BT-42

Infobox Weapon
is_vehicle=yes
name=BT-42


caption=BT-42 in Finnish Tank Museum
origin= flagicon|Finland Finland
type= Assault gun
service=
used_by=
wars= Continuation War
designer=
design_date=
manufacturer=
unit_cost=
production_date=
number= 18
variants=BT-43
crew=3
length=5.7 m
width=2.1 m
height=2.2 m
weight=15 tonnes
armour=6–13 mm
primary_armament=114 mm (4.5-inch) howitzer
secondary=
engine=M-17T
engine_power=500 hp (370 kW)
suspension=Christie
speed=53 km/h
pw_ratio= hp/tonne
vehicle_range=375 kmThe BT-42 was a Finnish assault gun, constructed during the Continuation War. It was constructed from captured Soviet BT-7 light tanks and British 4.5-inch howitzers (114 mm-calibre light howitzer, model 1908) from 1918, which had been donated during the Winter War. Only eighteen vehicles were constructed.

History

As the Second World War progressed, the Soviets were fielding better and better tanks. The Finnish Army, on the other hand, had to make due with a large number of captured tanks, which were for the most part lightly armored and armed.

The Finns decided to redesign the BT-7 model 1937 tank. They constructed a new turret and armed it with British-made 114.3 mm howitzers that had been supplied by the British during the Winter War (Q.F. 4,5 inch howitzer Mark II, also known as 114 Psv.H/18 in Finland). The Finns constructed 18 BT-42s and these were pressed into service in 1943.

The BT-42 saw action for the first time in 1943, at the river Svir, where it was used to take out enemy pillboxes. The design worked reasonably well against soft targets but was completely unsuitable in the anti-tank role. To counter this, the Finns copied a German-designed HEAT grenade for the gun, and it was initially thought that it could defeat the sloping armour of the T-34, however, this was not the case. [The Finnish HEAT shell was called "114 hkr 42/C-18/24-38 is 32-18/24" and it was equipped with a German-made "10.5 cm Hl/C" warhead. The German 10.5 cm HEAT grenade, which it had been modelled after, could penetrate 100 mm of steel at a 60-degree angle. Thus it was estimated that the Finnish shell, with its larger calibre, could penetrate 110-115 mm, but this was not to be the case. This was all attributed to the short-barreled, low-velocity character of the gun.] The BT-42 quickly became very unpopular among its crews. Its mechanical weaknesses could mainly be attributed to the tower, which apart from giving the tank a high profile also added significant weight to the vehicle, stressing the suspension and the engine.

The BT-42s were used again during the major Soviet offensive in 1944. They were deployed in the defence of Vyborg but were unable to stop the advancing Soviet forces. The BT-42 would suffer heavily during the fighting. At one point, a Finnish BT-42 managed to hit a Soviet T-34 18(!) times, failing even to immobilize the enemy vehicle. The Finns lost 8 of the 18 vehicles engaged without having made any significant contribution to the fighting. It should however be noted that the Finnish armored units were still comprised of old T-26s, T-28s, and BT-42 AFVs, and that all of these suffered losses during these days (including 25 of the 87 T-26s and a third of all A-20 artillery tractors). German emergency supplies of PzKpfw IVs, StuG IIIs and captured T-34s made it possible for the Finns to replace its aging tanks for more efficient ones. The BT-42 was retired soon after the Vyborg battles and was replaced in the role by German-made StuG IIIs.

BT-43

In March 1943, the Finnish armoured division suggested that 20 BT-7s should be redesigned into armoured personnel carriers. The Finnish HQ gave its approval sign on 18 May 1943, but limited the number of vehicles to 14. A prototype was designed my removing the turret of a BT-7 and by constructing a wooden platform on top of the chassis. Additional hatches were also installed to allow easier embarking and disembarking of the vehicle. The BT-43 prototype was tested in November 1943, but series production was never started. The single prototype was scrapped in May 1945. Not a single photograph has survived of the vehicle.

Footnotes