The 4th Antiaircraft Artillery Battalion (4th AAA Bn) was a United States Marine Corps antiaircraft unit that served during World War II. Formed in 1940 as the 4th Defense Battalion, its original mission was providing air and coastal defense of advanced naval bases. It was one of first five defense battalions deployed in support of the color-coded war plans that called for the defense of Hawaii and other outlying United States possessions in the Pacific Ocean. These five battalions were nicknamed the "Rainbow Five." During the war the battalion took part in combat operations during the attack on Pearl Harbor and at Vella Lavella. The battalion was decommissioned on 9 June 1945 before the end of the war.

History

Formation, Gitmo and Pearl Harbor

The 4th Antiaircraft Artillery Battalion was commissioned on February 1, 1940 at Marine Corps Recruit Depot Parris Island, South Carolina. The original manpower for the battalion came from a cadre from the 3rd Defense Battalion. The battalion departed the United States in February 1941 bound for Guantanamo Bay, Cuba. Upon arrival they immediately established camp at the Deer Point area of the base. The unit did not stay in Cuba long and in October 1941 it boarded ships headed for Hawaii. The battalion arrived at Pearl Harbor on 1 December 1941 and was present for the attack on Pearl Harbor six days later. Although the battalion did not have any heavy guns operational during the attack it was able to get antiaircraft machine guns operational against Japanese aircraft. On December 13th the battalion began manning air defense positions around Pearl Harbor. At the same time that portions of the battalion were manning those new antiaircraft positions a large portion of the battalion was loading onto the

USS Tangier (AV-8) The second USS ''Tangier'' (AV-8) was a Maritime Commission type C-3 cargo ship, converted to a seaplane tender in the United States Navy during World War II. The ship, the first of the C-3s to be launched and significant in a revival of Paci ...

as part of the relief force for the garrison on Wake Island. The ship was loaded by December 13th however it was unable to leave until December 16th because it had to wait for the USS Saratoga (CV-3) to refuel. The relief expedition did not make it to Wake Island in time and was instead diverted to Midway. 4th Defense Battalion units at Pearl continued to man their positions until February 23, 1942 when they were relieved in order to prepare for movement to the

South Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

Efate

The 4th Defense Battalion departed Pearl Harbor and on March 29, 1942 came ashore on Efate in the New Hebrides. The battalion provided air defense coverage for the island and endured a malaria epidemic during its first few months ashore. In July 1942, the battalion provided a detachment, alongside Marine Aircraft Group 21 to protect the newly constructed airfield at Espiritu Santo helping to ensure the lines of communication between Hawaii and

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

remained open prior to the allied landings on

Guadalcanal Guadalcanal (; indigenous name: ''Isatabu'') is the principal island in Guadalcanal Province of Solomon Islands, located in the south-western Pacific, northeast of Australia. It is the largest island in the Solomon Islands by area, and the seco ...

. In March 1943 the battalion departed Efate and sailed for New Zealand to rest and conduct additional training. It departed New Zealand in July 1943 and arrived at

on 30 July 1943. During this time the battalion conducted additional preparations for upcoming operations in New Georgia.

Vella Lavella and re-designation

The 4th Defense Battalion came ashore on D-Day during the assault on Vella Lavella and established positions near Barakoma Airfield. The battalion claimed five enemy airplanes shot down on the first day of the battle. Enemy air raids came frequently after the initial assault however they soon declined as enemy losses mounted. Between 15 August and 6 October 1943, the 4th Defense Battalion claimed to shootdown 42 Japanese aircraft during 121 total air raids. As the war progressed, the Marine Corps removed coastal artillery from the defense battalions in order to form additional heavy artillery units for the Fleet Marine Force. Because of the divestiture of the coastal defense mission, the battalion was re-designated as the 4th Antiaircraft Artillery Battalion on 15 May 1944. TAll elements of the 4th AAA Battalion were back on Guadalcanal by early July 1944.

Guadalcanal, Peleliu and decommissioning

The battalion remained on Guadalcanal until September 1944 when it was divided into a forward and rear echelon. The rear echelon remained on Guadalcanal while the forward echelon eventually arrived at the Kossol Roads on 25 October 1944 in order to assist the

12th Antiaircraft Artillery Battalion The 12th Antiaircraft Artillery Battalion (12th AAA Bn) was a United States Marine Corps antiaircraft unit that served during World War II. Formed in 1942 as the 12th Defense Battalion, its original mission was providing air and coastal defense ...

with defense of the Palau Islands. During this time they were under the operational control of the Army's 81st Infantry Division as the area ground defense commander for Peleliu. On 27 February 1945, two 90mm batteries, one 20mm battery and a searchlight battery that were part of the rear echelon on Guadalcanal were disbanded. The 2nd platoon of the Searchlight Battery still on

Saipan Saipan ( ch, Sa’ipan, cal, Seipél, formerly in es, Saipán, and in ja, 彩帆島, Saipan-tō) is the largest island of the Northern Mariana Islands, a Commonwealth (U.S. insular area), commonwealth of the United States in the western Pa ...

was maintained. On 20 April 1945 the battalion was relieved of its mission on Peleliu. The battalions 2d Platoon Searchlight Battery on Saipan was disbanded on 5 May 1945. During April/May 1945 the remainder of the forward and rear echelons of the battalion were consolidated on Guam. On 9 June 1945 the 4th Antiaircraft Artillery Battalion was decommissioned.

Unit awards

A unit citation or commendation is an award bestowed upon an organization for the action cited. Members of the unit who participated in said actions are allowed to wear on their uniforms the awarded unit citation. The 4th Antiaircraft Artillery Battalion has been presented with the following awards:

Citations

References

;Bibliography * * * * Part 1 * Part 2 * ;Web * {{US Marine Corps navbox AAA4 Military units and formations established in 1940 AAA Military units and formations of the United States Marine Corps in World War II