and the first Fresnel lenses used in an American lighthouse was installed in the light towers. During the rehabilitation, a cannon was found buried on the lighthouse grounds. It was placed in front of the Keeper’s quarters and for over a century was known as the “Mystery Cannon” of Twin Lights. There are still unanswered questions about the gun…but this is known.

The gun is a twelve-pounder ship’s cannon of the fourth quarter, 17th century, and of Dutch of Danish provenance. A comparable specimen, although an eight-pounder, is exhibited in the Tojhusmuseet Museum, Copenhagen, Denmark. That particular gun was recovered from a Danish ship that sunk in 1679.

A typical ship’s cannon of the period was a flat trajectory weapon with a point blank range of 300 yards and effective, accurate range of one-half mile. The muzzle-loading cannon fired black powder, a mixture of approximately 75 parts potassium nitrate, 15 parts charcoal and 10 parts sulphur by weight. Projectiles fired included shot, hot shot, bombs, chain and bar shot. The barrel is deeply incised with the marking “1756 XX J * Lopez.” The name and date led to speculation that the gun was a “pirate’s” cannon. A nice legend, but that’s all it is. Joseph Lopez was Keeper of Twin Lights when the gun tube was dug up in 1841, and obviously he inscribed his name on the barrel.

But in doing so, Keeper Lopez may have shed light on yet another mystery. The first lighthouse at the Navesink Highlands was noted in Samuel Smith’s book The History Of New Jersey. In his 1765 publication, Smith wrote, “at the Highlands of Navesink, the New York merchants have lately erected a commodious lighthouse for the security of navigation.” Did “lately erected” mean 1756, the date Keeper Lopez inscribed on the cannon?

During the Revolutionary War, Sandy Hook was occupied by British and Loyalist troops. Wartime reports mentioned the lighthouse at the Highlands, and in 1776 it was noted that two Loyalists “found means to pass the guard near the lighthouse.” Was the Twin Lights Mystery Cannon part of the American defenses at the Highlands?

Or was it a fog signal cannon fired at regular intervals during foggy weather to warn ships they were approaching the shore? Fog signal cannons were commonly emplaced at lighthouses during the 18th century. In 1909, author Thomas Leonard wrote that the “old field piece was cast in Spain, and used by the colonists as a signal gun.”

Pirate gun…defensive weapon…signal cannon…its purpose at Twin Lights is not exactly known. The cannon is still something of a mystery.