Sherman 17-pdr (Firefly) - conversion restrictions

Wiki has a note in its article on II Polish Corps in Italy that it had 50,000 personnel in 1944 but suffered heavy losses around Cassino. Then it expanded its ranks to 75,000 by 1945 and was able to transfer some 20,000 personnel to Western Europe in 1945.

In June 1945 the 2nd Polish Armoured Brigade, formed in 1943, was upgraded to an Armoured Division, although I understand that it may not have been quite full strength.

I must admit I don’t understand the Polish setup. I keep getting the feeling that the U.K. and Med parts of the Polish forces operated almost completely separately. Maybe someone can explain the relationship between the two parts.

We have also forgotten the existence of the 17pdr Challenger. Not big numbers, 145 built by the end of 1944 of an eventual 200, but worthy of note. 21 with units at 30 Dec 1944 growing to a peak of 47 by 7th April with another 44 held elsewhere = 91 in NWE. That total grew to 133 on April 21st 1945. Units with them were Guards, 7th, 11th and Polish Armd Divs and Czech 4th Armd Brig at various times.

 

I got a bit confused there, as I misremembered 1st Polish AD as being in Italy. Anyway, feast your eyes on this from 21 Army Group RAC Liaison Letter No.2 of 6th September 1944:

 

Except neither Brigade is fully Sherman I/II/V equipped, so just how many 75mm Shermans it releases is open to question.

Both brigades were part of 79th Armd Div.

1st Tank Brigade - 49th, 42nd & 11th RTR - all CDL units at the time of the above letter with a mix of Grant CDL and Shermans and had been pretty much inactive since landing in France. From Sept 49th RTR began to get broken up with Shermans being parcelled out to other units along with their crews, as indicated. But 11th RTR got LVT at the end of Sept and 49th RTR got Ram Kangaroos. In Nov the Brigade itself went into suspended animation with its constituent units allocated elsewhere. June 1944 162 Grant CDL and 77 Sherman I/II gun tanks.

30th Armoured Brigade’s main equipment was the Sherman Crab. June 1944 they had 180 Crabs and 72 Sherman V gun tanks.

So it looks to me like a search through 21AG trying to rake up as many 75mm gun tanks as possible that were not being fully utilised for the main Armoured divisions and brigades, and replaced with what was on hand but not wanted in those main units.

 

Fair enough. I'm just not interested enough in Shermans to bother researching them in detail, tbh, but if I come across any more useful info, I'll post it up here.

 

Based on their WEs it would have released a fair few Shermans. 1st Tk Bde WE had 31 Shermans per CDL Rget, so 93 in the Bde, and in 30th Armd Bde 24 in each Flail Regt. Potentially 165 75-mm gun armed Shermans . All 1st Tk Bde's obviously became available when the formations was put into suspended animation, while 30th Armd Bde halved its WE for standard Shermans from 24 to 12 per Regt by Jul/Aug 1944 as I recall.

Gary

 

9th Lancers...

Regimental-Histories_1936-1945 Bright_265.jpg - The Royal Lancers Museum at Derby

 

Spring 1945, 3 Firefly turrets were sent to Canada for testing, mounted on the M4A1 Grizzly hulls, and tested to see if the 17 pdr tank ammo storage, could be modified to fit the M4A1 style hull. The conversion worked and preformed well. Photo is the only survivor remaining now resting at Canadian Forces Base Borden Military Museum.

 

Memo from Canadian Archives (Reel C5779.264) about QF (Applique) Armour and VC explaining the rationale behind the decision not to fit the QF armour at that point of the war.

 

Which Sherman V to convert (C5779.566):

Edit - Another memo indicates the Canadian army had 38 x VC available for conversion at that time. If that was the total number of VC converted is unclear.

 

I wonder if the wider mantlet was necessary as part of the balancing of the gun?

 

The earlier tanks had the M34 gun shield and smaller mantlet.. neither capable of taking the 17pdr gun cradle.

To mount the 17pdr mk4 or mk7, the tank had to be fitted with the wider mantlet and M34A1 shield.

EDIT - Note on Sherman tank design

The gun shield is the part which bolts to the turret and has trunnions onto which the gun cradle sits, allowing the cradle to pivot up and down. The mantlet is an armoured cover which bolts through the shield into the gun cradle so that the mantlet moves up and down in accordance with the gun elevation, covering the shield.