The majority of the battleships up through World War I vintage had armor disposed in belts of varying thickness around the hull, concentrating the main thickness at the point where the majority of the enemy shells would impact. The result of long years of experience, these bands of armor were effective protection when ships fought at close range. As the caliber of guns grew and fire-control systems improved, engagement ranges increased, so that a greater number of hits would result from plunging fire against the ship's thin deck armor rather than its well-protected sides.