Most of the world left ww1 with the same artillery tactics. Defensive support fire, barrage fire, counter battery fire and harassing fire were the four kinds of fire artillery were supposed to deliver. And of those, defensive support fire was the hardest.
Defensive support fire
A front unit is under attack and requests support fire against the advancing enemy. This was one of the most important roles of artillery during both ww1 and ww2. Most nations had an artillery staff with an artillery commander and a number of forward observers and communication staff attached to the divisional staff or the artillery regiment of a division. When a unit occupied terrain and could expect enemy activity, the artillery staff would place a forward observer closeby and have the communication staff roll out a telegraph or phone line to the forward observer so he could communicate with the artillery batteries he would direct.
Things would happen like this.
- The commander of battalion Z would inform his regimental commander that his battalion is facing an enemy attack. The commander of Regiment A would request artillery support against this enemy attack either with the divisional commander or the artillery commander. They would coordinate that the enemy attack is happening at spot X on the map.
- The divisional commander or artillery commander would confirm that artillery resources are available and order defensive support fire to be delivered at spot X.
- The forward observer establishes contact with the battery that will provide support fire and confirms spot X and that the order is still relevant.
- The artillery battery calculates ballistic data for spot X – how much charge do they need? What elevation? These thins are affected by weather, height differences, distances between enemy and friendly troops, etc.
- The first gun in the battery fires. The forward observer notes where the grenade lands and reports back using distance and a clock to note how far from the target the shot landed. For example, 300 meters, 8 o’clock. This means the shot landed a little short and about 300 meters to the left of the target. The gun crew corrects and fires again. Within a few shots, they have zeroed in on the target.
- The process is repeated for the other guns in the battery.
- Once all guns are zeroed in on the enemy, they pour as many grenades as they can over the target until it has either retreated or is destroyed, as reported by the forward observer.
During ww1, balloons and airplanes were used for forward observing of targets far behind the front and destroying them (or protecting them) became a top priority for the fighters on each side.
As you can probably see, there’s a lot that can go wrong in this. If artillery command or the divisional HQ is out of contact, it gets hard to get artillery fire approved, or even to get through to the artillery. Telegraph and phone lines were often cut by enemy artillery fire and would need to be repaired.
But above all, this system took time. It could take everything between 10 minutes and 60 minutes to get fire from a single battery onto a desired spot. By that time, the enemy could have moved, their assault either having been repulsed or successful, a counter-attack might have happened and even moved into spot X, and many other things. This system worked decently well during ww1, when fronts moved slowly or not at all, but caused problems during ww2 when fronts and units could move very rapidly.
On the attack, infantry needed artillery fire to destroy MG and mortar nests, field fortifications and wooden bunkers that the enemy was using. They seldom had time to wait for artillery to zero in on these targets. Different nations took different aproaches to resolving this problem for ww2.
Most nations gave the infantry some small artillery to command and use themselves – mortars. Light and medium mortars, and in the case of the Soviets, Finns, Germans and Swedes, heavy (120mm) mortars. These weapons were fired directly in line of sight of the enemy, or with a forward observer integral to the mortar team and all under the command of the battalion or regimental commander, allowing the infantry to support themselves without having to go to divisional command or that much need to zero in (if firing within line of sight, the mortar team could correct their fire themselves).
Some nations (primarily the Germans and Soviets) gave the infantry regiment short-range infantry guns (the 7,5 leIG18 and the 76,2mm PP-27 respectively) that were meant to fire directly or at least within line of sight to support the infantry in their attack or defence.
Other nations, like France added extensive staff and long-range heavy cannons to their divisional artillery units to pre-calculate any possible scenario and have all the information needed already when the call for artillery support came. This was a superb system – if the front was stable. If there was no time to pre-calculate ballistics and do test fire, like in mobile warfare in France 1940, the system fell apart.
Yet other nations, like the British standardised their artillery to a single piece (the 25pdr) and reduced industrial tolerance to the extent that calculated data for one battery was enough for another, so that several batteries could deliver fire on one fire order with one calculation.
Some, like the British, produced enough radios so that forward observers became independent on telephone and telegraph lines and could move about (forward observers and the men putting out cablöes were a favourite target for snipers, sharpshooters and mortar crews and be less vurnurable and much more flexible.
Other nations, like the Germans and especially the Soviets, stared putting artillery on turretless tanks so that he infantry could have protected mobile guns ackompanying them – the StuG and the SU vehicles started out as such, and turned out to be excellent tank destroyers too.
Yet others, like the Finns and the British, added mechanical calculation machines to the artillery staff to enable them to calculate ballistic data much, much faster.
Yet again, others, like the British, the Finns and to some extent the Germans decentralised artillery command – forward observers were permanently attached to infantry units and given the power to call down artillery fire on their own authority, shortening the command structure.
The Soviets started grouping their artillery extremely tightly together, so that data for a single gun could be used for the entire battery.
What the Americans did was completely unique. Not only did they produce radios in such an amount that every platoon of infantry could have their own, they also made them so small that they could be carried and operated easily (the walkie-talkie) by a single man. They also decentralised artillery support commands not to only forward observers, but directly to NCOs of the infantry unit and in many cases gave them some similar training.
But the biggest thing the Americans did was to improve the French system (the Americans since ww1 built their artillery on French designs and French doctrine) to not calculate any available scenario when the unit had deployed – but to calculate any scenario for any gun, at any place!
This is completely insane – the amount of data needed was unparalleled (ballistics data is hard to calculate) and a small army of mathematicians supported by female staff and mechanical calculation machines started the work over western Europe in the 30s. The ENIAC computer was developed to help calculate this data, and the US defence department helped pay for some land surveys in western Europe to get accurate maps down to extreme detail.
Thus, when a US artillery unit got a frantic call for support from an NCO under German fire in France autumn 1944, he would confirm the spot X on the map, pull out pre-calculated data for hus 105mm howitzers from spot Y (where they were lined up) to spot X, and start firing accurately in a matter of minutes.
The Soviets could need 30-60 minutes for accurate defensive support fire from several batteries.
The Germans could need 15-30 minutes for the same.
The British could do it in 3-10 minutes.
The Finns managed to get it to 5-12 minutes or so.
The US could, in perfect circumstances, get it down to 30 seconds, although normal was 2-5 minutes.