Arguably, the first Mechanized infantry ever were 36 infantry pairs carried forward by Mark V* tanks at the Battle of Amiens in 1918. In a battle of such scale, their contribution went unnoticed.
The Mark V* was a modified Mark V tank that was lengthed, for better obs crossing abilities the infantry were carried in addition to the normal complement of crew.
Towards the end of World War I, all the armies involved were faced with the problem of maintaining the momentum of an attack. Tanks, artillery or infiltration tactics could all be used to break through an enemy defense, but almost all the offensives launched in 1918 ground to a halt after a few days. Pursuing infantry quickly became exhausted, and artillery, supplies and fresh formations could not be brought forward over the battlefields quickly enough to maintain the pressure on the regrouping enemy.
THe Mark V was an oft experimented with varient. As mentioned before, they came in male and female varients, the Mark Vs were turned in to hermaphrodites by puting a male sponson on one side (with the naval gun) and a female on the other side (with machine guns).
The first true APC was the Mark IX, these were troop carriers or infantry supply vehicles - among the first tracked Armoured personnel carrier not counting experiments with the lengthened Mk V’s. 34 were built out of an order for 200. Officially these vehicles could carry 50 men, although they had to stand up (no seats) it was more likely 30 to be carried, being a Platoon. Up to 10 tons of stores could be carried instead of men.
Mk ix “tank”.
During the first actions with tanks it became clear that often infantry couldn’t keep up with the tanks; not because soldiers were too slow - the early tanks themselves could only move at a walking pace - but because of enemy machine gun fire, the reason that tanks were invented in the first place.
Positions gained at very great cost would immediately be lost again for lack of infantry to consolidate. At first it was thought this problem could be solved by cramming a few infantry soldiers into each tank, hence the attacks with the Mk V*s. It soon transpired however that the atmosphere quality in the tanks was so poor that infantry, if not losing consciousness outright, would at least be incapacitated for about an hour after leaving the tank, merely to recover from the noxious fumes.
The crew of a Mk IX consisted of a driver, a commander sitting to the right of him (the first time for a British tank, showing adaptation to the traffic conditions in France), a mechanic and a machine gunner who could man a gun in a hatch at the back. A second machine gun was fitted in the front. Along each side of the hull were eight loopholes, through which the soldiers could fire their rifles, making the Mark IX also the world’s first Infantry Fighting Vehicle. Two of the loopholes were in the two oval side doors on each side.
Despite using thinner (10 mm) armour plate, the weight was still 27 tons and the speed only 4 mph (7 km/h). The tank could also carry supplies in a tray on the roof behind the commander’s armoured observation turret (being the highest point at 2.64 metres), while towing up to three loaded sledges.
An attempt to improve internal conditions by putting a large silencer on the roof together with ventilation fans was muted by the simple fact that there was no separate engine room. Because of this lack of compartimentalisation it is questionable whether the project reached its original goal of designing a vehicle capable of delivering a squad of infantry in fighting condition.
It was widely acknowledged that cavalry were too vulnerable to be used on most European battlefields, although many armies continued to use them. Motorised Infantry could maintain rapid movement, but their trucks required either a good road network, or firm open terrain (such as desert). They were unable to traverse a battlefield obstructed by craters, barbed wire and trenches. Tracked or all-wheel drive vehicles were to be the solution.
Practical soldiers such as Heinz Guderian in Germany and Mikhail Tukhachevsky in the Soviet Union recognised that tank units required close support from infantry and other arms. As the Germans rearmed in the 1930’s, they equipped some infantry units in their new Panzer (armoured) divisions with the Half-track SdKfz 251, which could keep up with tanks on almost any terrain. The French Army also created Light Mechanised divisions in which some infantry units possessed small tracked carriers. Together with the motorisation of the other infantry and support units, this resulted in highly mobile formations in both armies that could keep pace with armored formations. The Germans used these to exploit breakthroughs in Blitzkrieg offensives, the French envisaged them being used to shift reserves rapidly in a defensive battle.
The Soviet Red Army did not immediately follow this trend because of the confusion of the Great Purges (as the revolution proceded), although they did practice a technique called “tank desant”.
Tank desant is a military combined arms tactic, where infantry soldiers would ride into an attack on tanks. They dismount to fight on foot in the final phase of the assault. Desant is the Russian word for airborne or parachute drops, but it can be used more generally, describing amphibious landings or “tank desant”.
The tactic was institutionalized by the Soviet Red Army during the Second World War. Tank desant troops (tankodesantniki) were specialist infantry, trained in the technique. From WWII until the 1970s, Soviet tanks were built with hand-holds for this purpose. In the northern winter, similar tactics were used by Soviet infantry riding the skids of aerosans, or towed behind them on skis.
Riding on tanks during actual combat is very dangerous; soldiers are very vulnerable to machine gun and high explosive fire, and the high silhouette of most tanks would draw enemy fire. Smoke and covering fire may be used to reduce the hazards, but this tactic is mostly used by forces with a shortage of motor transport or armoured personnel carriers, as it enables troops to move about the battlefield faster than on foot.
Today, tank desant is considered a wasteful and human-costly improvisation, adopted by the Soviets because they failed to appreciate the problem of tank–infantry co-operation. Almost universal mechanization has rendered this tactic mostly obsolete, with infantry riding special-purpose armoured personnel carriers or infantry fighting vehicles into battle. The use of explosive reactive armor, which creates a danger zone around an armoured vehicle by detonating an explosive charge when the tank suffers a serious hit, makes tank desant impossible.
