There weren't many significant naval engagements in WWI, but in those that did happen many of the vessels were miles apart, moving at 20-30 knots in rough seas/weather, with no assistance from radar. If you're 10 miles apart, the curvature of the earth plays a roll, you're swaying up and down, and both vessels are moving quickly. Seems a darn near impossible task. How would gunners have calculated shell trajectories?
