Joint assault signal company

Members of the 1st JASCO on Saipan, 1944

A joint assault signal company (JASCO) was a joint service unit that provided ship to shore, air to ground communications to coordinate and control Naval Gunfire and Close Air Support to the United States Army. They were composed of specially trained Marines, Sailors and Army officers and enlisted. The Army component was composed of Air Liaison Officers, modern day Forward Air Controllers and enlisted communications technicians. JASCOs were created in the Pacific because of communication clutter, too many small teams to be effective. After the costly invasion of Tarawa the need for centralized command and control of air and naval fire support, utilizing Navy, Marine or Army gunners, spotters and radiomen was seen. Based on the Guadalcanal experience of Major General Alexander A. Vandergrift the Joint Assault Signal Companies were formed. ^[1]

Background

The formation of JASCOs parallels the formation of US Army Pathfinder teams. Because of a lack of foresight a deficiency was recognized and special units formed to correct the deficiency. The Pathfinder teams were formed to solve a problem discovered with the Battle of Sicily. Lacking guidance and control the paratroops were dropped all over the island. They managed to achieve their objectives due to the initiative and leadership of the officers and NCOs and the scattered airdrops made the occupying Germans feel overwhelmed. The German Fallschirmjäger had the same experience during the Battle of Crete; however, Adolf Hitler drew the wrong conclusion and never again committed his paratroops to an airborne operation, despite the great success they had at the Battle of Fort Eben-Emael during the attack on the Maginot Line. By contrast the US Army sought to rectify the problem by creating a special unit, which would jump in ahead of a parachute assault and mark the drop zones, providing terminal air guidance to the drop aircraft. These were Pathfinder units; JASCOs were a similar response to command and control deficiencies noted in the after action reports for The Battle of Guadalcanal and the Battle of Tarawa. ^{[2] [3]}

Units

The first Joint Assault Signal Company (JASCO) was formed in October 1943 as a battalion-sized unit named the 1st Joint Assault Signal Company attached to the 4th Marine Division, under command of Lieutenant Colonel James G. Bishop Jr, Captain Murrary L. Thompson (Executive officer), Warrant Officer William T. Farrar Jr (Adjutant). ^[4]

The Navajo code talkers were under their command. ^{[5] [6]}

JASCOs did not operate as a single unit, but were composed of 13 detachments supplied to Army and Marine divisions, regiments and battalions. Although JASCO units were first created for the United States Navy to coordinate ship-to-shore communications for naval gunfire and air support operations, they included United States Army personnel, Army pilots and enlisted communication personnel. As the Pacific War advanced the need for more JASCO units was realized, and units were created and attached to Marine divisions. By the time of invasion of the Philippines, the U.S., Army was creating its own JASCO's to support its infantry divisions. These JASCOs were primarily staffed by Army personnel, but had US Navy personnel as well. Each JASCO was divided into a battalion shore and beach party communication section, a shore fire control section, and an air liaison section, with each section further subdivided into teams. ^[7]

Unit assignments

Each Marine division had their own JASCO as follows: ^[8]

• 1st Joint Assault Signal Party, Signal Company – 1st Provisional Marine Brigade
• 1st JASCO – 4th Marine Division
• 2nd JASCO – 2nd Marine Division
• 3rd JASCO – 3rd Marine Division
• 4th JASCO – 1st Marine Division reorganized after Pelliu into 1st JASCO
• 5th JASCO – 5th Marine Division
• 6th JASCO – 6th Marine Division

Operations

JASCOs took part in the following European and Pacific Theater operations. ^{[3] [9]}

US Marine Corps JASCOs

• 1st Joint Assault Signal Party: Guam
• 1st JASCO: Roi-Namur, Saipan, Tinian, Iwo Jima
• 2nd JASCO: Enewitok, Saipan, Tinian
• 3rd JASCO: Guam, Iwo Jima
• 4th JASCO: Peleliu, Okinawa
• 5th JASCO: Iwo Jima
• 6th JASCO: Okinawa

US Army JASCOs

• 1st Joint Assault Signal Party: Guam
• 4th JASCO: Ryukyus
• 6th JASCO: Ryukyus
• 71st JASCO: Leyte, Naples-Foggia (ground), Sicily
• 75th JASCO: Eastern Mandates (ground), Leyte, Luzon, New Guinea, Ryukyus
• 76th JASCO: Ryukyus
• 286th JASCO: Algeria-French Morocco, Naples-Foggia (ground), Normandy, Northern France, Rome-Arno, Sicily
• 292nd JASCO: Ryukyus, Western Pacific
• 293rd JASCO: Luzon, New Guinea, Normandy, Northern France
• 294th JASCO: Normandy, Northern France
• 295th JASCO: Eastern Mandates (ground), Luzon, Northern Solomons, Southern Philippines, Western Pacific (ground)
• 593rd JASCO: Bismarck Archipelago, Leyte, Luzon, Ryukyus
• 594th JASCO: Ryukyus

Marshall Islands

The first JASCO operation involved the 1st JASCO and the capture of the island Roi-Namur, the northern half of the Battle of Kwajalein, Marshall Islands, attached to the 4th Marine Division (United States) under command of Major General Holland Smith's V Amphibious Corps. Landing on 1 February, the islands were seized and cleared the next day. No JASCO casualties were incurred. The short duration of the battle was, in essence, a live fire training operation, which enabled JASCO to work out some kinks. After the operation, on 24 August 1944 they returned to Hawaii for refitting and training. ^[10]

Mariana Islands

The next operation was in the Mariana Islands, the capture of Tinian and Saipan. The battle of Saipan lasted from 15 June to 9 July 1944, while the battle of Tinian was from 24 July to 1 August 1944. The battle cost JASCO 4 officers and 11 enlisted dead, 6 officers and 9 enlisted wounded, and 5 enlisted MIA. The communications teams of the 1st JASCO were the key to controlling the complex amphibian operation. ^{[11] [12]}

On Tinian, Navajo code talkers were used only on a few occasions and proved unsatisfactory due to the time it took to decipher long encrypted communications. ^[6]

Iwo Jima

Participating JASCOs were:

• 1st JASCO assigned 4th Marine Division
• 3rd JASCO assigned 3rd Marine Division
• 5th JASCO assigned 5th Marine Division ^[13]

The after action report for the 1st JASCO was critical of the Army component, stating that while the enlisted personnel were well trained, the officers provided were grounded pilots, and the qualifications of half of them "left much to be desired". The report also indicated a priority need for replacement personnel. There was such a loss of equipment, that the first two months of training back in Hawaii had to be limited to physical training, weapons training, and classroom work. ^[10]

Okinawa

The following JASCO units took part in the Battle of Okinawa:

• 1st JASCO attached to 4th Marine Division ^[4]
• 4th JASCO attached 1st Marine Division ^[14]
• 6th JASCO attached 6th Marine Division ^[14]
• 292nd JASCO attached 77th Infantry Division ^[14]
• 593rd JASCO attached 96th Inantry Division ^{[15] [14]}
• 594th JASCO attached 27th Infantry Division ^[14]
• 74th JASCO, attached 7th Infantry Division ^[14]

Central Pacific Army JASCOs

Two Army JASCOs supported the Central Pacific. These were:

• 75th JASCO Army – southern half Kwajalein, Marshall Islands attached 7th Infantry Division (US Army)
• 295th JASCO Army – Kwajalein-Marshall Islands, Marianas and Guam – Marshall Islands attached 27th Infantry Division (US Army) ^[16]

By the time of the Okinawa landing, the JASCO had improved its communications and transportation capabilities, with new equipment including radio jeeps. ^[1]

Air Liaison Parties (ALPs) from the Joint Assault Signal Companies (JASCOs) attached to each division enabled the smooth functioning of coordinating agencies and front line direction of close air support from carrier aircraft and Tactical Air Force at 10th Army Headquarters. ^[17]

Africa and Europe

In the African Campaign JASCO units were part of special engineer battalions, performing the same duties with a mix of Army and Naval personnel.

On 6 June 1944 there were three distinct JASCO units storming the beaches of Normandy. They were:

• 293rd JASCO
• 294th JASCO
• 296th JASCO ^[7]

Legacy

JASCO units were disbanded and their responsibility transferred to the US Navy with the signing of the National Security Act of 1947, at that time the Marine Corps began recreating JASCO capability under the ANGLICO designation. ^[18] The United States Army created its own JASCO units for the European Theater of Operations. Its function has been incorporated into the Signal Corps (United States Army).

References

1. Thompson, George Raynor; Harris, Dixie R. (1966). "The Signal Corps: The Outcome mid 1943–1945".
2. Doyle and Stewart, Charles H and Terrell (1988). Stand in the Door: The Wartime History of the 509th Parachute Infantry. Williamstown,N.J.: Phillips Publication. ISBN   978-0932572097.
3. "JASCO". Archived from the original on 9 November 2017. Retrieved 5 January 2019.
4. "History of the 4th Marine Division in WWII".
5. "Joint Assault Signal Company". Archived from the original on 7 February 2017. Retrieved 5 January 2019.
6. "4th Marine Division Report Tinian 24 July to 1 Aug 1944" (PDF). Archived (PDF) from the original on 7 July 2021.
7. "Getting it Right".
8. "Marines Together".
9. United States Department of the Army, Unit Citation and Campaign Participation Credit Register, 1961
10. "1st JASCO Operation Report for the Iwo Jima Operation".
11. "Saipan Casualty Report" (PDF).
12. Marines in WWII-Saipan,the Beginning of the End. 15 August 2014. ISBN   9781782892830.
13. "US Order of Battle Iwo Jima".
14. "Okinawa the Last Battle" (PDF).
15. "593rd JASCO".
16. "Tactical Planning for the Marshalls".
17. "JASCO in Okinawa".
18. "2nd ANGLICO,USMC".

Further reading

• Ruppenthal, Logistical Support, 1: 282–85 and ch. 8.
• Thompson and Harris, Outcome, pp. 231–33;
• TOE 11-147S (21 October 1943) – for the organization of the JASCO
• Vincent W. Fox, The Role of the JASCO, [1947], typescript in file of 592d Signal Company, DAMH-HSO;