File:Pt Allerton FCT.jpg
The top level DPF, at 179 feet, controlled fire for Battery Murphy, the 16-inch guns in Nahant. Next came the 6th story, at 171 feet, which controlled Battery Jewell, the 6-inch guns a short distance to the north, on Outer Brewster Island. Then came the fifth story, at 163 feet, which controlled fire for Battery 207, the 6-inch guns across the harbor entrance at Ft. Dawes.
A concrete crow's nest "basket" was located just below the roof level, with a trapdoor that opened up and provided space for an observer of the Ant-Aircraft Intelligence Service (AAIS) who stood watches spotting for intruding aircraft.
The railing around the edge of the roof was added (for the safety of visitors) by the present (2010) owner, who also installed a new staircase to the roof through the former AAIS crow's nest.