The Kranvagn - Sweden's Autoloading Heavy Tank - Tank Historia

The Kranvagn – Sweden’s Autoloading Heavy Tank

Sweden is not often thought of for its tank designs, but when it does make one, its almost guaranteed to be unique. The Kranvagn is no exception.

This 45 ton tank featured a pike-nose and a powerful 105 – 150 mm gun placed into an oscillating turret. Visually, the Kranvagn is an interesting looking vehicle.

The tank is relatively unknown, but has become a familiar sight to players of the popular game World of Tanks, where it is infamous for its nigh-impenetrable turret and impressive gun depression.

Contents

Background

Like so many other tanks from this era, the Kranvagn was influenced mostly by WWII and the IS-3.

WWII was arguably the most important period for tank development during the 100-plus years they have existed.

In just five years nations saw their tanks grow from small, light vehicles to powerful machines that incorporated armor, mobility and firepower all in one package.

This was not the case for Sweden though.

As a neutral country they had been side-lined by the main combatants in terms of tank development.

In 1943 they got their hands on a Soviet T-34, which was more than a match for their Strv m/42 tank.

A Strv M/42
The Strv m/42 was a decent design, but no match for later war vehicles. Image by Jorchr CC BY-SA 3.0

They knew they needed something better, so a number of tank projects were started. One of Sweden’s main desires for new tanks were speed and a high rate of fire.

When the war ended they received many of the latest vehicles – including a Tiger II from France – allowing them to inspect the very best tanks WWII had to offer.

With these, they quickly discovered that many of their native designs were simply obsolete against these tanks.

Meanwhile, the rest of the West were panicking about the newly unveiled IS-3 heavy tank.

The sight of these heavily armored and armed vehicles rumbling down the Charlottenburger Chaussee at the Berlin Victory Parades of 1945 was one of the most significant moments of the post-war period.

IS-3s at the Berlin Victory Parade of 1945
Soviet IS-3s roll along Charlottenburg Chaussee in Berlin during the Berlin Victory Parade of 1945.

Tanks like the Conqueror, FV215B 183 and M103 were designed specifically to counter the IS-3.

The IS-3 would end up proving to be a rather lacklustre design, but it shook the west to its core and impacted tank designs for years to come.

The Swedes first got wind of the IS-3 in 1950, and they too wanted to be able to stop it. Defeating the IS-3 would remain a constant goal in the future Kranvagn project.

A design based on the Strv m/42 carried a 105 mm gun, which was meant to be able to deal with the IS-3. However the direction of Sweden’s design was changed dramatically by France’s latest tanks.

A Run in with the AMX 50

Swedish engineers learned of France’s large heavy tank, the AMX 50, in the early 1950s. They were able to study both the AMX 50 and the AMX 13 light tank in great detail, and learned a great deal.

The AMX 50 weighed well over 50 tons – far too much for the Swedes – but it had some features that interested them; most notably its oscillating turret and autoloader.

The mighty AMX 50
The Kranvagn was influenced by the AMX 50, itself influenced by late war German tanks.

Its ammunition was stored in an overhanging rear turret bustle, and was loaded automatically into the gun. This design saved weight and reduced its overall size, while enjoying the obvious benefits of a fast firing autoloader.

In addition, strategically placed armor and a good power to weight ration meant the 60 ton AMX still had good mobility.

Impressed by these features, Sweden’s engineers began work on a completely original IS-3 killing design.

EMIL

One of the first designs made by the Swedes using these new features was a tank called EMIL. This vehicle was a drastic departure from usual Swedish designs, but still maintained characteristics important to them, like good mobility and a relatively low mass.

This vehicle featured a low-profile hull and an oscillating turret – complete with a 120 mm autoloading gun.

This L/40 gun fired HEAT rounds and therefore could be much shorter in length. HEAT rounds do not rely on velocity for penetration, making a shorter barrel possible.

Blueprint of the EMIL from 1951.
A technical drawing of the EMIL, drafted in 1951.

Thanks to its autoloader the EMIL would have had a fire rate of up to 40 rounds per minute.

Its armor was concentrated on the front, with a maximum of 120 mm on the hull and 170 mm on the turret.

Despite its heavy armor the tank would have weighed around 28 tons – thanks to its small size – and was powered by a 550 hp Volvo engine.

Its oscillating turret may have looked similar to France’s designs, but it was actually completely unique.

1951 blueprint of the EMIL, precursor to the Kranvagn
Thanks to its small size, the EMIL could carry plenty of armor and still remain reasonably light.

The AMX-50’s turret was constructed from two main parts: the lower section, which rotated the turret, and the upper section, which contained the gun and its autoloader.

In contrast, the entire front face of the EMIL’s turret was fixed in place, with the gun poking through it. This made it exceptionally well protected, reduced the chances of the turret being jammed and allowed for an excellent gun depression of 14 degrees.

Growing in Size

When all this began back in the 1940s the Swedes wanted a compact tank, but as changes were made to the design the EMIL started to grow in size, reaching 35 tons by the end of 1952.

Meanwhile, the Swedes were running out of time, with estimates that the first prototype wouldn’t be completed until 1955, and production wouldn’t start until 1958.

In 1952 the Swedes decided that the tank should have an IS-3-inspired pike-nose.

EMIL blueprints.
1954 blueprints of the tank’s hull. Note the pike-nose.

The following year Sweden began discussions with France to order AMX 13 tanks, but they soon realised that these vehicles were not suited to Sweden’s needs.

Talks with Britain, on the other hand, ended in an order for Mk 3 Centurions. Although they weren’t ideal – chiefly because of their size and weight – they solved Sweden’s need for a new tank.

However work on the EMIL continued, and by now it was barely recognisable to its original form.

Its gun increased to 67 calibres, while its frontal armor was thickened. Overlapping wheels were tried – and eventually thrown out – and a number of different engines were investigated.

Over the course of these changes the tank grew to a weight of 42 tons and had completely changed shape.

A Centurion Mk 3, a tank that solved Sweden's tank problem.
After taking deliveries of British Centurion Mk 3s, Sweden’s tank problem was solved. Image by Nilfanion CC BY-SA 4.0.

Its weight gain was not desirable, but had been permitted by Sweden’s securing of powerful engines in the 900 hp range.

Plans for the vehicle were completed in 1954, over a decade after Sweden’s first encounter with the T-34.

This final version’s upper hull armor 145 mm, and its side and rear armor was 40 mm. The turret face was 170 mm thick, while its side armor was 70 mm.

The frontal protection was chosen specifically to defeat rounds from the IS-3.

It would have either had a 105 mm, 120 mm or a 150 mm gun. With a weight of 41.8 tons, the tank was still quite mobile.

Finally, the Kranvagn

By this point the vehicle had little future as a tank, but the construction of two hulls went ahead anyway.

In 1956 the tank was still a closely guarded secret, and as such was given the cover name Kranvagn, or KRV, literally meaning “mobile crane”.

A Kranvagn suspended in the air.
The Kranvagn’s hull with a view of its belly and assembled tracks.

The Kranvagn weighed almost as a much as the Centurion, but was much smaller in all dimensions and had a much more powerful engine, which gave it a top speed of around 37 mph.

Due to issues with the proposed 105 – 150 mm guns, neither the turret nor the gun were ever completed, so the hull was tested with a dummy turret that represented the weight of a turret.

In tests the hull performed well, with thick frontal armor and good mobility, but without its intended turret, the Swedes racked their brains on what to do with this vehicle.

A Kranvagn hull with a test turret.
The Kranvagn hull with a dummy turret for mobility trials.

There was an idea to place the a Centurion Mk 10 turret onto the chassis, as the turret and 105 mm L7 gun were both very capable. This would also have solved the Centurion’s poor mobility.

However as with many of these sorts of ideas it was soon thrown out, with Sweden simply opting to buy whole Centurion Mk 10s.

In the end, it would never become the heavy tank it was designed to be. But it still wasn’t useless.

Partially assembled Kranvagn hull.
Kranvagn prototype hull during construction.

One of the two chassis was converted into a crazy self-propelled gun, that carried a 155 mm gun with a rapid fire rate of 14 rounds in 45 seconds – a world record.

This vehicle, known as the Bandkanon, was in service until 2003.

Meanwhile the second chassis was used as a test rig for Sweden’s newer Strv 103, better known as the S-Tank.

Strv 103 test rig.
The hull of the Kranvagn – minus four road wheels – acting as a test rig for the Strv 103 tank.

Today, this hull is in storage at the Swedish Tank Museum.

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Another Article From Us: Oscillating Turrets – How They Work

Without a turret or even a finalised armament its impossible to tell how the Kranvagn would have performed, but it is likely that it would have been a highly mobile asset on the field.

Frontally, and especially when hiding its hull, the vehicle would have been a formidable opponent to face in combat.