Military History |
World War II
Artillery and Mortar Tactics of WW2
Posted 27 Mar 2006
After reading a discussion of area effect for artillery in the Crossfire Discussion Forum I became curious about the tactics of artillery and mortars during WW2. I had a quick google for "Artillery Tactics" and looked up some of my books to get a sense of how it all worked.
A couple of general terms:
Time On Target (TOT) missions involved timing the firing of multiple batteries so that all fire on the same location, with the firing times adjusted to cause the rounds to all impact at the same time (Ellis, 1980; Evans, 2001-5; Hopkins, 1996). Bombardment may cease after the initial volley or be maintained in Fire For Effect mode, creating a sustained saturation of the area with detonations. This tactic was used by the Americans in WW2 (Sulzen, 2000), however, Sultzen is incorrect that only the Americans used it - the British also used this technique.
Fire For Effect means that the battery will fire continuously at it's maximun sustained rate (Ellis, 1980; Evans, 2001-5; Hopkins, 1996). The Americans stopped firing when the Forward Observer (FO) called "Cease Fire", but the British normally fired a certain number of rounds per gun. According to Ellis the Americans called this a 'Serenade' in WW2 although by Vietnam they were certainly using the term 'Fire for Effect'.
A Barrage was a belt of fire that could be stationary (standing) or moving in front of the attacking troops (Evans, 2001-5).
A Concentration was when two or more batteries engage the same target (Evans, 2001-5).
Effectiveness of fire
Evans (2001-5) lists four aims of artillery fire (Neutralising, Morale, Lethal, Material). All four happen at the same time, but the effects earlier in the list are much easier to achieve than those later in the list. For example, a 25 pounder needs to land 8 - 32 shells per hour for neutralisation (for about 10% casualties; Global Security Organisation, n.d.), but 600 shells in a 100 x 100 yard sector are required to militarily 'destroy' the target (meaning 30% casualties).
Neutralising: To prevent enemy movement and observation, and in cases of greater effect
to prevent the effective use of enemy weapons. The effect only lasted during the bombardment,
which meant in attack so the friendly infantry had to 'lean' on the bombardment to ensure they
reached the enemy positions before the enemy realised the bombardment had stopped and reached
Morale: To produce, in addition to neutralisation, a lack of will to resist continuing for some time after the end of the bombardment.
Lethal: To kill or wound enemy personnel. Military 'destruction' was generally considered to be 30% casualties.
Material: To destroy or damage enemy equipment
Terrain significantly reduces the effect of fire (Evans, 2001-5). 'Natural' or 'average’ ground offers about 5 times as much protection to a prone soldier as an 'unnatural' level surface like a football field.
Fortifications, being man made protective terrain, not surprisingly also significantly affects the lethality of fire. Evans (2001-5) lists some interesting estimates on how vulnerability changes with the posture of the target. The following table gives the relative risk of becoming a casualty to ground-burst shells on ‘average’ ground:
Firing from open fire trenches
|1/15 - 1/50|
Crouching in open fire trenches
|1/25 - 1/100|
In the Far East the allies found that a Japanese fortifications were resistant to anything except a direct hit from a bomb or large naval gun (Ellis, 1980). In one incident in 1944, where 684 rounds of 3.7-inch howitzer shells and 670 rounds of 25-pdr shells landed in an area 250 yards square, the Japanese suffered only two confirmed dead and minor damage on a few communication bunkers; there was no material damage on the main combat bunkers. The allies found that individual guns fired at point blank range were much more effective - the trick was getting the guns in place.
British Artillery Tactics
Fire plans of British artillery (technically called 'programme shoots') where either barrages, concentrations, smoke screens, or a combination (Evans, 2001-5). Targets in a fire plan were ranged or predicted. They could also be on a timed programme or on-call. Targets in fire plans were normally fired ‘time on target’ (ToT) from late 1942.
Note: A British Field Artillery Regiment was organised into two field batteries each of three troops of four guns, or later of three batteries of two troops (Hassett & Burns, n.d. a). In either case the Regiment comprised 24 guns.
A Barrage was a belt of fire that could be stationary (standing) or moving in front of the attacking troops (Evans, 2001-5). Barrages were largely used for covering fire, i.e. to neutralise the enemy. A Barrage was usually the main part of a British fire plan for an assault.
'Ordinary' barrages could be any shape, but the 'quick' barrages introduced mid war had to be a rectangular shape (Evans, 2001-5). In 1942 it took a regiment 3 hours to prepare an 'ordinary' barrage from when the commander issued orders, this included deploying the guns but not dumping the ammo. It was 10 to 12 hours for a division and 24 for a corps. 'Quick' barrages were only used by deployed units so preparation time was shorter: 60 to 80 minutes for a regiment (assuming no more than 10 lines).
Barrages were structured on a grid with vertical unit lanes and horizontal firing lines (Evans, 2001-5). In a barrage a troop fired within its own unit lane with each gun firing at aim-points spread evenly along lane width. Lines were usually 100 yards apart. The width of a unit lane depended on the size of unit firing (hence number of guns) and type of barrage.
- A 25-pdr troop (4 guns) lane was at most 140 yards .
- A regimental lane could any of the following:
- 560 yards maximum for a creeping barrage. This was normally two batteries wide, with the third battery superimposed across the full width of the lane.
- 400 yards for a dismounted infantry assault
- Full width (??) for an armoured assault.
Evans (2001-5) also provides a table showing the frontage covered by HE shells of various types (a various is given below). That for a 25 pounder is 35 yards, which when multiplied by 4 gun in a troops gives the the 140 yards mentioned above. This suggests larger guns had correspondingly wider troop lanes.
|Frontage covered by HE shell (yards)||Safe Distance (yards)|
In fire plans, when targets or barrage lines had to be engaged for a particular duration, 'rates of fire' (rounds per minute) were ordered with a duration in minutes (Evans, 2001-5).
A Pepperpot: barrage was where guns of all types (artillery, mortars, machine guns, infantry guns, anti-tank guns, anti-aircraft guns, naval guns, tank guns) and even aircraft were used (Ellis, 1980).
Moving barrages had as many lines as needed to achieve the depth required for the attack. Moving barrages could be either creeping, rolling or block.
- Creeping Barrage: only one line was engaged at a time. When fire lifted from one line, it moved backwards to the next line.
- Rolling Barrage: several lines were engaged at once (eg a-a & b-b, when fire lifted from a-a it went to c-c).
- Block Barrage: several lines engaged simultaneously and all lifting together to a new block.
A Concentration was when two or more batteries engage the same target (Evans, 2001-5). Early in
the war a concebtration basically mean all batteries fired at the same point. Statistical
variation meant the larger units covered a wider area. A regimental Concentration covered about
250 × 250 yards, divisional about 350 × 350 yards, divisional with Army Group Royal Artillery
(AGRA) about 400 × 400 yards. Timings for fire plans of concentrations were similar to those for
barrages, but where the number of lines affected the preparation time for a the barrage, each
separate concentration added to the preparation time.
Although used before, linear concentrations became popular around the time of El Alamein in 1942 (Evans, 2001-5). Popularly called "Stonks" there were in fact several types, only one of which was the true Stonk. The four Concentrations given below were used by the NZ Divisional Artillery (Hassett & Burns, n.d. a) but at least the Stonk and Murder were in use by British artillery in general:
Stonk ("Standard Concentration")
This was a Linear Target along a Regimental front of 600 yards identified by its centre point and vertical axis (Hassett & Burns, n.d. a). According to Evans (2001-5) by 1944 stonks were standardised as 525 yards long (Ellis, 1980, implies 1943). Evans also says " 2 NZ Division continued to use its 1200 × 300 yard stonks" but the dimensions actually correspond a Rumpus (see below).
Additional facts about a British "Stonk" (Hassett & Burns, n.d. b):
- The name "Stonk" is probably a portmanteau word for "standard concentration".
- The original 1940-1941 Stonk was a square of 300 yards by 300 yards, each battery covering a linear frontage of 300 yards, with the batteries echeloned plus and minus 100 yards from the centre point.
- The Stonk in the latter part of the war, post Alamein, was substantially different from the original version. It was a 600 yards linear regimental target based on a grid reference and bearing .
- Stonks were generally pre planned in the sense that they were nominated and recorded and it was unusual for them to be initiated on the spot.
- Observation Posts (OP) could initiate Stonks but there is no record of the technique ever being used as part of an observed fire programme.
- Each Stonk was given a codename or number.
- The number of rounds was nominated each time the Stonk was called for.
- In the post Senio period they were occasionally used by the medium guns as a means of covering an area where German tanks had been seen.
- The technique was used post Alamein for the definition of Defensive Fire Tasks in support of the infantry in static positions.
- They were also used in depth on some occasions ahead of the line of the barrage.
Originally known as Method A (Hassett & Burns, n.d. a). This was a concentration of all the guns of either a Regiment or the Divisional Artillery on a pin-point target. Evans (2001-5) says in Italy a murder was for 3 minutes.
Possibly not widely adopted at Regimental level but became the basis of RUMPUS (Hassett & Burns, n.d. a). This was originally a Regimental concentration of rectangular shape with a Battery frontage (i.e. 200 yards) for use against small company localities. The Batteries' tasks were echeloned along an axis 100 yards apart. If more than one round was ordered the Batteries searched 50 yards by 25 yards.
This was a Divisional Artillery variation of the original Regimental METHOD R. It went through several standardisation stages (Hassett & Burns, n.d. a). The first Regiment covered a normal frontage of 600 yards the other Regiments 100 yards apart on the vertical axis. Given more than one RGF the Regiments searched 50 yards by 25's. this was modified later with two Regiments side by side and one superimposed on a frontage of 1200 yards, all searching on the vertical axis 150 yards by 50's covering a depth of 300 yards.
Smoke screens were used in fire plans, they could be predicted, although a ‘tester’ to confirm the local wind was often used. Screens could be multi or single battery and positioned about 250 yards from the enemy to be blinded. Gun aim-points were placed on a linear, with the distance between them depending on the wind direction. If the wind was along the line of the required screen then points were 300 yards apart, if across the line they were 75 yards apart. Whenever smoke was used there were alternative HE targets in case the screen was ineffective. One technique was to create a lane a few hundred yards wide between two screens that screened tanks from defiladed anti-tank guns, if the wind was favourable these screens could be rolling. Smoke screens could be sustained for long periods, on at least one occasion all day.
Quick Barrages / Quick Fire Plans
The British were more concerned with speed than accuracy and introduced quick barrages in 1941, followed in 1942 by quick fire plans (Evans, 2001-5),. Both were regimental fire plans using simplified procedures and standard layouts (Evans, 2001-5). They were used used by Forward Observation Officers (FOO) to support small unit actions (patrol, company, squadron, or battalion). Orders were verbal and were usually just for FOO's own battery. Fire zones were rectangular and the fire plan mentioned only a few targets . The British found these fire plans particularly useful when operations turned to pursuit or during advances against light opposition. They were usually concentrations using a mix of timed and on-call targets. Increasingly battalion mortars were included in quick fire plans.
Defensive Fire Plans (or SOS targets)
Defensive fire (DF) was pre-planned by FOOs in consultation with the supported company commander (Evans, 2001-5). A DF was generally a standing barrage of one or two lines intended to block or harrass enemy advances; stonks were widely used, as were three sided box barrages. DF plans were 'on-call'. When not otherwise engaged a battery (and/or regiment or higher formations) would aim at the designated DF; by 1943 regimental DF plans were found to be the most effective. In Burma DFs were often 25 yards from the forward infantry positions.
The key to successful harassing fire was to avoid predictability in the times or places of targets (Evans, 2001-5). Unfortunately, the Germans learnt that the British tended to stop firing at meal times.
The British recognised five different categories of target outside fire plans, with a sixth
added in 1943 (Evans, 2001-5). These were:
Immediate neutralisation (IN) – the ‘standard’ type of shoot, section ranging. Although called neutralisation, the aim could be to cause casualties and damage.
Fleeting opportunities – moving targets or targets likely to move, could be ranged with gunfire (without bracketing) or section ranging with the guns firing at different ranges, the aim was usually to cause damage and casualties.
Close to own troops – special rules about maximum corrections.
Pin-point – normally a single gun target with the aim of destroying a 'point' target. The CPO selected the least worn gun and ordered angular elevations, with the gun laying using its field clinometer not the gun rule.
Registration – to record for future engagement. It could be recorded 'corrected' or 'uncorrected', the latter meant that it had to be used within the current meteor period because its registered location was not adjusted for correction of the moment.
Quick smoke – an abbreviated smoke screen procedure where guns aim-points were not laid out in
an optimum line. The observer calculated where to place it and how much to fire. Smoke was
considered a form of neutralisation because it ‘neutralized’ observation by the enemy.
German Artillery Tactics
Germans could also do map based fire ("blind") or impromptu fire spotted by an FO (Sulzen, 2000). Their impromptu fire was dependent on have accurately surveyed the battery's position and firing positions for the FO; it also involved complicated maths by the battery when called upon, and hence was slow to arrive, about 15 min from call to shell fall. The Germans carefully accounted for a range of factors (elevation changes, wind, temperature, etc.) that the British ignored. That meant, although slow, they tended to be quite accurate. Firing time against a previous target, or near a previous target, was faster as they kept their previous calculations. If the Germans had time to prepare they pre-plotted ("registered") firing points so that effective fire could be quickly delivered as needed.
American Artillery Tactics
The Americans used the British system but they pre-computed the firing data for a large number of variations of wind/temperature, barrel wear, elevation differentials, etc (Sulzen, 2000). This meant they could get almost the same accuracy as the Germans, but had a reaction time of only 3 min for impromptu fire. Higher level assets could also be called in; the inclusion of the division support supposedly added an additional three minutes to the fire mission, and including corps assets added another three minutes, so in theoretically 9 minutes an entire corps artillery could land in one grid reference.
Vietnam Artillery Tactics (Hopkins, 1996)
One Round - a ranging shot.
Battery One means that the 6 cannon fire one round in unison.
Fire For Effect means that the battery will fire continuously at it's maximun sustained rate, adjusting on the fly, until the FO calls "Cease Fire".
Zone And Sweep directed the battery to fire a Battery One pattern on the target and also one kill radius beyond, below, left and right of the target, expending 30 rounds, patterning an "X" on the target and surrounding area. Typical kill radius was 30 meters for a 105mm or 4.2inch round, 50 meters for a 155mm and 80 meters for an 8inch round.
Time On Target (TOT) missions involved timing the firing of multiple batteries so that all fire on the same location, with the firing times adjusted to cause the rounds to all impact at the same time (Hopkins, 1996). A typical TOT might involve 4 batteries (24 guns), of different calibers; some firing rounds fuzed for ground burst, some for airburst. The effect is that a particular jungle clearing might be quiet and peaceful one second and in the next second be totally enveloped and saturated with explosions in the air and on the ground. Bombardment may cease after the initial volley or be maintained in Fire For Effect mode, creating a sustained saturation of the area with detonations. This tactic was used by the Americans in WW2 (Sulzen, 2000), however, Sultzen is incorrect that only the Americans used it - the British also used this technique (Evans, 2001-5)
Mortars were general considered infantry weapons (??), although the Russians considered their 120mm mortar as true artillery (??).
The primary role of mortars is to provide immediately available, responsive indirect fires that support the maneuver of the company or battalion, and that reinforce direct fires during close combat (Global Security Organisation, n.d.).
In the early war the British considered a single 3" mortar to be a viable fire unit, but by 1944 the shot dispersal caused by longer ranges meant a fire unit was at least 2 tubes (Bull, 2005).
For a short period of time the six 3" mortars of in a British infantry battalion could bring down more weight of fire than an eight gun field battery (Bull, 2005). At intense rate one 3" mortar could put down 200 lb of projectiles at rapid rate in one minute. This compares favourably with the 125 lb a 25 pounder could put down in the same period.
A single American 81mm mortar could bring down a concentration 100 yards by 100 yards (Bull, 2005).
The American 81mm mortar was thought to have the same mobility as a heavy machine gun (Bull, 2005).
For the Americans priority was always given to observed targets, however, plotted targeting was also possible (Bull, 2005). For plotted targets, woods and reverse slopes were prime targets in both attack and defence as this could disrupt advancing/retreating enemy.
Each Russian 82-mm mortar company, with nine pieces, fired in support of its own rifle battalion (Intelligence Bulletin, 1946). The company could lay down a fixed barrage 275 yards wide, with each tube typically firing 14 rounds. Action was begun by firing two company concentrations of three rounds each, followed by four platoon salvos at 5-second intervals. Zone fire was conducted against enemy assembly areas and troop concentrations, the zone engaged by one medium mortar company being not larger than about 7 acres (an area about 180 x 180 yards in total). Zone fire was conducted at the rate of about 18 rounds per 2 acres per minute. Elevation and deflection was shifted in order to cover a zone adequately, each platoon firing 2 to 4 rounds for every shift of about 50 yards. Short, intense concentrations were fired at visible targets in exposed positions. These concentrations usually lasted for 2 to 3 minutes, with the ammunition expenditure being about 50 rounds per 2 acres per concentration.
In defence the mortars of a Russian Rifle Regiment were normally grouped into a provisional medium mortar battalion, containing 27 medium mortars (82mm) and six heavies (120mm) (Intelligence Bulletin, 1946). Such a battalion could fire a barrage 600 to 700 yards wide.
Mortars can be fired through the roof of a ruined building if the ground-level flooring is solid enough to withstand the recoil (Global Security Organisation, n.d.).
Bull, S. (2005). World War II Infantry Tactics: Company and Battalion [Elite 122]. Osprey.
Ellis, J. (1980). The Sharp End of War: The fighting man in World War II. London: Book Club Associates.
Evans, N. F. (2001-5). British Artillery In World War II.
Global Security Organisation (n.d.). Mortars. [Available on-line http://www.globalsecurity.org/military/systems/ground/mortars.htm]. Author.
Hassett, R. D. P. and Burns, J. (n.d. a). The Development of Artillery Techniques by 2 NZ Divisional Artillery of World War II. [Available on-line http://www.riv.co.nz/rnza/hist/tech1.htm]. Royal New Zealand Artillery Old Comrades' Association.
Hassett, R. D. P. and Burns, J. (n.d. b). The Mystery of the Origin of the Stonk. [Available on-line http://www.riv.co.nz/rnza/hist/stonk.htm]. Royal New Zealand Artillery Old Comrades' Association.
Hopkins, J.M. (06 Dec.1996). Artillery Terms and Tactics. [Available on-line http://www.vietvet.org/arty.htm].
Intelligence Bulletin. (May 1946). ON THE WAY! The Employment of Mortars in the Red Army. [Available on-line http://www.lonesentry.com/articles/ontheway/index.html]. Lone Sentry.
Sulzen, J. (2000). Artillery Practices by the Major Combatants of WWII. [Available on-line http://etloh.8m.com/strategy/artil.html]. Etloh Technologies.