The duties of the various crew members of the Mark IV tank are generally
similar to those performed by the crews of our own medium M3 and M4 tanks. A
German training pamphlet captured in Libya gives the following details
on the crew duties and communications of the Mark IV.
a. Duties of the Crew
The crew consists of five men: a commander, gunner, loader, driver, and
radio operator. The latter is also the hull machine-gunner.
(1) Tank Commander
The tank commander is an officer or senior NCO and is responsible for
the vehicle and the crew. He indicates targets to the gunner, gives fire orders,
and observes the effect. He keeps a constant watch for the enemy, observes the
zone for which he is responsible, and watches for any orders from the
commander's vehicle. In action, he gives his orders by intercommunication
telephone to the driver and radio operator, and by speaking tube and touch
signals to the gunner and loader. He receives orders by radio or flag, and
reports to his commander by radio, signal pistol, or flag.
The gunner is the assistant tank commander. He fires the turret gun, the
turret machine gun, or the submachine gun as ordered by the tank
commander. He assists the tank commander in observation.
This crew member loads and maintains the turret armament under the orders
of the gunner. He is also responsible for care of ammunition, and when
the cupola is closed, gives any necessary flag signals. He replaces the radio
operator if the latter becomes a casualty.
The driver operates the vehicle under the orders of the tank commander or in
accordance with orders received by radio from the commander's vehicle. So far as
possible he assists in observation, reporting through the intercommunication
telephone the presence of the enemy or of any obstacles in the path of the tank. He
watches the gasoline consumption and is responsible to the tank commander for
the care and maintenance of the vehicle.
(5) Radio Operator
He operates the radio under the orders of the tank commander. In action, and
when not actually transmitting, he always keeps the radio set to "receive." He
operates the intercommunication telephone and takes down any useful messages
he may intercept. He fires the machine gun mounted in the front superstructure. If
the loader becomes a casualty, the radio operator takes over his duties.
The following means of communication may be used:
(1) External: radio, flag, hand signals, signal pistol, and flashlight.
(2) Internal: intercommunication telephone, speaking tube, and touch signals.
For the radio, the voice range between two moving vehicles is
about 3 3/4 miles and CW about 6 1/4 miles.
The flag is used for short-range communications only, and the signal
pistol for prearranged signals, chiefly to other arms.
The radio set, in conjunction with the intercommunication telephone, provides the
tank commander, radio operator, and driver with a means for external and internal
voice communication, the same throat microphones and telephone receiver headsets
being used for both radio and telephone.
When the control switch on the radio is set at EMPFANG (receive) and that
on the junction box of the intercommunication telephone at BORD UND FUNK (internal
and radio), the commander, radio operator, and driver hear all incoming radio
signals. Any one of them can also speak to the other two, after switching his
microphone into circuit by means of the switch on his chest.
For radio transmission, the switch on the set is adjusted to TELEPHONIE. The
telephone switch may be left at BORD UND FUNK. Either the tank commander or
the radio operator can then transmit, and they and the driver will all hear the
messages transmitted. Internal communication is also possible at the same time, but
such conversation will also be transmitted by the radio.
If the radio set is disconnected or out of order, the telephone switch may be adjusted
to BORD (internal). The tank commander and driver can then speak to one
another, and the radio operator can speak to them, but cannot hear what they say. The
same applies when a radio receiver is available but no transmitter, with the difference
that incoming radio signals can then be heard by the radio operator.
The signal flags are normally carried in holders on the left of the driver's seat. When
the cupola is open, flag signals are given by the tank commander, and when it is closed, the
loader raises the circular flap in the left of the turret roof and signals with the
appropriate flag through the port thus opened.
The signal pistol is fired either through the signal port in the turret roof, through
the cupola, or through one of the vision openings in the turret wall. The signal
pistol must not be cocked until the barrel is already projecting outside the
tank. It is only used normally when the vehicle is stationary. Its main use is
giving prearranged signals to the infantry or other troops.
When traveling by night with lights dimmed or switched off altogether, driving
signals are given with the aid of a dimmed flashlight. The same method is also
employed when tanks are in a position of readiness and when in bivouac.
Orders are transmitted from the tank commander to the gunner by speaking tube and by
touch signals. The latter are also used for messages from the commander to the loader, and
between the gunner and loader.