Tank
With World War II the multi-turreted tanks proved impracticable, and as the single turret on a low hull design became standard, crews became standardized around a crew of four or five. In those tanks with a fifth crew member, usually three were located in the turret (as described above) while the fifth was most often seated in the hull next to the driver, and operated the hull machine gun in addition to acting as a co-driver or radio operator. Well-designed crew stations, giving proper considerations to comfort and ergonomics, are an important factor in the combat effectiveness of a tank, as it limits fatigue and speeds up individual actions.
Tanks in World War I
The first fifty had been delivered to France on 30 August. They were 'male' or 'female', depending upon whether their armament comprised two 6-pounder cannon and three Hotchkiss machine guns or four Vickers machine guns and one Hotchkiss. It had a crew of eight, four of whom were needed to handle the steering and drive gears. The tanks were capable of, at best, 6  km/h (4  mph), matching the speed of marching infantry with whom they were to be integrated to aid in the destruction of enemy machine guns. In practice, their speed on the broken ground could be as little as 1  mph.