FMST Student Manual - 2008 Web Edition*

1.    DEFENSIVE TERMINOLOGY

Defensive Area - an area of ground assigned to a unit to defend.  Troops and weapons do not physically occupy the entire defensive area.  Unoccupied portions are covered by fire.

Forward Edge Of The Battle Area (FEBA) - is an imaginary line joining the foremost limits of a series of areas in which ground combat units are deployed.

Sector of Fire - an area that is required to be covered by fire by an individual, a fire unit (squad or fire team), or crew served weapon.

Lateral Limits - readily identifiable terrain features are selected to indicate the line of sight along each side of the sector.

Forward Limits - established at the range at which the weapon will open fire, may extend to maximum effective ranges.

Threat Conditions In The Rear Area - in the face of threat, there must be a plan.  In the rear areas (which include the rear area BAS and other medical facilities), intelligence reports from forward units will alert the defending units and prepare them for action.  Depending on the type of information reported, the defending units move to the appropriate degree of readiness.  There are four degrees of readiness they are called threat conditions.

Threat Condition Alpha - 25%, All is normal

Threat Condition Bravo - 50%, Attack is probable

Threat Condition Charlie - 75%, Attack is likely

Threat Condition Delta - 100%, Attack is imminent 

2.  DEFENSIVE COMBAT 

Four Purposes of Defensive Combat

Retain or Control Terrain

Gain Time

Develop more favorable conditions for offensive action

Economize Forces - to economize on one front for concentrating superior forces for an offensive elsewhere. 

3.  ADVANTAGES AND DISADVANTAGES OF DEFENSIVE COMBAT

4.   DEFENSIVE MISSION OF THE INFANTRY

The mission of the infantry in the defense is, with the support of other arms, to stop the enemy by fire as he approaches the battle position. Repel his assault by close combat if he reaches the battle position, and to destroy him by counterattack if he enters the battle position.  For the rifle squad, this mission can be divided into three parts:

- To delay or suppress the enemy by fire once he comes into small arms range of the squad's fighting position.  The enemy is delayed or taken under fire as far forward of the squad's fighting position as possible.

- If the enemy continues to press the attack to the point where he launches an assault, the squad repels this assault by continuing to deliver fire as part of their units final protective fires and if necessary by hand to hand combat.

- If the enemy succeeds in penetrating the platoon’s battle position, the squad holds its fighting position, delivering fire and participating in counterattacks to destroy the enemy and restore the battle position. 

5.      TYPES OF DEFENSE

There are two basic types of defenses that a unit may be called upon to construct:

Hasty Defense - this is a defense you assume when you are in immediate contact with the enemy.   It utilizes hasty emplacements.  It is temporary in nature and may either be a 180-degree or a 360-degree defense.  This is the type of defense you would assume as part of an immediate action drill in patrolling.

Deliberate Defense - this is the type of defense you would set up when occupying an area for an extended time.  In a deliberate defense you always construct fighting positions with field fortifications and set a 360-degree perimeter. 

6.      DEFENSIVE POSITIONS

Fighting positions located on the ground from which fire is delivered by an individual fire unit or crew serve weapon.  It must allow for good fields of fire, make maximum use of available cover and concealment and facilitate exercise of fire control by the unit leader.  There are three types of defensive positions:

Primary Position - the best position from which the assigned sector of fire can be covered.

Alternate Position - used by crew served weapons and is located so that a crew served weapon can continue to fulfill its original task, when the primary position becomes untenable unit or individual to be occupied when the primary position becomes untenable.

Supplementary Position - a position prepared to guard against attack from directions other than those from which the main attack is expected, also providing security 

7.      FUNDAMENTALS OF DEFENSE

The following fundamentals of defense are applicable to all tactical levels (fire teams, squads, platoons, company, etc.).

Preparation - normally, the defender will arrive at the battlefield before the attacker.  Upon arrival at the position to be defended, the squad leader must ascertain:

- How much time is available to prepare the defensive position?

- If time is available, prepare the position.  If not, prepare a hasty defense.

Concentration - forces must be concentrated to prepare for attacks at the most likely spots. For the squad leader this means they will establish their position as directed by the PLT commander, this is called the main effort.

Flexibility - achieved through the continuous development of various courses of action. Unit leaders continuously ask themselves “What do I do if the enemy does this?”  This is called war gaming.

Maximum Use of Offensive Action - the platoon leader will normally task the squad to conduct various types of patrols to maintain contact with the enemy. Additionally, the squad leader must instill an offensive state of mind and an aggressive spirit.

Proper Use of Terrain - take maximum advantage of the military aspects of terrain.  An easy way to remember these aspects is the acronym: KOCOA

 Key terrain

 Observation and fields of fire

 Cover and concealment

Cover is protection from enemy small arms fire.

Concealment is being hidden from enemy observation.

 Obstacles

 Avenues of approach

Mutual Support - units and supporting weapons are located and employed so they can assist one another.  Positions should be located so that when attacking one, the enemy comes under fire from at least one position.

Defense In Depth 

The squad employs all three fire teams on line when deployed.  The squad engages the enemy at maximum small arms range and continues to fire until the enemy is stopped.  If the attackers penetrate the frontline squads, those squads may move to supplementary positions to continue and engage the enemy, or they may be part of a counter attack to drive the enemy back.

- Defense of depth can also be achieved by a series of patrols, delays, ambushes, and movement from one battle position to another.

Surprise - The squad leader must employ every means available to mislead the enemy. This includes the true location of the strength and the disposition of their organic weapons.

Knowledge of the Enemy - since the defense reacts largely to what the attacker does, the squad leader should find out the capabilities of the enemy facing him to help organize his defense to meet that threat.  Such as:

What can the enemy do?                         

What weapons will they employ?

What is their strength? 

8.      ESTABLISHING THE DEFENSE AND IDENTIFYING PRIORITIES

The acronym SAFEOCS is used to prioritize work once assignments have been made.

Post Security

Position Automatic Weapons

Clear fields of Fire

Entrenchment - Prepare fighting positions

Construct Obstacles

Camouflage, cover, concealment

Select supplementary fighting position  

REFERENCE

Marine Rifle Squad,  MCRP 3-11.2, Ch 5

Rev: July 2008

Defensive Operations Review

1.  List the four purposes of defensive combat.

2.    Describe a deliberate defense.

3.    Describe a supplementary position.

4.  List the nine fundamentals of defense.