Why We Do What We Do in LHY: Mortars

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This is the fifth part of the series regarding “Why we do what we do in The Last Hundred Yards.” This article deals with the use and effects of Mortars.

Before I discuss how Mortar support is represented in The Last Hundred Yards, I feel it necessary to share briefly various excerpts from different sources in the use and effectiveness of mortars in World War II.

Mortars in World War II – Mortars caused more casualties in Normandy than any other weapon. The main reason why was because there is NO incoming sound, so no warning to take cover. Having said that, it is absolutely true that German mortar fire was a serious concern amongst the Allies in the OVERLORD campaign. For instance, in the 21st Army Group, a specific committee was formed to study the problem and recommend counter-measures. The operational research unit in 21st Army Group produced a report on the subject, which is reproduced in Terry Copp (ed) Montgomery’s Scientists: Operational Research in Northwest Europe:

“The Germans use mortars in large numbers…  In the present campaign, casualties from mortars have been particularly heavy and have contributed as much as anything else to making advances slow and costly. The casualties in the present campaign from mortars have been very heavy, heavier in fact than from all other weapons put together, at least as far as the infantry are concerned. … [However] exact figures for mortar casualties are hard to get. Medical records only show the weapon causing the casualty in a few cases. A number of infantry battalion MOs … all agreed in placing the proportion of mortar casualties to total casualties among their own troops as above 70%.”

In their book, D-Day, Zetterling and Tamelander, two very good Swedish military historians, discuss German infantry tactics in regards to the use of mortars, which for the German infantry was a key weapon. The battlefield of Normandy was somewhat confined, meaning the defensive area, including likely approach routes, was mapped and plotted in by artillery and mortar observers. When allied infantry entered the German defensive area they would come under fire from a few German riflemen. The idea was to get the allied soldiers to drop to the ground for cover on a likely spot selected by a forward observer. When the allied soldiers ducked for cover, a barrage of mortar fire was immediately under way. The mortar fire would come in quickly, hit with great accuracy and usually have a devastating effect. This is because they knew in advance where to fire and the crew was ready and waiting to fire. The allied officers had a hard time convincing the soldiers that when taking light small arms fire, to not stop but keep moving which was far less dangerous than to stop. The 70% losses to mortar may be exaggerated but in Normandy and probably elsewhere the mortar was the most deadly German light infantry weapon.

Roles of the Mortar – All maneuver units require indirect fire and the mortar was invariably the single most powerful element of the Infantry Battalion. The primary role of mortars was to provide immediately available, responsive indirect fires that supported the maneuver of the company or battalion, and to reinforce direct fires during assaults. In the attack, the mortar was used to suppress the enemy, inhibiting his fire and movement, while allowing friendly forces to gain a tactical mobility advantage. At the company and battalion-level battle, mortar fire acts both as a killer of enemy forces and as an enhancer of friendly mobility. In the defense, the mortar was used to breakup enemy troop concentrations, reduce the enemy’s mobility and channel his assault forces into engagement areas, break up the enemy combined arms team and destroy his synchronization.

Each mortar section was capable of firing an effective concentration in an area up to 100 yards square, making the 6 tube mortar platoon a potent force. Although there were significant tactical limitations to what could be achieved. Perhaps the biggest drawback of the mortar was the high rate of ammunition expenditure and the need to husband ammunition. Thus, target selection was vital. The average 80 mm mortar round weighed 9 to 10 lbs. With a rate of 15 to 20 rounds a minute, a section could easily burn through 300 to 400 lbs. of ammo in a single minute and that’s just for one section and for a mortar platoon that would mean almost a 1000 lbs. of ammo.

Mortars could also deliver smoke against the enemy.  Smokescreens provided an important, but always troublesome, tool.  The intent was to deceive the enemy; did the appearance of smoke signal an advance under its cover against a particular sector, or did it merely conceal a feint by a few men while the real blow was struck elsewhere?  The trouble came in that smoke rarely adhered to the plan in quite the way it was intended.  A sudden gust of wind could reveal the force maneuvering behind it to enemy view, or worse still blow it back into the advancing troops blinding them instead.  In the event of a forced withdrawal, mortars could quickly lay a smokescreen to cover the retreat of a Company and greatly mitigate the effectiveness of harassing enemy fire.

Organization – Mortars were at their most devastating when used in numbers. Placing individual Mortar Sections under the direct control of Rifle Companies depleted the Mortar Platoons firepower. Splitting them up into Company level units denied the Battalion Commander the opportunity to deliver a single, concentrated barrage from the necessary minimum of four tubes.  If, as with the later German model, he had more than six tubes to work with, he could afford a more generous allocation to his Rifle Companies, but ultimately the Mortar Platoon was a Battalion asset not a substitute for lack of explosive firepower in the rifle units. The American Mortar Platoon typically consisted of six 80mm mortars while a German Mortar Platoon consisted of six 8 cm mortars and later an additional two 8 cm or 12 cm mortars. Each American Rifle Company had its own inherent 60 mm Mortar Section fire support. Although the German Rifle Companies did not have inherent Mortar Sections, it was not uncommon for a single 8 cm Mortar section to be assigned as direct support to a Rifle Company.

Fire Control – Mortar fire control was reliant upon cooperation between the mortar crews themselves and their forward observers.  Fire control could be exercised either from an Observation Post or Mobile Fire Observer. The observation post (OP), more commonly used in a defensive role, was sited forward of the mortar position and was linked by telephone line, a more reliable method than the radio of the day. The mobile fire controller, more commonly used in an offensive role, would typically accompany the Headquarters of a Rifle Company and would be linked by radio to the mortar position. This allowed him to call in fire missions to engage targets of opportunity or help overcome stubborn points of resistance out of sight of the OP.

As stated above, mortar support was a key element in combat at the Battalion level. As such, I have made every effort to model it as accurately as possible and yet keep it simple. Both Mortar Platoons and Mortar Sections are represented in The Last Hundred Yards. Every effort was made to represent not only the fire control systems accurately, but also the brutal effects and behavior of men under mortar fire. I feel the mortar fire system is one of best and most fun in The Last Hundred Yards. The following is a summary of how the request and execution of Mortar support works in The Last Hundred Yards.

Mortars in The Last Hundred Yards There are no mortar counters onboard in The Last Hundred Yards. Instead, each Mortar Platoon or Section is represented by its own Forward Observer (FO) marker.

Mortar Support Availability – The mortar support available is stated in each Mission, or Mission Special Rule, and can be requested during any action or reaction. Once the mortar fire support mission ends, or fails to extend, the corresponding Forward Observer is removed from play and placed in a holding box on the Game Track. In subsequent game turns, the controlling player makes a die roll to determine whether further mortar support is available. This delay represents the variable time required for the immediate resupply of the ammunition and the time required for the FO to maneuver to a new location if necessary. Once used, a player will never know for sure when his mortar support will be available again. Therefore, it is very important that mortar support be used judiciously.

Requesting Mortar Support – To call for Mortar support, a player first places a Forward Observer (FO) marker specific to the Mortar Platoon or Section requested in the requesting unit’s hex and specifies the target hex. The requesting unit must be in LOS of the target hex, undisrupted, not under Assault nor in a hex currently under mortar fire. In addition, if the requesting unit is a combat unit (instead of a leader) it must be within communication range of its Platoon Leader and that Platoon Leader cannot be disrupted, under Assault or in a hex under Mortar fire.

Provided the previous requesting conditions have been met, the firing player declares whether the mortar is firing HE or Smoke. If HE, the player immediately places a RED Mortar Die Roll Modifier (MDRM) marker in the target (Primary Impact Hex) hex. The value of the MDRM marker is based on the caliber of the firing Mortar Section or Platoon, terrain and any fortifications. For instance, the base MDRM value of a 60mm mortar is 0 while that of a 80 mm mortar is +2.

The firing player then places a number of additional MDRM markers in Secondary Impact Hexes according to the requested mortar type, caliber and whether HE or Smoke is used. The firing player makes an accuracy die roll for each Secondary Impact Hex and refers to the scatter diagram on the map.  For instance, on a die roll of 7-10, an additional MDRM is placed in the Primary Impact Hex. If the die roll is 1-6 the MDRM is placed in one of the six adjacent hexes.

Example: If using a 80mm mortar against an open terrain target hex, a +2 MDRM marker is placed in the Primary Impact hex. Per the Mortar Fire Mission Table an additional two MDRM markers will be placed in corresponding Secondary Impact hexes, depending on the accuracy die rolls. 

Continuation of a Mortar Fire Mission – Mortar fire is resolved in the Fire Resolution Phase after all fire and maneuver has taken place. At the end of the game turn, a player may attempt to continue an existing mortar fire attack once, targeting the current target hex or any other target within two hexes of the original target hex – provided his FO has LOS.  If the mortar fire extension attempt is successful, the player repeats the mortar fire process. This extended mortar fire is resolved during the Fire Resolution Phase of the following game turn.

Mortar Effects – A great effort was made to model not only the killing and suppression effects of mortar fire but also its effects on a unit’s ability to maneuver. Non-vehicular units may not enter a hex that is under mortar fire as it would have been disastrous to do so. Units in a hex under mortar fire have no LOS outside the hex – they are hunkered down – and may not conduct any action or reaction, except possibly to withdraw. If they do withdraw, they immediately suffer the mortar fire attack as if in open terrain – another ugly prospect. Smoke from mortars could be very effective when maneuvering against an enemy AFV, but otherwise mortar fire had little effect against fully armored vehicles. As a result, fully armored vehicles may enter and exit a hex under mortar fire, with only a slight possibly of immobilization, and may fire normally but are subject to hindrances when firing from, through or into mortar fire.

As it was historically, mortar fire is the single most powerful element in The Last Hundred Yards. The timing and use of one’s mortar support is critical in the success of combined arms operations.

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One thought on “Why We Do What We Do in LHY: Mortars

  1. Thanks for keeping us informed about the mechanics!

    It helps to understand what the game will model and why it will model it like that, as well knowing which design considerations influenced the mechanics.

    Manuals often don’t contain too much information on the design considerations, which can make what a mechanic represents a complete mystery to the player.