Ft. Ruckman Fire Control Tower (Location 130-1A)
The Fort Ruckman fire control tower, which survives today as One Harris St. in Nahant, is a 6-story tower which was constructed with an attached wood frame cottage. It was completed on May 29, 1943.
On its top (6th) level, the tower housed the Battery Command (BC) observation point for Battery Gardner (the 12" guns across the street at Ft. Ruckman). The optical axis of the depression position finder (DPF) on this level was 128.0 ft. above sea level. On the fifth level, at an observational height of 120.0 ft., was a DPF that served as a base end/spotting station (B 4/10 S 4/10) for Battery Whipple, the 6-inch guns at Fort Standish on Lovells Island. Also located here was an observer for the North group (C2) of artillery, which contained the three batteries at Nahant and was to have included the 6-inch guns at Ft. Dawes, which were never installed.
The fourth floor, at an observational height of 112.0 ft., housed a a base end/spotting station (B 4/4 S 4/4) for Battery McCook, the 6-inch guns at Fort Andrews on Peddocks Island. The first floor of the tower was 81.59 ft. above sea level. All told, the tower is 49.5 ft. tall, from the surface of the first floor to the surface of the roof.
The second and third floors of the tower (which were empty) were reached by concrete stairs from the level below, while the top three levels and the roof were accessed by steep ladders set against the walls. The concrete walls of the tower were one foot thick, and the internal dimensions of its observation levels were 12 ft. square. The slab floors at each level were 6" thick.
The one-story "cottage" attached to the rear of the first floor of the tower (today remodeled into a private home) was 40 ft. long and 29 ft. wide. The (southernmost) front 10 ft. contained separate toilets for officers and enlisted men and a boiler room, providing the buildings with steam heat (a rarity for these facilities in the Boston defenses).
In the center of the cottage was a large, open plotting room, 21 ft. deep by 29 ft. wide, that almost surely served Btty Gardner. Adjacent to that was a Squad Room, taking up the last (northernmost) 10 ft. of the cottage's length. The presence of both a battery command post and a command post for the North artillery group probably accounted for the extra space an amenities provided in the Ruckman tower.
Given the attention paid to blast-proofing most of the harbor's plotting room facilities (many of which, like that for nearby Btty Murphy at East Point, were actually built underground), it is hard to understand why the the plotting room for the second most powerful set of guns in Boston Harbor (Btty Gardner) was housed in a rather flimsy wood frame structure. Aiming at the tower and knocking out the plotting room below would likely have put Btty Gardner out of action for a good bit of time.
In 1946, the tower acquired a resident caretaker, and the barracks building was remodeled as a residence for him. In the late 1940s and continuing into the 1950s, an experimental radar array was constructed atop the tower, as part of MIT Lincoln Labs' development of the SAGE radar system for the Nike missile defense program. The same program also outfitted the fire control tower at Halibut Point with rader equipment.