Tankspot 9: Sentinel AC I & Sentinel AC IV

Sentinel Mk. I

The Sentinel 1 was designed in Australia in WW2 in response to the war in Europe, and to the threat of Japan expanding the war to the Pacific or even a feared Japanese invasion of Australia. It was the first tank to be built with a hull cast as a single piece, and the only tank to be produced in quantity in Australia. The few Sentinels that were built never saw action as the armoured had been equipped by that time with British and American tanks.

In world of tanks this tank would probably be a tier 3-4 premium medium for the British tech tree.

Known Stats:

Tier: 3-4

Classification: Medium

Tech Tree: Premium

Gun Type: 2pndr Canon

Wikipedia Information: The AC1 began as a 2 pounder gun-equipped design in November 1940, and was initially intended to be a true Cruiser tank. Like the Canadian Ram the Australian Cruiser was to be based on the engine, drive train, and lower hull of the American M3 Medium tank, mated to an upper hull and turret built closely along the lines of a British Crusader. By 1942, trying to keep pace with German tanks, the design specification had become more like an American medium tank.

Due to a lack of home grown experience in tank design a mission was sent to the US to examine the M3 design and Colonel W.D. Watson MC, an artillery officer with many years tank design experience was provided by the UK. He arrived in December 1940.

The Australian Cruiser tank Mark 1 (AC1) was designated "Sentinel" in February 1942. Fabrication was by Sydney's Chullora Tank Assembly Shops with serial production vehicles emerging in August 1942, the premises also being used as a testing ground. The design used existing parts where available from other tank designs, simplified where necessary to match the machining capacity present in Australia. The hull was cast as a single piece, as was the turret; a technique not used on the hull of any other tanks of the era.

The original vehicle was designed to mount a QF 2 pounder this was later changed to a QF 6 pdr (57 mm, 2.25 in). However none of these were available and the first 65 tanks were built with the 2 pounder. Two Vickers machine guns were carried as secondary armament, one in the hull and a second mounted coaxially beside the main gun. The preferred engines suitable to power a 28 tonne tank, a Pratt & Whitney Wasp single row petrol radial, or a Guiberson diesel radial, were not available within Australia, so the Sentinel was powered by the combined output of three Cadillac 346 in³ (5.7 L) V8 petrol car engines installed in clover-leaf configuration (two engines side-by-side to the front and a single to the rear: all three feeding a common gearbox). Sixty-five production vehicles had been completed by June 1943.


The Sentinel AC IV
The AC IV was an upgunned version of the Mk. 1. It was experimented with a 17pnder and 25pndr gun. This tank would be around the same tier as the TOG II* or higher because of its slightly similar characteristics of low armour / great gun.

Known Stats:

Tier: 6-7 

Classification: Medium

Tech Tree: Premium

Gun Type: 17pndr Canon / 25pndr Canon

Crew: 4

Weight: 30 tonnes

Engine: Perrier-Cadillac (397 bhp)

Maximum speeds:

1st 6km/h (3.5 mph)

2nd 12km/h (7.3 mph)

3rd 23km/h (14.3 mph)

4th 42km/h (26.3 mph)

5th 56km/h (35 mph), 

Reverse 6km/h (4 mph)

Status: Intended for production. Design incomplete. 400 ordered.