Pentropic organisation
Encyclopedia
The Pentropic organisation was a military organisation used by the Australian Army
between 1960 and 1965. It was based on the United States Army
's pentomic
organisation and involved reorganising most of the Army's combat units into units based on five elements, rather than the previous three or four sub-elements. The organisation proved unsuccessful, and the Army reverted to its previous unit structures in early 1965.
s in South East Asia in which there was a chance that nuclear weapon
s might be used. Both structures were designed to facilitate independent operations by the sub-units of divisions
. The Australian Pentropic division was intended to be air portable, capable of fighting in a limited war and capable of conducting anti-guerrilla operations.
The key element of the Pentropic organisation was the reorganisation of divisions into five combined arms
battle groups
. These battle groups consisted of an infantry battalion
, field artillery regiment, engineer field squadron and other combat and logistic elements, including armoured, aviation and armoured personnel carrier units as required. These battle groups would be commanded by the commanding officer of their infantry battalion and report directly to the headquarters of the division as brigade
headquarters were abolished as part of the reorganisation.
When the Pentropic organisation was implemented in 1960 the Australian Army was reorganised from three divisions organised on what was called the Tropical establishment (the 1st
, 2nd and 3rd divisions) into two Pentropic divisions (the 1st and 3rd). While two of the Army's three regular infantry battalions were expanded into the new large Pentropic battalions, the 30 reserve Citizens Military Force (CMF) battalions were merged into just nine battalions. There was a similar effect on the other CMF units, with most being merged into new, larger units. The other regular infantry battalion remained on the previous tropical establishment as it formed part of the 28th Commonwealth Brigade in in Malaysia. As part of this reorganisation the Army replaced its outdated weapons with more modern weapons, most of which were supplied from the United States. It was believed that these new weapons would further improve the Army's combat power and the ability of sub-units to operate independently.
The Pentropic organisation was trialled during exercises in 1962 and 1963. These exercises revealed that the battle groups' command and control arrangements were unsatisfactory, as battalion headquarters were too small to command such large units in combat situations. While the large Pentropic infantry battalions were found to have some operational advantages over the old tropical establishment battalions, the divisions' large number of vehicles resulted in traffic jams when operating in tropical conditions.
The experience gained from exercises and changes in Australia's strategic environment led to the decision to move away from the Pentropic organisation in 1964. During the early 1960s a number of small counter-insurgency
wars broke out in South East Asia, and the large Pentropic infantry battalions were ill-suited to these sorts of operations. As the US Army had abandoned its pentomic structure in 1962 and the British Army remained on the tropical establishment, the Australian Army was unable to provide forces which were suited for the forms of warfare it was likely to experience or which were organised along the same lines as units from Australia's main allies. In addition, concentrating the Army's limited manpower into a small number of large battalions was found to be undesirable as it reduced the number of deployable units in the Army. As a result of these factors the Australian Government decided to return the Army to the tropical establishment in November 1964 as part of a wide-ranging package of reforms to the Australian military, which included increasing the size of the Army. The Army returned to the tropical establishment in 1965, and many of the CMF battalions were re-established as independent units.
Australian Army
The Australian Army is Australia's military land force. It is part of the Australian Defence Force along with the Royal Australian Navy and the Royal Australian Air Force. While the Chief of Defence commands the Australian Defence Force , the Army is commanded by the Chief of Army...
between 1960 and 1965. It was based on the United States Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
's pentomic
Pentomic
Pentomic refers to a structure for infantry divisions adopted by the U.S. Army in 1957 in response to the perceived threat posed by tactical nuclear weapons use on the battlefield....
organisation and involved reorganising most of the Army's combat units into units based on five elements, rather than the previous three or four sub-elements. The organisation proved unsuccessful, and the Army reverted to its previous unit structures in early 1965.
History
The decision to adopt the Pentropic organisation was driven by a desire to modernise the Army and ensure that Australian units were able to integrate with those of the United States Army. While the US Pentomic organisation had been implemented in 1957 to improve the Army's ability to operate during a nuclear war, the Australian organisation was optimised for limited warLimited war
A limited war is a conflict in which the belligerents participating in the war do not expend all of each of the participants available resources at their disposal, whether human, industrial, agricultural, military, natural, technological, or otherwise in a specific conflict...
s in South East Asia in which there was a chance that nuclear weapon
Nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...
s might be used. Both structures were designed to facilitate independent operations by the sub-units of divisions
Division (military)
A division is a large military unit or formation usually consisting of between 10,000 and 20,000 soldiers. In most armies, a division is composed of several regiments or brigades, and in turn several divisions typically make up a corps...
. The Australian Pentropic division was intended to be air portable, capable of fighting in a limited war and capable of conducting anti-guerrilla operations.
The key element of the Pentropic organisation was the reorganisation of divisions into five combined arms
Combined arms
Combined arms is an approach to warfare which seeks to integrate different branches of a military to achieve mutually complementary effects...
battle groups
Battlegroup (army)
A battlegroup , or task force in modern military theory, is the basic building block of an army's fighting force. A battlegroup is formed around an infantry battalion or armoured regiment, which is usually commanded by a Lieutenant Colonel...
. These battle groups consisted of an infantry battalion
Battalion
A battalion is a military unit of around 300–1,200 soldiers usually consisting of between two and seven companies and typically commanded by either a Lieutenant Colonel or a Colonel...
, field artillery regiment, engineer field squadron and other combat and logistic elements, including armoured, aviation and armoured personnel carrier units as required. These battle groups would be commanded by the commanding officer of their infantry battalion and report directly to the headquarters of the division as brigade
Brigade
A brigade is a major tactical military formation that is typically composed of two to five battalions, plus supporting elements depending on the era and nationality of a given army and could be perceived as an enlarged/reinforced regiment...
headquarters were abolished as part of the reorganisation.
When the Pentropic organisation was implemented in 1960 the Australian Army was reorganised from three divisions organised on what was called the Tropical establishment (the 1st
1st Division (Australia)
The 1st Division is the main formation of the Australian Army and contains the majority of the army's regular forces. Its headquarters is in Enoggera, a suburb of Brisbane...
, 2nd and 3rd divisions) into two Pentropic divisions (the 1st and 3rd). While two of the Army's three regular infantry battalions were expanded into the new large Pentropic battalions, the 30 reserve Citizens Military Force (CMF) battalions were merged into just nine battalions. There was a similar effect on the other CMF units, with most being merged into new, larger units. The other regular infantry battalion remained on the previous tropical establishment as it formed part of the 28th Commonwealth Brigade in in Malaysia. As part of this reorganisation the Army replaced its outdated weapons with more modern weapons, most of which were supplied from the United States. It was believed that these new weapons would further improve the Army's combat power and the ability of sub-units to operate independently.
The Pentropic organisation was trialled during exercises in 1962 and 1963. These exercises revealed that the battle groups' command and control arrangements were unsatisfactory, as battalion headquarters were too small to command such large units in combat situations. While the large Pentropic infantry battalions were found to have some operational advantages over the old tropical establishment battalions, the divisions' large number of vehicles resulted in traffic jams when operating in tropical conditions.
The experience gained from exercises and changes in Australia's strategic environment led to the decision to move away from the Pentropic organisation in 1964. During the early 1960s a number of small counter-insurgency
Counter-insurgency
A counter-insurgency or counterinsurgency involves actions taken by the recognized government of a nation to contain or quell an insurgency taken up against it...
wars broke out in South East Asia, and the large Pentropic infantry battalions were ill-suited to these sorts of operations. As the US Army had abandoned its pentomic structure in 1962 and the British Army remained on the tropical establishment, the Australian Army was unable to provide forces which were suited for the forms of warfare it was likely to experience or which were organised along the same lines as units from Australia's main allies. In addition, concentrating the Army's limited manpower into a small number of large battalions was found to be undesirable as it reduced the number of deployable units in the Army. As a result of these factors the Australian Government decided to return the Army to the tropical establishment in November 1964 as part of a wide-ranging package of reforms to the Australian military, which included increasing the size of the Army. The Army returned to the tropical establishment in 1965, and many of the CMF battalions were re-established as independent units.
Structure
The main elements of the Pentropic divisions were:- Divisional Headquarters
- Reconnaissance Squadron
- Administration Troop
- Survey Troop
- Five reconnaissance troops
- Armoured Regiment
- Three tank squadrons
- Artillery Headquarters
- Five field artillery regiments
- Field engineer regiment
- Five field squadrons
- Five infantry battalions
- Administration Company
- Support Company
- Five rifle companies
- Four rifle platoons
- Weapons platoon
- Reconnaissance Squadron
- Light aviation company
- Signals Regiment
- Supply, transport, ordnance and other services