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Matilda II in Australian Service

Commonwealth of Australia (1942-1945)
Infantry Tank – 400 Delivered

Her Majesty Heads East

By 1940, the Matilda II Infantry Tank had made a name for itself in the western deserts of North Africa, aptly earning the moniker of ‘Queen of the Desert’. However, by 1941, the Matilda II had fallen behind the increasing pace of desert warfare in terms of mobility and firepower. The Matilda II was gradually being replaced by the cheaper and equally as effective Valentine infantry tank. The career of the Matilda II would not end here however.
In early 1942, the situation in the Pacific had grown dire. The Japanese empire had overrun much of the British territory in the region and, by February, the Japanese advance had extended far enough south that Japanese airpower could launch aerial attacks directly against the Australian mainland.
Australia, for its part, had recognized the need for tanks in the second Australian Imperial Force and had planned on raising a full armored division by the end of 1941 with plans for an additional two armored divisions to follow. The problem was the availability of such vehicles. The locally designed Australian Cruiser tanks had only just been produced in prototype form and, with the Japanese now in control of some of Australia’s closest neighbours, the need for tanks was urgent.

Matilda II tank of 9 troop ,B Squadron, 2/4 Armoured Regiment, moving along a track in the Hatai junction sector. Bouganville. 17 May 1945 -Source: Australian War Memorial
By mid-1942, just over 200 Matilda II tanks had arrived in Australia, although roughly half of these had to be cannibalized for parts to maintain the remainder of the fleet. Realizing the increased importance of close support in jungle fighting, additional tanks fitted with 3’ (76.2 mm) howitzers were obtained from New Zealand stocks in exchange for a corresponding amount of 2 pounder gun tanks. The 3’ howitzer tanks were employed as troop leader’s vehicles and usually took point during advances, supported by one or two 2 pounder gun tanks.
Close to 400 Matilda  II tanks would ultimately enter Australian custody. They would continue in Australian service until the end of the war, making the Matilda II the only British tank to see continual service from 1939 until 1945

Markings and details

The Royal Australian Armoured Corps typically followed British practice in the marking and detailing of their vehicles. However, some local variation did inevitably arise and many of the trends instigated in the Second World War (such as the naming of vehicles) continue to be used by the Royal Australian Armoured Corps (RAAC) to this day.

Formation sign

Following British practice, all Australian vehicles displayed an 8×8 inch insignia denoting the formation that they were part of. In the case of the Australian Matilda II tanks, all operational units were from the same formation, the 4th Armoured Brigade Group. The insignia of 4th Armoured Brigade Group was a white palm tree over a crocodile and a boomerang on a black background. All tanks displayed two formation signs, one located frontally next to the unit sign and the driver’s viewport,  with the second located between the external fuel tank brackets on the rear of the tank.

Arm-of-Service sign

The Arm-of-Service sign identified a vehicle based on its regimental type within the greater formation (in the case of Matilda II tanks, Armour). Two different types of Arm-of-Service signs could be seen on Australian Matilda IIs. The first type, implemented in 1943, followed the British vehicle marking system. This consisted of a white number 51 on a red square and was painted on tanks of the 1st Army Tank battalion (later 1st Armoured Regiment) in New Guinea.
The second type was locally developed and implemented after 1943. It consisted of a white fraction sign of the regimental number over a numerical designation of the unit type. For example, the 2-4 Armoured Regiment was displayed as 2-4/52 (52 designating armored regiment), while the 2/1 Armoured Brigade reconnaissance squadron was displayed as 2-1/214 (214 designating reconnaissance squadron).
Arm-of-Service signs were painted on the front and back of the vehicle, next to the formation sign, except for the Frog flame tanks, on which the rear sign was displayed on a vertical plate attached to the right-hand rear track guard. Official policy was that the fractional type Arm-of-service sign was to be painted on a green square, however, it appears that in some instances it was painted directly onto the base paint of the vehicle.

Squadron insignia

In common with British practice, Australian armored vehicles were marked with a colored insignia comprising of a number inside a geometric shape which indicated the vehicle’s regiment, squadron and troop. The color designated the regiment; 1st Armoured Regiment (red), 2/4 Armoured Regiment (yellow), 2/9 Armoured Regiment (blue), 2/1 Armoured Brigade Reconnaissance  Squadron (white).
The shape designated the squadron; A squadron (triangle, point up), B squadron (square), C squadron (circle), Regimental HQ (diamond), armored brigade reconnaissance squadron (triangle, point down). The number inside the shape designated the squadron which the tank was part of. For instance, a tank displaying a red square with the number 9 would be from 9 troop, B squadron, 1st Armoured Regiment. These insignias were displayed around the turret at three points, on both turret cheeks and the rear of the turret.

Restored Matilda II tank showing Australian markings for 10 troop B squadron 2/4 Armoured Regiment. 1.squadron insignia (troop number) 2. squadron insignia (Squadron shape and Regiment color) 3. Formation sign for 4th Armoured Brigade Group 4. Arm of service sign. 5. Bridging weight sign. Source Gizmodo

War Department numbers and embarkation markings

The War Department numbers were the registration numbers of the tank, beginning with a capital T, although this was not displayed on the vehicle. The War Department number was painted in 3-inch-tall white lettering above the center mud chutes of the tank’s side plate. It should be noted that in some unit specific cases, there was some variation in the placement of the numbers, either on the angled section of the upper side plate or on the front and rear of the vehicle.
The embarkation numbers consisted of a 5-digit code accompanied by a 3-color bar, with the colors corresponding to the last 2 digits of the code. The embarkation codes were derived from British practice to allow for easy and orderly loading of equipment onto shipping and thus ensuring that regimental vehicles were grouped together for delivery to the front.

Fording and bridging markings

The fording markings are one of the most distinctive visual markers of an Australian Matilda II and were intended to provide crews with a visual aid for the water depth at which the tank could safely and effectively cross. They consisted of two red lines approximately 1-inch-high on each side of the tank, the lower marker painted just below the top of the mud chutes and the higher marker a few inches above it.
Each line was labeled with white lettering reading ‘Flaps open’ for the lower marker and ‘Flaps closed’ for the higher marker. In some cases, the words ‘fording height’ were also present near or interrupting the higher line.  The bridging marker indicated the weight limit of the bridges which the Matilda II could safely cross. It consisted of a yellow circle containing a black number 25, indicating the Matilda II’s bridging weight of 25 tonnes. The bridging marker was painted on the front of the tank, either to the right of the driver’s viewport or on the front of the right-side tool box.

Fording markings on a restored Australian Matilda II tank. Source: The Australian Armour and Artillery Museum 

Names and miscellaneous markings

Matilda II tanks in Australian service were frequently, but not universally, painted with identifying ‘names’ on the angled side plate of the hull. Vehicles were named per the letter initial of their squadron. For instance, tanks of C squadron would have names such as ‘Courageous’ while tanks from A squadron would have names like ‘Asp’ or ‘Apache’. The name for each vehicle was typically selected by its crew, and the Australian soldiers (colloquially named diggers) often expressed themselves through humor or other creative choices.
The Matilda Frog tanks appear to be the exception to the rule of tank names starting with the squadron letter. For instance, a Matilda II Frog Flame tank operating with the 2/9 Armoured Regiment was named ‘Devil’ by its crew, despite there being no D squadron, while another was named ‘Charcoal’. Some crews also went to additional levels of detailing their tanks, such as tank T29923 ‘ACE’ which was also painted with a small Ace of Spades playing card to the left of its name. Crews also sometimes scrawled personalized slogans onto their tanks, such as one vehicle bearing the inscription ‘Cop this’ above the coaxial machinegun. However, these markings appear to be less frequent.

Trooper R.Fox pointing to the markings on the turret of his Matilda II tank. Huon Peninsula, New Guinea. 26 February 1944 -Source: Australian War Memorial

Modifications and experimental work

In response to local conditions prevalent in Australia and the Pacific, several modifications were implemented to Matilda II tanks in Australian service. These modifications were often applied at a regimental level, in response to the conditions each regiment was facing and, while useful for identifying Australian Matilda IIs, they were not ubiquitous.

Wireless and tank phones

The Second Australian Imperial Force first deployed tanks to the Pacific during the battle of Buna-Gona in December of 1942. Prior to Buna, Allied commanders had erroneously believed that tank and battery strength artillery support was not viable in a jungle environment, instead attempting to fill the lack of substantive fire support with air support and man-portable light artillery, such as mortars. The 19 available M3 Stuart light tanks were hastily rushed to the front and were not suitable in terms of design or equipment for jungle fighting.
Despite its valuable contributions to breaking through Japanese positions, one of the greatest flaws of the M3 Light at Buna was the incompatibility of the tank radios with the infantry wireless sets and lack of external infantry telephones. This meant that the infantry was unable to easily coordinate with the tanks and forced soldiers to brave Japanese machinegun fire and tree-top snipers to ride on the rear deck of the tank and direct the commander through the pistol ports.
Considering this, Australian Matilda II tanks underwent modifications to the radio position within the turret to allow for a locally produced modified MK 19 wireless set to be fitted. Additionally, tanks were fitted with a headset and microphone receiver on the rear deck of the vehicle, which allowed infantry to communicate with the tank crew, although this was later replaced by a more standard infantry phone. US produced ‘Walkie Talkie’ radio sets were also used by officers to direct fire from Matilda II tanks against Japanese positions, with many tank commanders frequently dismounting to fulfill forward observation duties for the troop.

Corporal R Stoddart and Seargent J R Edwards of 3 Troop, 2/9 Armoured Regiment testing the infantry phone of a Matilda II tank. White beach area, Morotai. 22 May 1945- Source: Australian War Memorial
Corporal E.G.Molyneaux netting a wireless
Corporal E.G.Molyneaux netting a wireless set no 536 ‘Walkie Talkie’ to a Matilda II tank of 8 troop, B squadron, 2/9 Armoured Regiment. A soldier can be seen in the background testing the infantry telephone. White beach area, Morotai. 21 May 1945 – Source: Australian War Memorial

Track idler guards and turret ring guard

In operations in New Guinea in 1943, it had been demonstrated to both sides that the Japanese lacked an AT gun sufficient to penetrate the main armor of the Matilda II. Having realized this, the Japanese began to focus on disabling the Matilda IIs by targeting the few vulnerable points on the tank, namely the track idlers and the turret ring. Targeted shots from Japanese 37 mm (1.46 in) AT guns were sufficient to smash the track idler and its surrounding plate as well as jam the turret mechanism, leaving the tank vulnerable to infantry attack with magnetic bombs or by lighting a fire under the tank.
To protect against fire from Japanese AT guns directed against the track idlers, armored guards were provided. The idler guards were cast from Australian Bullet Proof Plate 4 (ABP4) armored steel, the same steel developed for the AC I Sentinel tank, to a thickness of 1 7/8 inches (47mm). The guards were attached via a hinged mounting welded to the track guard, allowing the guards to be raised out of the way for track tensioning and other maintenance.  A bump stop was also fitted on the side of the tank to prevent the guard from fouling the track while moving cross country.
In order to protect the turret ring of the tanks, a collar of rectangular armored plate was fabricated and welded to the hull of the tank starting at the driver’s hatch and encompassing the side circumference of the turret but open at the rear. This armored collar was visually similar to that featured on the experimental A27 turreted Matilda II, and some sources claim that hulls fitted with the collar were delivered to Australia from stock intended to mount the A27 turret. Conversely, photographic evidence shows turret collars being welded on locally.

2/9 Armoured Regiment personnel fitting a turret ring guard onto a Matilda II of 15 troop, C squadron, during a post-exercise vehicle overhaul prior to deployment. The track idler guard has been lifted and is visible on the left-hand side while a trooper can be seen adjusting the bump stop with a shifting spanner. Wondela Queensland, Australia, 27 December 1944 – Source: Australian War Memorial

A Matilda II of 12 troop, C squadron, 2/9 Armoured Regiment fitted with track idler guards on exercises prior to deployment. Malanda area, Queensland, Australia. 11 December 1944 – Source: Australian War Memorial

Grenade protection and improvised armoring

In the closing stages of the war, Australian armored units were faced by an increasingly tenacious and desperate Japanese foe who, bereft of suitable conventional anti-tank weapons, began to use increasingly creative (and in some cases, borderline suicidal) means to defeat Australian tanks. Previous experience had revealed the risk of Japanese infantry attacks utilizing Type 99 magnetic mines and grenades thrown onto the back of the tank.
While these weapons were not sufficient to penetrate the main armor of the tank, they could damage the thinner engine louvers and the automotive components behind them, potentially leaving the tank immobilized and vulnerable to further close attack. To protect against the bomb threat, Australian armored regiments in Borneo began to improvise anti-grenade screens to protect the rear of their tanks in 1945. The anti-grenade screens were constructed from different materials depending on the regiment in question and typically conform to two types.
The first consist of repurposed pierced steel landing planks (also known as sand channels) formed into a conjoined plate and placed above the engine louvers, supported by a frame of steel tubing.  Additional plates were also placed around the engine area and wire mesh was used to fill gaps around the perimeter of the main plate. This type of protection was implemented on vehicles belonging to the 2/9 Armoured Regiment.
The second type consists of a wire mesh mounted above the engine louvers. In some cases, this was supported by a frame of steel tubing. In other cases, additional mesh was bent or welded around the sides to form angled supports. This type was used on tanks of 1 Armoured Regiment and 2/4 Armoured Regiment.
Spare tank tracks were also liberally affixed to the hull to act as extra armor. It is debatable as to just how effective this track armor was, however, by 1945, the practice was common throughout the active regiments of the 4th Armoured Brigade Group. Typically, the spare links were attached to the tank around the driver’s compartment on the angled side plates and, in some cases, on the glacis plate. The track links were welded onto the hull in strips, usually with the horns facing outwards, although in some cases the tracks on the glacis plate appear to be attached to some form of crossbar between the track guards, presumably so as not to interfere with the driver’s viewport and the tool boxes.

Personnel fitting perforated steel anti-grenade plates to a Matilda II of 2 troop, A squadron, 2/9 Armoured Regiment. Morotai 21 May 1945 – Source: Australian War Memorial

A pair of Matilda IIs from C squadron, 2/9 Armoured Regiment engaging a Japanese position. Both have been fitted with spare track links for extra armor. The tank in the foreground is armed with a 3’ (76.2 mm) howitzer while the tank behind is armed with a 2 pounder. 11th June 1945 Tarakan, Borneo – Source: Australian War Memorial

Troops welding spare track links onto Matilda II tanks of 1 troop, A squadron, 1 Armoured Regiment. 21 May 1945, Morotai – Source: Australian War Memorial

Matilda II ‘Beau ideal IV’ of B squadron, 2/4 Armoured Regiment fording the Puriata river. The rear engine deck has been fitted with a mesh cover to protect the engine louvers from grenades. Bougainville, 30 March 1945 – Source: Australian War Memorial

Mud scraper

On Bougainville island, in Borneo, Australian Matilda IIs faced a new challenge in the form of the coral mud which was frequent in the area of operations. The coral mud was thick and, due to its concrete-like composition of sand and coral shards, it tended to solidly pack any recess it could fill, most commonly on the inner surface of the tank’s drive sprockets. As the mud built up it increased the effective diameter of the sprocket and put additional tension on the track, which would, over time, either cause the track to break or warp the front idler axles.
To fix this problem, personnel of B squadron, 2/4 Armoured Regiment, developed a simple mud scraper for field installation. The scraper consisted of a piece of metal shaped like a bent capital Y and affixed forward of the drive sprocket behind the suspension skirting. Under operation the wedge part of the scraper sat between the rims of the sprocket close to the inner face and would deflect off mud as it built up around the inner circumference of the sprocket. The scraper appears to have been a simple and ingenious solution to the mud problem, although it is unclear how widespread the installation was across vehicles in the unit.

Coral mud built up in the sprocket of a Matilda II tank of B squadron, 2/4 Armoured Regiment. Bougainville, 21 February 1945 – Source: Australian War Memorial

The mud scraper undergoing tests (right) fitted to a Matilda II tank. As you can see, the sprocket on the left-hand side remains clogged with densely packed mud while the right-side sprocket has been cleared of mud by the scraper. Bougainville, 21 February 1945 – Source: Australian War Memorial

The mud scraper detached from the tank. The 3 flat surfaces on the left are the mounting brackets which are welded to the tank, the angled and vertical piece sit between the sprocket and remove the mud, Bouganville, 21 February 1945 – Source: Australian War Memorial

Improved cupola

Combat conditions in New Guinea revealed a need for improved vision on the Matilda II tank. The standard Matilda II turret cupola was typical of early war British designs, featuring only one rotatable periscope for vision when the tank was ‘buttoned up’ with the hatch closed. In jungle combat, tanks made for prominent targets and attracted heavy fire from concealed machineguns, which, while unable to damage the tank, frequently necessitated that the crew to operate the vehicle buttoned up.
In early 1944, a prototype for an ‘All around vision’ cupola was produced and subjected to preliminary (non-combat) tests in New Guinea. Weighing approximately 900 lbs (408 kg), the new cupola was cast by the Charles Ruwolts firm of Melbourne using ABP4 armored steel. The cupola was taller than the late model Matilda II cupola general found on Australian tanks and the sides were substantially thicker to offer increased protection. The cupola featured 8 vision slots around the circumference, backed by armored glass and was mounted on a ball bearing race allowing for it to be freely rotated by the tank commander. The two-part hatch from the standard cupola was retained and fitted to the new style cupola. A locking pin was also provided to prevent unwanted rotation of the cupola.

The prototype cupola mounted on the test turret prior to firing trials. The standard Matilda II hatch, Commander’s vision blocks and Commander’s traverse hand rail can all be seen. Gusika, New Guinea, 15th March 1944-Source: Australian War Memorial

Australian Matilda II
Illustration of the Australian Matilda II by David Bocquelet

Matilda Mk.V of the Australian 2/9th Armoured Regiment, at the battle of Tarakan, Borneo, May 1945.

Matilda II CS, Australian 1st Tank Battalion, battle of Huon (New Guinea), January 1944.
The tests revealed that the cupola was satisfactory in providing convenient all round vision for the commander and that the bearing race was satisfactory, with rotation of the cupola on even ground being easy and controllable. However, significant defects were also encountered in the cross-country trials. On rough ground, it was found that it was impossible to control the cupola rotation in any sort of usable manner. As the reporting officer put it ‘the commander receives a severe buffeting, and requires all his strength to “hold on” to avoid personal injury.’ Furthermore, it was found that the locking pin was mounted too high in the cupola to engage with the standard locking mechanism, requiring field modification for the tests. The locking pin also failed several times on the cross-country course due to the springs being insufficient to withstand the jolting of off-road movement.
Subsequently, the cupola was fitted to the turret of a damaged tank from C squadron (named Calamity Jane) and test firing of various small arms and AT weapons was conducted at a range of 70 yards (64m). The cupola proved to be resistant to 9 mm (0.35 in) and rifle caliber small arms as well as high explosive shells from a 3’ (76.2 mm) howitzer. While largely proof against .55 in (14 mm) Boys anti-tank rifles, it was shown that they could penetrate the viewing slots and glass. The cupola failed under fire from a 2 pounder gun, resulting in several clean penetrations of the turret which the cupola was supposed to be proof against.
Subsequently, a metallurgical analysis was requested to explain the armor failure and it was proposed that another prototype be cast by the Sydney firm Bradford & Kendall. However, it is not known if this was proceeded with. The cupola was ultimately not adopted.

The prototype cupola mounted on the test turret post firing trials. Three Armor Piercing  2 pounder shells have cleanly penetrated the turret side and embedded 1/4-1/2″ on the interior . Gusika, New Guinea, 15th March 1944-Source: Australian War Memorial

Matilda II Tank T29923 ‘ACE’ of A squadron 1st tank battalion test firing  3′ howitzer shells against the prototype cupola, which can be seen to the left of the image. Note the differences between the prototype cupola and the standard low profile cupola fitted on ACE. Gusika, New Guinea, 15th March 1944-Source: Australian War Memorial

Smoke generator

In 1944, a smoke generator unit was tested for use on the Matilda II tank in order to allow tanks to lay a smokescreen for advancing infantry. The smoke generator was a pre-existing design intended to be fitted to a variety of tank types, however modification was required to fit the system to the Matilda II, such that it could not be installed on other tanks. The unit consisted of two fuel atomisers fitted into the fuel tanks connected to a compressed air system located in the driver’s compartment with the smoke being expelled through the exhaust system. Testing revealed that, under optimal conditions, the generator could produce a continuous smoke screen approximately 15 feet (4.57m) high and 160 yards (146.3m) long with a maximum generation time of 2 minutes and 18 seconds. The generator kit was ultimately not adopted due to smoke laying requiring the tank to advance at speed (5th gear was considered optimal) which was not possible in jungle conditions.

Matilda II tank laying a smoke screen during testing of the Smoke Generation unit. Australia 1944 -Source: National Australian Archives MT801/1 – TI1069


New Guinea

Huon peninsula

Australian Matilda IIs first saw action in 1943 when a squadron (C squadron) of tanks from the 1st Tank Battalion made landfall on the 20th of October at Langemak bay on the Huon peninsula. The landing of the tanks was kept a tight operational secret. Extra security was deployed to prevent Japanese reconnaissance observing the build up of man and equipment. This kept the presence of the tanks a tactical surprise. The tank squadron was a central feature in the Australian advance towards Sattleberg in November of 1943.
Nine tanks were moved to Jivevaneng and attached to support the advance of the 26th Infantry Battalion. To maintain surprise, an artillery barrage was used to cover the noise of the tank advance. The initial attack began on the 17th of November. However, the sheer hills (dubbed ‘razorback ridges’) and thick jungle hindered the advance, requiring substantial engineering support to move the tanks up. Subsequently, it was decided that the advance would proceed under infiltration tactics, with small company sized forces of men advancing on narrow fronts ahead of 1-2 supporting Matilda II tanks with an attached engineering contingent.

Australian Matilda II tanks debarking from a Landing Craft Medium (LCM), Finschhafen area, New guinea, September 1943 – Source: Australian War Memorial
Despite close cooperation between tanks, engineers and infantry, the advance was still slow, with only 450 yards (411m) gained on the first day. Despite the slow progress, the presence of the Matilda II tanks was a distinct advantage; utilizing machine-gun fire and High Explosive shells, the tanks could strip away jungle foliage to spoil Japanese ambushes and keep infantry casualties to a minimum. The Japanese, for their part, quickly learned that their 37 mm (1.46 in) offered no substantial threat to the tanks and began to formulate ad hoc anti-tank defenses or retreat to defensive positions on the higher ridges that they assumed the tanks could not reach.
An incident from the 2nd of December 1943 illustrates the sheer durability of the Matilda II tank. Having advanced in support of infantry pinned down by Japanese fire, a Matilda II was engaged at close range (50 yards/45 m) by a Japanese 37 mm AT gun and suffered a broken track. A group of twenty Japanese soldiers advanced on the tank and began to hurl grenades and anti-tank mines from a ditch close to the vehicle. The tank could not move nor depress its weapons sufficiently to return fire on the Japanese infantry but continued to fire with the main gun and coaxial MG to deter enemy advances. Shortly afterwards, a Japanese 75 mm (2.95 in) howitzer opened fire on the stricken tank, damaging the frontal track idlers and suspension. When all ammunition was expended the crew locked the main access hatches and crawled back to the nearby allied infantry via the escape hatch under the tank. Having sustained a total of fifty direct hits from enemy fire, the tank was still able to drive away after field repairs on the following day and was back in action by December 4th.
The advance beyond Sattleburg continued at an increased pace as Japanese resistance wilted under the weight of the advancing Matilda II tanks. The Japanese holdout at Fortification Point was subdued after a difficult creek crossing by A squadron of 1 Armoured Regiment with the advance to the final objective of Sio beginning on the 21st of December 1943. By the 2nd of January 1944, the Australian advance across the Huon peninsula had reached the halfway point, just 46 days after the first tanks had entered action. The Huon campaign effectively concluded for the Australian armor by the 9th of January 1944, with 1 Armoured Regiment returning to the mainland in May-June of 1944.
In the wake of the Huon campaign, Lieutenant-General Sir Leslie Morshead tendered a report emphasizing the value of the Matilda II tank in jungle operations. The slow rate of advance under jungle conditions was considered ideal for the low gearing of the Matilda II tank and the heavy armor and effective armament allowed the tanks to easily accomplish the role the infantry tank was designed for, supporting infantry and engaging enemy strong points.
Combat experience had shown that the 3’ (76.2 mm) howitzer was an ideal weapon for jungle fighting, its moderate caliber allowing for a large quantity of ammunition to be carried while still being sufficient to destroy hostile strongpoints. The Matilda II was also praised for its compact size, being transportable on the Landing Craft Medium (LCM), as opposed to the Churchill, which would have required the use of the much larger, and more scarce, Landing Craft Tank (LCT).

Wewak and Bougainville

in preparation for further operations, the 2/4 Armoured Regiment sailed to Madang from Brisbane on the 25th of August 1944. Anticipating operations in widely separated areas, the regiment had broken down into squadron groups, each with their own signals personnel, field workshop and field park detachment. By November of 1944, C squadron was moved up from Madang to support the 6th Division in clearing out remaining Japanese forces at Wewak.
Having had no combat experience in New Guinea and no previous cooperation with tanks, the first order of business was to conduct field training for cooperative action between C squadron and infantry of the 6th Division. Much like the Huon campaign, conditions in Wewak were not ideal for tank operations and, given the scattered nature of the Japanese forces that had retreated in the wake of the Australian advance at Huon and the Americans at Aitape, the advance of the Matilda IIs was constantly delayed.
Hence, despite being deployed in November of 1944, C squadron did not see combat until the 6th of January 1945 at Matapau. For two weeks, starting on the 16th of February, C squadron supported the 2/1 Battalion across multiple creek crossings and difficult terrain in clearing the ridges south of Dogreto bay. After this, the tank advance was found to be untenable due to lack of bridging supplies and the squadron was withdrawn to Dogreto bay to wait for landing craft before later re-joining the infantry at Dagua airfield.
Given their lack of experience operating alongside tanks, the infantry units of 6th Division apparently did not see the value of the available tank support. C squadron found itself with little to do until the final assault on Wewak on the 3rd of May, during which the tanks took a leading role in subduing enemy strongpoints and became highly popular amongst the infantry. Unfortunately, this boost in confidence came too late, as by mid-May 1945 C Squadron’s role in the war was over and it subsequently returned to the mainland for discharge.

A Matilda II of B squadron, 2/4 Armoured Regiment traversing fallen logs while advancing along a jungle track. 18 April 1945 Bougainville – Source: Australian War Memorial
Meanwhile, B squadron, 2/4 Armoured Regiment, had sailed from Madang to Torokina, Bougainville, on the 16th of December 1944. In parallel to C squadron’s experience, B squadron had to spend several months undertaking in-theater training with the infantry of 3rd Australian Division. After moving their base of operations to Toko, B squadron finally saw action on the 30th of March 1945, when two troops were requested forward to counter attack in support of two companies from the 25th Division, which had been encircled and were under heavy Japanese fire.
With much difficulty, including multiple tanks bogging down in the muddy conditions and the loss of one tank in a creek crossing, the tanks arrived at the allied position north of Slater’s Knoll on the 31st of March. After assessing the disposition of allied forces, they began a counter attack which repulsed the Japanese force before operations were ceased at nightfall. Subsequently, between 5-6 of April, the Japanese resumed attacks against Slater’s Knoll but were again repulsed by the Matilda II tanks.
After the attacking Japanese entrenched themselves outside of the Australian position, one troop of tanks supported by infantry advanced to clear them out. The advance of the tanks upon the infantry positions was not something the Japanese had prepared for and the subsequent retreat collapsed into a rout in the space of roughly ten minutes, resulting in the almost complete destruction of the Japanese force.
From the 13th of April, the Australian forces advanced southeast towards Buin with the main Japanese force expected to be encountered between the Hongorai and Hari rivers. As the Australians advanced, it became clear that the Japanese lacked Anti-Tank  (AT) guns sufficient to damage the Australian Matilda IIs, and so instead resorted to improvised measures such as firing artillery over open sights, utilizing aircraft bombs as high yield mines and burying anti-tank mines in wooden boxes to fool magnetic detectors.
These new anti-tank methods also included the use of a 15 cm (5.9 inch) artillery field gun firing high explosive fragmentation (HE) shells at the Australian tanks. These howitzers could substantially damage a Matilda II tank and the other weapons were effective as well. This forced a reversal in the previously established method of tanks leading the advance. Instead, infantry and mine detection teams began to lead, with tanks following to attack once enemy positions were located and mines cleared. B squadron continued operations in the Bougainville area until the news of Japanese surrender on the 11th of August 1945.

Tarakan and Balikpapan

In February of 1945, Australian forces had been preparing for a joint assault to retake the Philippines alongside American forces. However, in mid-February, it was decided that Australian forces could instead be better used to retake strategically important oil fields and rescue allied prisoners of war held in horrific conditions on the Island of Borneo. The various battles of Borneo campaign were given the designation of ‘Oboe’. Australian Matilda Tanks would see combat at Balikpapan on the mainland of Borneo (Oboe two) and on the nearby Islands of Labuan (Oboe Six) and Tarakan (Oboe One) .


Australian tank crews faced their fiercest challenge of the Second World War on the island of Tarakan, where the Matilda II was forced to contend with not only the harsh conditions of the Pacific but also against an established network of bunkers and defences. The attack began on the 1st of May 1945 and would last for 6 weeks with C squadron, 2/9 Armoured Regiment and elements of the 2/1 Australian Armoured Brigade reconnaissance (recce) Squadron.

This Matilda II tank of 14 troop, C squadron, 2/9 Armoured Regiment was hurled 18 feet (5.5 m) into the air when it hit a Japanese improvised AT mine. As a testament to the toughness of the Matilda II the crew only suffered minor injuries.  8th May 1945, Tarakan, Borneo – Source: Australian War Memorial
Much like on Bougainville, Japanese defences to the tank problem proved innovative, utilising buried explosive caches as improvised mines. In some cases, even if the tank did survive, they left 30 foot (9m) craters in the valuable swamp roads. In another instance, the Japanese filled a canal surrounding the airfield with oil from the nearby refinery and set it ablaze to deter the Australian advance, and 75 mm (2.95 in) howitzer shells were slid down wires from high ground to try and disable Australian Matilda IIs during fighting in the north of Tarakan town.
Despite dogged Japanese resistance, the Rippon airfield had been secured by the Australians by May 5th 1945. Subsequent action along Snags track and towards Point 105 proved difficult terrain for the tank advance, with the assault on the Japanese position at ‘The Margy’ at point 105 requiring a combined infantry-tank attack as well as point blank fire from field artillery and even a quick firing QF 3.7-inch (94 mm) anti-aircraft (AA) Gun! By May 8th 1945, the oil fields and airfield had been fully secured and repair and rehabilitation works were underway.


Much like the corresponding operations in Tarakan, the invasion of Balikpapan was intended to capture vital assets in the form of the local airfield and oil refinery. Action at Balikpapan would commence on the 1st of July 1945, led by the Australian 7th Division and a supporting force of the Australian 1 Armoured Regiment and attached squadrons of specialist equipment from 2/1 Australian Armoured Brigade reconnaissance (recce) Squadron.
Again, the Australian infantry commanders failed to apply the hard learned lessons that had come from the New Guinea campaign. Cooperation between the infantry and armor was sporadic during the initial offensive, as the 7th Division had no previous experience fighting in jungles with armored support. However, this was somewhat offset by the 1 Armoured Division’s previous jungle experience at New Guinea, as well as preparatory training in cooperation with the Matilda Frog flame tanks that were to be deployed by 2/1 Recce Squadron.
The tactical formula that had been developed involved a formation of one troop of 3 gun tanks and one troop of 3 flame tanks for a total of 6 tanks. The formation would advance in line ahead in the order of two gun tanks, followed by two flame tanks, with a gun tank behind and finally a flame tank bringing up the rear. When a target was engaged, the lead gun tanks would break off to provide crossfire from the flanks while the two flame tanks closed the range. The flame tank and gun tank in the rear provided further covering fire and security in the event of an enemy ambush. Thus, the formation could mutually support its members with both gunfire and flame attack from any direction with any of the required tanks on hand to exploit any success or cover for withdrawal as needed. Having realized the previous need for bridging on New Guinea, the 2/1 recce squadron were also equipped with a Covenanter bridge laying vehicle.

A Matilda II tank of 5 troop, 1 Armoured Regiment, pushing over a coconut palm during operation Oboe 2. Balikpapan, Borneo. 1st July 1945 – Source: Australian War Memorial
The Balikpapan landings took place near the heavily defended region of Balikpapan town, on the rationale that the initial bombardment would eliminate large amounts of hostile resistance while allowing for the fastest progress towards the main objectives. Soon after 9 am, the first tanks had made it ashore on Balikpapan in the 6th wave of landing craft, consisting of one troop from A squadron and two troops from B squadron, although there was some difficulty with tanks bogging down in the earlier stages of the beach exits. Balikpapan would prove to be the largest single deployment of Australian armor in the entire Second World War. By the end of the day, a total of 33 Armoured Fighting Vehicels (including 2 D8 tractor dozers) had landed on Balikpapan, including the specialist troops of Frog flame tanks, Dozer tanks and the Covenanter Bridgelayer.
Despite the initiative shown in equipping tanks with dozer kits to allow for immediate engineering and recovery work without the need for the D8 tractor dozers, the Matilda Dozer tanks unfortunately proved unsatisfactory during the first hours of the attack on Balikpapan and permission was given to detach the dozer blades for operation as regular gun tanks. The cooperative work between the gun tanks and Frogs proved highly effective, with success by B squadron and a supporting Frog (albeit delayed by terrain) in breaking through the built-up area of the Vassey Highway and in clearing Signal Hill in a methodical house to house sweep.
Subsequent actions along Signal hill, Tank plateau, and through Balikpapan port and town showed the effectiveness of the tank and flame combination at breaking enemy strongpoints and clearing the numerous interlinked tunnels.
On the 5th of July, two amphibious operations were conducted at Penadjam and Manggar Airfield with the support of tanks from A and B squadrons. The Penadjam operation was something of an embarrassment for B squadron, as the landing site had not been previously surveyed. This resulted in the first two tanks to hit the beach sinking up to their turret rings in the soft mud. The subsequent tanks, now forewarned, selected a better location some distance away and continued operations. The drowned tanks were later winched out and recovered.

The three knocked out Matilda II tanks of A Squadron 1 Armoured Regiment, testament to the danger of the Japanese 120mm guns. Manggar, Balikpapan, Borneo, 5 July 1945 – Source: Australian War Memorial

A Japanese Type 10 120mm dual purpose gun, captured by Australian troops at the position known as ‘the Metal’. Similar guns were positioned around the Manggar Airfield.  Balikpapan, Borneo, 9 July 1945 – Source: Australian War Memorial
A squadron’s attack on Manggar airfield would prove to be one of the few instances where Australian Matilda II tanks faced any sort of viable threat from Japanese anti-tank defenses. Two troops were initially landed about 10 miles (16 km) east of the airfield, supported by the Covenanter Bridgelayer. However, upon advance, it was found that the only bridge in the region had been destroyed and the span was too great for the bridge layer to cross. Subsequently, two troops still aboard landing craft were to be put into action, with one to see immediate deployment and the other staying afloat in reserve. The first troop deployed just beyond the river mouth under cover of a smoke screen and what was assumed to be a covered position.
The tanks immediately met with heavy Japanese mortar fire before being engaged at a range of 1200 yards (1.1 km) by Japanese 120 mm (4.72 in) dual purpose guns sited at the airfield. These heavy guns were more than capable of damaging the Matilda IIs and all three tanks of the squadron suffered hits, with two being destroyed and the other severely damaged. With the bridge destroyed and the presence of the 120 mm guns, the wounded crews were evacuated by sea and the remaining tanks of A squadron withdrawn from action at Manggar, marking one of the few occasions where the Japanese successfully repelled an attack by Australian Matilda IIs.

Captain D.B Hill and Corporal I.R Corr inspecting Japanese artillery damage on Matilda II tank ‘Beaufighter’ of B squadron, 2/4 Armoured Regiment. 16 May 1945 – Source: Australian War Memorial

Troops loading high explosive 2 pounder shells into a Matilda II of 2 troop, B squadron, 1 Armoured Regiment – Source: Australian War Memorial

Obsolescence, disposal and surviving vehicles

Matilda II tanks remain common in AFV collections globally. As Australia was the last major operator of Matilda II tanks, a large majority of surviving Matilda II tanks are either located in Australia or sourced from Australia. At the end of the war in 1945, the Matilda II was declared obsolete by the Australian army and officially replaced in Australian armored units post-war by the Churchill.
Matilda II tanks deployed to the Pacific were not required to be returned to Australia and many were either abandoned in situ or dumped at sea. By 1946, it was determined that there were insufficient parts to maintain the remaining Matilda IIs and that the remainder of the fleet would only be operable for the remaining 6 months, leading to the tanks being retired from service. A small number of Matilda IIs were retained by the School of Armour at Puckapunyal post-war for training use. Tanks remaining in Australia were disposed of by the Commonwealth disposals commission.
Like the stockpiles of M3 medium tanks and the local produced AC I tanks, Matilda II tanks were sold off to civilians for conversion into agricultural tractors. Many of these tractor conversions were used across Australia and subsequently abandoned when they broke down beyond easy repair or were replaced by cheaper civilian vehicles. As such, many Matilda II hulls and components can be found in varying states on rural Australian farms and scrapyards. In recent years, these rural stocks have provided a boom in both whole hulls and components for private collectors.
One such tank was recovered in Moss Vale, New South Wales, in 1997. It was determined by the NSW Lancers Memorial Museum that this tank was number T29923, a 3’ gun tank named ‘ACE’ of A squadron, 1st Armoured Regiment (now the New South Wales Lancers). ACE was the first Matilda II tank to land on Balikpapan during operation OBOE 2 in 1945, and can be distinguished in historical photos by its distinct Ace of spades playing card mascot. After two years of volunteer work, ACE was reunited with the original 3’ gun turret and restored to full running condition in 2015, and is now held in the collection of the New South Wales Lancers memorial museum
The Royal Australian Armoured Corps museum at Puckapunyal, Victoria, has the largest single collection of Australian Matilda II tanks. The Puckapunyal museum has a total of six tanks in the collection, including two 2 pounder tanks and one 3-inch gun tank, as well as 3 examples of special equipment tanks
The Australian Armour and Artillery Museum at Cairns also has two Australian Matilda II tanks in their collection. The AAAM tanks are a 2 pounder gun tank fitted with the track idler guards and turret collar and a recently arrived number 3 type Dozer tank. Neither tank is functional.

Matilda II tank T29923 ‘ACE’ of A squadron 1st tank battalion replenishing 3′ howitzer ammunition. Kiliga, New Guinea. 16 March 1944 – Source: Australian War Memorial

Matilda II tank T29923 ‘ACE’ of A squadron 1st tank battalion, post restoration on display at the NSW Lancers Memorial Museum, Parramatta New South Wales 2017 – Source: NSW Lancer Memorial Museum

Matilda II specifications

Dimensions 18 ft 9.4 in x 8 ft 3 in x 8 ft 7 in (5.72 x 2.51 x 2.61 m)
Total weight, loaded 25.5 tons (25.6 tonnes)
Crew 4 (driver, gunner, loader, commander)
Propulsion 2x Leyland E148 & E149 straight 6-cylinder water cooled diesel 95 hp engine
Max. Road Speed 15 mph (24.1 km/h)
Operational Road Range 50 miles (807 km)
Armament 2-Pdr QF (40 mm/1.575 in), 94 rounds
Besa 7.92 mm machine-gun, 2925 rounds
Armor 15 mm to 78 mm (0.59-3.14 in)
Total production 2,987
Data source Infantry Tank Mark II Specifications, by J.S. DODD The Vulcan Foundry Ltd, Locomotive Works, August 1940


Infantry Tank Mark IIA* Specifications, The Vulcan Foundary Ltd by designer Sir John Dodd August 1940
Infantry Tank Mark II manual, War Department
Osprey Publishing, New Vanguard #8, Matilda Infantry Tank 1938-45
Hopkins, Ronald Nicholas Lamond and Australian War Memorial Australian armour : a history of the Royal Australian Armoured Corps, 1927-1972.
Fletcher, David and Sarson, Peter Matilda infantry tank 1939-1945.
Bingham, James Australian Sentinel and Matildas.
The National Archives of Australia
Infantry Tank Mark II Specifications, by J.S. DODD The Vulcan Foundry Ltd, Locomotive Works, August 1940

WW2 Australian Tanks

Matilda Frog and ‘Murray FT’ Flame Tank

Commonwealth of Australia (1943-1945)
Flamethrower Infantry Tank – 25 Built

A Need for Firepower

In early 1943, a General Staff specification was issued for a tank mounted flame projector for use by Australian units in the Pacific. Plans were submitted for a cordite based flamethrower designed by Major A.E Miller, the commanding officer of the Australian 2/9 Armoured Regiment Workshop, but no action was taken to develop the design. A separate Matilda II mounted design utilizing compressed air propellant was produced by the Munitions Supply Laboratory under the designation of ‘Flamethrower, Transportable Aust No. 1 Mk I’. The flamethrower was tested but with an unsatisfactory range of 14-19 yards (13-17 m). In November 1943, a panel including Major Miller was formed to investigate potential new designs for a tank based flame projector. On January 7, 1944, a new requirement was issued for a flamethrower mounted in the turret of a Matilda II infantry tank, with the design to be completed by February 7, 1944. The working design was a cordite based flame projector refined from Major Miller’s original design, however, it required fabrication of components which would extend completion past the deadline.
Major Miller proposed an alternative design based on a hydro-pneumatic cylinder which could be fabricated from available components and was approved, with a budget of 250 pounds. The new system utilized an electrically powered hydro-pneumatic piston to generate pressure for the flame projector and a prototype designated ‘Frog’ was completed on February 21, 1944. The prototype Frog was tested on April 2, and a refined system was approved for production of 25 units. Major Miller was transferred to the Master General of Ordnance (MGO) branch to oversee design and production. The first tank was delivered by July 22, 1944, and successfully demonstrated to the Commander of the Australian Military Forces, General Thomas Blamey, at Monegeetta Proving Grounds on July 26. The production flame tank was officially adopted under the name of ‘Flamethrower, Transportable Frog (Aust) No. 2 Mk I’, but is more commonly known as the ‘Matilda Frog.’

Diagram of the major components of the ‘Frog’ flame system. Source: The Australian War Memorial

Design and Specifics

The flame projector on the Frog replaced the Matilda’s standard 2-Pounder (40 mm/1.57 in) main gun. The flame projector was encased in a mild steel tube designed to resemble the 3-inch close support howitzer, but fitted with a counter weight near the end of the barrel for balance. The hydraulic traverse of the regular gun tank was retained and a new hand cranked chain-sprocket mechanism was affixed to the turret roof to control elevation. The coaxial BESA machine gun was also retained although the bulk of the flame projector made loading and servicing the weapon in combat extremely difficult. The most novel feature of the flame projector was the electrically powered hydro-pneumatic cylinder which generated pressure for the weapon instead of the more conventional cordite or compressed gas.
The hydro-pneumatic cylinder was comprised of a floating piston contained within two nested steel cylinders. During operation, fuel was electrically pumped into the inner cylinder, pushing the piston down and triggering a limit switch. Simultaneously, the air in the outer cylinder was pressurized by the depression of the piston, charging the weapon to fire. At full retraction, the inner cylinder contained 10 gallons of fuel. Firing the weapon released a pintle valve, allowing the pressurized air in the outer cylinder to expand and force the piston upwards, thus discharging the stored fuel through the projector barrel. A foot trigger controlled the release of fuel from the pressure cylinder while a thumb switch on the traverse controller was responsible for triggering the electrical igniter located at the end of the barrel. Releasing the foot trigger or expenditure of the stored fuel activated the fuel pumps and re-primed the system.
Much of the commander and loader positions were replaced by the flame projector’s 80-gallon ‘Geletrol’ fuel tank and the hydro-pneumatic compressor system with the commander’s seat moved and affixed to the pressure cylinder. Geletrol was a locally produced thickened flame fuel produced by adding Aluminum Oleate to petrol, diesel or a petrol-diesel mixture (referred to as ‘Dieseline’). The decreased space in the turret meant that the Matilda Frog carried a crew of only three (driver, gunner and commander). Testing was conducted between August-November of 1944, however, tests were interrupted by the failure of the hoses connecting the hydro-pneumatic cylinder to the flame gun. Metal pipes articulated by ball joints were designed to replace the rubber hoses. Development proved difficult and this upgrade was not satisfactorily implemented until 1945 when Frog tanks were refitted in the Pacific Theater, although it is not known how many tanks were refitted before the conclusion of the war.

Photo of the turret interior of a Matilda Frog, taken from the commander’s cupola facing forward. The fuel tank can be seen towards the front of the turret next to the gunner’s position, with the compressor piston behind it. The system of ball jointed pipes (painted white) normally connects the barrel of the flame projector to the fuel tank and compressor, however, in this instance, the projector barrel has been removed. Source: Batrac

A Matilda ‘Frog’ Flame tank of 1 Armoured Regiment attacking a Japanese bunker during operation OBOE 2. The anti-grenade mesh is visible on the rear deck. Balikpapan, Borneo. July 3, 1945. Source: Australian War Memorial

Matilda Frog flame tank, 2/1 Australian Armoured Brigade reconnaissance (recce) Squadron

Matilda Frog (flame-thrower version), ANZAC 1st Tank Battalion (support) at the battle of Huon (New Guinea), October 1943.
Matilda II Murray FT. Both illustrations are by Tank Encyclopedia’s own David Bocquelet

Initial Blueprint of the Hydro-pneumatic system installed in a Matilda II tank (February 1944). Note that the connection from the Pneumatic cylinder to the flame projector is at the bottom of the cylinder as opposed to the production vehicles where it is on the top of the cylinder.  Source: The Australian War Memorial
Unlike the Churchill Crocodile, the flame equipment and fuel storage were entirely stored on board the tank with no need for an external trailer. In addition, there were up to seven additional auxiliary fuel tanks linked into the flame projector’s fuel system, a 100-gallon tank affixed to the rear deck in place of the regular external fuel tank, up to four 32 gallon tanks stowed under the side armor, and two 30 gallon tanks fitted within the stowage boxes on the front of the tank. Naturally, tank crews were less than enthused to have flammable liquid stored in a position exposed to enemy fire and the frontal storage tanks were rarely used in combat.

Closeup photo of a 30-gallon tank mounted in the front stowage boxes, RAAC museum Pucakpunyal, Victoria. Source: BATRAC
The effective range of the Frog was typically 80-90 yards (73-82 m), although it was claimed that 140 yards (128 m) was possible under ideal conditions. The maximum rate of fire was 20 gallons per minute in either two 10 gallon shots or eight 2 ½ gallon shots. With the main gun replaced by the flame projector, a 90 yard range may seem somewhat limiting, however in jungle combat of the Pacific, the typical engagement range was 15-30 yards (13-27 m) which made the Frog more than effective against Japanese positions.

Matilda Frog tank in action. Balikpapan, Borneo, 1945. Source: Australian War Memorial
The Frog was issued to No. 5, 6, 7 and 8 troops of the 2/1 Australian Armoured Brigade reconnaissance (recce) Squadron and operated successfully in Borneo at Tarakan and Balikpapan (Operation Oboe 1 & 2) and at Labuan/Brunei (Operation Oboe 6). Although the Frog performed satisfactorily, the use of a compressed air system to propel the flame meant that a waiting 30 seconds was required between bursts (10 gallon shots) while the system built up sufficient pressure. This, along with the substantial bulk of the system, was considered workable although less than desirable.
In 1944, seeking to improve upon the weaknesses of the Frog, a modified system was developed utilizing cordite charges as a propellant for the flame projector. The system was a continuation of Major Miller’s earlier cordite based designs which used components from the ‘Breeze’ percussion starter on the diesel engine of the M3 light tank. This system generated pressure by using the expanding gases from a cordite charge to impinge on a piston in the flame projector’s fuel chamber. The use of cordite resolved the delay between firing shots and also extended the range of the weapon beyond 100 yards (90 m). The more size efficient nature of the cordite system also allowed for the turret fuel tank to be increased to 130 gallons. The cordite system was designated ‘Murray FT’ and, although completed, did not enter service before the conclusion of the war.
In total, 25 Matilda Frog tanks were built.  The Murray FT was constructed as a prototype in 1944 and tested throughout 1944-45 with the intention of replacing the Frog, although, with the conclusion of the war, production was never completed.


Dimensions 18 ft 9.4 in x 8 ft 3 in x 8 ft 7 in (5.72 x 2.51 x 2.61 m)
Total weight, loaded 25.5 tons (25.6 tonnes)
Crew 4 (driver, gunner, loader, commander)
Propulsion 2x Leyland E148 & E149 straight 6-cylinder water cooled diesel 95 hp engine
Max. Road Speed 15 mph (24.1 km/h)
Operational Road Range 50 miles (807 km)
Armament Compressed air powered flame thrower, up to 368 Gallons of ‘Geletrol’ Fuel
Besa 7.92 mm machine-gun, 2925 rounds
Armor 15 mm to 78 mm (0.59-3.14 in)
Total production 25
Data source Infantry Tank Mark II Specifications, by J.S. DODD The Vulcan Foundry Ltd, Locomotive Works, August 1940


Infantry Tank Mark IIA* Specifications, The Vulcan Foundary Ltd by designer Sir John Dodd August 1940
Infantry Tank Mark II manual, War Department
Osprey Publishing, New Vanguard #8, Matilda Infantry Tank 1938-45
Hopkins, Ronald Nicholas Lamond and Australian War Memorial
Australian armour : a history of the Royal Australian Armoured Corps, 1927-1972 D Fletcher
Matilda infantry tank 1939-1945 Bingham, James
Australian Sentinel and Matildas AWM54, 347/4/1, [Flame Projectors – Inventions:] Flame throwers, Submission of designs. Narratives of the development, design and production of flame thrower transportable No 2, Aust “Frog” and flame thrower Cordite operated, designed by Major A E Miller, 21 April 1945
Infantry Tank Mark II Specifications, by J.S. DODD The Vulcan Foundry Ltd, Locomotive Works, August 1940

WW2 Australian Tanks

Matilda Dozer

Commonwealth of Australia (1945)
Infantry Tank – 18 Built

Clearing the way

Although the Matilda II could negotiate a wide variety of jungle undergrowth, even toppling trees when the need arose, conditions in the Pacific were not ideal for tanks and some areas were still considered impassable to them. The Japanese took advantage of the rough terrain across several engagements with Australian tanks by establishing ambushes or mining the only viable routes for tanks to take or, alternatively, retreating to positions where it was simply impossible for the tanks to attack.
To cope with the terrain, a close association between the tank forces and Australian engineer units had been established since the Huon campaign of 1943. The engineering squads made wide use of commercial bulldozers to fill shell holes, clear Japanese roadblocks and level heavier sections of jungle to create new routes for the Matilda II tanks to outflank Japanese positions. Additionally, the bulldozers were used as recovery vehicles to extract bogged Matilda II tanks, although the bulldozers didn’t always have it their own way and, in some cases, the tanks had to return the favor and unbog the dozers!

Armored bulldozer undergoing tests at Bougainville, May 26, 1945 – Source: Australian War Memorial 092587
As effective as the bulldozers were, they still had substantial limitations. While a lack of speed was not a problem in the sluggish jungle battles of the Pacific theater, the commercial bulldozers were not designed for military needs and left the operators exposed to enemy fire while lacking any defensive armament of their own. In 1945, tests were conducted on bulldozers equipped with locally produced armored cabs, but these proved unsatisfactory. Subsequently, a bulldozer blade mounting for the Matilda II tank was developed. It allowed engineering work to be conducted in situations where the vehicles were under fire. This gave greater tactical mobility to the tank units.

Tank number 6940 (‘Minstrel’) Matilda Dozer Number 1 Mark I displaying its capabilities at Morotai, 9 June 1945 – Source: Australian War Memorial 109011
The first type, officially named the Dozer Matilda (Aust) No.1 mark I, was developed in early 1945 and tested on Morotai Island in June of 1945. The No. 1 dozer kit consisted of a Caterpillar D7 dozer blade with single push arms, mounted on pivots attached to the tank below the second mudchute. The height of the blade was controlled by a cable winch attached to the frontal glacis and powered by a re-purposed Jeep engine.

Illustration of the Mathilda Dozer by David B
Illustration of the Matilda Dozer by David Bocquelet
The No. 2 mark I and No. 3 mark I kits instead used hydraulic power to control the height of the blade. Power for the hydraulics were provided by a re-purposed Jeep engine in the No. 2 kit and drew power directly from the main drive shaft via a sprocket and chain linkage in the No. 3 kit. Additionally the No. 3 kit used a locally manufactured Britstand blade, fitted to the tank at the same point as the D7 blade on the No. 1 kit. The No.2 kit was superseded by the superior arrangement of the hydraulic power source in the No.3 kit. This resulted in the cancellation of the order for the No.2 type pilot model in June of 1945. As such, no examples of the Number 2 Mark I type were manufactured.
In order to control the height of the blade the No. 3 kit had two large metal cams attached to the push arms, above the blade mounting pivots. These cams were triangular shaped pivoting structures that changed the pushing motion of the hydraulics into a lifting motion on the dozer blade arms. The cams were actuated by a pair of hydraulic rams mounted on the front track guards protected by armored covers. The hydraulics were driven by a pump mounted inside the tank and linked to the rams by pressure lines running through the driver’s vision port. This arrangement meant that the diver’s viewport could not be closed, however, the presence of the dozer blade would have offered adequate protection in action. Unlike the No. 1, the No. 3 could raise the blade substantially higher which allowed the driver greater visibility and allowed for better obstacle crossing. However, at full elevation, the blade blocked the use of the turret armaments.

Matilda Dozer Number 3 Mark I traversing obstacles on trials. The Britstand logo can be partially seen on the cover of the hydraulic ram – Source: Australian War Memorial 133689
Matilda Dozers, a mixture of No.1 and No.3 kits, were deployed by Nos. 3 and 4 troop of the 2/1 Australian Armoured Brigade reconnaissance (recce) Squadron at Borneo during the Oboe series of operations in 1945. In action, the Dozer kits were found to be less than effective with the additional weight frontloading the suspension and hindering steering. The No. 1 equipped tanks were also found to be unable to elevate the blade sufficiently, which caused issues where the blade was unable to be elevated clear of low obstacles due to sinkage of the suspension on soft ground. Subsequently, the Dozer blades were removed and the tanks continued as gun tanks until the conclusion of the war.

The Number 3 Mark 1 Dozer tank on display at the Australian Armour and Artillery Museum, Cairns. Source: Jason Belgrave
The Number 3 Mark 1 Dozer tank on display at the RAAC museum, Puckapunyal, Victoria. Note that this tank is missing the armoured covers on the hydraulic rams and some of the hydraulic lines have been disconnected. Source: Bukvoed

Matilda II specifications

Dimensions 18 ft 9.4 in x 8 ft 3 in x 8 ft 7 in (5.72 x 2.51 x 2.61 m)
Total weight, loaded 25.5 tons (25.6 tonnes)
Crew 4 (driver, gunner, loader, commander)
Propulsion 2x Leyland E148 & E149 straight 6-cylinder water cooled diesel 95 hp engine
Max. Road Speed 15 mph (24.1 km/h)
Operational Road Range 50 miles (807 km)
Armament 2-Pdr QF (40 mm/1.575 in), 94 rounds
Besa 7.92 mm machine-gun, 2925 rounds
Armor 15 mm to 78 mm (0.59-3.14 in)
Total production 2,987
Data source Infantry Tank Mark II Specifications, by J.S. DODD The Vulcan Foundry Ltd, Locomotive Works, August 1940


Infantry Tank Mark IIA* Specifications, The Vulcan Foundary Ltd by designer Sir John Dodd August 1940
Infantry Tank Mark II manual, War Department
Osprey Publishing, New Vanguard #8, Matilda Infantry Tank 1938-45
nfantry Tank Mark II Specifications, by J.S. DODD The Vulcan Foundry Ltd, Locomotive Works, August 1940

WW2 Australian Prototypes

AC IV 17-pdr Armed Sentinel Cruiser Tank

Commonwealth of Australia (1942-1943)
Cruiser Tank – 1 Prototype Built

The one with the big gun

Another offspring of the AC I Sentinel was the AC IV, which was to be equipped with the new British Ordnance QF 17-pounder anti-tank gun. After the July 1942 decision to proceed with increased armament for the Australian Cruisers, a plan for expedited local production of 17 pounders was initiated to replace the previously planned 6 pounder production.
Artists rendition of the AC IV
Artists rendition of the AC IV. Source: National Australian Archives MP730 10
A new prototype turret was fabricated to facilitate mounting the 17 pounder gun, and fitted to the E1 prototype hull. The new turret had increased dimensions over the previous AC I and AC III turrets, notably featuring a slightly taller roof and an extended rear bustle with an angled rear facing as opposed to the vertical rear face of the previous types. The turret ring diameter was also increased from 54 inches to 64 inches, with the E1 hull being suitably modified.
Testing began in October of 1942. The first test was a simulation of the recoil force of a 17 Pounder, and its effect on the tank. This was done by mounting two 25 Pounder howitzers side-by-side in the turret and firing them simultaneously, this gave an estimated recoil force 20% greater than that of the 17 pounder. The dual 25 pounder mount took up the majority of the turret space and had to be fired remotely via lanyard. In the same month, the first Australian produced 17 pounder guns were completed at the Maribyrnong Ordnance Factory.
The tank was fitted with a locally produced 17 pounder (allegedly one of the first guns produced) equipped with a modified recoil system based off of that developed for the 25 pounder tank mounting. The tank and gun mounting were first test fired on the 11th of November at Fort Gellibrand in Williamstown, Victoria, with tests continuing on until early 1943. These tests proved quite successful and made the AC IV one of the first Allied tanks to mount the 17 Pounder gun.

A constant improvement

This, however, was not the finalized design and work would be ongoing for the AC IV until the cancellation of the tank program in mid-1943. Concerns had been raised about the design which would further complicate the matter. The 54 inch turret ring had been considered cramped but workable with the 25 pounder, but there were doubts about the efficiency of loading a 17 pounder in a 64 inch turret ring. It was therefore decided to increase the turret ring diameter to 72 inches for production vehicles.
Additionally, the Army was not satisfied with the proposed quantity of 54 rounds of ammunition carried in the prototype, and insisted that a minimum of 74 rounds be met. It was also considered desirable to mount the 25 pounder in the new turret to take advantage of the potential benefits of the 25 pounder gun alongside the 17 pounder.
The DAFVP responded to these requests with a proposal for an AC IVA design. Documents, however, are unclear as to what the AC IVA design actually entailed. Some documents claim the AC IVA was to be a variation of the AC IV fitted with the 25 pounder and produced at a rate of one 25 pounder armed tank for every three 17 pounder armed tanks. Other sources list the AC IVA as a design with enlarged hull dimensions to allow for an increased turret diameter and increased ammunition stowage for either the 17 or 25 pounder gun.

New powerpacks

16 cylinder 410 horsepower gypsy major engine mock-up
gypsy major engine mock-up
16 cylinder 510 horsepower Gipsy Major engine mock-up. Source: National Australian Archives MP730 10
To cope with the added weight, two new engine designs were proposed. The first consisted of four Holden Gipsy Major engines, providing an estimated 510 horsepower, to be mounted together in a two layer opposed piston setup and utilizing air cooling as opposed to the water cooled engines used previously.A non-functional mock-up of the engine, utilizing as many genuine parts as were available was produced. However, funding to continue development was denied due to termination of the tank project.
The second design was a 600 horsepower Michell type crankless engine, the design of which had been extensively developed by respected Australian Inventor A.G Michell in the 1920s. Director of Armoured Fighting Vehicle Production, Alfred Reginald Code, had been the chief draughtsman for Michell’s Crankless Engine Company from 1925 until the company’s closure in Australia in 1928. The crankless tank engine would have had several advantages, such as a smaller size to horsepower output ratio as well as a higher fuel efficiency. The design did not proceed beyond the drawing board.
600 horsepower crankless tank engine
This cutaway drawing of the proposed 600 horsepower crankless tank engine. Source: National Australian Archives B6118 7

The AC IV prototype, based on the AC E1 – Illustrator: David Bocquelet
The AC E1 tank
The AC E1 – Fitted with the new turret and 17 pdr gun, Fort Gellibrand Victoria,  summer of 1943. Source:- Australian War Memorial PO3498.010

The AC E1 with the turret traversed to the right showing the elongated rear of the turret and higher turret roof, Fort Gellibrand Victoria,  summer of 1943. Source:- Australian War Memorial PO3498.009

Always changing requests

In the quest for a modern tank design the army added a veritable laundry list of new requirements from late 1942 through to 1943, largely focused on standardising with the latest developments in US tank design. By early 1943, it was not clear to Australian authorities if the M4 Sherman would continue to be the standard tank of the US forces or be superseded by the T20 series of medium tanks.
Based on information received from US sources and the assessment of Col G.A Green on behalf of the US Army, desired upgrades included: US style all round vision cupola with additional crew vision blocs to be added around the turret. Ford GAA 525 horsepower tank engine to replace locally designed engines. Oilgear hydraulic turret traverse mechanism and Westinghouse 24 volt gyroscopic gun stabiliser. Removal of the turret basket in favor of crew seats suspended from the turret ring. Torsion bar suspension, or, if not possible, the implementation of US M4 type road wheels and revision to US rubber tracks. Replacement of the Methyl bromide fire suppression system with a Carbon Dioxide system. Arguably the most ambitious and outlandish proposal was the suggestion of a mechanical ammunition rack to better facilitate loading the 17 pounder gun.
‘Accordingly, a magazine containing 18 shells has been designed and this is located across the rear of the turret. The noses of the shells point towards the gun and the magazine has been equipped with gear to traverse each shell in turn to the centre for loading’ – tank production programme Report, on behalf of Director AFVP A.R Code to Mr Pryke, July 21st 1943

Not in vain

The termination of the entire Australian Cruiser program in mid-1943 was dictated by a mixture of practical and budgetary reasons as well as an ongoing political rivalry between the Ministry of Munitions and the Army.
Despite the Australian tanks never seeing combat use, one notable benefit to the development of Allied tanks did occur as a result. In 1943, Colonel Watson returned to the UK after his secondment to the Australian tank program ended. Watson brought with him documents related to the Australian tank program, including photographs and drawings of the 17 pounder mounting on the AC IV prototype.

The experimental 17 pounder mounting complete with  mantlet dismounted from the E1 tank. The modified recuperator system can be seen extending out into the mantlet bulge above the gun barrel. Source: Ed Francis
Watson received a great amount of interest regarding the Australian work with the 17 pounder, notably from Sir Claude Gibb who was adamant that the 17 pounder could be mounted in an M4 Sherman turret, but faced severe opposition from the parties arguing otherwise. Subsequently, a series of meetings was convened where Watson was invited to provide detailed information about the Australian 17 pounder tank mounting, information which significantly expedited the decision to mount the 17 pounder gun on what would later become the Sherman Firefly.

Surviving vehicle

The Australian Armour and Artillery Museum displays a mock-up of the AC IV prototype, assembled from a 17 pounder gun barrel fitted to a fabricated replica of the AC IV mantlet and a salvaged AC III turret, mounted to a salvaged AC I hull. The remains of the AC I E1 prototype hull were held in the collection of the Melbourne tank museum until its closure in 2006. The E1 hull was not listed as an item in the auction of the Museum’s collection and its eventual fate is not known.
An article by Thomas Anderson

AC IV specifications

Dimensions 6.32 x 2.77 x >2.56 m
(20’9” x 9’7” x >8’4”)
Crew 4 (commander, loader, gunner, driver)
Propulsion 3 x V8 Cadillac ‘Cloverleaf’ 330 hp total, 12 hp/t
3 x V8 Cadillac ‘Perrier Cadillac’ 395 hp total
Ford GAA, 525 hp
16 cylinder Gypsy Major, 510 hp
Michell type crankless engine, 600 hp
Suspensions Horizontal volute springs (HVSS)
Armament : 17-Pounder (76.2 mm/3 in), 54 rounds
Vickers .303, (7.9 mm)
Armor From 45 to 65 mm (1.77-2.56 in)

Links and Resources

Australian War Memorial Archives
The AC Sentinel on Wikipedia
Tank Hunter
ACVI tank
Mock-up of the AC IV prototype on display at the Australian Armour and Artillery Museum

WW2 Australian Prototypes

AC III Thunderbolt Cruiser Tank

Commonwealth of Australia (1942-1943)
Cruiser Tank – 1 Prototype Built

The inadequate 2 Pounder

In 1941, The QF Vickers 2-Pounder had been recognised as likely to become obsolete by the time that the AC tanks were scheduled entered production. The armament of the Mark I “Sentinel” was seen as transitional since the beginning, and the tank had been designed and balanced with the intent of mounting the Ordnance QF 6 Pounder (57 mm/2.24 in) gun before said gun was even available, shadowing the evolution of the British cruisers such as the Crusader.
Artists rendition of the AC III tank
Artists rendition of the AC III Tank. Source: National Australian Archives MP730 10


Tanks equipped with the 6 pounder gun were to be designated AC IA and would have been in all other details identical to the AC I, with one minor exception. Tanks fitted with the 6 Pounder gun were to have the hull machine gun and accommodations for the hull gunner removed to make way for remodelled ammunition storage, of which 100 6-pounder rounds were to be carried. Due to production delays and a lack of supply of 6 pounder guns the AC IA never left the drawing board and was superseded by the AC III. Additionally, other armaments were investigated for the AC tanks.
As early as December 1941, Colonel Watson had proposed the possibility of mounting an ordnance QF 25 Pounder (87.6 mm/3.45 inch) field gun via means of an adapted gun cradle for the 3 inch (76.2mm) 20 cwt Anti-Aircraft gun. This proposal met with Army approval and in February of 1942 two 25 pounder guns were delivered to the DAFVP for experimental work.
The proposed 25 pounder tanks were to be designated AC IB and were in all aspects identical to the AC IA design bar the changes to mounting and fittings suitable for the 25 pounder gun. By June 1942, a 25 pounder gun, with a modified recoil system, was fitted to an enlarged turret and mounted on the E2 prototype chassis.
Test firing of the gun proved extremely positive results, with the Director of Artillery remarking in his 1942 report ‘Accuracy is superior to that of a field mounting. Noise and blast within the turret is minimal, similar to that of a big air rifle. It was discovered, from personal experience, that once layed successive shots could be fired on target without needing to re-lay the gun’
Like the AC IA, the AC IB would ultimately remain unproduced. Events in the North African theatre and changes in army policy at home would overtake both designs, leading to a more radical revision in the form of the AC III. The new AC I was intended to be sent to North Africa by late 1942, however concerns had been aired in regards to dealing with the latest 50 mm (1.97 in) armed Panzer III and up-gunned Panzer IV F2.

AC III, the howitzer version prototype

Tank number 8066, the AC III prototype fitted with the 25 pounder main gun . Source:- Australian War Memorial 101155

An interim solution

By mid-1942, the 2 pounder was widely derided by Australian officers as a ‘pea-shooter’ and ‘popgun’ and the 6 pounder was looking increasingly obsolete in the face of German gun advancements. To address these fears, Field Marshal Sir Thomas Blamey, Commander in Chief of the Australian Forces, tendered a proposal to the Australian war cabinet in July of 1942.
Blamey proposed that the Australian tanks needed to get ahead of the Germans in terms of firepower, and the only solution was the QF 17 pounder (76.2 mm/3 inch) anti-tank gun. However, the 17 pounder had barely entered production in the UK and surplus guns for shipment to Australia were not at all available in the UK. Hence the 25 pounder gun, mounted on the refined AC Mark III, received much consideration as a stopgap measure.

Frontal shot of tank 8066. Notice the absence of the AC I’s ‘Distinctive’ MG mounting and gunner’s hatch, as well as the large mantlet bulge housing the 25 pounder gun recuperator above the gun barrel. Source: Ed Francis

Three quarter rear shot of tank 8066. The spare track bracket on the rear of the hull covers the hull casting number which was ground flush to the hull. Unlike on AC I tanks the casting number on the rear of the turret is still visible as no turret stowage box is present. Source: Ed Francis

AC III turret and basket being assembled on a turret stand, the turret front, mantlet, and gun have not yet been fitted. The rear bustle of the turret is slightly longer than on an AC I turret, stowage boxes for 25 pounder propellant charges can also be seen on the turret basket. Source: Ed Francis

AC III Thunderbolt specifications

Dimensions 6.32 x 2.77 x 2.56 m
(20’9” x 9’7” x 8’4”)
Total weight, battle ready 28 tons
Crew 4 (commander, loader, gunner, driver)
Propulsion 3 x V8 Cadillac ‘Perrier Cadillac’ 395 hp total
Suspensions Horizontal volute springs (HVSS)
Max speed 48 km/h (30 mph)
Range (max) 240 km (150 mi)
Armament : 25-Pounder (87.6 mm/3.45 inch)
Vickers .303, (7.9 mm)
Armor From 45 to 65 mm (1.77-2.56 in)
Total production 1

Links and Resources

Australian War Memorial Archives
The AC Sentinel on Wikipedia
Tank Hunter

AC III Thunderbolt
The AC III “Thunderbolt”  was fitted with a 25-pdr (90 mm/3.54 in) howitzer. More than 100 hulls were in varying states of completion when the entire program was cancelled in July 1943.

The AC III Scorpion

The AC III designation was actually given to two tank designs, named ‘Scorpion’ and ‘Thunderbolt’ respectively. The Scorpion was a standard AC I, but modified to mount the desired Pratt and Whitney Wasp radial engine. Director Alfred Reginald Code and the DAFVP had struck a deal with the Commonwealth Aircraft Corporation (CAC) in October of 1941, CAC would deliver 200 engines for tank use by mid-1942 with the loss to aircraft production being taken up by engines ordered from the USA. The Cloverleaf Cadillac engines would be installed as an interim measure for the first 65 tanks, after which the new engine and other sundry modifications would be implemented from the 66th tank onward.
Production of the AC III Scorpion was planned to be conducted at a new tank assembly annex to be constructed in Port Melbourne, Victoria, in order to supplement the output of the Chullora Tank Assembly Workshops in Sydney. Hull castings were to be produced locally in a purpose built foundry operated by the Charles Ruwolts Company, however automotive components such as the gearbox and final drives were to be imported from the United States. The Australian type crash gearboxes were contracted to be produced by the US based Oliver Farm Equipment Company.
For tank use the Wasp was to be down rated to 400 horsepower and re-designated ‘Scorpion’ with tanks using the engine carrying the same name. However, experimental testing with the Scorpion engine revealed undesirable traits, such as poor torque output at low RPM and a high RPM ceiling required to reach maximum power output.
By Mid-1942, DAFVP engine expert Robert Perrier had proposed a new design of the triple Cadillac engine, named the Perrier Cadillac. The Perrier Cadillac took the V8 engines used in the AC I and rearranged them in a radial formation connected together on a common crank case, much like the Chrysler A57 multibank. This new engine took up less space than the previous cloverleaf configuration and also delivered an increased output of 396 hp with the army’s new higher octane petrol. The Perrier Cadillac was also shown to perform significantly better than the Scorpion engine in terms of torque and horsepower, particularly at lower RPM.
Perrier Cadillac 395 horsepower engine. Source: National Australian Archives MP730 10
Perrier Cadillac 395 horsepower engine. Source: National Australian Archives MP730 10

Perrier Cadillac 395 horsepower engine. Source: Ed Francis

The AC III Thunderbolt

The AC III ‘Thunderbolt’ was a distillation of many of the previous innovations mentioned. The 25 pounder gun was selected as the main armament, contrary to popular belief not for use as a close support weapon, but for the value of its 20 pound Armour Piercing shot as well as its obvious advantages in terms of High Explosive shells. The finalised version of the 25 pounder mounting was fitted with a shortened recoil system, later used in developing the QF 25 Pounder Short pack howitzer, mounted above the barrel in a distinctive bulge in the mantlet. Additionally, the barrel length was increased by 18 inches (457.2mm) yielding an estimated increase in muzzle velocity of 150 fps (45.72 m/s).
To make room for the more voluminous ammunition, the hull machine gun was eliminated and the crew reduced to four, although, again contrary to popular belief, the turret coaxial machinegun was not deleted from the design. The hull was remodelled with the deletion of the machinegun position, with an increased frontal slope and new design for the driver’s primary and escape hatches.

Interior photo of the driver’s position of the AC III, the driver’s seat backrest is folded down. The redesigned primary and escape hatches can be seen in the top right and the hull machinegun and gunner’s position of the AC I are absent. Notably the 25 pounder ammunition rack  normally located on the left side of the gearbox does not appear to be fitted in this photo. Source: Ed Francis

Closeup of the driver’s position of the AC III. The locally produced crash gearbox can be seen on the left, notably the driver’s instrument panels have been revised from the AC I, reflecting the changes to the engine. The similarity of the gearbox and driver’s controls to those of the M3 or M4 medium tanks can be clearly seen. Source: Ed Francis
Given its advantages, the new Perrier engine was chosen with the rear of the tank being remodelled to accommodate. Notably, the engine deck was distinctly flatter than on the AC 1 and the amount of access hatches was changed. To accommodate the new 25 pounder gun a new turret was produced, identical in layout and general fitting to the AC I, but with slightly increased dimensions, particularly at the rear. Turret ring diameter on the first production tanks was 54 inches but this was intended to be enlarged to 63 inches on later tanks (later suggested to be further increased to 70 inches) (1.37/1.6/1.78 m). Armor was intended to be raised up to 75 mm (2.95 inches) but this was never implemented.
The first production prototype (tank number 8066) AC III arrived in January of 1943 with a 1000 round test firing of the 25 pounder on the E2 tank occurring in the same month. Trials were delayed due to uncertainty on the future of the tank program and army prevarication on finalising the stowage requirements. Under testing a number of minor faults were revealed but overall the tank was received well, with the testing officer remarking that the production models would be ‘A good fighting vehicle with excellent armament’.
Interestingly, the prototype was not fitted with semi-automatic gear on the gun, and the test report recommended against the installation of semi-automatic gear or the use of one piece ammunition for the gun. The first prototype had just finished its trials and the first production batch of between 120-150 tanks was under construction in July 1943 when the entire program was terminated by the Australian Government.

An AC III hull on the production line at the Chullora Tank Assembly Workshop. The relocated driver’s escape hatch and increased angle of the glacis plate are clearly visible. Chullora, Sydney, New South Wales, 1943. Source: Ed Francis

Dead end

The termination of the entire Australian Cruiser program in mid-1943 was dictated by a mixture of practical and budgetary reasons as well as an ongoing political rivalry between the Ministry of Munitions and the Army.

Surviving vehicle

The prototype AC III (tank number 8066) is held in the collection of the Australian War Memorial in Canberra, formerly on display outside it has since been replaced by an RAAC Centurion 5/1, and is now housed in the Museum’s Treloar Technology Centre which is not open to public viewing.
Prior to closing in 2006 the Melbourne tank museum displayed an AC III tank assembled from castings salvaged from firing ranges, distinctly having a 2 pounder shell lodged in the side of the commander’s cupola. This composite tank was internally unfurnished and missing several parts, such as the main gun,  turret front & mantlet , and the driver’s hatch. The gun was substituted by a salvaged 25 pounder barrel mounted in the turret with the turret front covered over by a shaped tarpaulin. The driver’s hatch was substituted by  a driver’s view hatch taken from an M3 medium tank. After the closure of the Museum and auction of the collection the location of the tank is not currently known.

An article by Thomas Anderson

WW2 Australian Prototypes

AC II Cruiser Tank

Commonwealth of Australia (1941)
Cruiser Tank – None Built

The Sentinel that never was

Contrary to a popular misconception the AC II was not a design for the installation of an Ordnance 6 pounder gun in the AC I Sentinel cruiser . Such a design did exist, entitled AC IA, but this is covered more appropriately with the AC III Thunderbolt. In reality the AC II was a simplified design intended to expedite production of the tanks Australia so desperately needed.
Due to the lack of progress by mid-1941, doubts were raised about the practicality of Australia attempting to manufacture such a complex tank design as the AC I. As a result, Australian AFV engineer Alan H Chamberlain proposed a competing design in June of 1941. The proposed design, entitled AC II, was intended to overcome the limitations of Australian industry by substituting the complex M3 drivetrain and gearbox for a commercially available Mack truck gearbox and drive, imported from the USA.
Due to the Mack components not being required for US munitions production it was estimated that deliveries could begin in October of 1941 with series production of the AC II beginning in January of 1942 at a rate of 8 tanks per week. Compared to 5 tanks per week in mid-1942 for the AC I. The Mack components however required a reduction in the weight of the vehicle and were limited in the horsepower that could be used to power the tank. It was alternatively mooted that the Mack gearbox could simply be substituted into the AC I design. However concerns that in a 28 tonne tank the Mack gearbox would be overloaded, risking the gear teeth stripping at low gears, put an end to this idea. As proposed, the AC II weighed 19.5 tonnes with a hull armor basis of 2 ¼ inch (57.15 mm) frontal and 1 inch (25.4 mm) side and rear, and 2 ½ inches (63.5 mm) of all around turret armor.
The intended engine was to either be a twin mounting of the same Cadillac V8 engines used in the AC I or a 225 horsepower GM 6-71 diesel engine. A Curtiss aircraft engine was also investigated but found to be overly powerful for the Mack gearbox and thus unsuitable without substantial modification . Despite the decreased weight, the corresponding decrease in engine power resulted in an estimated top speed of 19 mph (30 km/h). The armament was the same as on the AC I.
Line drawing and armour specifications of AC II
Line drawing and armour specifications of AC II. Source: National Archives of Australia MP730/13 14

Unable to meet the Requirement

The Army were concerned by the armor of Chamberlain’s AC II design, arguing that 1 inch (25.4 mm) of side and rear armor was too thin to protect against light anti-tank weapons such as anti-tank rifles and 20 mm (0.79 in) cannon shells. Subsequently, the Army tendered a modified 22 tonne version of the AC II with an increased armor basis of 2 ½ inches (63.5 mm) frontal armor and 1 ¾ inch (44 mm) side and rear armor. However, the increased weight of the modified design was considered to be the absolute limit of the Mack components and the speed had been further reduced to 16 mph (25 km/h).

Artist's rendition of a production AC II
Artist’s rendition of a production AC II

The AC II design was favourably reviewed by Mr Michael Dewar of the British Purchasing Commission, claiming that the design was likely to be the equal of and in some respects superior to the British Valentine Infantry tank. This was small consolation however, as the Army had already rejected the Valentine as too slow and inconsistently armored. The Army would not accept the AC II due to it not meeting the listed top speed requirement of 35 mph (56 km/h). Some consideration was given to increasing the front and side armour to a basis of 3 and 2 1/16 inches (76.2-55mm) respectively and implementing the AC II as an infantry tank with a top speed of roughly 10mph (16 km/h), however this was not further pursued due to lack of army interest in infantry tanks.

For emergency use only

The AC II also caused considerable problems with relations between Australia and the US Lend Lease authorities. From the perspective of US authorities Australia seemed to be wasting resources on pursuing two almost identical designs simultaneously, which made the US reluctant to invest support in the project. Such was the level of hesitance and confusion associated with the AC II that it required Director of AFV Production , Alfred Reginald Code, to travel to the US in late October of 1941 in order to personally expedite deliveries of US parts to Australia and reassure US authorities that Australia only wanted one design of tank.
By October of 1941, no shipments of parts for the AC II had been delivered and initial production was estimated for mid-1942, the same time as the preferred AC I. Consequently consideration was given to producing the AC II as a lead up to AC I production, after which excess production would be exported to allied nations in need of tanks, but this plan was not pursued. After October of 1941, the AC II was only ever considered as a stopgap measure for emergency defence and ultimately did not progress beyond the drawing board.

An article by Thomas Anderson

AC II specifications

Dimensions 6.32 x 2.77 x 2.56 m
(20’9” x 9’7” x 8’4”)
Total weight, battle ready 22 tons
Crew 5 (commander, loader, gunner, driver, machine gunner)
Propulsion 2 x V8 Cadillac, 220 hp total
GM 71 diesel, 225 hp
Suspensions Horizontal volute springs (HVSS)
Max speed 16 mph (25 km/h)
Armament 2-Pounder QF (40 mm/1.57 in), 130 rounds
2x Vickers .303, (7.9 mm) 4250 rounds
Armor 57.16 mm frontal (2.25 in)

Links and Resources

Australian War Memorial Archives
The AC Sentinel on Wikipedia
Tank Hunter

WW2 Australian Tanks

AC I Sentinel Cruiser Tank

Commonwealth of Australia (1942-1943)
Cruiser Tank – 65 Built

The only WWII Australian tank design

Among the Commonwealth nations, Canada probably had the best industrial capacities and helped Allied tank production during the war. Canadian factories built Shermans and Valentines, as well as the Ram or the Sexton, which were indigenous designs.
Australia and New Zealand had more limited industrial capacities, but nevertheless pushed on with their own designs, especially as the Japanese threat grew steadily in early 1942.
If the Bob Semple tank was an oddity, more conceived as a last ditch defensive vehicle than a real frontline tank, the Australian AC I Sentinel was a fully-fledged cruiser tank. First intended for combat in North Africa, the AC I was the first and only domestic production tank in Australia’s history.
Sketches of what would become the Australian Cruiser (AC) tank were first drawn in June 1940, when the situation in Europe was so dire that the Commonwealth was mobilized, and later dramatically escalated when war broke out with Japan in 1941.
To save time, the automotive basis had to be the American M3 Lee but with a British cruiser style low-profile turret and hull, and British armaments. However industrial limitations repeatedly hampered production, by late 1941 no prototype was ready and production only began on a limited basis in mid-1942.
The design was altered at several points along its development resulting in several distinct variations that, while innovative, ultimately did not enter production. While the AC tanks never reached substantial production they did display a remarkably refined design for a country that had no prior history with the production of AFVs, as well as several notable features such as the mostly cast hull, whereas most contemporary British tanks still had welded/riveted plates.
Preserved RAAC Sentinel AC1 Cruiser Mk.1 Australian WW2 Tank in the Australian Armour and Artillery Museum
Preserved RAAC Sentinel AC1 Cruiser Mk.1 Australian WW2 Tank in the Australian Armour and Artillery Museum, Cairns, Queensland, Australia

Initial attempts at design

The first steps towards an Australian tank began on the 12th of June 1940 at a meeting between representatives of the Australian Military, Prime Minister Robert Menzies and Director General of the Ministry of Munitions, Essington Lewis. Chief of the General Staff (CGS) Sir Brudenell White announced the Army’s intention for the Master General of Ordnance (MGO) branch to produce a light cruiser tank in the range of 10 tonnes with a requirement for 859 vehicles by the end of 1941.
Sentinel Assembly
The AC I under construction at the Chullora tank annex. (Source:- Australian War Memorial)
At this point in time, no official CGS design specification had been issued however. The Army design section under control of Major (later Lt.Colonel) Alan Milner, had nonetheless produced a design by the end of the same month. The intended vehicle had a proposed weight of 12 tonnes, of which 7 tonnes represented all round armored protection on a basis of 28 mm (1.1 in), powered by twin Ford Mercury engines.
Primary armament was to be the QF Vickers 2-Pounder (40 mm/1.57 in) gun accompanied by one .303 (7.7 mm) machine gun and one 2” (50.8 mm) trench mortar. In light of the deteriorating situation in Europe by August of 1940, the Australian Army had revised their requirement to a 15 tonne tank with heavier armor.
Although the Army had revised the requirements for the proposed tank, still no design specification had been issued by the CGS. Realising that undue delay was occurring in the design of the Australian tank, Prime Minister Menzies telegrammed the War Office on the 20th of August 1940 requesting the loan of one or more tank design experts to assist the Australian project. A reply was received on the 4th of October 1940 announcing the dispatch of Colonel W D Watson (MC) of the Royal Artillery to Assist.
Watson did not travel directly to Australia, instead crossing to the United States where he rendezvoused with Australian engineer Alan H Chamberlain to make a join assessment of tank developments in the USA and Canada. During the same month, information was received from Australian representatives in the USA indicating that the current design for a 15 tonne tank was not sufficient to compete with German tanks.
Australian Cruiser Tank AC1 Sentinel at the Tank Museum Bovington, England
Australian Cruiser Tank AC1 Sentinel at the Tank Museum Bovington, England
The recommendations called for a design based on the current Anglo-American design (what would become the M3 Lee/Grant medium tank), a 25 tonne tank with a minimum armour basis of 60 mm, preferably 80 mm (2.36-3.15 in), and a 350 hp aircraft type engine.
The formal CGS specification for an Australian produced cruiser tank was finally issued on the 11th of November 1940. The CGS specification was a lengthy document still cluttered by the technological indecision and tactical confusion that had prevailed previously.
The major points were as such. An immediate requirement for 340 tanks to equip one armored division and a further 119 tanks for the 1st Australian Corps and the AMF (84 and 35 respectively), an additional 400 tanks for 12 months reserve, with a total production of 859 tanks. No weight restriction was issued beyond the lowest possible allowing for all other requirements to be met, with armor required at 50 mm (1.97 in) minimum, although this was later amended to 65 mm (2.56) frontal with 45 mm (1.77 in) minimum sides and rear.
RAAC tank crew on their new Australian Cruiser Tank AC1 Sentinel
RAAC tank crew on their new Australian Cruiser Tank AC1 Sentinel
Dimensions were restricted to conform to the loading gauge of Australian railways, a maximum width of 9 feet 4 inches and maximum height of 8 feet 6 inches with no restriction on maximum length. In regards to mobility, it was requested that the tank be able to operate on sand or black soil, with no requirement for cold weather operation.
Minimum required top speed was to be 35 mph (55 km/h) on level ground, with a slope traverse of 45 degrees, and trench and vertical obstacle crossing capabilities of 6 foot 6 inches and 3 foot 6 inches respectively. Operational range was specified as a minimum cruising range of 150 miles (240 kilometres).
Armament was to be one Ordnance QF 2 Pounder accompanied by one .303 machine gun mounted in the turret with another machine gun mounted in the hull considered desirable. Minimum ammunition load was set at 120 2-pounder shells and 5000 rounds of small arms ammunition for the machine guns (7000 if two guns were mounted).
All weapons were to have a minimum elevation of 36 degrees and minimum depression of 10 degrees. A requirement for 12% of tanks to be equipped with armament capable of smoke laying and firing High Explosive shells for Close Support (CS) purposes was also presented. Additionally supply and anti-aircraft tanks were also listed as requirements but specified as requiring their own separate design brief.

Design of the Australian cruiser

Col Watson arrived in Australia in late December of 1940 and was immediately appointed head of design for the Tank project. Based on the industrial conditions of Australia the AC I borrowed multiple elements of the M3, in particular the drive train and suspension layout, however extensive modifications had to be made in order for the tank to be produced locally.
Diagram of the major castings of the AC I tank. Source: National Australian Archives MP730 10
Diagram of the major castings of the AC I tank. Source: National Australian Archives MP730 10
With the tank project arriving at a relatively late juncture in the Australian munitions program there were no available facilities equipped to roll armored plate in the thicknesses required. The solution devised was to cast the hull in six sections which would be bolted or welded together to form a rigid whole. Additionally, Australian stocks of nickel, typically used in cast armour, were earmarked as critical war resources and thus unavailable.
To deal with the nickel problem metallurgists at Broken Hill Proprietary (BHP) developed a new armored steel formula, Australian Bulletproof Plate 4 (ABP4), utilising zirconium in place of nickel. Zirconium was chosen due to Australia possessing some of the world’s largest readily available stocks of naturally occurring zircon sand.
The engine presented yet another problem. In order to meet the army’s requirement of a 35 mph (55 km/h) top speed it was estimated that an engine of at least 300 hp would be needed. However, both the intended original engines, the radial Pratt & Whitney Wasp and the Guiberson diesel, were not available.
The Pratt & Whitney Wasp had been produced in Australia under licence by the Commonwealth Aircraft Corporation (CAC) since the mid-1930s, but immediate war needs meant that all Australian Wasp production was tied up in aircraft orders for Australia and the UK. To circumvent the engine issue, Watson proposed the use of three regular Cadillac V8 346 in³ 5.7L engines, arranged in a clover-leaf formation through a transfer case leading into a common driveshaft, giving a total output of 330 horsepower.
In April of 1941 the clover leaf Cadillac setup was assessed by Professor Burstal of the University of Melbourne and the Chief engineer of the Vacuum oil Company, Mr Alfred Reginald Code, with both men concurring that while the setup was less than ideal it would be workable as an expediency.
The last issue to be overcome was that of the gearbox. The US M3 Medium tank used a state of the art synchromesh gearbox with helical toothed hardened steel gears running on multiple bearing races, and was difficult to produce even in the USA. In Australia, the machinery required to cut gears of that type was not available and a shortage of bearings meant that the synchromesh gearbox could not be manufactured in Australia. The solution was to simplify the gearbox to a crash type design that used the same gear blanks and maintained the dimensions of the synchromesh type. This meant that the gearbox could be replaced with the more modern type should supplies become available from the USA. The gearboxes were produced by the firms Coote & Jorgensen, and Sonnedales.
While remarkable progress had been made in the first six months of 1941, the AC I was still on the drawing board and no closer to the arrival of a pilot model. Noting the inefficiencies of the established organisation Prime Minister Menzies again intervened in June of 1941 to create the Directorate of Armoured Fighting Vehicles Production (originally titled AFV division), with Alfred Reginald Code appointed as Director. Code was known both as a respected engineer and a skilled administrator and Prime Minister Menzies deliberately gave the DAFVP an unorthodox structure beyond both the Ministry of Munitions and the Army in an attempt to fast track tank production.
Code immediately set to building a skilled staff of designers and production engineers in order to simplify the tank design into the most viable design for Australian industry. Australian foundries had been emboldened by the idea of a cast hull for the tank and insisted that not only was it possible, but that it could be cast as a single large piece with only the axle housing and other external fittings being bolted on separately.
Proof of this concept was borne out in August-September of 1941, when the first test hulls were cast in foundries at the New South Wales city of Newcastle. The one piece cast hull reduced the amount of time required in machining and assembling the tank. Additionally, the new team at the DAFVP made several revisions to the design to streamline assembly. This included modifying the final drive design so that they could be installed from the side after the axle housing had been fitted and implementing a new ‘scissor’ type Horizontal Volute Spring Suspension (HVSS) bogie, resembling the French Hotchkiss H35, which offered equal performance to the American type while being easier to manufacture.
The suspension changed configuration during the development stage, with prototype vehicles having a trailing return roller, and production vehicles having the return roller on top. The AC I was designed to be able to use either locally produced steel tracks of a similar configuration to those used on British Cruiser tanks or alternatively US produced rubber block tracks. Installation of each type of track required the fitting of a different drive sprocket. Australian manufactured road wheels were functionally identical to US produced M3 road wheels, however they can be identified by either 4, 6, or 8 holes drilled radially around the inner diameter of the wheel.
The turret was fully cast with a 54 inch (1.37 m) turret ring, very similar to the British cruiser design, and the hull kept a low profile as intended. Armament was also similar to the British tanks, with the Ordnance QF 2-Pounder (40 mm/1.57 in) as the main armament. Due to the BESA machine gun not being in production in Australia, secondary armament consisted of one coaxial Vickers .303 (7.7 mm) machine gun and one hull mounted Vickers .303 machine gun protected by a massive cast armor mantlet, encasing the machine-gun watertank.
Ammunition for the main gun was 46 rounds stowed horizontally in the rear of the turret with 74 rounds stowed vertically in two racks bolted to the hull floor under the turret basket. The turret was rotated either manually or via an electric power traverse. The traverse mechanism was a 40 volt system with current drawn from a dynamo in the transfer box linking the three engines to the main drive shaft. To ensure consistent power supply at variable RPM three shunt motors were provided to stabilize the current flow.
diagram of the Turret traverse mechanism of the AC I
Diagram of the turret traverse mechanism of the AC I. The main traverse motor and traverse gear is leftmost, manual traverse hand wheel, traverse control motor and sprocket linkage are on the right, Source: Australian Cruiser Mark I Instruction book
The manual traverse wheel was linked directly to the main turret traverse motor as well as to the traverse control motor via a sprocket linkage. Under manual power the traverse motor armature was immobilized via a solenoid brake. This meant that the gunner did not have to overcome additional resistance from the turret motor while using manual traverse. For power traverse a grip trigger on the traverse hand wheel disengaged the manual gearing and engaged input to the control motor via the sprocket linkage.
An interesting feature of this setup was that the turret control motor possessed a separate control hand wheel that could be used to run the main traverse motor at a constant rate. This allowed for a technique where the gunner could set the traverse mechanism to run at a constant rate and then, using manual traverse, cause the turret gearing to ‘run back’ in order to make precise adjustments to aim while rotating the turret. This feature was touted as being beneficial to making accurate shots against moving targets.

AC I Sentinel
Australian Cruiser Tank Mark I (AC I) number 8013 during tests near Sydney, early 1943. A design influenced by the British Crusader and the M3 Lee, using local and US tank parts. Despite having stronger armor than the British Cruiser VI, this model was never tested in combat. In a what-if scenario, they would have not even been ready for action in Tunisia.


Despite the streamlining of the AC I and using many parts already available from other tank designs, the development took time. The automotive prototype of the definitive design, entitled E1, came out in January 1942. In February 1942, a memo was issued from the Army Director of AFVs, Lt.Colonel Crouch, officially formalising the name of the AC I as Sentinel.
The second prototype, E2, arrived in March of 1942. Armor casting was conducted at the Bradford & Kendall foundry annex in Alexandria, Sydney. Hulls were cast in hand packed sand moulds before being transferred to the first of 6 electric tempering furnaces. Hulls were produced at a rate such that each hull moved to the next tempering furnace in the series in time with a fresh hull being removed from the mould, for a total rate of 5 hulls per week.
Armoured Fighting Vehicles Production Alfred Reginald Code inspect the AC I E2 prototype
(From left to right) Minister of Munitions Norman Makin, Field Marshal Sir Thomas Blamey and Director of Armoured Fighting Vehicles Production Alfred Reginald Code inspect the AC I E2 prototype at a demonstration of AFVs at DAFVP headquarters, Fishermans Bend, Port Melbourne Victoria. April 1942. Source: Australian War Memorial
An industrial mould packing machine was purchased from the USA but shipping delays meant that it did not arrive until late 1942 at which point the Bradford & Kendall foundry men were confident that they could hand pack the moulds at the same rate as the machine. It therefore went unused. Assembly of AC I tanks was contracted to New South Wales Government Railways with work carried out at Chullora Tank Assembly Workshops at Chullora, Sydney.
The Chullora Tank Assembly Workshops were repurposed for construction and maintenance of rail stock post war, and still exist to this day. The first production vehicle (no. 8001) arrived in July of 1942. The first 12 vehicles delivered were found to suffer from temper brittleness, which caused certain pieces of casting to inconsistently harden during the tempering process. As a result, the armor of these tanks was deemed potentially unreliable and subsequently labelled as ‘unarmored’.
An additional post tempering water quench was introduced to solve the problem in subsequent hulls produced. ABP4 plate was evaluated as being equal in resistance to British cast armor and slightly less hard than American cast armor, while displaying remarkably low levels of spalling or flaking on impact.
The first allotment of tanks began trials in August 1942 with trials completing in January of 1943. Full production of AC I tanks totalled 65 and the 2 prototype machines, delivered to the Army from November 1942 to June 1943. Despite delivery to the Army, no AC tanks were accepted for active use by Australian units. As such, no tanks were issued with Army Vehicle Registration Numbers (AVRN).
Standard camouflage for AC I tanks was the mid 1942 Australian two tone camouflage scheme of light stone base with green swatches. An additional interesting feature for a cruiser tank was the installation of a Graviner methyl bromide fire suppression system in the engine bay, which could be activated either manually by the driver or automatically by flame switches in the engine bay.

Photo of the turret ring, ammunition stowage, and engine setup. The transfer case is the rectangular object in the lower centre of shot, the front two engines and rear engine drive shaft can be seen through the access hatch on the fighting compartment firewall. Source: Ed Francis
Chullora Tank Assembly Workshop, January 1943
Chullora Tank Assembly Workshop, January 1943. Sentinel tank hulls can be seen progressing down the production line on the left with accompanying turrets on the centre line. Completed tanks are present on the right. M3 Lee tanks are also present undergoing refits and refurbishment. Source: NSW state records

Never tested in combat

The termination of the entire Australian Cruiser program in mid-1943 was dictated by a mixture of practical and budgetary reasons as well as an ongoing political rivalry between the Ministry of Munitions and the Army. Testing of the AC I tanks had revealed several issues with the vehicles, some major and others sundry.
The main issues consisted of problems with cooling the triple Cadillac engines, weaknesses in the turret traverse mechanism (this was due to the turret being balanced for the weight of a 6 pounder gun and therefore being unbalanced when fitted with the 2 pounder), and unacceptably high rate of wear on the road wheel rubber. Granted, many similar problems were common in the early models of a lot of tanks, and the DAFVP were confident that they had identified the causes of the problems and could rectify them, but the delays to production that these problems entailed were ultimately too severe and too costly to be acceptable to the Army and Government.
The Lend-Lease authorities in the USA had also become increasingly sceptical of the Australian tank program and it was considered that the resources used in producing Australian tanks could be better used in maintaining and expanding Australia’s increasingly neglected rail network, in order to better support the increasing Allied presence in the country.
Considering that the proven M4 Sherman was now available in substantial quantity from the USA and the decreased threat of the Imperial Japanese Navy to Allied shipping it was argued that imported vehicles were a more cost effective and immediate means to fulfil Australia’s armour requirements. Entreaties were made to divert an allotment of M4 tanks from stocks earmarked for delivery to the UK, however only 2 M4 tanks arrived in Australia for tropical testing and were subsequently transferred into custody of the Army.
Both M4 tanks are now on display at the Royal Australian Armoured Corps museum at Puckapunyal base, Victoria. Additionally, Australia was now fully committed to a war in the Pacific and the idea of an African or European campaign against German and Italian forces was a distant memory.
In 1943, the need for tanks was seen as drastically lower in the Pacific theatre and the experience of facing German anti-tank guns in North Africa had diminished the perceived effectiveness of tanks. As a result, the requirement for tanks had been reduced from 859 to 434 and the majority of Australia’s nascent armoured divisions had been disbanded.
Due to the lack of need to equip armored units, the entire stock of AC I tanks was never shipped abroad, but kept for training and testing purposes instead, then placed into storage until being declared obsolete after the end of the war.
A few tanks operated by crews from the 3rd Army Tank Battalion made an appearance (under German colours) during the 1944 “Rats of Tobruk” movie, firing blank shells. After the war, all but three AC tanks were sent for scrap although some hulls were modified and refitted with commercial engines for use as cheap industrial or agricultural tractors.
Surviving AC I Sentinels are displayed today at Bovington and Puckapunyal museums, as well as an example constructed from a salvaged hull and turret on display at the Australian Armour and Artillery Museum.

An article by Thomas Anderson


AC I in trials
Sentinel AC I tank undergoing trials. Source:- Australian War Memorial 101156
Sentinel Tanks on exercise
Sentinel AC I tank on exercise.
Preserved AC I on display at the RAAC museum
Preserved AC I on display at the RAAC museum – Credits: Wikimedia Commons

AC I Sentinel specifications

Dimensions 6.32 x 2.77 x 2.56 m
(20’9” x 9’7” x 8’4”)
Total weight, battle ready 28 tons
Crew 5 (commander, loader, gunner, driver, machine gunner)
Propulsion 3 x V8 Cadillac 330 hp total, 12 hp/t
Suspensions Horizontal volute springs (HVSS)
Max speed 48 km/h (30 mph)
Range (max) 240 km (150 mi)
Armament : 2-Pounder QF (40 mm/1.57 in), 130 rounds
2x Vickers .303, (7.9 mm) 4250 rounds
Armor From 45 to 65 mm (1.77-2.56 in)
Total production 65

Links and Resources

Australian War Memorial Archives
The AC Sentinel on Wikipedia
Tank Hunter