 After the Fall of France in 1940, the Army's Harbor Defense Board met to consider the future of coast defenses.The board decided to replace the turn-of-the-century defenses with new casemated 16-inch gun batteries with two guns each, typically one or two batteries per harbor defense command; most previous 16-inch batteries were also to be casemated.Due to their range advantage over previous weapons, most 16-inch batteries were at new forts, usually called "military reservations" to conceal their purpose.