Instructions for digging defensive positions for AA halftracks from “Antiaircraft Artillery Notes,” HQ ETO, No. 8, December 1944:
Digging in Half-Tracks
Source: AA Section, Headquarters Twelfth Army Group
The principle of digging in equipment is one which all AAA combat units understand and practice. Some units have learned from experience that the deeper one is dug in, consistent with the field of fire to perform the assigned mission, the better protection the crew and equipment are afforded against artillery and mortar fire. As an example of the policy that it pays to dig in deep, Figure 1 shows the plan practiced by the 554th AAA AW Bn (M). Approximately eight hours is required to prepare the emplacement, including sandbagging. This battalion, commanded by Lt Colonel L. V. Linderer, has seen continuous action since arriving on the continent 18 June, being attached to XIX Corps until 5 November when it was attached to the 29th Inf. Div. During this period the battalion has been subjected to mortar and artillery fire on numerous occasions, and to date has suffered no fatal personnel casualties due to this fire.Notes:(a) Minimum thickness of revetment.(b) The depth of emplacement and heighth or sandbags will depend entirely on the terrain.(c) Log or plank for track to rest on.(d) Floor of emplacement slopes to the center and front to sump hole where water will drain and can be bailed out.