The Battle of Milne Bay, fought in August and September 1942, was the first major defeat of Japanese land forces during the Pacific War. Australian troops, supported by United States engineers and Allied air power, repelled a Japanese attempt to capture the newly constructed airfields at the eastern end of Papua.
The Allied victory depended upon the rapid development and reinforcement of Milne Bay before the Japanese attack. Ships of the Koninklijke Paketvaart-Maatschappij played an important part in that effort.
KPM vessels transported Australian and American personnel, construction equipment, airfield supplies, weapons and other cargo into Milne Bay. During and immediately after the battle, they continued operating despite the threat of Japanese aircraft and warships.
Their contribution should not be overstated as if KPM ships alone determined the outcome. The battle was won by the troops fighting ashore, supported by the Royal Australian Air Force and American air units. Nevertheless, the soldiers and aircraft could not have operated without the maritime supply system that brought them to Milne Bay and kept the base functioning.
Why Milne Bay mattered
Milne Bay is a large, sheltered bay at the southeastern end of Papua. Its geographic position made it important to both sides. For the Allies, it offered a base from which aircraft could help protect the approaches to Port Moresby and support future operations along the northern coast of Papua.
For Japan, capturing Milne Bay would have removed a developing Allied air base and strengthened Japanese control over the seas east of New Guinea. It could also have supported further operations against Port Moresby and Allied communications between Australia and the South West Pacific.
In June 1942, General Douglas MacArthur’s South West Pacific Area command ordered the rapid construction of an airfield near the head of the bay. The area had minimal port facilities, few roads and heavy tropical rainfall. Almost everything needed to build and defend the base had to arrive by sea.[1]
The first KPM ships arrive
The KPM vessels Bontekoe and Karsik formed the first important convoy to Milne Bay. They arrived on 25 June 1942 carrying Australian troops, United States engineers and construction equipment for the proposed airfield.[2]
The American engineers and Australian labour units began developing the site under extremely difficult conditions. Heavy rain turned roads and construction areas into mud, while malaria and other tropical diseases affected personnel.
The arrival of Bontekoe and Karsik was therefore more than an ordinary supply voyage. Their cargoes helped establish the infrastructure upon which the subsequent defence of Milne Bay depended.
The KPM vessel Swartenhondt later transported the first Royal Australian Air Force personnel required to operate from the new base. Aircraft began using the developing airfield during July.[3]
Tasman also contributed to the military build-up. After carrying the vanguard of the Australian 7th Brigade to Port Moresby in early July, the ship sailed from there on 11 July with an advance force sent to strengthen the Milne Bay garrison.[4]
These voyages demonstrate that KPM’s role began well before Japanese troops landed. The ships helped transform an isolated and largely undeveloped location into a defended Allied air base.
Building the garrison
The Allied force at Milne Bay expanded during July and August. Australian infantry, artillery, anti-aircraft units and supporting personnel were deployed to protect the airfields and surrounding coastline.
The principal Australian formations were the 7th Brigade, a Militia formation, and the veteran 18th Brigade of the Second Australian Imperial Force. United States engineers continued constructing airfields and roads, while Australian and American aircraft operated from the base.
Bringing these forces to Milne Bay required repeated voyages from Australian and New Guinea ports. KPM’s pre-war inter-island vessels were well suited to this work. They were smaller and more manoeuvrable than many ocean-going transports and were accustomed to operating where harbour and cargo-handling facilities were limited.
The ships remained vulnerable. Milne Bay lay within range of Japanese aircraft, while reports of Japanese cruisers and destroyers created a continuing threat to unprotected transports.
The Japanese attack
Japanese naval troops began landing at Milne Bay on the night of 25–26 August 1942. They intended to seize the Allied airfields but underestimated both the size of the defending force and the difficulty of the terrain.
The Japanese advance took place along a narrow coastal strip through plantations, swamps and dense vegetation. Australian forces conducted a fighting withdrawal before halting the Japanese near the airfields.
Allied aircraft operating from Milne Bay attacked Japanese landing craft, supply positions and troops. The destruction of much of the Japanese landing and supply capability made it increasingly difficult for the attackers to maintain their advance.[5]
The fighting continued into early September. Australian forces counter-attacked and drove the Japanese back towards their landing areas. Japan began withdrawing its surviving troops by sea, and the battle ended with the failure of the attempt to capture the airfields.
Tasman returns under threat
KPM ships continued attempting to supply Milne Bay while the threat was developing.
On 25 August, HMAS Arunta escorted Tasman towards the bay. Reports that Japanese cruisers were nearby caused the ships to turn back to Port Moresby. This decision illustrates the danger involved in sending merchant vessels into an area where Japanese surface forces might be operating.[6]
Tasman returned to Milne Bay on 1 September with cargo described as exceptionally welcome by the local military commander. Japanese aircraft attacked the ship the following day, but it escaped serious damage.[7]
During the night of 2 September, Japanese warships entered Milne Bay to assist in evacuating wounded personnel. Tasman remained in the area but was not attacked by the surface force.
The vessel’s presence during the battle demonstrates the risks accepted by KPM officers and crew members. Tasman was a merchant ship rather than a purpose-built naval transport and had limited capacity to defend itself against aircraft or warships.
Convoy Q2 and the loss of Anshun
On 5 September, Convoy Q2 reached Milne Bay. It included the KPM vessel ’s Jacob and the British merchant ship Anshun, escorted by HMAS Arunta and HMAS Swan.[8]
The ships brought additional supplies at the point when the Japanese assault was collapsing. That night, Japanese warships entered the bay during their withdrawal operations.
Anshun was caught while unloading, shelled and capsized. The Japanese ships did not sink ’s Jacob. The loss of Anshun demonstrated how exposed Allied merchant shipping remained even after the land battle had effectively been won.
The continued arrival of supply ships also showed that the Allies could maintain their maritime connection with Milne Bay despite Japanese efforts to isolate the base.
Reinforcing Milne Bay after the battle
KPM voyages continued after the Japanese withdrawal. Japara and Van Heemskerk delivered cargo on 12 September. Because Japanese naval forces were still active in nearby waters, a strong escort of Allied destroyers was provided.[9]
Van Heutsz and other merchant vessels supplied Milne Bay on 17 September. The continued flow of cargo helped consolidate the Allied position and prepare the base for its next role.
Milne Bay became the principal starting point for the coastal supply route towards Oro Bay and the battlefronts at Buna, Gona and Sanananda. The experience gained in transporting troops and cargo to Milne Bay helped prepare KPM officers and crews for the more demanding voyages that followed.
The extent of the KPM contribution
It is important to distinguish between the Battle of Milne Bay and the subsequent Operation Lilliput.
Operation Lilliput was the organised convoy system that transported reinforcements and supplies from Milne Bay to Oro Bay between December 1942 and June 1943. It did not take place during the Battle of Milne Bay itself.
The lists of 19 Dutch ships, 39 convoys, 3,802 reinforcements and 60,000 tons of supplies relate principally to Operation Lilliput and should not be presented as statistics for the Battle of Milne Bay.
The KPM contribution to Milne Bay was more specific:
- delivering engineers and construction equipment needed to establish the airfields;
- transporting Australian troops and RAAF personnel into the base;
- carrying weapons, fuel and general supplies;
- maintaining voyages while Japanese ships and aircraft threatened the area; and
- continuing to reinforce the base after the Japanese withdrawal.
This was an important logistical contribution, but it formed part of a much larger Australian, American and Allied effort.
A foundation for the Allied advance
The victory at Milne Bay demonstrated that Japanese land forces could be defeated. It raised Allied morale and secured an air and maritime base that became increasingly important to the campaign in Papua.
KPM ships and their Dutch officers and predominantly Indonesian crews helped establish and maintain that base. They did not fight the land battle, but they transported many of the people and much of the material that made the defence possible.
The experience also revealed a recurring feature of the New Guinea campaign: Australia and the United States possessed troops, aircraft and equipment but initially lacked sufficient specialised shipping to move them through coastal and island waters.
KPM provided part of that missing capability.
After Milne Bay, the focus shifted towards the Japanese positions at Buna, Gona and Sanananda on Papua’s northern coast. Supplying that offensive created an even greater logistical challenge and led to the establishment of the KPM-supported maritime lifeline known as Operation Lilliput.
Endnotes
[1] Dudley McCarthy, South-West Pacific Area—First Year: Kokoda to Wau, Australian War Memorial, Canberra, 1959; Douglas Gillison, Royal Australian Air Force 1939–1942, Australian War Memorial, Canberra, 1962, pp. 562–565.
[2] Jonathan Ford, “The Netherlands Merchant Navy in the Pacific War,” Journal of Australian Naval History, Vol. 6, No. 1, 2009, p. 86; Gillison, Royal Australian Air Force 1939–1942, p. 564.
[3] Ford, “The Netherlands Merchant Navy,” p. 86; Gillison, Royal Australian Air Force 1939–1942, p. 564.
[4] Ford, “The Netherlands Merchant Navy,” p. 86.
[5] McCarthy, South-West Pacific Area—First Year; Gillison, Royal Australian Air Force 1939–1942.
[6] Ford, “The Netherlands Merchant Navy,” pp. 86–87.
[7] KPM, The Koninklijke Paketvaart-Maatschappij Lines and the War in the South West Pacific, p. 1; Ford, “The Netherlands Merchant Navy,” p. 87.
[8] Ford, “The Netherlands Merchant Navy,” p. 87; G. Hermon Gill, Royal Australian Navy 1942–1945, Australian War Memorial, Canberra, 1968.
[9] Ford, “The Netherlands Merchant Navy,” p. 87.
