What can the Australian Army learn from the 1945 Borneo Oboe operations?

From 22 April to 06 May 2023, thirteen Australian Army members were lucky enough to attend Exercise STARCEVICH, an Australian Army Staff Ride focused on the WWII Oboe operations. With the assistance of a senior instructor and an expert historian, during these two weeks, we had the opportunity to study the relevant battlefields across Indonesia, Malaysia, and Brunei. We debated the successes and mistakes made during these battles and considered the implications for today’s Australian Army.

Why Study the Oboe Operations?

‘Oboe’ was the codename given to the Allied campaign to secure Borneo in 1945. The campaign consisted of three operations (in chronological order): OBOE I in Tarakan in May 1945, OBOE VI at Labuan in June 1945, and OBOE II at Balikpapan in July 1945. This campaign was primarily conducted by Australian forces, with the 1st (Australian) Corps [Australian Imperial Force (AIF)] as the lead and the 7^th Amphibious Force (US Navy) and 1st Tactical Air Force (RAAF) supporting. For those wanting further information, a summary of the Oboe operations can be found here, and the Australian Army History Unit has recently released an excellent book on this topic.

Many historians have argued that the Oboe operations are especially worthy of study by the Australian Army.[2] The operations were the most extensive WWII campaign planned and conducted by Australians. They involved three large amphibious assaults (two at division and one at brigade level) and represented the zenith of Australian Army combat operations during the war.[3] The operations also involved sustained joint land combat in the Primary Operating Environment (POE), including the littoral, urban and jungle environments. They occurred in a coalition setting with the US, which continues to be the most likely context for future Australian Army operations. Further, they contain lessons from the platoon level up to the corps level. It must be said, however, that all these lessons should be caveated by the fact that the well-resourced Allies had air and naval superiority and faced a poorly resourced and isolated enemy.[4]

What did we learn?

During the staff ride, participants identified five key lessons that today’s Army could learn from the Oboe operations: the value of combined arms against fortified positions, the utility of littoral manoeuvre, the importance of amphibious equipment, the need for a capable Beach Team, and the requirement for robust operational logistics. All have clear contemporary relevance as outlined below.

The Value of Combined Arms Against Fortified Positions

The use of combined arms historically saves lives. The Oboe operations are littered with stories of brutal clearances of fortified Imperial Japanese Army (IJA) or Navy (IJN) positions by Australian troops. Examples include the heavily defended hills of Helen, Margy, and Freda in Tarakan during OBOE I, the assault on Parramatta Ridge and Manggar airfield during OBOE II, and the clearance of "the Pocket" in Labuan during OBOE VI.[5] These clearances needed to occur as the IJA or IJN had the advantages of the defence, specifically being able to choose the terrain on which they would fight and time to develop fortified defensive positions. This level of preparation allowed the IJA/N defenders to survive the significant RAAF and USN shaping fires. The clearance of these positions was made even more difficult by the challenging jungle terrain.

Combined arms provided the 1^st (Australian) Corps with the ability to clear these heavily fortified IJA/N positions. Joint fires – including artillery, mortars, close air support and naval gunfire – suppressed and reduced enemy positions. Matilda tanks – including the Frog flamethrower variants – provided intimate support, combat engineers dealt with obstacles. Meanwhile, infantry cleared and occupied the positions. While this is not a new lesson, it was continually reaffirmed throughout the staff ride. Also, Australian forces often successfully manoeuvred tanks and artillery to the point of need in the challenging terrain of Borneo. This feat should be caveated, however. The tanks and artillery used, the Matilda and 25-pounder, respectively, and their supporting assets were purposely chosen as they were lighter and thus more suitable for operations in the POE.[6]

Unfortunately, the Oboe operations also contain examples of combined arms not being used to clear these positions, costing several Australian soldiers their lives. For instance, during the early stages of OBOE I, the 26^th Brigade encountered significant IJN resistance at a feature near Tarakan town called “Helen”. Over four days, the 2/3^rd Pioneer Battalion attempted to clear Helen. It was only after an intense air bombardment, followed by combined arms operations that the IJN force withdrew. Unfortunately, the damage had already been done, with the 2/3^rd Pioneer Battalion suffering numerous casualties, the majority from the initial infantry-only assaults. Without the extensive use of combined arms, far more than 668 Australian lives would have been lost in the Oboe operations.[7]

The Oboe operations affirm the Australian Army's advocacy regarding the use of combined arms in the POE. Specifically, the need to clear well-prepared defensive positions is unlikely to disappear in war. Future adversaries, like the IJA/N, will likely identify the natural defensive features the POE provides and seek to use this complex terrain to negate Australia's advantages in joint fires. The only difference is that this terrain may be urban rather than jungle; however, combined arms are still required for this environment. Any failure to use combined arms in POE clearance operations will likely result in more significant casualties. The Oboe operations also demonstrate the ability to manoeuvre armour and artillery in the POE. Whilst this manoeuvre was undoubtedly tricky, it should cause those who argue that it ‘cannot occur’ to reconsider their arguments.[8] Further, the Oboe operations give rise to the question of whether Australia should consider whether a lighter tank or armoured vehicle is warranted if it wants to operate more effectively in the POE.[9]

The Utility of Littoral Manoeuvre

A littoral manoeuvre capability enables tempo for land forces in the POE. During the Oboe operations, the 1^st (Australian) Corps made several subsequent landings that would probably be described as ‘littoral manoeuvre’ in contemporary parlance. These operations include the battalion-sized unopposed day landings at Lutong (OBOE VI Coconut) and Weston (OBOE VI West) during OBOE VI and Penadjam (Operation Independence) during OBOE II.[10] These operations allowed 1^st (Australian) Corps to generate operational tempo by quickly expanding from their Beach Landing Sites (BLS) to occupy key terrain or open a new approach. Other employment of the littoral manoeuvre capability included patrolling by Australian Army LCMs and USN patrol boats during OBOE I and the movement of tanks to support the Manggar airfield clearance during OBOE II (but not with the best result).[11] These operations demonstrated the flexibility a littoral manoeuvre capability provides a land force.

The most interesting littoral manoeuvre example from the Oboe operations was the Battle of Beaufort during OBOE VI. Post-landing at Weston, the 24^th Australian Brigade used small landing craft to advance up the Padas River. This move allowed the brigade to advance on an unexpected avenue of approach, which had a decisive impact on the battle. It also allowed the movement of heavy weapons (specifically Matilda tanks and 25-pounder artillery) to terrain that lacked roads. [12]

The Australian Army should learn from its past to maximise its forthcoming littoral manoeuvre capability. Whilst it has retained a littoral manoeuvre capability via its LARCs and LCM-8s – and has conducted littoral manoeuvre operations in the past – it has been almost 20 years since the Army has had a capability comparable to the Littoral Manoeuvre Vessel (LMV) Medium, Heavy and Patrol that will soon be acquired. Once these vessels are in service, the Army should look to its past for examples on how to get the most out of them. In this regard, the Oboe operations offer several case studies worth exploring. In particular, the Battle of Beaufort during OBOE VI. The success of the 9th Division’s 24^th Brigade during this engagement supports the proposition that Army should seek littoral manoeuvre capabilities capable of being used in amphibious and riverine contexts. It should also seek opportunities within exercise Sea Raider – the Australian Amphibious Force (AAF) certification exercise – to practice littoral manoeuvre post landing. Further, opportunities exist to test Army’s land force manoeuvre capabilities within riverine environments, for example, in Shoalwater Bay Training Area.

The Importance of Amphibious Equipment

The Oboe operations demonstrated emphatically that an amphibious APC capability is valuable for amphibious and littoral manoeuvres. During the Oboe campaign, LVT-A Alligators, provided by the US Army Engineer Special Brigade (ESB), enabled the 1st (Australian) Corps to project forces ashore, with protection and firepower, across almost all beach gradients and conditions. This ability proved particularly useful for the 7th Division during OBOE II. Here, the most suitable land force tactical course of action was assessed as a potentially fiercely contested landing at the heavily defended Klandasan Beach, where the assaulting infantry would be exposed to direct fire. Also, post the landing at Klandasan, the LVTs were called upon again to enable an infantry battalion (2/9^th) to secure Penajam when it was feared the enemy still had coastal defence positions that could interdict shipping entering Balikpapan harbour. Both these operations were considered feasible only because of the organic firepower, mobility and protection the LVT-4s provided.

OBOE II provides a strong basis for arguing that the Australian Army should invest in an amphibious APC capability. Such vehicles would provide more tactical options to manoeuvre commanders and protect soldiers’ lives during amphibious operations. The US Marine Corps has acknowledged the need to invest in the Amphibious Combat Vehicle (ACV) program. A similar initiative would nest nicely within the intent expressed in the 2023 Defence Strategic Review for the Army to be “optimised for littoral operations in Australia’s northern land and maritime spaces”.[13]

The Need for a Capable Beach Team

The Beach Team needs to be able to do more than just manage the BLS. During the Oboe operations, the 1^st (Australian) Corps was fortunate to be supported by two Beach Groups. The formation of the Beach Groups was a lesson the Army learned from its allies and its own experiences after the successful amphibious assaults at Lae (OP POSTERN) and Finschhafen (OP DIMINISH). These Beach Groups were designed to support a division-sized amphibious landing and consisted of pioneers, engineers, transport, medical, military police and navy beach commandos.[14] This composition enabled the Beach Group to manage the force flow through the beach landing site while concurrently maintaining it, establishing store dumps, supporting medical evacuations, handing prisoners of war, and resisting attack if necessary.[15]

All these capabilities were required throughout the Oboe operations, with the Beach Group defending itself at Tarakan,[16] providing medical support to a large number of civilians in Balikpapan,[17] and handling prisoners of war, bogged vehicles and insufficient exits in all operations.[18]

The Australian Army should invest more in its BLS management capability. The current organisation – the Amphibious Beach Team (ABT) – is insufficient for current and future needs. Specifically, only one ABT (a platoon-sized organisation) is allocated to the amphibious capability. This modest size is insufficient to generate a company minus strength ABT for an Amphibious Ready Group (ARG) sized AAF. Also, consideration should be given to the composition of a Beach Team. The 1945 Battle of Porton Plantation in Bougainville provides a clear example of the risk of being unable to recover landing craft during a littoral manoeuvre.[19] An adjustment in investment to enhance the ABT may require the Army to divest other capabilities as it orientates to a force optimised for littoral operations.

Also, the Australian Army should look to exercise an enhanced ABT. Whilst the ABT is exercised yearly during the AAF sea series, there is only a baseline capability able to conduct BLS management. The ABT currently does not have the capability to manage POW, manage casualties or defend itself as it is not assigned MP, medical and infantry units to do so. Also its headquarters – currently just a platoon headquarters – would be insufficient for this expanded force. The OBOE operations demonstrated that an ABT, in conflict, needs to be able to handle POW, manage casualties and defend itself. The Australian Army should look to exercise an enhanced ABT to understand what a modern ABT, able to operate in a contested environment, looks like.

The Need for Robust Operational Logistics

Expeditionary operations do not occur without a robust operational logistics capability to move and sustain forces. The Oboe campaigns required a staggering number of men and materials to be projected into the POE. For example, OBOE II required the landing of 33,600 personnel and 53,600 tons of supplies and equipment.[20] All these men and supplies needed to be moved from Queensland to Balikpapan. To achieve this, the Australian Army established an Intermediate Staging Base (ISB) in Morotai, Dutch East Indies (modern-day Indonesia). This ISB was managed by the 1^st Base Sub Area, which supported up to 60,000 troops. Once the staging area was semi-established, the force flow started with a maximum of 36,720 1^st (Australian) Corps troops on 1 Jul 45 (out of the 52,000 Australians on Morotai in July 1945).[21]

Once the 1^st (Australian) Corps arrived in Borneo, it was sustained by different logistics forces. For the landings, the 7^th Base Sub Area was attached to the 7^th Division, while the 8^th Base Sub Area was attached to the 9^th Division. The two logistic organisations sustained their respective supported divisions for their entire operation. They built supply dumps, roads, piers, ports and hospitals to achieve this. [22]

Facilities for moving logistics across the shore in the absence of port infrastructure was a critical need. For example, during OBOE I (Tarakan), there was a requirement to build pontoon jetties due to the high tidal variation and mudflats (common in the POE).[23] The Australian Army should invest more in its logistics capabilities to project and sustain itself in the POE. The Australian Army and the joint force lack the depth and capacity to support troops in the POE. A potential area for investment is a pier system, such as the US Joint Logistics Over The Shore (JLOTS) capability which was deployed during exercise Talisman Sabre 2023 and enabled the land force to be sustained in the POE.

Conclusion

The Oboe operations remain worthy of study by all members of the profession of arms, but particularly by Army professionals. They are the most significant joint and combined operations planned by an Australian formation and include examples of amphibious assaults, littoral manoeuvre, combined arms close-combat, and contested tactical logistics. However, the fact these actions occurred in the POE makes the lessons of increased utility for current Army professions. While there has been some change, lessons learnt in the jungles, urban areas and littorals of Borneo remain relevant to today's POE. Army members from all trades and backgrounds will likely identify lessons pertinent to their specific context.

As a member of Exercise STARCEVICH, I was honoured to have the opportunity to study the Oboe operations in depth. During the staff ride, we developed our understanding of the POE and an important Allied campaign. Many lessons were identified, however, five – the value of combined arms against fortified positions, the utility of littoral manoeuvre, the usefulness of amphibious APCs, the need for Beach Teams to do more than manage the BLS, and the requirement for robust operational logistics – were assessed as the most important. The study of the Oboe operations is one of the best ways we, as Australian Army members, can honour the work of our predecessors and the 668 Australian lives lost in the campaign.

ACKNOWLEDGMENTS

The members of EX STARCEVICH would like to thank the Australian Army Research Centre for allowing them to undertake a staff ride to study the Oboe campaigns. In particular, we would like to thank Associate Professor Garth Pratten – the historian – for his insights into the Oboe campaign, LTCOL (retd) Ross Cable – the Chief Instructor – for his provoking thoughts, and MAJ Lindsay Adams – SO1 Staff Rides – for doing the administrative work which made the trip possible.