The Human Element In Tanks

By Captain R. M. Jerram, M.C., R.T.C. Canadian Defence Quarterly, Vol. V, Oct 1927 to Jul 1928 [First published in The Royal Tank Corps Journal for October, 1927.

Any doctor will tell you that the nervous systems of the present mechanical era are very much more liable to strain and disorder than those of preceding generations. The work of the more junior ranks of the R.T.C. lies essentially in and about machines, and the surroundings and work of a man in action subject him to a very severe nervous strain.

This article is an attempt to analyse the factors that combine to cause this strain. It is also an attempt to make suggestions for its alleviation. The words "comfort" and "discomfort, where used, should be considered in their relation not to the ease but to the efficiency of the man.

All formations are teams made up of units of various sizes. The unit most suitable for our consideration is the tank crew. Take the tank crew, rating by rating, and consider their duties, their working conditions and their complete interdependence.

The Tank Commander.

It is not fully realized what a very important rating this is. The tank commander is in charge of fire power roughly equivalent to a company of infantry, and of men and material difficult and expensive to replace. His duties in action are:—

He has to do all these things in a constrained position. and one which entails a considerable amount of exertion to preserve himself from injury by the motion of the tank. For these duties he must have a quick brain, coupled with great initiative and power of leadership. Above all he must have the complete confidence of his crew.

The Driver.

Although the driver gets no rest when once the tank is under way, he has the enormous advantage of being the only member of the crew who is ever really comfortable. This is, because he is the only man who knows exactly what movement the tank is going to make, and can therefore brace or relax himself accordingly. He bears the responsibility of the efficiency of the mechanism which is directly under his charge. He must remember that on him depends the comfort of the crew, and that the amount and accuracy of the fire which can be produced is very largely dependent on his skill.

The 3-Pounder Gunner.

This man is dependent on the tank commander for fire orders. and on the driver for comfort. He who hits first wins. Therefore the very existence of the tank and its crew rests on his shoulders and those of the machine-gunner. The manipulation of his equipment requires skill, quickness, and accuracy of movement.

The Machine-Gunner and the Loader.

The machine-gunner is dependent on the tank commander for keeping him on his target by fire orders and manœuvre. Both he and his loader, having no forward observation, are completely dependent on the driver for comfort. Both have the most arduous and unpleasant maintenance duties. Against this they have no responsibility or anxiety except the efficiency of their equipment.

Considering the above conditions the most outstanding essentials for efficiency are team work and quickness of hand, eye and brain. These can be improved by training and by improvement in working conditions. As regards training, it is essential that the crew should work, live, and play together in order that they may be welded into a perfect team.

Improvement of Working Conditions.

A comparison between medical reports on the light tank and on earlier types of tank emphasizes the vast improvement in design from a medical point of view, although the medical standpoint seems to take in only conditions which are liable to produce actual bodily harm apart from injuries. It does not cover discomfort.

The report made at the end of the war contains a list of effects noted in early types of tank.

The fact that none of these effects are noted in the report on the light tank clearly shows the great improvement that has been made in design. It is attributable mainly to the separate engine room and fan ventilation. What is not brought out is that the increased speed of the tank has added greatly to the discomfort of the crew and that this is not fully compensated by the suspension system.

Discomfort in tanks is principally caused by:—


This is what causes the minor injuries such as cuts, burns, and bruises Such injuries are sometimes unavoidable but experience is very quickly gained and it is only when going over a very bad and unexpected hump that an old hand will sustain any worse injury than a slight cut or bruise. Eighty per cent. of violent movement is due to bad driving. the ground only being responsible for the remaining twenty per cent. This is due firstly to inefficiency and secondly to “showing off”. There should be no necessity for either. The way to avoid injury is:—

Sea sickness is seldom caused in a tank by motion alone, though it is a frequent effect of combined motion and fumes.


The report on the light tank says that no noxious fumes are present. Fumes are very unpleasant without being at all noxious.

The fumes present are caused by:—

If fans are kept working efficiently these fumes are all quickly cleared from the tank. They may also be kept down by good maintenance in the following particulars:—

Exhaust fumes are injurious if not quickly dissipated. Carbon monoxide is a product of petrol combustion, is very deadly, and gives no warning.

Most of these fumes are irritant to the eyes and throat.


The highest temperatures recorded in the report on the light tank were:—

125 F. is a very high shade temperature for an Indian plains station. 80 F. wet bulb is the border line of toleration to work in.

The only way to cut down heat is to keep the engine room and access doors closed, all possible doors and ports open, and the fans running properly.

A natural corollary of heat is the necessity for some form of water carrier. An easily removable tank is the ideal. A fixed tank (as in the Mark V) quickly becomes very foul.


Only improvement in design can cut this down. A long spell in continous noise of this sort has a slightly stupefying effect and produces great irritability.

The noise of the light tank is not bad up to speeds of 12 m.p.h. Above that speed it develops into a scream and rapidly becomes almost unbearable.


What is the correct clothing and equipment of a tank crew for fighting? What is to be done with that part of their equipment which is not worn in the tank, but which is essential for their immediate use on breaking off action.

It is not possible for a man to wear his full equipment in a tank. Even fighting order with the haversack on the back is very inconvenient, and the heat of a jacket under overalls is often insupportable. All this points to the fact that in future types of tank some provision must be made for the stowage of kits.

Enemy Action.

The inevitable effect of being in contact with the enemy is an immediate increase in the ordinary elements of strain and anxiety which are always present inside a tank. Other effects are:

Detonation of Shell Inside Tank.—This almost inevitably puts the tank out, but not necessarily the crew. The writer has experience of a 77 mm shell bursting on the front end of a Mark V engine. Neither the driver nor the Tank Commander were scratched, although they were sitting only a foot above the burst.

Machine Gun Fire.—The effect of m.g. bullets striking on plate is the appearance of a shower of sparks inside. "Splash" is caused by particles of lead entering through chinks, pinholes, etc. "Flake" is caused by paint chipping off the inside. Both are harmless unless they enter the eyes. Splash is mitigated in the light tank by the fact that the plating is overlapped. It can also be cut down by painting dummy slits all over the tank. The Medium "A" in the tank museum at Bovington is painted in this manner.

A.P. Bullets.—There is no remedy for these. They do not penetrate unless the hit is practically at right angles to the plate. A round let off inside the tank has the same effect. It is fatally easy to let a revolver muzzle slip off the edge of the port it is being fired through.

Gas.—Wearing a gas mask in a tank is not so unpleasant as might appear. The eyepieces cloud badly but the air is purified in some way, and is actually cooler and sweeter to breathe than the ordinary tank atmosphere.

Effect of Armour.

Every one has at one time or another put his head under the bedclothes when there has been a noise in the night, and kept it there. Armour has the same psychological effect. When it is remembered that the only way to get decent observation is to keep the head outside, it will be seen how this failing must be fought against.

The effect is curiously reversed by the fact that the first idea of any man who is in the least injured is to get outside the tank. His efforts to do so are quite liable to develop into panic. This equally needs controlling. This second effect of armour has its counterpart in the instinctive efforts of the wounded infantryman to tear off his gas mask.

A point which seems to stand out after consideration of the ruling conditions of tank fighting is that adequate means of rest must be provided. There are three ways of doing this:—

The first two are ruled out by consideration of economy. The last has been adopted in spite of the obvious drawback that it is always the last two or three numbers who will be duplicated. It is unlikely in the extreme that Tank Commanders and drivers will be provided with understudies