Sherman Firefly

Sherman Firefly
Sherman VC Firefly
Type	Medium tank
Place of origin	United Kingdom
Specifications
Mass	36 tons (33 tonnes)
Length	19 ft 4 in (5.89 m)
Width	9 ft (2.75 m)
Height	8 ft 7 in (2.62 m)
Crew	4 (Commander, gunner, loader / radio-operator, driver)
Armour	89 mm (turret front)
Main armament	OQF 17 pdr (76 mm) gun
Secondary armament	Flexible .50 Browning M2 machine gun (12.7 mm) Coaxial .30 Browning M1919 machine gun (7.62 mm)
Engine	Chrysler Multibank (5 x inline-6) petrol 425 hp
Power/weight	11.8 hp/ton
Suspension	Coil spring
Operational range	120 miles (193 km)
Maximum speed	25 mph (40 km/h)

The Sherman Firefly was a World War II British variation of the American Sherman tank, fitted with the powerful British 17 pounder anti-tank gun as its main weapon. Originally conceived as a stopgap tank until future British tank designs armed with the 17 pounder came into service, the Sherman Firefly in fact became the most common British tank fielded during World War II with the 17 pounder as its main armament followed by the 17 pdr SP M10 "Achilles".

Origins

The concept of fitting a 17 pounder gun into a Sherman tank had initially been rejected by the Ministry of Supply's Tank Decision Board because of its use of an American Sherman tank as a mount for the gun. The British Army had decided in early 1943 that, with the emergence of the new British tanks designs that at the time were to be superior to American supplied tanks, the British Army would once again start equipping their armor divisions with British tanks rather than American ones. This view was based on the fact the upcoming Cromwell tank was expected to mount the Vickers High Velocity 75mm gun (later modified to become the 77 mm HV and mounted on the Comet tank), a gun that was to have greatly superior anti-tank performance over the US 75mm and 76mm guns as well as a good high explosive shell, and the A30 Challenger, which was a modified Cromwell able to take the even more powerful 17 pounder gun . As a result, mounting a 17 pounder on a tank chassis the British were planning on retiring from service was not seen as desirable. .

Although there was no official backing for a Sherman mounting the 17 pounder, many individuals for a variety of reasons attempted to mount a 17 pounder on the Sherman tank. The earliest attempt to fit a 17 pounder gun into a Sherman Tank can be credited to Major George Brighty of Royal Tank Regiment while he was at Lulworth Armoured Fighting School in early 1943. Despite the fact the A30 Challenger was undergoing initial trials at Lulworth, Major Brightly seemed to be convinced the Sherman was a better mount for the 17 pounder. However he was stymied by the short, small turret of the Sherman which prevented the tall 17 pounder and its recoil cylinders fitting into the turret, as well as the very long recoil of the gun which prevented it from being able to fire within the cramped turret. In a rather desperate move, Brighty removed the recoil system and locked the gun in place, thus forcing the entire tank to absorb the recoil of the gun, but this was hardly an ideal situation and there was no telling how long the tank could handle such a set-up. .

Around this time in June 1943 a colleague of Major Brighty, Lt. Col. George Witheridge of the Royal Tank Regiment, arrived at Lulworth. A Tank Veteran of North Africa, Lt. Col. Witheridge had experienced first hand the imbalanced battles between British tanks armed with 2 pounders against Rommel's formidable Panzer's and Pak Guns. During the disastrous Battle of Gazala in mid 1942 Witheridge had in fact been blown out of his Grant tank, and though he recovered from his wounds he was declared unfit to return to duty. Instead in January 1943 he was posted to Fort Knox in the United States for six months were he was sold on American tanks. While Witheridge also believed in the American concept of tanks as infantry supporting weapons with the ability to fire an effective High Explosive shell, he did not believe that a tank should sacrifice anti-tank fire-power for high explosive capability . While at Lulworth, Lt. Col. Witheridge inspected the A30 Challenger, and finding the design flawed, joined in the chorus of complaints about the tank. Upon looking up Major Brighty and learning of his attempts to fit a 17 pounder into a Sherman, Witheridge lent his assistance to Brighty and his efforts. .

Not long after, Lt. Col. Witheridge and Major Brighty received a notice from the Department of Tank Design (DTD) to cease all efforts to mount the 17 pounder in the Sherman Tank. Unwilling to abandon the project, Witheridge, using his connections with such influential people as Maj. Gen. Raymod Briggs of the Royal Tank Regiment, successfully lobbied Claude Gibb of the Ministry of Supply to make the mounting of a 17 pounder on a Sherman tank an official project of the Ministry of Supply. However in doing so the project was taken out of the hands of the highly enthusiastic and devoted designers at Lulworth that had started the project and given to the professional tank developers .

Design

It was in the hands of Mr W.G.K Kilbourn, at the time working for Department of Tank Design, that the 17 pounder armed Sherman Prototype would become the tank that was to serve British Forces from D-day to the Armistice. The first problem Mr. Kilbourn had to fix was the lack of a workable recoil system for the 17 pounder mounted on the Sherman. In the Anti-tank gun role for which the gun was designed, the 17 pounder would travel 40 inches back as it absorbed the recoil of the blast. Not only was this recoil movement too much for the Sherman turret to allow, Mr. Kilbourn experienced the second problem, the 17 pounder in its current configuration with its recoil cylinders was too tall to be mounted in the short turret of the Sherman. .

Sherman Firefly of 7th Armoured Division in Hamburg, 4 May 1945

Rather ingeniously, Mr. Kilbourn solved both problems by redesigning the recoil system completely rather than modifying it. The recoil cylinders were shortened to allow the turret to take the gun and its recoil, and the new cylinders were placed on both sides of the gun to take advantage of the width of the Sherman's turret rather than be hindered by its height. The next problem that was encountered by Mr. Kilbourn was that the gun cradle, upon which the gun sits, had to be shortened to allow the gun to fit into the Firefly, and thus the gun itself was not very stable. To solve this, Kilbourn had a new barrel designed for the 17 pounder that was wider at the base which helped solve the stability problem. A new mantlet was designed to house the new gun and accept the modified cradle. Thus, while the 17 pounder which was to be fitted in the Firefly was a modified variant, it would have to be factory built specifically for the Firefly.

Now that a suitable recoil system had been designed for the Firefly, Mr. Kilbourn turned his attention to other problems with the tank. The new gun took up much more room than the standard 75mm gun in the Sherman's turret and the gun breech and recoil cylinders blocked the turret hatch for the loader on the left, effectively eliminating any chance of a speedy exit from the tank if it was knocked out. As a result a new hatch for the loader had to be cut in the top of the Sherman's turret. .

The final major change was the elimination of the hull gunner in favor of more 17 pounder ammunition, which was significantly longer than the 75mm shell and thus took up more room. However the hull gunner also doubled as the Radio Operator, so an armored box ( a 'bustle') was attached to the back of the turret to house the new radio, and the loader was to double as the radio operator. In action however it was to be found this situation was far from ideal, as the loader, who had to handle the much larger 17 pounder shell in a significantly more cramped turret would find it almost impossible to work the Radio in the heat of battle, and as a result coordinating with its fellow tanks would be more difficult during battle while he was busy reloading the gun. As a result Troop commanders responsible for a troop of 4 tanks including their own were discouraged from crewing Fireflies because of the impossibility of coordinating their entire Troop during a battle.

By October and November 1943, enthusiasm began to grow for the project. The 21st Army Group was informed of the new tank in October 1943. Even before final testing had taken place in February 1944, an order for 2,100 Sherman tanks armed with 17 pounder guns was placed. This reaction was understandable, as the Challenger program was suffering constant delays and few would be ready for Normandy, and even worse, the realization that the Cromwell tank did not have a turret ring big enough to take the new High Velocity 75mm gun (50 calibres long), so the Cromwell would have to be armed with the weaker Ordnance QF 75 mm. Thus the Sherman Firefly represented the only available tank with firepower superior to the QF 75 mm gun in the British Army’s arsenal. Not surprisingly, it was given the ‘highest priority’ by Winston Churchill himself.

The nickname "Firefly" is however not found in wartime official documents. It was sometimes used at unit level (Brigade/Regiment) war diaries from March 1944, with another nickname being 'Mayfly'. During the war, Shermans with 17 pounder guns were usually known as '1C' '1C Hybrid' or 'VC', depending on the basic mark of the vehicle. In British nomenclature, a "C" at the end of the Roman numeral indicated a tank equipped with the 17 pounder.

Further information: M4 Sherman variants § UK Nomenclature, and and an explanation of the various marks

Armament

The shell of a 17 pounder

The main armament of the Sherman Firefly was the Ordnance Quick Firing 17 pounder. Designed as the successor to the British QF 6-pounder, the 17 pounder was the most powerful British tank gun of the war, and one of the most powerful of any nationality, being able to penetrate more armour than the Tiger I's 8.8 cm KwK 36, the Panther tank's 7.5 cm KwK 42, and the M26 Pershing's 90 mm gun.

The 17 pounder mounted on the Sherman Firefly was able to penetrate some 140mm of armour at 500 meters and 131mm at 1000 meters using standard APCBC (Armour Piercing, Capped, Ballistic Capped) ammunition at a 30 degree angle, more than sufficient to defeat the German Tiger I and Panther tank at standard combat ranges. When supplied, APDS (Armour Piercing, Discarding Sabot) ammunition could penetrate some 209mm of armour at 500 meters and 192mm at 1000 meters at a 30 degree angle, thus in effect, almost every German tank at any likely range . However, APDS was not as accurate as APCBC ammunition, and being a sub calibre shot, the actual penetrating device was around 50mm wide, thus being less destructive after it had penetrated enemy tank armour than the 76.2mm APCBC shell. In any case, APDS ammunition was rare, with very little being available until late 1944.

One major disadvantage of the Sherman Firefly during its first few months in service was its lack of an effective High Explosive shell for its main gun, which meant Firefly crews faced much the same disadvantage of British tank crews some two years earlier in the North African Campaign when their 2 pounder armed tanks lacked an effective means of dealing with soft targets such as anti-tank guns or dug-in infantry. An effective HE shell only became available in late 1944 and even then, it was not as potent as the standard Sherman 75mm HE shell. Another problem was that the powerful blast from the 17 pounder gun kicked up large amounts of dirt as well as smoke, making it difficult for the commander and gunner to observe the fall of the shell and correct their aim if they missed. Also, this dirt and dust revealed the position of the tank, so Sherman Fireflies would have to relocate every few shots to avoid detection. It should be noted that this was a common problem on any tank armed with a high velocity gun, including the German Panther and Tiger tanks. Finally, the cramped nature of the turret meant that loading the large 17 pounder shell was more difficult, so Fireflies had a reduced rate of fire compared to regular M4 Shermans.

The Firefly's secondary armament was one .30 cal machine gun located in the turret. Its hull gun was eliminated to increase ammunition storage for the main gun. A top-mounted .50 cal machine gun was also attached, though many crews removed it due to its mounting which required its commander to stand on the engine deck behind the turret, thus exposing himself to enemy fire. A small number of Fireflies carried launching rails for two RP-3 rockets, one on each side of the turret. This weapon was highly inaccurate when fired from a tank, but was valued by crews for the destructive effect of its 60 pound warhead..

Production and distribution

Three different variants of Sherman Firefly served during the Second World War, each based on different variants of the M4 Sherman. The Firefly conversion was carried out on Sherman I (M4), Sherman I Hybrid (M4 Composite) and Sherman V (M4A4) tanks. Some sources state that several Sherman IIs (M4A1) were converted and used in action, but photos allegedly showing these conversions are in fact views of the front half of Sherman I Hybrid Fireflies. To complicate matters, a very small number of Canadian licence-built Sherman IIs (M4A1), known as Grizzlies, were converted to Fireflies in Canada and used for training, but none saw action. The majority of Shermans converted were the Sherman V/M4A4 model, of which the British received about 7,200. The Sherman VC and IC variants can be easily distinguished by their lower hulls; the VC having a riveted lower hull with a curved shape while the IC has a welded and angled lower hull. The Hybrid can be distinguished by its upper hull which is cast and which gives it a distinctive curved look in comparison to the more boxy hull of a typical Sherman.

A Sherman Firefly crosses 'Euston Bridge' over the Orne as it moves up to the start line for Operation 'Goodwood', 18 July 1944.

Production of the Firefly started in early 1944, and by May 31, some 342 Sherman Fireflies had been delivered to Montgomery's 21st Army Group for the D-Day landings. As a result, British armour troops were composed of three regular Shermans and one Firefly. The same distribution occurred in Cromwell units, but this caused logistical problems, as each Cromwell troop now needed parts for two different tanks, and the Fireflies were slowly replaced by Challenger tanks as they came out. Churchill units received no Fireflies, and as a result often had to rely on any attached M10 or M10 Achilles units to provide increased firepower to deal with tanks their 75mm guns could not eliminate.

From D-Day in June to the end of the Battle of Normandy in late August, some 550 Sherman Fireflies were built, more than sufficient to replace any permanent tank losses during the battle. In late 1944, with the creation of an effective High Explosive shell for the 17 pounder gun, British units started to receive two Fireflies per troop. By February 1945, some 2,000 Sherman Fireflies had been built and all British armour troops were equipped with a 50/50 mix of 75mm and 17 pounder armed Shermans.

In the spring of 1945, production of the Firefly was scaled down, with the last tank being delivered in May 1945. This was the result of several factors, from home-grown designs like the Comet and Centurion coming into service which would replace the Firefly, to the impending destruction of Nazi Germany, and the inferior design of Japan's tanks, which it seemed would be the next opponents the British would have to face after the fall of Germany.

Overall production of the Sherman Firefly reached some 2,100 - 2,200 tanks; exact numbers are hard to determine as documents give contradictory totals. Jane's World War II Tanks and Fighting Vehicles gives a production of 1783 over 1944 and 563 over 1945, for a total of 2348.

Service

Fireflies were introduced to armoured brigades and divisions in 21 Army Group in 1944 just in time for the Normandy landings. The timing was fortunate as the Allies were to discover immediately that the Germans were fielding a much larger number of heavy tanks, like the Panther, than had been expected in the Normandy theatre. In fact the Allies had mistakenly assumed the Panther, like the Tiger, would be a rare heavy tank with a limited production run, rather than a total replacement for their medium tanks, and the larger-than-expected number of Panthers came as a nasty shock to the Allied commanders as well as the majority of Allied tank crews forced to engaged them with guns that could not penetrate the frontal armour at long range.

While the number of Panthers and Tigers only accounted for some 30% of the nearly 2500 German tanks deployed in Normandy (the rest being composed of Panzer IVs, Sturmgeschütz IIIs and other tanks the standard Shermans were able to effectively handle), Montgomery's strategy of drawing the bulk of the German armour units around the vital town of Caen so the American units could break out to the west meant that British and Commonwealth units had to face over 70% of all German armour deployed during the Battle of Normandy, as well as almost all the elite, well-equipped SS units which contained the fearsome Tigers and Panthers. Thus, despite the relatively low number of Panthers and Tigers deployed, they would almost all be facing British and Commonwealth troops. As a result, the Sherman Firefly was perhaps the most valued tank by British and Commonwealth commanders, as it was the only tank in the British Army able to effectively defeat the Panthers and Tigers at the standard combat ranges in Normandy.

This fact did not go unnoticed by the Germans, who realized that these long-barrel Shermans posed a much greater threat to their heavy tanks than the regular Shermans, and German tank crews and anti-tank gun crews were instructed to eliminate Fireflies first. Similarly, the Firefly crews realized that the distinctive long barrel of their 17 pounder gun made the Firefly stand out from regular Shermans, so crews attempted to disguise their tanks in the hope they would not be targeted. Some crews had the front half of the gun barrel painted white on the bottom and dark green or the original olive drab on the top to give the illusion of a shorter gun barrel. Another suggestion was for a shorter wooden dummy gun would be mounted on the rear of the turret and point forward; however, this tactic does not appear to have been used in combat.

A Belgian Firefly with countershadowing pattern used to disguise the increased length of the barrel

Despite being a high priority target for the Germans, Fireflies appear to have had a statistically lower chance of being knocked out than standard Shermans, and this was likely more due to how they were employed rather than the actual effectiveness of the attempted camouflaging of the long barrel. Given the high value the British and Commonwealth commanders placed on Firefly tanks, a common tactic was for commanders to reconnoitre the battlefield before a battle to look for good hull down positions for the Firefly tanks. During the battle, Firefly tanks would stay behind in those position and cover the regular Shermans as they pushed forward, eliminating any enemy tanks that revealed themselves when they opened fire on the advancing M4s and only moving forward when the regular M4s had secured the area, or when they could no longer cover them from their current position. However, given the relatively unpredictable nature of battle, this setup was not always practical or possible, and many times, Fireflies were forced to engage enemies in the open where they could be identified.

Despite this, the Fireflies increased firepower was much valued by British and Commonwealth tankers, and during many engagements, the Firefly proved its worth, knocking out the feared Tigers and Panthers at long range, as well as less formidable tanks like the Mark IVs and StuGs.

One example of this increased firepower was displayed by Lt. G.K Henry's Firefly during the defense of Norrey-en-Bessin on June 9th against an attack by the 3rd Company of the 12th SS Panzer Regiment of the 12th SS Panzer Division. Determined to capture the town in preparation for a larger offensive to drive the British and Canadians back into the sea, Kurt Meyer ordered an unsupported tank attack by 12 Panthers of the 3rd Company to attack Norrey-en-Bessin and drive the Canadians out of the town. The attack got underway at 1300 hours with the Panthers racing to the town at full speed only to stop to fire their guns. Within 1000 meters of the town, 9 Shermans of the 1st Hussars opened fire into the advancing Panthers flanks. Lt. Henry's gunner, Trooper A. Chapman, waited until the Panthers "lined up like ducks in a row" and quickly knocked out five German panthers with just 6 rounds. Overall 7 of the 12 Panthers were lost in the attack, the majority credited to Lt. Henry's single Firefly. .

Another similar example occurred on 14 June, during Operation Perch, Sgt. Harris of the 4th/7th Dragoon Guards, along with three standard Shermans, set up defensive positions along with the infantry after successfully driving out the Germans in the village of Lingèvres, near Tilly-sur-Seulles. Looking through his binoculars, Sgt. Harris spotted two Panthers advancing from the east. He opened fire at a range of 800 meters, knocking out the lead Panther with his first shot, and the second Panther with his second. Relocating to a new position on the other side of the town, he spotted another three Panthers approaching from the west. From his well-concealed flanking position, he and his gunner Trooper Mackillop eliminated all three with just three rounds. Harris and his gunner had knocked out five Panthers with as many rounds, once again demonstrating the potency of the Firefly, especially when firing from a defensive position on advancing enemy tanks.

A Dutch Firefly

In perhaps its most famous action, a group of seven Tiger tanks from the 3rd Company and HQ Company, Schwere SS-Panzer-Abteilung 101 supported by several Panzer IV and Stug IV were ambushed by Fireflies from A Squadron, 1st Northamptonshire Yeomanry, 33rd Armoured Brigade, A Squadron, the Sherbrooke Fuisilier Regiment, 2nd Canadian Armoured Brigade and B Squadron, The 144 Royal Armoured Corps, 33rd Armoured Brigade.

Tanks of the 1st Northamptonshire Yeomanry and elements of the 51st (Highland) Division reached the French village of Saint-Aignan-de-Cramesnil on the morning of 8 August 1944 during Operation Totalize. While B Squadron stayed around the village, A and C Squadrons moved further south into a wood called Delle de la Roque. C Squadron positioned themselves on the east side of the woods and the understrength A Squadron in the southern portion with No. 3 Troop on the western edge of the wood. From this position, they overlooked a large open section of ground and were able to watch as German tanks advanced up Route nationale 158 from the town of Cintheaux. Under strict orders from the troop commander, they held their fire until the German tanks were well within range before opening fire. Ekins, the gunner of Sergeant Gordon's Sherman Firefly (called Velikye Luki, A Squadrons tanks were named after towns in the Soviet Union), had yet to fire his gun in action. With the Tiger tanks in range, the order was given to fire, what followed was an almost twelve minute battle that saw Ekins destroying all three Tigers that No. 3 Troop could see (there were actually 7 Tiger tanks in the area heading north along with some other tanks and self propelled guns). A short time later, the main German counterattack was made in the direction of C Squadron. A Squadron (minus Sgt Gordon who had been wounded and had already bailed out of the Firefly) moved over to support them and in the resulting combat, Ekins destroyed a Panzer IV before his tank was hit and the crew were forced to bail out. One of the Tigers Ekins is credited with knocking out was that of Michael Wittmann, though there is still some controversy over whether Ekins really killed Wittman as Fireflies of the Sherbrooke Fuisilier Regiment were also firing at the Tigers from a closer range of 500m.

Overall the Firefly proved itself a very successful tank despite the fact it was only intended as a stopgap tank until future British tanks like the Comet and the Centurion came into service. While Normandy had priority, Fireflies also served with distinction in Italy in British and Commonwealth units.

See also

• M4 Sherman tank
• M4 Sherman variants
• Lend-Lease Sherman tanks
• Allied Technological Cooperation During WW2

External links

• Sherman Firefly Book Homepage
• Camouflage of 17-pdr Gun Mounted in Sherman Tank