In view of all of a tank commander's responsabilities, the least thing that a tank designer can give him is the ability to see whats going on outside the tank.

Unfortunately for German and Soviet tank designers, the problem of giving their tank commanders the gift of sight would prove a difficult one. Cutting big holes in the tank would expose the men inside to enemy fire (and defeat the entire purpose of all the tank's armor), and adding glass windshields would bring about similar problems.

Having the commander stick his head out of the top hatch to see what was going on seemed like a solution. But then again a tank commander popping out of the hatch like a little rabbit would present a fine target for infantry, and the last thing a tank commander wants to be worried about is dodging small arms fire.

Finally, a solution was reached: add an armored box (called a copula) that fit over the hatch. The commander's head would thus be protected even when he stuck it out of the hatch, and vision slits provided him with the excellent all-round view he needed. Problem solved. . . or was it?

Throughout WWII, the copula designs were continually modified and updated. But the idea had its limitations. The copula itself proved a tempting target for enemy tanks since blowing the copula off the tank more often than not would leave the enemy tank with a headless commander. Some other method of giving tank commanders the all-round view they needed had to be developed. After much deliberation, the episcope was developed.

HOW TO LOCATE A COPULA

Copulas are more often than not pretty obvious, protruding structures on top of the tank's turret. Many are cyllindrical, and all have several vision slits that allow the tank commander to see.