Why aircraft carriers could not routinely operate backwards

Were warships designed to go backwards as well as forwards?

Generally no; carriers inspired theories about operating aircraft in both directions, but the arrangement proved impractical.

The question begins with a ferry crossing stern-first and asks whether warships were similarly designed for equal forward and reverse operation. Warships generally were not, although aircraft-carrier thinking did explore using the deck in both directions. The attraction was operational flexibility if a carrier could launch or recover without turning around. In practice the idea did not work well enough to become normal carrier operation.