Foss Unglossed: Hurrah! More mobility for infantry mortars

By Chris F Foss

I recently chaired a conference in Europe which also included a subsequent demonstration at an army range of a highly mobile 120mm mortar system that could revolutionise the deployment of mortars by light forces.

Armoured and mechanised infantry typically have their 81mm or 120mm mortars installed in tracked or wheeled armoured fighting vehicles and fire through open roof hatches.

However, airborne, light and commando forces usually carry their mortars in light unprotected vehicles together with the crew and a small quantity of ready use ammunition.
The main drawback of this is that these mortars have to be dismounted and assembled to engage the target, which takes valuable time.

In addition, when coming out of action after a sustained fire mission in soft soil, the mortar base plate can take time to be extracted from the ground as it becomes embedded and physically has to be dug out!

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Once the mortar has completed its fire mission, it should rapidly move to another fire position to avoid counter-battery fire. Many potential threat forces are equipped with locating radars that can rapidly pinpoint the location of indirect threat weapons such as mortars.

But technical advances and a little ingenuity have now demonstrated that a 120mm mortar can be integrated onto the rear of much lighter platforms such as the widely deployed Land Rover long-wheelbase and Toyota Land Cruiser, or similar vehicles.

The 120mm mortar is mounted on the very rear of the platform and, when required, is lowered to the ground under power control until the large baseplate is in touch with the ground. This absorbs the recoil force when the weapon is fired.

The number of 120mm mortar bombs carried depends on the platform, but is typically around 54 x 120mm mortar bombs with a mix of high-explosive, smoke and illuminating, when installed on a Toyota LC79.

In the demonstration I witnessed, the system came into action, carried out a fire mission and moved off again in less than two minutes. The maximum rate of fire is up to 12 rounds a minute with a sustained rate of four rounds a minute – talk about shoot and scoot!

As well as giving the 120mm mortar greater mobility, there is also a reduction in crew members required to deploy and operate the mortar, which is becoming increasingly important in many countries that are having difficulties recruiting and retaining their officers and men.

In addition to being installed on any pickup type vehicle with a typical payload of 1,500kg, it can also be installed in the rear of an armoured fighting vehicle such as an armoured personnel carrier. When retracted, this combination makes it difficult to detect what its real mission is.

There are two other significant mortar system developments, which are already attracting customers: turret-mounted mortars and turntable 120mm mortars fitted with a load assist device to increase the rate of fire and reduce crew fatigue.
Turret mounted mortars have the advantage that they can be aimed loaded and fired with the crew under complete protection from the elements as well as small arms fire, shell splinters and NBC attack.

Although their primary role is indirect fire, they potentially also have a beneficial direct fire role against building and bunkers, which would be helpful in counter-insurgency operations.

The latest generation turntable mounted 120mm mortars are fitted with power-assisted traverse and elevation, enabling them to be rapidly laid onto the target using a joystick and associated flat panel display.

While first-generation systems were typically fitted with hydraulic power for elevation and traverse, the latest ones have all-electric systems for improved crew survivability. Still, they have manual backup controls in case of power failure.

In addition, the latest generation vehicle-mounted mortars are usually coupled to a computerised fire control system and a land navigation system, which would typically include a global positioning system and/or an inertial navigation system. The latter is of importance in case there is a loss of GPS data due to jamming.

The installation of a FCS enables the mortar system to receive target information from the forward observer or aerial assets to allow the target to be rapidly engaged.

Mortars have always been an area effect weapon, but today there is a move to enable high value targets to be engaged with a more precision effect and less collateral damage.
The mortar bomb can be fitted with nose guided guidance kits for increased accuracy against high-value targets or when friendly forces are close to the target.

This also has the added advantage of reducing the number of mortar bombs required to neutralise the target, reducing the logistic burden.

In addition to providing HE 120mm mortar bombs with a more precision effect, a number of more advanced 120mm guided mortar bombs have also been developed and deployed, with some of these being laser-guided.

The main drawback of the latter is that of target designation, which can be via direct line of sight with the target or having the target designated from an aerial platform such as an uncrewed aerial vehicle.

With all these new capabilities coming to market at the same time, I don’t see why mortars will not continue to be a vital part of the infantry arms indirect fire capability.
In some countries, the 120mm mortars now come under the command of the artillery and form just one part of an army’s indirect fire capability – along with towed and self-propelled artillery, this also includes artillery rocket systems.

The question, as always, will be whether armies are willing to invest in these capabilities, which I continue to see as an essential part of the military toolset.

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