1963 US Army Vietnam War Armor Operations ... - Survival Books

WWW.SURVIVALEBOOKS.COMing organic equipment or that furnished from (3) Select landing points on the far shorethe rear support units. Listed below are someand determine bank conditions atcommon field expedients; only time, personnelthese points.available, and the tactical situation restrict the (4) Insure that the carriers are checkedinitiative and ingenuity of the small unit corn-properly before they enter the watermander in his employment of these or otherand upon leaving the water.means.b. Stream Velocity. The maximum streama. Using Organic Equipment. velocity in which the carrier can be operated(1) If a marshy shoreline exists at the safely depends on such factors as the choppientrancesite, the armored vehicle ness of the water, the amount of debris or icelaunched bridge (AVLB) may be laid in the water, and the maximum acceptableacross this area from firm ground into downstream drift distance. When the rate ofthe water. The carriers may then flow is greater than 4 miles per hour, particucrossover and begin swimming as lar attention must be given to drift distance,they enter the water.balance of load, entry into the water, and abil-(2) If the armored personnel carrier can- ity of drivers. A simple way to determine thenot climb out of the stream on the far stream velocity is to use a floating device overbank, it should be backed up to the a measured distance. Measure a distance of atleast 100 feet along the near riverbank. Designatethe upstream end as point A and the downsonneldischarged. If the water is toostream end as point B. At point A, throw intodeep to lower the door, personnel may the fastest part of the stream any object thathave to exit from the top hatch. will float, such as a piece of wood or cork.b. Using Supporting Engineer Equipment. Using a stopwatch or the second hand of a(1) Bridging equipment from corps and watch, determine the time it takes the floatingarmy units, when required, may be object to move from point A to point B (fig.prefabricated in the rear area and de- 27). For example, if it takes 20 seconds for thelivered by air vehicle to the work par- object to float 100 feet, the rate of flow of theties at the shoreline.stream is 5 feet per second. This figure in feetper second must then be converted to miles per(2) For an expedient raft, the AVLB may hour. This is done by using the conversionbe laid across floats and lashed se- chart shown in figure 28. At least two testscurely. When an AVLB is used in should be made with floating objects, the aversucha manner, the bridge must be age time being used to determine the rate ofrecovered as soon as other conven- flow in feet per second. For additional infortionalmilitary ferries are in opera- mation on water operations with vehicles seetion. TM 21-306.352. Employment of Armored Personnelc. Stream Characteristics.(1) Changes in velocity. A sluggishOperationsstream or river may become a torrentin a few hours or even minutes as aa. Precrossing Considerations. Upon reach- result of sudden heavy rainfall. Thising a water obstacle, the armor unit com-is more likely to happen in tropicalmander, to minimize delay, follows a definiteand arid regions. Stream velocitiessequence or checklist before employing his ar-must be checked at frequent intervalsmored personnel carriers. This sequence is-to provide warning of such changes.(1) Determine the velocity of the stream (2) Channels. Velocities may vary in difandits characteristics.ferent parts of a stream. The rate of(2) Determine bank conditions at the en- flow is usually slowest near the shoretrance to the stream.and fastest in the main channel.AGO 9139A 173