Seacoast Defense in The United States - World War II

World War II

The air attack on Pearl Harbor demonstrated the obsolescence of coastal artillery; however, perhaps in its absence surface raiders would have been bolder. Coastal defense emplacements in the Philippines and Singapore were locally effective; however, the Japanese just attacked where there were no defenses and then enveloped the fortifications. Heavily fortified positions such as Japanese Rabaul and Fort Drum in the Philippines demonstrated tactical success amongst a strategic failure.

The United States planned an extensive Harbor Defense Armament Program during World War II to use stockpiled 16-inch (40 cm) naval rifles intended for the canceled battleships numbered 49-54 and battle cruisers numbered 1-6 and 8-inch (20 cm) naval rifles removed from USS New Jersey (BB-16), USS Kansas (BB-21), USS Minnesota (BB-22), and USS New Hampshire (BB-25). Plans were formulated for 38 new 16-inch (40 cm) batteries with a range of 25 miles (41 km), three new 12-inch (30 cm) army mortar batteries with a range of 17 miles (27 km), eleven new 8-inch (20 cm) batteries with a range of 20 miles (32 km), and 87 new 6-inch (15 cm) batteries with a range of 15 miles (24 km). Fortifications were planned for:

Approximately a third of these batteries remained incomplete at the end of the war as a result of changing priorities; and some on Oahu were completed with turrets from USS Arizona (BB-39), USS Lexington (CV-2) and USS Saratoga (CV-3) rather than the designed guns. As tactics and strategies evolved throughout the war to become more reliant on sea-based air power in the Pacific and land-based battles in Europe, defending a harbor against ships became a superfluous activity, and even before the war ended, some seacoast guns were scrapped to become new weapons, and soldiers of the heavy artillery were transferred to anti-aircraft or even infantry duties. By 1947 most guns remaining in the seacoast defense were declared surplus, and the last weapons were removed in 1950 when the Coast Artillery was deactivated.