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.
Steering engine
Large steam-powered warships with manual steering needed huge crews to turn the rudder rapidly. The Royal Navy once used 78 men hauling on block and tackle gear to manually turn the rudder on HMS "Minotaur", in a test of manual vs. steam powered steering.