Operation Rimau (What went wrong) Pt1

The following is a report regarding “Operation Rimau” and the subsequent events after the operation. We have tried to present this report as authentically as possible & thus have used the same layout, terms & grammar as the original report reads. 


Since World War II the failure of Operation Rimau has continued to draw public attention. The number of enquiries on the incident still being received by the Department of Defence is evidence of this. In particular an earlier proposal by the South Australian Film Corporation to produce a documentary film on the subject.

Previous summaries on Operation Rimau by various researchers is largely incomplete because they failed to appreciate the scope of the operation. Deficiencies in the earlier studies can also be attributed to the fact that researchers were denied access to the full range of World War II records; the restriction on access to classified documents, and the fact that the related records on the incident were disbursed between the Australian War Memorial and Australian Archives, and the more sensitive documents being retained in the custody of the Department of Defence.

As a consequence, a Research Officer from the Department of Defence analysed all available information on the topic with the purpose of developing a Monograph on Operation Rimau which would take into full account the chronological sequence of events associated with the ill-fated venture, and also to arrive at any conclusions as to the assumed reasons for the failure of the operation.

All sources of information, cross referencing to Departmental files and other documents are identified in the Index and Notes section of the Monograph.

This revised edition is mainly a consequence of a requirement to make editiorial changes which have been brought to the attention of the sponsors. It does not contain any new evidence. However, future editions may contain evidence brought to light as further research is carried out into Operation Rimau.


1. It is difficult to arrive at firm conclusions about Operation Rimau in view of the many diverse accounts expounded on the subject. After the war, the evidence collected from the many’postwar crimes’ trials suggests that the Japanese tried to conceal all traces of the existence of the Rimau prisoners and other POWs gaoled in Singapore by burning masses of documents directly related to their incarceration and ensuing fate. The Japanese only cooperated when the prisoners’ graves were discovered.

2. It was Allied policy to bring charges only where there was a very good chance of obtaining a conviction. During the Rimau investigation the Japanese falsified events by producing an alleged account of the trial and a story of how the Rimau prisoners had been treated as heroes and only put to death in the end very reluctantly because of their sabotage activities. The Japanese also started the myth that the prisoners had been beheaded as a tribute so that they would die in a manner befitting heroes.

3. The operation was conducted in extreme secrecy. However, as more information is released from the various archival authorities in Australia and overseas. It is apparent from ULTRA intercepts now released, that Allied intelligence authorities knew of the operation but this information was safeguarded in order not to compromise, the ULTRA secret.

4. From the material now available it is evident that the original investigations were incomplete and subsequently raised more problems than they solved. After the war independent inquiries were conducted by one Australian and one British team, however, the information collected from the different geographical locations was rarely cross-checked. Although it was difficult to obtain accurate information and many of the ULTRA intercepts were missing, a more accurate assessment could have been made had a more professional approach been used to seek evidence. Whilst the evidence was there, no real in-depth examination appears to have been conducted. For example, more information could have been obtained from eyewitnesses many of whom have since died. The South Australian Film Corporation (SAFC) interviewed some of the remaining witnesses in the 1980s and produced the evidence (paragraphs 11 to 84). In contrast, a British investigating officer LTCOL C.H.D. Wild on Japanese treatment of prisoners in Singapore wrote in June 1946:

‘..the Rimau prisoners were treated remarkably well by the Japanese who honoured and respected them’.
Recent evidence shows that the dates and locations given in LTCOL Wild’s investigation reports were all incorrect.

5. Historians based their writing on records existing at the time and from the inaccurate accounts of the Japanese, who it is now known falsified much of their evidence regarding the deaths of the Rimau personnel in an attempt to escape prosecution for War Crimes. Other writers such as Ronald McKie in his book, ‘The Heroes’, and the notable Japanese interpreter, Furuta in his 1957 magazine article, based their stories on the inadequate evidence available in 1944/1945.
6. The discovery of many anomalies as the search for additional information progressed could not be ignored. This may have provided an impulse to alternative explanations. In short, an adequate assessment must combine the views of many postwar historians given that the present evidence points to earlier information gathered after 1944 being inconclusive. The aim of this paper is to retrace the development of the events through the phases which succeeded each other during the period 11 September, 1944 to 7 July, 1945 from the information so far gathered on Operation Rimau.


7. The Australian Services Reconnaissance Department (SRD) during WWII was the cover-name for special operations Australia (similar to the British Special Operations Element (SOE). SRD was tasked with special operations to the North of Australia and closely associated with the Allied Intelligence Bureau. (8) In early 1944, SRD London planned ‘Operation Hornbill’, an attack directed against Japanese shipping by way of the Natuna Islands in the South China Sea, the primary target being Saigon. In this operation, two new weapons were to be introduced, the Australian built ‘Country Craft’ and the ‘Sleeping Beauties’. The ‘Country Craft’ had the outward appearance of a native sailing boat and was equipped with a powerful engine. It could either be used as a sailing boat or be motorised. However, union disputes in Melbourne caused lengthy delays in the final stages of its construction, resulting in the cancellation of Operation Hornbill and of the emergence of Operation Rimau.

8.  The Rimau party comprising 23 British and Australian Servicemen under the command of LTCOL I. Lyon, left Fremantle on 11 September, 1944 in a British submarine, the HMS PORPOISE. The party were to enter Singapore Harbour in fifteen motorised submersible canoes known as ‘Sleeping Beauties’ (SBs). The SBs were Top Secret, and were metal one-man canoes with a battery-powered electric motor. The occupant was to sit in an open cockpit wearing Davis breathing apparatus. The SB could be used on the surface or travel semi-submerged, with the operator’s head above the water or fully submerged similar to a small submarine. Problems also existed with the ‘Sleeping Beauties’. They were designed for operation in Europe but were completed too late to be used on the Continent. As well, they had never been put into operation before and because of their short range operational capability they would have to be delivered to within 8-10 miles of their targets. To overcome this technical problem, SOE London decided that the Rimau party would capture a junk and anchor it in the Bay of Kepala Jernih Late on 9 October for 24 hours to allow an officer to carry out a reconnaissance from Pulau Subar. The officer was to spend the observing targets and later rendezvous with the junk in order to participate in the attack. The plan was for two canoes to travel north to the vicinity of Labon Island to secure a hide for the junk and for another canoe to proceed to Subar. Soon after darkness, the crew was to move the junk to an attack base at Labon. Using the ‘Sleeping Beauties’, the party was to attach limpet mines to Japanese ships, sink thirty of them, damage another thirty, and escape to their base on Merapas Island by paddling their way back in two-man folboat canoes, seventy miles to the east of Singapore.

9. After landing an officer (Carey), and stores) at Merapas Island the submarine followed Karimato Strait along the Borneo coast (Map 1), searching for a junk to capture. The submarine encountered difficulty, as contrary to SRD belief, junks were hard to find in the area under investigation. After much searching, a Prahu from Ketapang known as ‘Mustaka’ was seized with a Malay crew of 9 near Pontianak on 28 September, 1944 by seven of the Rimau group. The PORPOISE then submerged and with the ‘Mustaka’ following, sailed to a forward operational base at Pedjantan Island. The next two days were spent transferring provisions and operational stores, (a total of 15 tons), to the junk (Annex F). The submarine then left; for Australia to refuel, bringing with it the crew of the ‘Mustaka’, its papers and documents, as previously planned by SRD on 1 October. (10) The Rimau party then departed by way of the Java Sea and Karimata Straits and eventually set up a base on Merapas Island on 4 October, 1944. From about that time the Rimau party appears to have divided into two groups, 19 operators were to take part in the raid whilst the remaining four assumed to be WO Warren, SGT Cameron, CPL Craft and LT Carey, stayed on Merapas Island (11). The 19 men departed from Pejantan Island for Pulau Laban (undetermined date). Pulau Laban is located at a distance of 11 miles from Keppel Harbour and was the intended forward point from which the attack was to be launched.

LTCOL I. Lyon ex ‘Jaywick’ (Infantry Officer)
LCDR A. Davidson, RNVR Expert in Navigation and ex ‘Jaywick’.
MAJ R.N. Ingleton Royal Marine with gunnery training. Architect in civilian life.
CAPT R.C. Page ex ‘Jaywick’ (had a camera) Infantry Officer.
LIEUT W.G Carey Kept a diary to record shipping and aircraft movement. (Infantry Officer)
LIEUT H.R B. Ross Reymond RANR Expert navigator Expert navigator
LIEUT A.L Sargent Infantry Officer
SBLT J.G.M. Riggs RNVR Expert in navigation and in General maritime training. SB pilot.
W02 J. Willersdorf Maintenance Technician
W02 A. Warren Maintenance Technician
SGT C.B. Cameron Maintenance Technician
SGT D.P. Gooley Maintenance Technician
CPL A.S.R Campbell Infantry
CPL C.M. Stewart Signaller
CPL C.M. Craft Signaller
CPL R.B. Fletcher Infantry and Maintenance
L/CPL H.J. Pace Infantry and Technician
L/CPL J.F. Hardy Transport and Technician
A/B W.C. Falls ex Jaywick
A/B F.W. Marsh ex Jaywick
A/B M.W. Huston Had participated in Commando training
PTE D.R. Warne Maintenance Technician


11. The original plan was not followed. Postwar information recorded in the diaries kept by Cruiser Division 16 indicated that between 9 and 10 October, 1944 there were many Japanese vessels from the Cruiser Division 16 cruising the Phillip Channel near Kepala Jernih Bay. The Japanese Task Force was taking part in battle manoeuvres in conjunction with other units of the fleet and was due to leave almost immediately for Operation ‘SHOGUN’ (SHO-1)?. Drawing upon a logical deduction and quite apart from the imminent danger had their presence been discovered by the Japanese, the naval exercise must have generated strong waves which swamped the junk. This probability and in addition two other factors – a heavy rainstorm in the afternoon and the adverse tidal currents existing in the region caused the Rimau crew to navigate away from the danger zone (KASU)? to seek shelter and wait for 3 or 4 hours before darkness set in (Map 2).

12. On 10 October, 1944 the Rimau crew were spotted two hours before sunset by Native Hei Ho in the vicinity of Kasoe “Island and Samboe Island then under the control of the Japanese, who had been making a routine check. The Rimau party were surprised just an hour or so before they were due to launch the raid. (12) (Map 3)

13. The Japanese had increased surveillance since ‘Jaywick’ by converting junks and small boats to counter espionage in their immediate region, in addition to all the neighbouring islands under Japanese control. Providing extra native patrols equipped with radios. In addition, they had established observation posts manned by the Water Kempei Tai along the coast and strategic locations on many islands. (13) The Japanese scrutinized all vessels which they recognised from the flags they carried. Indicators of the ships’ country of origin and destination. (14) Also when a boat was on officially-approved business a Japanese flag had to be shown.

Voyage: Number of Flags and Identification
On a Coastal run : No Japanese Flag necessary
For Java and Malaya: Two Flags: Japanese Flag, (‘Rising Sun’ or ‘Poached Egg’) and the Red Anchor on a White Background
For Borneo: Two Flags: ‘Poached Egg’ and ‘Red Anchor’ on a White Background. (15)

15. Various explanations have been offered for the cause of the tragedy. For instance: an assumption was made that the group had flown the ‘Poached Egg’ on its own; may have hoisted the wrong flag, or a combination of wrong indicators. (16) The ‘Mustaka’ was intercepted because of its unusual appearance, compared to other junks. (17) The event took place in broad daylight and at close quarters (approximately 50-80 yards off Pulau Kasoe jetty), it may be assumed that the patrol saw white men on the deck ‘badly disguised as Northern Indians’ and wearing makeup. Some of the Rimau crew were bared to the chest, a behaviour Malays regards as immodest. (18) There is also the speculation that Major Ingleton, an architect by profession, was observed sketching enemy vessels and Japanese naval shore defence installations, whilst LT Carey photographed Japanese naval facilities. (19)

16. Any one of these factors or a combination of them would have been sufficient to make the Malay Police suspicious. At approximately 1700 hours Tokyo time or 1530 Singapore time, Tuesday, 10 October, 1944 something was shouted to the junk from the approaching patrol boat, which was possibly flying the ‘Rising Sun’, and firing started soon after. Two Malays who managed to swim ashore unhurt reported the incident to the Japanese authorities. According to an event account given by a surviving member of the Hei Ho, a tall man spoke to someone beside him. A man was seen by the Hei Ho reaching for a long gun with a bipod and placed it on the gunwhale of the ‘Mustaka’, that and five smaller guns (later identified as sten-guns with silencers) fired on the police launch. There has been frequent mention by the Malays interviewed after the event that a tall man gave the order to shoot at Kasoe. It is assumed that by Malay standards anyone above five feet is comparatively tall. All three senior officers were tall, LTCOL Lyon (about 6′). LCDR Davidson (about 6′ 2), and MAJ Ingleton who weighed about 15 stones. The implication here is that LTCOL Lyon might have been on Subar observing targets as previously planned in the Operation. If he was engaged in this activity, then leadership would have been assumed by LCDR Davidson (an expert mariner and navigator and Intelligence Officer), failing this, MAJ Ingleton would assume leadership.


17. Postwar investigations disclosed the probability that the Rimau crew opened fire believing that their operation had been compromised soon after sighting the barge, mistaking the crew for Japanese. An assumption has also been made that the Rimau crew fired to prevent the occupants on the barge sending a warning call to other Japanese units. It is suggested that a Japanese flag was hoisted on the barge and in order to protect their secret the Rimau party had no option but to open fire. (20)

18. Whether the raid was successful or not is pure conjecture. India had sent a hopeful message in the December 1944 based on RAF aerial photographs: ‘damage in area intended for strike’. (21) On the raid Japanese intercepts were ambiguous, either they revealed nothing substantial, or gave misleading intelligence. One report dated 25 January, 1945 reported on a naval strike in these terms: After this, they divided up into small boats (called SBs) which can be concealed in darkness and approached the ships at anchor in Singapore Harbour at about 0300 and attached magnetic mines (time limit of about six hours)’ (22)

19. After the ‘Jaywick’ operation, 1 Southern Expeditionary Fleet had identified the situation in similar terms. Japanese transmissions contained many errors such as names, dates and locations. Low standards of communication existed between units which inhibited information flow. Generally the Japanese system of dispatching radio messages required the operator to send sections of a completed message with the result that the recipient had to wait lengthy periods. With such a procedure one can only surmise that an operator had confused the two operations. Local inhabitants are sure that there was a series of explosions coming from Singapore Harbour on the night of 10 October, 1944 following the Rimau appearance which might have been mistaken as a naval strike by many villagers. According to the evidence, the Japanese demolished all the wrecks that were blocking wharves and waterways that night.

20. A graphic presentation of the Japanese Navy in war time includes a list of combatant and non-combatant ships sunk or damaged. It shows the extent of Allied activities in the immediate region in October, 1944. It should be noted however, that the only damage reported was that sustained by the heavy cruiser AOBA when tying up alongside KINU in Singapore harbour on 11 October 1944.

21. The sinking of the junk with its secret equipment is not well documented and consequently has generated the most heated debate. The fifteen ‘Sleeping Beauties’ took precedence over anything else. They were secret war weapons and as such had to be kept from the Japanese to prevent them being copied for use against Allied shipping. LTCOL I. Lyon had received specific orders for their destruction; they were to be sunk in a depth of 8 fathoms. It is assumed that he took care that the highly secret equipment hidden in the hold of the junk did not fall into the hands of the enemy. Japanese documents issued on the 10 October, 1944 did not report on their confiscation, but many reports were made of an explosion heard near Kasu Island. Japanese divers were immediately sent to the area. (24) Their search was reportedly unsuccessful.

Batam Island Pangkil Island Soreh Island Tapai Island Merapas Island Mapor/Pompong Islands -Sebangka Island Selajar Island Singkep Island Pedjantan Island Pontianak Buaja Island Gentung Island Surabaja Island Maja Island Pelapis Island Kandapongan Dilli Romang Island (See Map 3) (Riau Archipelago) (Riau Archipelago) (Riau Archipelago) (Riau Archipelago) (70 miles east of Singapore) (near Temiang Strait) (Lingga Archipelago) (North of Singkept) (Lingga Archipelago) (West of Sebangka Island and mid-way of Borneo) (On the West Coast of Borneo) (Lingga Archipelago) (Lingga Archipelago) (near Potianak) (Off South West Coast of Borneo) (Off South West Coast of Borneo) (Off South Eastern tip of Borneo southwest of Laoet Island, Pulau Lao) (Timor) (East of Timor)


23. Tuesday, 10 October, 1944 – From the shore villagers -,aw the junk move into deeper water only 100 yards from the accident and observed the Rimau party with boats, laden folboats and leaving Kasoe area in 9 folboats. It is assumed :hat the group divided into four boat parties under the command an officer: LTCOL Lyon, LCDR Davidson, CAPT Page and LT Ross, and kept to the original planned crew. They set off for -heir Merapas base travelling towards North in the direction of Singapore Harbour possibly heading for Labon to rendezvous with one or both of the Reconnaissance Officers (Lyon or Davidson). Eyewitnesses saw a boat party immediately after the incident travelling in that direction presumably to a pre-arranged pick Up point. Two boats were seen by local witnesses north of ‘;zatam, whilst two others proceeded down the west coast of Batam proceeding east through the Strait of Tiung.


24. Wednesday, 11 October and Thursday 12 October, 1944 -it is probable that some of the boat parties stopped on the headland of north-western Batam and left. Batam had been used during ‘Jaywick’ as a hiding place by LCDR Davidson in 1943. The Japanese made an entry in their War Diary that some white men were seen by local inhabitants.


25. The Punitive Force came from a Singapore Garrison, an infantry company of 100 approximately soldiers led by Major Fujita and included the following: – The 3rd Vessel Transport Headquarters – One Patrol Boat – Five Landing Boats – Singapore Water Military Police Division – Division Commander and 10 Soldiers (Japanese War Diary Extracts) The search parties combined of Army, Navy and drafted native Police undertook vigorous investigations of every island chain swooping down on Islanders, and generally causing terror among them retrieving information on the fugitives. However, according to the evidence, local involvement in the search was quite significant because the Japanese rewarded informants handsomely. Obviously, the relatively narrow expanses of water between these particular islands would have facilitated the monitoring of the 9 folboats, even if these were travelling by night.


26. Saturday, 14 October, 1944 – An informant, Raja Mun, noticed white men on the island and reported them to the Japanese authorities. He received $20 for the information. Postwar speculation suggests that they were members of CAPT ‘age’s boat party. At 7.30, 10 Special Naval Base Unit, Singapore dispatched a detailed signal to all Units on the Rimaus’ presence. Although a company was sent to Pankgil the Rimaus had already escaped to the adjacent island of Soreh, about one or two miles away.

SOREH (East of Singapore in the Riau Archipelago off the west coast of Bintan):

27. Sunday, 15 October and Monday 16 October, 1944 – The following .reconstruction of events are inconclusive but it appears that by the 15 October, the remaining party by virtue of prevailing tides weather conditions, came unexpectedly upon their new refuge of Soreh Island. Some locals spoke to them between 0800 and 0900 that morning. Soreh is egg-shaped, its length running North/South is three quarters of a mile, while its breadth running East/West is about a quarter of a mile. The terrain is flat, it is lacking in trees, rocks and vegetation, and offers little safety. In fact, the expanse of the island could be covered in about thirty minutes.

28. At about 1400 hours with 5 hours of daylight remaining, heavily armed Japanese troops arrived in a landing barge. The eighteen men were in no condition to repel a sustained enemy attack. They were equipped with the ammunition that they had managed to salvage from the junk; which was thought to be four bren guns (600 rounds), five stens fitted with silencers, (400 rounds), 18 revolvers (24 rounds) and about twelve No. 36 hand-grenades. They withdrew to the western end of the northern beach, having selected two defensive positions in an unexposed area. LTCOL Lyon took position in a small depression with a suitable field of fire and LCDR Davidson manned the second position which consisted of a trench 15 feet by 9 feet and about 18 inches deep covered with stones. Each officer carried one bren gun, and one silenced sten gun.

29. Preliminary defensive measures taken, the other members of the fourth boat positioned themselves for the imminent engagement, with CAPT Page keeping watch by the landing point. At 1500 hours the enemy barge dropped its ramp unloading an estimated 40-45 native auxiliary troops (Hei Ho) under Japanese command and NCOs from the Water Kempei Tai. According to the Japanese account, the patrol was routine. Only one small party walked towards the ambush whilst the rest of the Japanese unit remained in reserve. The Rimaus were clearly at a disadvantage having lost the benefit of surprise. They opened fire inflicting heavy casualties among the Hei Ho, and killing one Japanese Officer. The whole engagement had an unfortunate aftermath as the Japanese 2 I/C and remaining Hei Ho took refuge behind trees and responded with intense rifle and machine gun fire. This stand-off continued for several hours. Escaping from their situation obviously depended on the opportunity and on the lunar conditions. It was a dark night with no moon, CAPT Page and two other sten gunners took flight at this point. LTCOL Lyon and LCDR Davidson in the front row and Corporal Campbell or Able Seaman Huston (identity still uncertain) directly behind them fired intermittently having exhausted most of their ammunition, until shooting on both sides lessened. A Malay man and woman sent by the Japanese to investigate only saw two badly wounded men in a repression. One of them, a tall man, spoke to the woman in Malay. The other defensive position was empty. It is assumed that LT Ross and CPL Campbell made their escape leaving LTCOL Lyon and LCDR Davidson to cover their withdrawal. At about ?COO hours another barge presumably coming from south-west of Pangkil unloaded more troops. This caused action to recommence which continued for approximately 2 to 3 hours. Thereafter, two bodies with multiple wounds and fresh head wounds were located. It had been speculated that the two men had either shot each other in the head, died as a result of their multiple injuries. Another version is that, both officers may have lifted themselves out of the depression, allowing the enemy to shoot them. It is significant that LTCOL Lyon (29) and LCDR Davidson (35) dominated the battle by holding 80-90 opposing soldiers forcing them to stand and fight for 9 hours and inflicting heavy casualties among them.

TAPAI (5 miles from Soreh):

30. Monday, 16 October, 1944 – 1500 hours to about 0800-0930 Tuesday, 17 October, 1944 – When LT Ross and CPL Campbell reached Tapai they were both seriously wounded. After beaching their boat they scrambled on to a rocky ledge. A Japanese patrol discovered them early on Tuesday morning and subsequently the Rimaus began firing at the patrol who returned fire. The Rimaus had very little ammunition, which they used by taking the 24 rounds of .38 pistol ammunition and fired 23 rounds at the enemy. LT Ross (20s) and CPL Campbell it is thought committed suicide by firing the 24th round into their heads rather than surrender. The patrol found their bodies, a fresh wound in their heads, and an empty pistol in their hands. (Map 4)

To be continued.