Hermanville Gap-Filler Annex (P-55B / Z-55B)
Trip Report -- Sunday, 04 February 2001

Contributed by Tom Page

On this date, SJ Shaffran and I drove over to Lexington Park, MD, to see what -- if anything -- remained of the old gap-filler radar site known as the “Hermanville Gap-Filler Annex.” SJ Shaffran last visited the Hermanville GFA site in 1960 when he was serving as the Radar Maintenance Officer for the 647th Radar Squadron at Manassas AFS, VA. At that time, the Hermanville GFA radar facility was still in full operation.

SJ recalled that the Hermanville GFA site was about two hundred yards or so off to the right (southeast) of the main gate (Gate 2) of the Patuxent River Naval Air Test Center, down a (then) dirt road to a small rise, just outside the fence of the base. Today, that location (if it is indeed the correct location) is inside the fence of Patuxent River Naval Air Test Center, along a paved road. Clearly, much has changed over the 40+ years since SJ last visited the site. A side road was found to the top of the rise at the suspected site; this short road was paved with coarse amalgam concrete, typical of old military roads. At the top of the rise, the road ended abruptly, and the ground was fairly level, with no evidence of any past construction. The elevation was consistent with what one would expect for placement of a radar tower, and the location was where SJ remembered, but no building or tower foundations at all remained. This area at the top of the rise was large enough to have hosted a gap-filler annex, but no clues remained to verify its suspected former use.

We thoroughly scouted the area outside of the other base gates, too. SJ was quite certain that Gate 1 was not the place. The road from Gate 3, which was further to the south, actually leads to Hermanville Road. However, SJ was fairly sure that this was not the right location, either. To the right of Gate 3, down Pine Hill Run (Road) about five hundred yards or so, is a water tower, and near its base is the remains of a small cinder-block building. Nothing about this structure resembled a typical L-shaped GFA building, though. It was probably an old pumping building for the water tower (?). However, this is not conclusive, and the site cannot be ruled out absolutely as the GFA location. Still, this site near Gate 3 is not consistent with what SJ remembers -- its location is out of sight from Gate 3, and is about twice as far away. SJ does remember clearly that the GFA site was visible from the main gate of Patuxent River Naval Air Test Center. Consequently, that must have been present-day Gate 2.

So, we returned to the area near Gate 2. We even scouted around across the modern highway, which was not there in 1960 according to SJ. No viable candidate was discovered across the modern highway, either. Thus, through the process of elimination, we concluded that the rise which is about two hundred yards or so to the right (southeast) of Gate 2 was the most-likely location of the old Hermanville GFA radar facility. However, with no visible traces remaining, we could not be positive. Hopefully, records can some day be obtained from the U. S. Army Corps of Engineers and/or from the base civil engineer at Patuxent River Naval Air Test Center that provide the actual location of the radar site. Only then will we be sure we were, or were not, at the right spot. In any event, it appears that the Hermanville Gap-Filler Annex radar facility is no longer extant.