The Mortar Platoon
There was surprising consistency in the organisation of the typical Mortar Platoon during World War Two, with British, American and German units all deploying six tubes split into three Sections of two mortars apiece. The Red Army Mortar Company offered the greatest variation, but in the reduced strength formations settled on six mortars in just two Platoons.
The Mortar Platoon was invariably the single most powerful element of the Infantry Battalion. Dependent upon the particular model and ammunition, it could project fire anywhere between 2400 and 3000 metres, close to a maximum of two miles. The results of a single, well executed barrage could be decisive, and equally appalling.
Deployment considerations
Unlike their counterparts serving machine guns and anti-tank guns, mortar crews did not have to be able to see their target to hit it. The range of the 81 mm type mortar meant it was unusual if they did. As a result, mortar crews could use natural barriers, such as woods, buildings or terrain to shield themselves from enemy view. This was a tactic not available to other men of the Battalion, who had to obviate such features to target the enemy.
It was also something of a double-edged sword, in that for the mortars to accurately target the enemy, they relied upon what became ever more sophisticated methods of fire control.
Fire Control
The abilities of the mortar quickly became apparent to commanders in the field. The Platoon provided the Battalion with its own organic ‘artillery’ support, which unlike the real thing could always be maintained under direct control. But to live up to its potential it had to be responsive to the needs of the infantrymen and deadly accurate in its execution.
Mortar fire control was reliant upon cooperation between two parties; the mortar crews themselves and their forward observers. The former were responsible for the correct setting of the elevation, traverse and charge, the manipulation of which determined exactly where the bomb would land. But their remote position meant they were unable to make the necessary corrections for the fall of shot. That was where the observers came in.
Fire control could be exercised in one of two ways, through a fixed observation post or a mobile fire controller, but ideally a combination of the two was used.
The observation post (OP) was sited forward of the mortar position and was linked to it by telephone line, a more reliable method than the radio of the day. The OP needed to be sited in such a position that the observer could see the target area assigned to his mortars. He had to be a skilled mortar man, usually a Detachment commander, and had to judge precisely where the salvoes were falling and by how much off target. He then had to translate the shortfall or overshoot into mathematical calculations that the crews could use to adjust their range.
The mobile fire controller (MFC) took the principle one stage further. Again drawn from the Platoon, he would accompany the Headquarters of a Rifle Company operating further forward of the established OP. He would be linked by radio to the mortar position and undertook largely the same role as the observer, correcting fall of shot. However, his presence with the Rifle Company 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. This again extended the reach of the mortars and greatly expanded their ability to support the Rifle Companies.
To achieve this though required a great deal of communications equipment. A British Platoon fielded 14 radio sets and 8 telephones by 1944, while the German equivalent had 6 radios plus telephones. This level of equipment enabled each Section to deploy a forward controller with a radio who could keep in contact with the base-plate position through a second set. The picture for the US and Red armies was a little different.
The US Mortar Platoon was intended to operate as a single entity rather than in individual Sections (discussed below). Its radio equipment was officially limited to a single set at Platoon HQ. Local support to the Rifle Companies was provided by their integral 60 mm mortar Section in the Weapons Platoon. This is not to suggest mobile controllers and observers were not used, indeed they were, but the reliance would seem to have been on telephone communications from the signallers at Battalion rather than their own assets.
The Red Army offered the bleakest picture. Their 82 mm weapon had excellent range and in its revised form was the lightest of the class. However, Red Army doctrine did little to embrace communications and there no radios issued. Telephone lines could have played a significant role instead, but either way the Platoons were robbed of the responsive nature enjoyed by their German adversaries. The only solution to such shortcomings was either to push the weapons forward so the crews could see their targets, ignoring a major strength of the mortar, or restrict support to rigid fire plans on pre-determined positions, severely limiting the potential for engaging targets of opportunity.
Section level operations
A major consideration in placing individual Mortar Sections under the direct control of Rifle Companies was the depletion of firepower.
As mentioned above, the US Army largely shunned this tactic, preferring to use the 81 mm Platoon for Battalion support while the 60 mm Sections served their own Company. The British, unsurprisingly, favoured a compromise system. One Section would be placed under the command of the main effort Rifle Company, using the combination of OP and MFC to control fire. The remainder of the Platoon would operate under the direction of its commander providing general support or adding its weight to the vanguard Section when needed. The introduction of the 12 cm Mortar Platoon into the German Battalion enabled the 8 cm unit to operate in a more dispersed manner, two tubes supporting each Company while still retaining a powerful reserve. In those units still awaiting the issue of the 12 cm weapon its place was often taken by additional 8 cm ones instead. I cannot claim to be qualified enough to venture an opinion on Red Army tactics.
This scan would not go amiss in the Rifle Company segment. Note the Fire Platoon giving support on the right flank, while the mortars target the position
The problem was that mortars were at their most devastating when used in numbers. 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 in 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.
Offensive fire
In the offensive, the Mortar Platoon acted as a part of a much larger fire plan, which encompassed the Divisional Artillery, Regimental and even Corps guns. The heavy artillery though would quickly shift its fire to other, deeper ranged targets, leaving the advancing riflemen heavily reliant on their own mortars for support.
Mortars could deliver high explosive or smoke against the enemy. Smokescreens provided an important, but always troublesome tool. Their 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 its architects intended. A sudden gust of wind could reveal the force manoeuvring 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 much mitigate the effectiveness of harassing enemy fire.
But it was high explosive firepower that the mortar was employed for. Unlike the field guns situated well back from the frontline the mortars were relatively close. The gunners likewise relied on forward observers, who suffered the larger portion of artillery casualties as a result of their exposed position, but their guns could easily be switched to other targets deemed of greater importance.
A good indication of the level of communication required to make mortars responsive to the needs of the riflemen. Two mortars are detached here to another Company
The Battalion mortars would concentrate their fire upon known or suspected enemy positions during the opening bombardment, which preceded most assaults. Their high trajectory made them especially effective against dugouts, which, if properly constructed, were largely safe from conventional artillery fire. Their primary objectives were other weapons of their kind; machine guns, anti-tank guns and, of course, enemy mortars, all of which would be sited in well prepared weapons pits.
As the battle developed, the depth of the enemy defences would become more apparent and new targets would continually emerge. It was here that the swift response of mortar fire could help clear the way for the infantry assault by keeping the defenders heads firmly down. This should not be taken to deride the value of conventional artillery, but the mortars were better placed to deliver intimate support.
As has been noted in the segments on the rifle units, consolidation on the objective was a primary concern following a successful assault. Here again, mortars were on call to deliver a salvo against any enemy counterattack delivered against the riflemen in this most vulnerable stage as they shifted from assault to defence.
Where an attack succeeded it would open the gap between the mortar positions and the leading riflemen. To continue effective support fire, the mortars had to close that gap by moving forward. This could not be done by the whole Platoon at once, less the Battalion be entirely deprived of its fire for the duration of the movement. Rather, the Platoon would relocate by Sections, perhaps regrouping around the base of fire provided by an already detached forward Section operating with a Rifle Company. Such a position would already have been identified and made known, as an important part of accurate mortar fire was reading the local terrain.
Defensive fire
In the defence, mortars were better employed as a single Platoon, allowing the greatest concentration of fire to be produced. Their role was much the same as in the offence, launching counter battery fire against enemy mortar positions to relieve the pressure on their own riflemen and gun crews, targeting likely assembly areas for the enemy infantry and generally disrupting his intentions. Mortars could also provide excellent support to units on outpost duty and help cover their withdrawal with a combination of smoke and high explosive fire.
In the withdrawal, the Platoon would again relocate by stages. The advantage was of course that the route and new positions would have been well prepared beforehand. Supplies of ammunition could be located at both the current and secondary sites, allowing the mortars to move quickly into action on arrival at their new home. Secondary observation posts would likewise be prepared.
In static situations, the Mortar Platoon would be loathed to fire from its main position prior to a major assault, as this would inevitably reveal its location to enemy observers. Detachments and Sections could however launch harassing strikes from temporary sites before removing themselves quickly to avoid the inevitable retribution. Such ‘shoot and scoot’ missions would have to be performed well away from the dug in riflemen to spare them the retaliatory bombardment. These tactics could also be used to support fighting patrols gathering information on enemy dispositions, as well as outposts subjected to probing attacks.
Summary
The medium calibre 81 mm mortar came of age during World War Two, providing a lethal and previously unseen level of support to the infantryman. Countless promising attacks were literally torn to pieces by a single, violent, accurate barrage of often only brief intensity. In the offence, they could stun the enemy defenders long enough to allow the riflemen to move into the close battle. Of all the weapons at his disposal, the mortar undoubtedly provided the Battalion Commander with his most lethal tool.
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Infantry Tactics of World War Two