The M51 is arguably the best example of upgrading a piece of equipment far beyond original expectations to meet new requirements. It is also perhaps the greatest proof of the Sherman’s excellent and adaptable design.
Nearly 20 years after the first Shermans rolled off the production line Israel modified around 180 of their own to carry an enormous 105 mm gun. This was nothing like the 105 mm howitzer used on Shermans during WWII, but a long, tank killing weapon designed by the French.
With gun barrels almost as long as the tanks themselves, these once-obsolete Shermans became a formidable force in Israel’s arsenal, which were able to punch through the very newest tanks.
The iconic M51 fought in a number of wars and remained in service for decades.
Development of the M50 and M51
As a relatively young country, Israel was under a constant threat of war with its Arab neighbours in the years after WWII.
Soon after its 1948 independence, the country formed the Israel Defense Forces (IDF) to serve as the military component of the nation.
However at this time the IDF fielded few heavy vehicles, mostly using armored cars and jeeps captured or supplied from all over the world.
This was a similar story for their Sherman tanks. Shermans began arriving in Israel in the late 1940s, and despite being obsolete for a major power such as the US, were still extremely useful for the IDF.
In 1953 a group of Israeli representatives visited France and inspected their new AMX-13 light tank. This tank only weighed around 15 tons, but carried the powerful CN 75-50 75 mm gun.
Side note – it is often said that this weapon was a French version of the Panther’s KwK 42 75 mm gun, however the two guns are actually very different. In reality, the French CN 75-50 was likely only partially “inspired” by the the Panther’s gun.
Israel was impressed with this gun and placed an order for 400. Soon they realised that this gun could be adapted for use in their stocks of the Sherman tank, greatly increasing its firepower.
France helped lay the groundwork of the project by modifying a Sherman 75 mm gun turret to receive the CN 75-50 gun. The following year Israel started converting their Shermans themselves with this guidance, creating the Sherman M50.
Around 300 Shermans were converted to the M50 standard between 1956 and 1964.
These 75 mm armed Shermans performed admirably in the 1956 Suez Crisis, but the potential of facing IS-3s and Centurions in the near future concerned Israeli officials enough to search for an even more powerful gun.
At first they turned to foreign designs like the US M47 and British Centurion, but the US refused to sell and Britain didn’t have the capacity to fulfil Israel’s requests. Britain eventually agreed to sell their Centurions in 1959, but these were only the 20-pounder versions.
This left Israel in a sticky situation: it would be a while before they received Centurions in any appreciable amount, and even when they had them they lacked the 105 mm guns Israel wanted to handle the bigger tanks.
War was coming and they needed 105 mm guns.
With time running out, Israel once again looked to their ageing fleet of Sherman tanks. Thanks to their previous experiences with French engineers, they approached the Bourges Arsenal in France for help.
Israel presented their requirements to France, who then got to work creating a vehicle to suit their needs.
Two prototypes were soon built on the chassis of the M4A1 (cast hull) Sherman tank. These were fitted with the older (relatively speaking) VVSS suspension and Continental R-975 radial petrol engine.
The turrets were heavily modified to fit an enormous 105 mm gun – the Modèle F1.
This was the same gun as used in the French AMX-30 main battle tank and was tremendously powerful. Naturally, such a gun was never designed to fit in a tank like the Sherman, but the French made it work.
The turret used for this was the T23, a type originally designed for the T23 medium tank. The T23 medium was a proposed replacement for the Sherman, but would eventually evolve into the M26 Pershing.
The T23 turret was introduced onto the Sherman in 1944, armed with the 76 mm M1 gun. It was roomier than the previous D50878 and D78461 turrets used on 75 mm Shermans, enabling the use of the French 105 mm.
A large cast iron counterweight was attached to the rear of the turret to balance the rotating mass.
However the power of this gun soon proved to be too much for the Sherman tank to handle, resulting in the French creating a slightly shorter version of the gun with a lower muzzle velocity. This was designated the D.1508 and was fitted to the second prototype.
Despite its formidable size, its most distinct feature was its huge muzzle brake, added to help reduce some of the gun’s immense recoil.
As this was a modified version of the AMX-30’s Modèle F1, the two guns could fire the same projectiles, namely high explosive anti tank (HEAT).
The prototype was known as the ‘Revalorisé’ in France, which meant “upgraded”.
With this successful prototype, Israel introduced the tank into service as the M51 – albeit with some changes to the hull and running gear.
After France’s initial prototypes, the conversions were carried out in Israel.
Like the Revalorisé, the M51 was built on the cast hulls of M4A1 Shermans, although a few M4A3 hulls were used too. The M4A1 was powered by the Continental R-975 radial engine, which produced around 400 hp, while the M4A3 was powered by the Ford GAA V8, which produced around 450 hp.
The use of cast Sherman tank hulls were a specific choice, as these hulls were more spacious inside, allowing for more of the large ammunition for the 105 mm gun to be carried.
As the hulls were taken straight from Shermans, the armor thickness remained the same with 63 mm on the front.
The tank had a crew of five, but this was later reduced to four to better spread out Israel’s manpower. The hull machine gunner was removed, as was his .30 caliber machine gun.
Unlike the Revalorisé though, these units were equipped with the “newer” horizontal volute spring suspension (HVSS) and wider tracks. The bogies on this type of suspension compressed horizontally, as indicated by its name.
The design enabled the use of shock absorbers to smoothen the suspension’s behaviour, making the tank a more stable platform to fire from. In addition, each arm on the HVSS suspension was fitted with two side-by-side road wheels, enabling much wider 23 inch tracks to be used.
The suspension added 1.5 to 2.4 tons of weight to the Sherman tank, but the vehicle’s overall ground pressure was reduced, thanks to the wider tracks.
The first units still used R-975 engines as they did not have enough time to fit outfit them with more powerful powerplants.
The resulting vehicle was truly a marvel – an exceptional example of revitalising older equipment far beyond its original design requirements.
In most ways the M51 resembled the humble Sherman it was built upon, but its enormous gun meant this upgraded version was anything but humble.
The gun protruded from a new, custom made mantlet on the front of the T23 turret (which was originally designed to accommodate a 76 mm gun). Four smoke launchers were fitted to the turret cheeks and a large lamp was mounted above the mantlet.
The sides of the hull above the mudguards were covered in spare wheels, track links, jerry cans and storage bins.
A large travel lock for the main gun was fitted on the engine deck.
Near the end of the 1950s Israel experimented with a Cummins VT-8-460 V8 turbo-diesel engine. This produced 460 hp, much more torque and had much better fuel consumption than their pre-existing R-975 radial engines.
The diesel fuel also had a lower chance of igniting when hit.
Israel had swapped these V8s into all of their M51s by 1965. In total around 180 M51s were built.
All in the M51 weighed 40 tons and had a top speed of 25 mph.
Israel’s M51s saw plenty of action over the next few decades. Despite their completely outdated chassis, their 105 mm guns were capable of dealing with the latest Soviet armor.
Arguably the M51’s most famous action occurred in 1967 during the Six Day War, where it served alongside its M50 siblings. Israeli tankers were highly trained, especially in engaging targets at ranges of 1,500 meters.
In the West Bank, Sinai peninsular and Golan Heights they faced massive numbers of T-34-85s, T-54s, T-55s and T-62s.
All of these except the T-34-85 were vastly more modern and capable designs on paper, but were turned into smouldering wrecks by Israeli crews in their up-gunned Sherman tanks.
The 105 mm gun’s HEAT rounds proved to be capable of punching through the frontal armor of the T-62 in these engagements.
In one engagement on the night of June 5th 1967, M50s and M51s climbed Burquim Hill. In the pitch black, one Sherman crew noticed a disturbance ahead of them in the dark.
They switched on their spot light above the gun, which illuminated a whole Jordanian armored company of M47 Pattons less than 50 meters away.
The two groups fired on each other, and despite being in the older tanks, the Israelis managed to knock out 12 M47s for the loss of just one M50 and no crew.
Interestingly, Shermans once again engaged with Panzer IVs two decades after the end of the WWII when M51s clashed with Panzer IVs in the Golan Heights. Its safe to say that the Shermans’ 105 mm guns made quick work of the Panzers.
M50s and M51s were used again in the 1973 Yom Kippur War. Like the Sherman tank they were based on, crews appreciated them for their reliability, sturdiness, safety and comfort.
The M50s and M51s retired in the late 1970s and early 1980s, with the M51s remaining in service the longest.
Israel provided over 70 to supported militias during the 1976 Lebanese Civil War. Another 100 were sold to Chile, who made further modifications and used them until 1999. Incredibly, they remained in Chilean reserves until 2006.
The “Super Sherman” Myth
The name “Super Sherman” is often used by many sources – even this article – and model kits when referring to the M51. This, however, is not factually correct.
Israel never officially named their M51s, only identifying them as M51. Ironically they did name a Sherman variant the “Super Sherman”, just not the M51. This name was instead applied to earlier Shermans armed with 76 mm guns and HVSS suspension.
Despite this, the name has seen widespread usage outside of Israel to identify the M51, and the link between the two will likely never be broken.
So, in a way, it has since become the tank’s nickname. Indeed, it is certainly fitting for such a vehicle, one that was already a legend long before it carried a mighty 105 mm gun.