Cruiser Mk I

Tank, Cruiser, Mk I (A9)
Tank, Cruiser, Mk I (A9)
Type	Cruiser tank
Place of origin	United Kingdom
Service history
In service	1938–1941
Used by	British Army
Wars	Second World War
Production history
Designer	Sir John Carden
Manufacturer	Vickers
Produced	1936–1941
No. built	125
Specifications
Weight	12 tons
Length	19 ft (5.8 m)
Width	8 ft 4 in (2.5 m)
Height	8 ft 8 in (2.65 m)
Crew	6 (Commander, gunner, loader, driver, 2x MG gunners)
Armour	6 - 14 mm
Main armament	QF 2-pdr 100 rounds
Secondary armament	3 x 0.303 Vickers machine gun 3,000 rounds
Engine	AEC 179 6-cylinder petrol 150 hp (110 kW)
Suspension	sprung triple wheel bogie
Operational range	150 miles (240 km)
Speed	25 mph (40 km/h)

The Tank, Cruiser, Mk I (A9) was a British cruiser tank of the interwar period. It was the first cruiser tank: a fast tank designed to bypass the main enemy lines and engage the enemy's lines of communication, along with enemy tanks. The Cruiser Mk II was a more heavily armoured adaptation of the Mark I, developed at much the same time.

In 1936, the British War Office designated two different kinds of tanks for future development: heavily armoured infantry tanks to be used in close co-operation with infantry during attacks, and fast mobile cruiser tanks designed to make forays deep into enemy territory.

In 1934, Sir John Carden of Vickers-Armstrong was asked to provide a "reasonably cheap tank" as a replacement for some of the medium models then in use. The pilot model of his design was finished in 1936 and given the designation A9E1.

It incorporated the best features of the earlier Mk III Light Tank, and was powered by a commercial petrol engine. However, this was still in the time of the Great depression and the tank had a number of cost-cutting measures applied. It was the first British tank to have a centrally located turret and to have powered traverse. The system was by Nash & Thompson and similar to that being introduced on the Vickers Wellington bomber aircraft. The armour was light, with a maximum of 14 mm thickness. Many armour faces were vertical, and there were numerous shot traps, but it could achieve 25 mph and carried the new high velocity QF 2-pounder (40 mm) gun.

The driver's compartment and the fighting compartments were not separated. As well as the turret armament, which consisted of an Ordnance QF 2 pounder gun and a coaxial Vickers machine gun, there were two small turrets either side of the driver's compartment, each with a Vickers machine-gun. Both of these smaller turrets were permanently manned, which gave the tank a total crew of 6 (Commander, gunner, loader, driver and two machine-gunners).