Observation Towers

Soldiers in a fifty-two-foot observation tower could identify an enemy vessel, calculate its speed and distance, note weather conditions, and communicate this information to the main plotting room and the ten-inch guns at Battery Harker so gun crews could compensate for weather, set firing range and direction, and potentially fire at an unsuspecting vessel. Completed in 1903, the tower had two levels: a glass-topped upper level with an observation room and meteorological station, and a lower target plotting room from which critical data was relayed to soldiers aiming the big guns. When the guns were fired, vibrations like a small earthquake affected the delicate instruments in the towers, so Army engineers designed a concrete-filled tube below the tower, attached between the instrument platform and the ground and encased in a steel jacket, to dampen vibration and also insulate power and phone wiring. A two-story range finder at Fort Mott helped soldiers detect enemy vessels traveling on the Delaware River and relay their course to gun crews, and a second fifty-five-foot tower across the moat toward the river had a single observation level whose primary function was to obtain target information for the twelve-inch guns of Battery Arnold.

New Jersey · United States