Anchors are used to create a solid point of attachment for connecting rigging during recovery operations. Multiple anchors provide additional points of attachment for rigging mechanical advantage, add resistance to the effort, and prevent vehicle slide when recovering on a slope. Frequently, wheeled vehicles must have some anchoring means when winching heavy loads with tackle. An anchor can assist in holding a recovery vehicle, improvising a change of direction pull, or supporting part of the load during a winching operation. Most existing recovery vehicles have ground chocks or spades to provide resistance while performing recovery; however, additional anchoring may be required if the recovery vehicle continues to slide when the winch is operated.
Note: Trees, tree stumps, large rocks, or other vehicles may be used as anchors in recovery operations.
An anchor that does not have to be constructed is a natural anchor. Examples are trees, tree stumps, and large rocks or other vehicles. Avoid dead or rotten trees or tree stumps, and examine rocks and trees carefully to make sure they are large enough and embedded firmly in the ground.
There are several types of mechanical anchors. The anchor type used/ constructed depends on holding ability requirements, the type of soil required, the availability of material, and the situation.
A log deadman is one of the best types of anchors for heavy loads. The deadman consists of a log buried in the ground with the dead line connected to its center. When constructing a deadman—
- Place the deadman where the direction of pull is as horizontal as possible. Take advantage of sharp banks or crests to increase the holding power with less digging.
- Dig a trench large enough for the deadman and as deep as necessary for good bearing. When digging, slant the trench in the direction of the pull at an angle of approximately 15 degrees from the vertical. To strengthen the anchor, drive stakes in front of the deadman at each end.
- Dig a narrow inclined trench for the dead line at the center of the deadman.
- Tie the dead line to the center of the deadman, so that the main or standing part of the line leads from the bottom of the deadman. This prevents the deadman from rotating out of the trench. If the dead line has a tendency to cut into the ground, place a small log under the line at the outlet of the trench. The strength of the deadman depends on the strength of the log and the holding power of the earth.
A picket holdfast is constructed by using two or more sound wooden pickets at least 3 inches in diameter and 5 feet long.
Drive the pickets approximately 3 feet into the ground, 3 to 6 feet apart, and in line with the dead line.
- Tie a pair of pickets together.
- With fiber rope, tie one end of the rope to the top of the front picket with a clove hitch.
- Then make four to six wraps of the rope from the top of the first picket to the bottom of the second picket, ending with a clove hitch to the bottom of the second picket.
- Insert a stake between the rope wraps midway between the pickets.
- Tighten the rope by twisting it with the stake.
- Drive the stake into the ground.
- Repeat this procedure for each successive pair of pickets.
Note. The strength of the holdfast depends on the strength of the first or front picket. To reinforce it, drive two or more pickets into the ground close to the front picket. Tie all pickets in the front picket together using a clove hitch; wrap the front picket to the second picket, insert the stake, and drive the stake into the ground.
A sand parachute can be used in sandy areas when trees or other attachable devices are not available. Construct a sand parachute as follows:
- Dig a hole, line the hole with a tarpaulin, and fill the hole with sand removed from the hole.
- Lash the four corners of the tarpaulin together with rope and attach rigging to the rope.
Note. Multiple sand parachutes can be used in tandem by attaching them to a chain or Y-sling. This will provide additional holding strength, but the sand parachute has a limited holding ability. A sand parachute should not be used when a major effort is required.
A scotch anchor is used to anchor a wheeled vehicle during winching operations when natural anchors are not available.
- Select a log at least 6 inches in diameter and 2 feet longer than the width of the vehicle.
- Dig a shallow trench (the length and width of the log and approximately 3 or 4 inches deep) parallel to the front axle, just ahead of the front wheels.
- Lay a tow chain across the center of the trench (width), place the log in the trench, and move the vehicle forward until both front wheels are against the log.
- Attach both chain ends to the bumper lifting shackles and remove all slack from the chain.
Note. As pressure is applied to the winch, the front wheels are pulled onto the log, making the chain taut and anchoring the vehicle.
Using Two Tow Chains
If more than one tow chain is available, a similar method may be used.
- Lay two tow chains across the center of the trench (width) next to the inside of each front wheel.
- Place the log in the trench and move the vehicle forward until both front wheels are against the log.
- Wrap the chains through the bumper lifting shackles, remove the slack from the chains, and fasten them together using chain hooks.
A vehicle can be used as an anchor to assist in the recovery of a mired vehicle equipped with a winch. The winch cable from the mired vehicle is payed out to the anchoring vehicle and the mired vehicle winches itself out. The anchoring vehicle should not attempt to pull; it is only an anchor.
Source: U.S Army FM 4-30.31, Recovery and Battle Damage Assessment and Repair