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Cruiser Tank Sentinel AC (Australian Cruiser)

1942 WORLD WAR 2

History of the cruiser tank Sentinel AC (Australian cruiser)

The Sentinel tank was an indigenous Australian design during World War II and emerged at a time when Australia lacked tank design expertise and manufacturing facilities for mass production designs and the greater threat of Japanese expansion into the Pacific to the mainland. So Sentinel was developed to fill that void, and by all appearances, it's an impressive design in its own right.

With the Japanese invasion of the Australian mainland never taking place and tanks pouring off assembly lines across the United States, Sentinel tanks appeared in limited numbers at one point and were eventually relegated to training Australian tank crews by the end of the war.

In 1939, the Australian government decided to update its list of insufficient weapons. Japan's expansion in the Pacific Ocean is ominous, and an invasion of Australia's north coast appears imminent. Australia has no manufacturing infrastructure to speak of, not even a sufficient auto industry to enable mass production of such vehicles, and its allies appear to be unable to meet Australia's current needs with additional weapons in their stockpiles. Also, Australia is hardly involved in any type of tank design.

Because of this, Australia set out to solve the problem, enlisting the help of British tank engineers and observing tank engineering practices while traveling to the United States.

Set out to create a competent design using as many components as possible from the American M3 General Lee tank series. This particular tank will be called the Cruiser Tank Sentinel and will be a successor to the original Sentinel AC1 (short for "Australian Cruiser 1"). During the development of the AC1, production facilities were also constructed and prepared.

The AC1 is armed with a 40mm (2lb) main gun and two 7.62mm machine guns for self-defense. Power comes from an astonishing assembly of three Cadillac engines coupled into a single powerplant system. Armor is cast throughout the design (2.5 inches thick in places) and requires a crew of up to 5 people for optimal operation.

The design features a sturdy hull with six wheels on each side. The main gun is built into the square turret. An attempt was made to improve the AC1 in the form of the AC2, but the former was given production rights.

A striking aspect of the Sentinel range is that it took only 22 months from paper to production.

Sentinel AC1 was prime-time ready in 1942, and the speed of development caused some minor flaws. Additionally, the 2-pdr main gun's armor was much thicker than it could possibly face, so the design was further developed in the form of the AC3. The Sentinel AC3 model series is equipped with a large 87.6 (25 pound) main gun, an artillery weapon that is already in production.

Despite its larger caliber, the gun was considered insufficient. The Sentinel AC3 was followed by the AC4 prototype - this model was armed with an Allied 76.2mm main gun (British 17-pounder), although by then the threat of invasion off the Australian coast had been all but eliminated as a distraction.

In addition, American tanks flew off overseas assembly lines and fell into the hands of Allied forces around the world.

Finally, the existing Sentinel units were used to train the Australian Armoured Forces throughout the war. Production stopped as suddenly as it started. As we all know, the Sentinel is often seen as a successful endeavor, although it can never be compared to the baptism of fire of its peers.

The system has a solid design, but more importantly, it forces the Australians to seek solutions to tank shortages from their own resources, updating their production infrastructure in the process.