There are two types of weapon systems on the battlefield: direct and indirect firing. Tanks are in the former, artillery and mortars are in the latter. Direct fire weapons are those where the gunner can see the target, engage it and carry out corrections. In indirect fire weapons, the gunners do not see the target and use an artificial aiming reference to engage and carry out corrections. The reason both are needed is that when a unit gets engaged with the enemy, it’s freedom of maneuver is limited because of enemy fire. At that point, indirect fire weapons, not in direct view of the enemy, are brought to bear on enemy positions providing lethal fire support.

Every operational situation requires an overwhelming quantum of fire support so that the enemy can be neutralised, canalised, destroyed or his vision obscured thereby limiting his ability to acquire and attack own targets. Artillery, therefore has a number of tasks chalked out, like providing close support to attacking/maneuver forces, counter bombardment, and interdiction of the battle field. To accomplish one or all of these a variety of field and medium guns as well numerous rockets and missiles systems are being employed. However, there is always a paucity of the number of artillery fire units available and it is but desirable to utilize all available weapon systems to carry out the many tasks that have been enumerated.

Concept of Employment

The existing Indian battle tanks are equipped with a 120 or a 125 mm main gun that is capable of firing a variety of ammunition. The primary aim of a battle tank in war is to destroy another tank. This is accomplished by employing the main armament of the tank in a direct firing role, using kinetic energy ammunitions like the ‘armour piercing fin stabilised discarding sabot’. In addition to the kinetic energy ammunition, tanks use a secondary ammunition, mainly high explosive, to engage softer targets like vehicles, buildings and personnel. This secondary ammunition can be fired both in a direct or indirect firing mode.

The article does not advocate changing the primary role of tanks from that of killing another tank by employing its main armament in indirect firing mode. It emphasises the need to employ every available weapon platform to engage the enemy, thereby ensuring overwhelming volume of fire support to facilitate victory. Every military operation, be it offensive or defensive has a fair proportion of tanks which are not in direct contact with the enemy or are located in areas where contact with the enemy is not immediately imminent. Selected units/sub-units from these troops can therefore be employed to augment the close fire support being provided by the artillery. Such indirect fire support by tanks can be provided from ranges as far away as 10 km. This additional firepower would vastly enhance the quantum of fire and consequent lethality produced at the target which in turn would result in lowering the number of casualties to own troops as well reducing the time taken for capture of the objective.

Technical Feasibility

All tanks can, using high explosive ammunition, bring down accurate fire to engage soft targets up to 10 km. This engagement which is undertaken at ranges beyond visual range, is directed by an observer who views the target in the same fashion as is done when bringing down in direct artillery fire.

Necessary corrections required to be carried out in terms of elevation and azimuth are communicated to the tanks by the observer. The tanks apply these corrections to ensure the fire is accurate and effective. Requisite equipment required to carry out such an indirect shoot including that required for corrections is an integral part of the tank fire control system.

Number of Tanks to be Employed

The number of tank platforms to be committed for this role though being a command decision, will depend on a number of factors:

• Residual life of the gun barrel. It would be prudent to use only those tanks whose gun barrels are in the first or second quarter of life.
• Out of a squadron of 14 tanks, a maximum of 12 tanks may be used leaving the squadron commander and the second-in-command to exercise command and control.
• All tanks employed for the purpose must be utilized for providing only close fire support to attacking troops thereby limiting the duration of their employment to a maximum of 45 minutes to an hour.
• Vintage tanks such which may have been allotted for defensive purposes may also be employed for this purpose.

Training

A number of personnel in all armoured regiments are trained to direct artillery fire. In addition, tank crews should get enough practice in the engagement of targets in indirect firing role during annual field firing tests. A suitable FMR for practicing the crews in this mode can also be created.

Correction of Fire

Correction of fire may be carried out either by OP Officers from artillery or by members of the recce troop of the armoured regiment who are trained to call artillery fire.

Communications

Orders for call of this fire may either be directed through the artillery fire direction centre (FDC) or passed directly to the tanks through the command channel. Necessary coordination and training for communicating with the FDC also needs to be imparted.

Suitability to Provide Indirect Fire Support

By virtue of their mobility, armoured protection, flexibility and high rate of fire, tanks apart from being the primary choice for an offensive, are also ideally suited to provide fire support by both direct as well as indirect means. Some of the factors that favour their employment in providing indirect fire support are as follows:

• Communications: Availability of communications with each platform facilitates good command and control and excellent intelligence, surveillance and recce information which equip the tank crew to effectively engage the target.
• Armour Protection: This provides survivability to the crew from the envisaged threat of counter bombardment that artillery units fear in combat.
• Mobility: Enables the tanks to rapidly deploy and redeploy and change positions and roles depending upon the battle situation, thereby giving it all the advantages that tracked self-propelled artillery enjoys.
• High Rate of Fire: At approximately six rounds per minute, tanks can bring down a high volume of firepower and cause substantial damage of the enemy in a short duration.
• Flexibility: The flexibility which results from a combination of the above mentioned features, equips the tank to be employed in offensive or defensive operations and in the assault as well as the fire support (including indirect firing) role.

Drawbacks

Despite the many features that make a tank suitable to provide indirect fire support, the following points merit consideration:

• Availability of Ammunition: Most tanks carry approximately 44 rounds on weapon. Considering that a squadron is employed to provide indirect fire support for one engagement of four minutes, each tank would consume approximately 24 high explosive rounds. Hence, in order to employ tanks in this role, adequate quantities of ammunition must be ensured. This can be done by carrying additional ammunition on wheels much the same way as is done in the artillery.
• Wear and Tear: In order to ensure there is uniform wear and tear of gun barrels, it will have to be ensured that the same tanks are not repeatedly employed for this task. This can be resolved by employing guns in the first or second quarter of life and by careful planning.

Recommendations

Having analyzed the employment of tanks in indirect firing mode the following is recommended:

• Tanks must be selectively employed for short durations to provide indirect fire support to augment the existing degradation resources in the battlefield. Such employment can be done in support of all offensive and defensive operations. The long ranges of engagement of up to 10 km and the heavy weight of attack that can be brought to bear on the enemy must be exploited.
• Suitable training of tank crews to fire in the indirect role as well as to direct such fire must be carried out by all armoured regiments during the field firings. Crews must attain proficiency in directing artillery fire.
• Problems of high ammunition expenditure must be catered for by grouping suitable wagon line vehicles to carry additional ammunition much in the way it is done for self propelled artillery. When employed in a defensive role in pivot corps formations, suitable dumping of ammunition can be resorted to.
• Spare crews must be utilised for carriage and handling of the additional ammunition. Accordingly the first and second line authorisation of high explosive ammunition to armoured regiments must be revised.
• Additional vehicles for carriage of ammunition should be authorised to armoured regiments.
• This mode of employment of tanks in indirect firing be an exception rather than the rule and be undertaken only in crucial stages of the operation where overwhelming fire support is essential to ensure victory.

Conclusion

Ever since tanks became part of the modern battlefield, they have been employed for a variety of tasks.Tanks have been used to break through defences, reconnoiter defences, execute battlefield liaison, conduct reconnaissance missions as well as transport essential supplies. Tanks have been used as the main force in attack, as well as defence, and even for roles as diverse as establishing a road block and providing fire support.

The idea of providing indirect fire support by tanks is not a new one. In November, 1937, three Japanese tanks formed a stationary battery while infantry were crossing the Suchow Canal. In February, 1938, 40 tanks were similarly employed at the crossing of the River Hwai. The longest ranges at which tanks have been recorded to have provided fire support is 11 km in 1966 by Israeli M51 Sherman and Centurion tanks with other tank crews on foot providing corrections. The tank is a versatile weapon platform and it is only in the order of things that we utilise its great potential in all fields so as to enable us to win the next war.

Major General Vikram Dev Dogra is the Provost Marshal of the Indian Army.