concertina. In the second row, two rolls are placed at the
third picket and two at every fourth picket thereafter. As
each roll is placed in position, its binding wires are
unfastened but are left attached to the hoop at one end
of the roli.
As they complete the first operation, organize all
men in four-man parties (fig. 8-27) to open and install
concertinas, beginning at the head of the fence. The
sequence shown in general in figure 8-27 is as
1. Open the front-row concertinas in front of the
double line of pickets and the other two in the rear.
2. Lift each front-row concertina, in turn, and drop
it over the long pickets; then join concertina ends, as
shown in figure 8-28.
3. Fasten the bottom of the concertina to the ground
by driving a staple over each pair of end hoops: one over
the bottom of the coil at each long picket and one at the
one-half and one-fourth points of the 12.5-foot picket
spacing. Securing the front concertina to the ground is
Figure 8-27.--Installing concertina.
essential and must be done before installing another.
concertina in the rear unless the enemy side of the
entanglement is sure to be accessible later.
4. Stretch a barbed-wire strand along the top of
each front row and fasten it to the tops of the long
pickets, using the top-eye tie for screw pickets. Stretch
these wires as tightly as possible to improve the
5. Install the rear-row concertina as described
above for the front-row concertina.
6. Install the concertina in the top row (fig. 8-27),
fastening the end hoops of 50-foot sections with plain,
steel-wire ties. Begin this row at sections with plain,
steel-wire ties. Begin this row at a point between the
ends of the front and rear of the lower rows, thus
breaking all end joints.
7. Rack the top concertina to the rear horizontal
wire at points halfway between the long pickets. If there
is safe access to the enemy side of the fence, similarly
rack the top concertina to the forward horizontal wire.
Figure 8-28.--Joining concertina.
This is a 4- and 2-pace double-apron fence in which
medium pickets replace long pickets in the fence center