page_title: Seacoast defense in the United States
section_title: Other coast defense operations
hierarchical_section_title: Seacoast defense in the United States / World War II / Other coast defense operations
caption_attribution_description: English: 4TH DEFENSE BATTALION 155MM GUN, emplaced near Barakoma, is prepared to give General McClure's Northern Landing Force seacoast protection. The Marines' eight Long Toms never had a chance to fire at a live target, but were ready to do so if necessary.
context_page_description: Seacoast defense was a major concern for the United States from its independence until World War II. Before airplanes, many of America's enemies could only reach it from the sea, making coastal forts an economical alternative to standing armies or a large navy. After the 1940s, it was recognized that fixed fortifications were obsolete and ineffective against aircraft and missiles. However, in prior eras foreign fleets were a realistic threat, and substantial fortifications were built at key locations, especially protecting major harbors.
  The defenses heavily depended on fortifications but also included submarine minefields, nets and booms, ships, and airplanes. Therefore, all of the armed forces participated in seacoast defense, but the U.S. Army Corps of Engineers played the central role in constructing fixed defenses.
  Designs evolved and became obsolete with changes in the technology available to both the attacking forces and the defenders. The evolution of the U.S. seacoast defense system is generally identified among several "systems", which are somewhat defined by the styles used, but more so by the events or trends which periodically stimulated new funding and construction.
context_section_description: Two related aspects of seacoast defense in the early part of the war were coastal beach patrols in the continental United States (CONUS) and the maintenance of mobile forces there to respond to potential enemy raids. The Coast Guard began these patrols after Pearl Harbor, and in early 1942 the Eastern and Western Defense Commands were assigned the equivalent of up to eight infantry regimental combat teams each for both beach patrols and mobile response. With a rapidly diminishing threat after 1942, by mid-1943 these forces were cut back significantly, and were mostly demobilized in early 1944. On the night of 12 June 1942, a patrolling Coast Guard sailor observed German agents landing from a U-boat near Amagansett, Long Island, New York. Communication difficulties precluded an immediate response, but the four agents were rounded up over the next two weeks, along another four landed near Jacksonville, Florida on 17 June. Capture was made easier when two of the agents in New York decided to defect within a few days. They were tried by a military court-martial, with six of the eight executed; one of the defectors received a life sentence and the other 30 years in prison.
  Besides the Coast Artillery, key islands in the Pacific theater were defended by U.S. Marine defense battalions throughout the war. Their most famous engagement was the Battle of Wake Island in December 1941, in which heavy casualties were inflicted on a Japanese invasion force that eventually took the island. The U.S. Navy participated in harbor defense with anti-submarine nets and magnetic indicator loops for detecting submarines; joint harbor defense command posts and harbor entrance control posts were established at harbor defense commands to coordinate army and navy operations. The 155 mm Long Tom artillery piece, an evolution of the 155 mm GPF concept, was used in island and harbor defense in the Pacific from 1943 by both the Marines and the Army. Seven Army Coast Artillery Groups (155 mm Gun) were activated in May–June 1944 as a result of breaking up the tractor-drawn 155 mm gun regiments, which may have been rearmed with the new weapon. Three were deployed to Okinawa and the Philippines in 1945 while one was activated in Trinidad; the remainder never left CONUS.
caption: 155 mm Long Tom gun "Scorpion" of the 4th Marine Defense Battalion in Barakoma, Solomon Islands.
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