Civil engineer guide to fighting positions, shelters, obstacles

AFH 10-222 Volume 14 1 August 2008 76
4.4.2.3. Log Cribs. Log cribs are simple obstacles consisting of short sections
of logs (or other materials such as steel planks if available) fashioned
together as bins to contain dirt or rocks. Log cribs can be rectangular or triangular
and are used to block vehicle paths of travel on narrow roads (Figure
4.5). When possible, fill the cribs with material excavated by digging a shallow
ditch in front of the cribs. Anchor revetment materials to prevent them
from being easily pushed out of the way. These obstacles are effective against
wheeled and tracked vehicles, especially in restricted areas like narrow mountain
roads. Unless substantially built, these types of obstacles are not effective
against heavy tracked vehicles. To make these obstacles more effective, log
hurdles can be constructed ahead of the cribs to force vehicles to slow down
prior to encountering them.
Figure 4.5. Log Cribs.