FM 7-10 Appendix C

APPENDIX C

OBSTACLES

An obstacle is any natural or man-made obstruction that disrupts, turns, fixes or blocks movement.

C-1. EMPLOYMENT

Obstacles are most useful in the defense, but can be used in all operations. A variety of obstacles should be used to keep the enemy from finding, clearing, or bypassing all of them.

a. In the offense, the company uses obstacles--

To aid in flank security.
To limit enemy counterattacks.
To isolate objectives.
To cut off enemy reinforcement or routes of withdrawal.

b. In the defense, obstacles are employed to reduce the enemy's ability to maneuver, mass, and reinforce; and to increase his vulnerability to fires. Individual obstacles do this by performing one of four tactical obstacle functions - disrupt, turn, fix, or block.

(1) Disrupt. These obstacles disrupt march formations, break up operation timing, exhaust breaching assets, and cause separation between forward combat elements and wheeled supply vehicles. Obstacles also are used to disrupt assault formations, attacking the low-level command and control while the attacker is under direct fire.

(2) Turn. Turning obstacles move and manipulate the enemy to the force's advantage by enticing or forcing him to move in a desired direction, by splitting his formation, by canalizing him, or by exposing his flank.

(3) Fix. Fixing obstacles slow and bold the enemy in a specific area so that he can be killed with fires, or they can generate the time necessary for the force to break contact and disengage.

(4) Block. By themselves, obstacles never serve to block an enemy force. Blocking obstacles are complex, employed in depth, and integrated with fires to prevent the enemy from proceeding along a certain avenue of approach (or to proceed only at unacceptable costs). Blocking obstacles serve as a limit, beyond which the enemy will not be allowed to go.

c. In retrograde operations, the company uses obstacles to gain or increase a mobility advantage over the enemy or to strengthen delay positions.

d. Obstacles are normally constructed by engineers with help from the company. There may be times when the company must build obstacles without engineer help. In such cases, the commander should seek engineer advice on the technical aspects.

C-2. TYPES

The company commander is normally concerned with the following types of obstacles: reinforcing and existing.

a. Reinforcing. These are man-made obstacles constructed by units. They include road craters, abatis, log cribs, antitank ditches, log hurdles, minefields, and wire obstacles.

b. Existing. These include obstacles (either natural or cultural) that are already there. Natural obstacles are created by nature. They include such things as steep slopes, ravines, gullies, ditches, rivers, streams, swamps, and forests. Cultural obstacles are man-made, such as buildings, fences, and canals.

C-3. PLANS

The battalion receives a copy of the brigade plan that may specify obstacle belts, limiting the battalion to employing tactical obstacles within these belts and focusing the defense within the brigade. These belts consist of a system of obstacles designed to perform one of the four primary obstacle functions. This allows brigade-level maneuver outside of obstacles belts. Protective obstacles are the only obstacles that can be employed outside of designated belts. Or brigade may allow the battalion maximum flexibility and specify the battalion is free to employ tactical obstacles throughout its sector. Additionally, the plan may include brigade- or higher-directed obstacles critical to the plan at this level. These become priority obstacles and may be reserve obstacles. The brigade plan specifies allocation of resources, the priority of effort, and required completion times. (See FM 5-100).

a. After receiving the brigade obstacle plan, the battalion begins planning for the execution of its portion of the plan. The battalion commander and staff also consider METT-T and determine what additional obstacles are needed to support the battalion tactical plan. The battalion's obstacle plan is then distributed to the company commanders for execution. The battalion commander will also allocate engineer assets as required to support the plan.

b. Upon receiving the battalion plan, the company commander begins planning for the execution of his portion of it. He also considers METT-T and determines what additional obstacles are needed to support his tactical plan. (These obstacles, however, must be approved by battalion before their construction.) When planning for obstacles, the company commander considers:

(1) Mission. What does the company have to do (defend, attack, withdraw, or delay) and for how long?

(2) Enemy. from where will the enemy come? Will he be mounted, dismounted, or both? Where can he be forced to go?

(3) Terrain and weather. What are the existing obstacles and how will they affect the enemy? How can existing obstacles be reinforced? When there are no existing obstacles, how can obstacles be made to support the company's tactical plan? How can these obstacles be observed and covered by direct and indirect fire? How will weather conditions affect the use of obstacles?

(4) Troops and time available. Will engineer support be available? How much work can be done by infantry troops? How much material, equipment, and transport are available? Is field artillery and helicopter support available for emplacing minefields? How much time is available for constructing obstacles?

c. The CO applies the following principles when planning obstacles:

(1) Support the tactical plan. The use of obstacles must support the tactical plan. The CO uses them to supplement his combat power, to decrease the mobility of the enemy, and to provide security for his unit. While considering enemy avenues of approach, he also considers his own movement requirements, such as routes for resupply, withdrawal, counterattacks, patrols, and observation posts.

(2) Tie in. He must tie in his reinforcing obstacles with existing obstacles. This increases the enemy's difficulty in bypassing the obstacles. He must also tie in the obstacle plan with his plans for fire support.

(3) Cover by observation and fire. He ensures that all obstacles are covered by observation and fire. This reduces the enemy's ability to remove or breach the obstacles and increases the possibilities of placing fire on the enemy when he encounters the obstacles. It is preferable that obstacles be covered by direct fire, but if this is not possible, they may be covered by indirect fire. In such cases, however, the obstacles must be covered by observation in order to call for and adjust the fire. Units must often reposition during limited visibility to cover the obstacles.

(4) Construct in depth. Although the company has limited assets to construct obstacles, he should attempt to construct them so that the enemy will encounter several obstacles before reaching the company's position.

(5) Camouflage and conceal. The company camouflages and conceals its obstacles to deny the enemy the ability to detect them and plan for breaching or bypassing them. A degree of camouflage or concealment can be achieved by properly siting the obstacles and by delaying the execution of demolition obstacles.

(6) Afford no advantage to the enemy. The company should use barbed wire, mines, and booby traps to deny the enemy the use of any cover and concealment that might be provided by an obstacle.

(7) Provide for lanes and gaps. He must plan lanes and gaps through obstacles to allow movement of friendly units. He must, however, ensure that these are constantly secured and that plans are made to close them before enemy contact.

d. As there are seldom enough resources to construct all the desired obstacles, priorities must be set to wisely use time, equipment, and materiel. Normally, those obstacles that improve the defense against armored vehicles are constructed first; then those that improve the close-in defense; and last, those that improve flank and rear security.

C-4. ENEMY OBSTACLES

When confronted by an enemy obstacle, the company will either bypass or breach it. The decision on what to do is based on the mission, the situation, and the assets available. Obstacles intended to stop dismounted soldiers usually are made of mines and barbed wire. They are normally covered by fire. Dismounted soldiers can bypass many obstacles designed to stop or canalize mechanized and armor units. However, dismounted soldiers may have to breach these obstacles so that tanks and support vehicles can follow them. While breaching these obstacles, soldiers must look for antipersonnel mines as well as antitank mines.

a. Bypassing. When by passing an obstacle, the CO must report its type and location to the battalion commander. As the enemy may cover the bypass routes by fire, the commander must be alert for unexpected enemy contact. Suppress places from where the enemy can cover the obstacle by fire.

b. Breaching. A breach is the employment of any means available to break through or secure a passage through an enemy obstacle (Figure C-1).

Figure C-1. Breaching an obstacle.

(1) There are two types of breaches: hasty and deliberate.

(a) In the hasty breach, the company attacks quickly using smoke to conceal its movement and well-rehearsed battle drills to get through the obstacle while controlling the far side by suppressive fires. The commander synchronizes his combat elements, making the most of surprise and initiative, to get through the obstacle with a minimum loss of momentum.

(b) A deliberate breach is done after detailed reconnaissance, planning, and preparation. It is normally planned by battalion and done with engineer assistance.

(2) The company may breach different obstacles using different techniques and types of equipment and explosives. Some of the equipment and explosives that may be used include rocket-propelled line charges, mine detectors, bangalore torpedoes, surface-launched fuel-air explosives, direct fire weapons (such as the combat engineer vehicle), and hand-emplaced explosives. When using such things, the company should seek engineer advice and assistance.

(3) The fundamentals for breaching any obstacle are:

Suppress the enemy to allow the breach element to create a breach.
Obscure the breach site from enemy observation.
Secure the breach site, execute the breach, and secure the far side.
Reduce the obstacle to facilitate follow-on forces.

(4) The company SOP should discuss breach operations. A breach kit can be prepared and carried in the battalion trains. It may include grappling hooks, ropes, bolt cutters, wire cutters, engineer tape, chemical lights, smoke grenades, and a demolition kit.

(5) When the company must breach an obstacle, the company commander will normally organize his unit into support, breach, and assault elements.

(a) The support element has the primary mission of suppressing enemy fires to support the breach and assault elements as they cross through the obstacle and move on to eliminate the enemy overmatching the obstacle.

It suppresses the far side with direct and indirect fires.
It may also coordinate and control the weapons/equipment used for obscuration of the breach site.

(b) The breach element has the primary mission of reducing the obstacle (create lanes) to pass the force through to the far side.

It creates a lane through any type of obstacle.
It provides local security for personnel creating the lanes.
It marks the lane.
It guides a force through the lane.
It hands off the lane to trailing forces.
It may assist the assault element in securing the far side.

It physically attacks through the lane created by the breach element.
It ultimately secures the far side by occupation.
It protects the passage of the breach and support elements.

(6) The CO may elect to have some portion of his, unit perform dual functions, such as conduct both the breach and assault.

(7) The procedures for breaching minefields, abatis, log cribs, tank ditches, craters, and wire entanglements are explained in FMs 7-8 and 20-32.

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