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Sherman Firefly In Canadian Service
The Sherman Firefly was a most successful result of British attempts to upgun a tank with the 17-pdr anti-tank gun. It was common practise for the British to mount anti-tank gun designs in their tanks, after the guns had proven effective in their carriage mounts. In addition to the Firefly, the British mounted the 17-pdr gun in a Cromwell cruiser tank and it became known as the Challenger. It was distinctive in that it exhibited an unusually high slab sided turret made necessary by the recoil cylinders of the 17-pdr gun that were on the upper and lower sides of the barrel and it was never as successful as the Firefly.
The major problems in mounting the 17-pdr gun in a Sherman turret were the positioning of the recoil cylinders and the recoil carriage that proved to be too long for a Sherman turret mount. The tapering shape of the gun barrel ahead of the breech assembly made shortening the carriage impossible so the tapered section was machined down and a sleeve was fitted over this area to provide the necessary barrel support in a new cradle. This tank version of the 17-pdr was designated the "Ordnance, Quick Firing, 17 Pdr. Mark IV". To alleviate the recoil cylinder problem, a new mounting that surrounded the barrel was manufactured and it contained both recoil cylinders which were now located on the sides of the gun. The gun had also been turned so that the breech block operated horizontally to facilitate the loaders job and to prevent the long rounds jamming between the breech and the turret ring. As the gun took up a large portion of the restricted room within the turret, it became apparent that the loader would be seriously hampered in exiting the turret in an emergent situation. To alleviate that problem, a new hatch was provided for the loader in the turret roof. It was also standard practise for the British to mount the No.19 wireless set in the turret bustle. Because of the massive size of the gun and the length of recoil, it was decided to add an armoured box on the turret rear, which while proving to be the ideal mounting place for the wireless set, also served to counter balance the turret which proved necessary because of the heavier gun mount. The simple rectangular box had a removeable top to permit the installation of the wireless set. The set was operated through a rough cut hole in the rear of the turret. The final 17-pdr mount also had a .30 calibre Browning machine gun mounted co-axially on the left side of the main gun and a sighting telescope on the right.
The Sherman hull also underwent major modifications, primarily due to the average 32.8 inch length of the round. The hull gunners position was eliminated, as was the hull machine gun, to provide additional stowage for the ammunition. The machine gun aperature was blocked off with an armour plug. The additional four foot length of the gun tube compared to the standard 75mm gun necessitated the inclusion of a gun travel lock. For the most part, it was mounted on the left rear corner of the engine deck although photographic evidence exists to show that early Fireflies had it installed centrally on the deck at the extreme rear.
Canadian armoured regiments earmarked for the campaign in North-West Europe were initially issued Fireflies on a scale of one per troop. The Fort Garry Horse and 1st Hussars, who landed on D-Day, had only one squadron each equipped with their Firefly allotments as the other two squadrons were equipped with Duplex Drive Shermans. The DD swimming fittings were not able to be fitted to the Firefly due to the extreme length of the gun barrel. Canadian armoured regiments in the Italian theatre were not equipped with the Firefly until they arrived in North-West Europe in early 1945. It would appear that the Sherman VC was the first Firefly variant to equip Canadian armoured units in Normandy but they would be supplemented with the Sherman IC and IC Hybrid as the stocks of VCs dwindled. As the Firefly became more available, each armoured troop would eventually field two of them plus two regular 75mm Shermans. A British study indicated that 75% of all ammunition expended was HE. The 75mm gun tanks still had a prominent role in action due to the better performance of the American HE round compared to the unreliable low velocity HE round developed for the 17-pdr. In regards to armour piercing capabilities though, the 17-pdr gun out-performed the 75mm gun by far.
Although the Firefly had serious design shortcomings, it was to prove to be a most valued addition to Canadian armoured regiments for defeating enemy armour. While the 17-pdr gun put Canadian tank crews on equal footing with the Panther 75mm gun, the outdated armour protection of the Sherman still left the crew at serious risk.
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© Chris Johnson, 1997
