FM 3-19.4 - Army Electronic Publications & Forms - U.S. Army

• Barges.
FM 3-19.4
DANGER
Ports pose special dangers for MP foot patrols. MP
leaders must ensure that soldiers are thoroughly briefed
on the hazards of patrolling too close to the water’s edge.
6-230. While most of the barriers described above will
stop or impede access to facilities from boats or
swimmers, nets are among the most effective. Wellmarked,
partially submerged objects are also effective;
however, there may be legal prohibitions against the
emplacement of barriers that may constitute a hazard to
navigation. The barriers should be emplaced only after
coordination with and approval by the appropriate legal
and HN authorities. Sometimes it is best to just close off
the waterside of a pier. A floating boom will keep small
boats out. Suspending a cable or chain link net from the
bottom of the boom will deny access underwater.
6-231. MP establish at least two security zones on a
facility’s waterside: the reaction zone and the keep-out
or exclusion zone. MP in these zones notify vessels, craft,
and swimmers that they are entering restricted waters
andshouldaltertheircourse.MPmaystopandsearch
intruders if necessary. Security zones should be
extended at least 1,000 meters from the nearest
protected asset; however, in some port areas, a security
zone this large is not possible. In such cases, other
measures, such as boat patrols, must be increased to
mitigate the possibility of attack. The two zones are
defined as the—
• Reaction zone. The reaction zone extends from
the high water mark to a distance beyond the
maximum range of anticipated waterborne
threats is the reaction zone. Inside the reaction
zone, MP will stop and challenge intruders.
Area Security 6-77