Britain Cruiser Mk VI (Crusader III AA MkI)

World War 2 Tank and Gun Database

The Cruiser Mk VI was a Self Propelled Anti Aircraft vehicle designed in 1942, manufactured by Nuffield, it was based on the fully tracked A13 III(Covenanter) chassis and was in use from 1942 to 1945. It was commonly called a Crusader III AA MkI.

Photo of Cruiser Mk VI (Crusader III AA MkI)

Menzies (Cpl) War Office official photographer, Public domain, via Wikimedia Commons

General Details (SP Anti Aircraft)

Specifications
Operational Date(s)	1942 - 1945
Ordnance classification	A15
Quantity Produced	5300
Weight	20 tonne
Crew	3
M.G's small	n/a
M.G's large(>10mm)	n/a
Length	6.05 mtr
Width	2.66 mtr
Height	2.62 mtr
Engine Details/Performance
Max Road Speed	28 mph
Max Cross Country Speed	15 mph
Range Road	112 miles
Range Cross Country	44 miles
Fuel Type	Petrol
Fuel Capacity	120 gal
Horse Power	340 hp
Power/Weight	17 hp/tonne

General Information

The Cruiser Mk VI was a Self Propelled Anti Aircraft vehicle designed in 1942, manufactured by Nuffield, it was based on the fully tracked A13 III(Covenanter) chassis and was in use from 1942 to 1945. It was commonly called a Crusader III AA MkI.

The vehicle was powered by Nuffield 'Liberty' petrol powerplant producing 340 HP which could drive the vehicle on roads at up to 28 mph with a range of about 112 miles before refuelling. Its cross country performance was good providing a max speed of about 15 mph and a range of about 44 miles.

Its main armament consisted of an Bofors 40 mm L/60 weighing 0.950 kg.

The Crusader tank was a redesigned A13 Mk III as a heavy cruiser tank that could rapidly move and provide good A/T performance.

The Mk I AA turret was a plain shape that held the 40mm Bofors AA gun. The auxiliary machine gun turret was removed in the MkIII Crusader.

Armour Details

Turret
Front	49mm	@	7°	(49mm)
Side	24mm	@	45°	(34mm)
Rear	30mm	@	32°	(35mm)
Top	12mm	@	90°	(12mm)

Superstructure
Front	20mm	@	60°	(40mm)
Side	14mm	@	0°	(14mm)
Rear	14mm	@	11°	(14mm)
Top	7mm	@	90°	(7mm)

Hull
Front	20mm	@	45°	(28mm)
Side	14mm	@	0°	(14mm)
Rear	14mm	@	11°	(14mm)
Top	7mm	@	90°	(7mm)

Armour (x)mm @ (y)° (Effective mm @ 0°)

Effective Armour - Maximum 49 mm - Minimum 7 mm


Weapon Details
	Bofors 40 mm L/60 (Anti Aircraft)

		History
		Designed in 1930 in Sweden the Bofors had two variants the L/60(really L/56) and the L/70 which didn't reach production till 1948, so the data shown is for the L/60 version.
		Manufacturer	Bofors
		Manufactured	1932 - Present
		Calibre	40mm
		Length	L/56
		Rate of Fire	120rpm

Ammunition Details
Name/Id	Calibre Weight MVelocity					Explosive Content
40 × 311 mm R (HE High Explosive)	40mm 0.95Kg 850M/Sec					≈0.143Kg explosive
Range(Mtr)	1000	2000	3000	4000	5000	6000	7000	8000
Flight Time(Secs)	1.39	3.2	5.33	7.69	10.2	12.77	15.36	17.93
lateral dispersion means the side to side variation of the shell from the aiming point
50%(CEP) of shells land within +/- (mtr)	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
80% of shells land within +/- (mtr)
95% of shells land within +/- (mtr)
range dispersion means the back to front variation of the shell from the aiming point
50%(CEP) of shells land within +/- (mtr)
80% of shells land within +/- (mtr)
95% of shells land within +/- (mtr)
Direct Fire
Range(Mtr)	100	200	400	800
Flight Time(Secs)	0.12	0.25	0.52	1.13
Hit Probability(%)	79	79	76	71
Blast/Fragmentation Effects
Burst radius Infantry in open 99% kill	2 mtr	Burst radius Infantry in open 66% kill						5 mtr
Burst radius Infantry in open 33% kill	13 mtr	Armour Penetration inc roof at 1 mtr						0 mm
An explosion within 2 mtr of infantry in the open will cause 99% casualties - lethal.
An explosion within 5 mtr of infantry in the open will cause > 66% casualties and could damage some AFV's.
An explosion within 13 mtr of infantry in the open will cause 33% casualties.
The blast effect of this shell exploding within 1 mtr of an armoured vehicle will not cause any significant armour damage.

About Penetration Figures

All penetration figures in this database are calculated to a common standard based on German WWII testing criteria (complete penetration with functioning fuze). This allows direct comparison between all nations' guns.

Original national test figures would be higher for some nations due to different criteria:

German: 1.00? (baseline - strictest)
British: 1.02? (slightly looser)
American: 1.05? (50% mass through plate)
Soviet: 1.10? (75% mass through plate)

For example, a Soviet gun showing 159mm here would be published as ~175mm in Soviet documents, and a German gun showing 120mm would be published as 120mm in German documents. The 159mm figure is directly comparable to the German 120mm - the Soviet gun really was more powerful.

National Testing Standards
German:	1.00? - Complete penetration, fuze functions (strictest)
British:	1.02? - Complete penetration
American:	1.05? - 50% of shell mass through plate
Soviet:	1.10? - 75% of shell mass through plate
All database figures are normalized to German standard for direct comparison. Multiply by the factor above to see original national test figures.

Hit probability is based on a static 2 x 2.4 metre panel at 0 degrees(vertical) at the range specified.

The data that has been used to create these records has come from Wikipedia, The Lone Sentry, The Bundes Archive and numerous books and websites that have provided the detailed information that has not been available anywhere else. The information we use to calculate the penetration tables, flight times and the hit probability comes from the Gun Calibre, the Shell Mass(Kg) and the muzzle velocity, plus range reductions to allow for gravity and wind resistance. This calculation originally came from a pre-war Krupp calculation which has been modified, and seems to fit the actual test results.