Derek Pullem
Donor
I'd settle for an alt-CometPossibly, and of course final timing will be up to Allan, but I'd rather be too pessimistic than assume "oh yes, we'll have Centurions by D-day". (Exaggeration for comic effect)
Sir John Valentine Carden survives.
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Now THAT I think is not unreasonable - a "heavy cruiser" by Vickers with a HV 3" gun. And improved fusing for the HE shell.
That would help the British out a lot. Not having to rush resources to a conflict area while they're still rearming (no matter what, a lot of materiel will be lost in France, the only question is whether there's going to be a panic over it, or whether they feel secure enough to not go "we need something NOW", or whether they're content to wait for better kit in the near future) will make things a lot easier.
Also, more men recovered. The numbers stack even more favourably if it's Calais they retain rather than Dunkirk, as there's the possibility of getting out at least a portion of the vehicles and equipment (someone mentioned that Calais has a Train Ferry capability, which should allow at least a number of unneeded soft-skinned vehicles to be removed without too much issue, excepting enemy action).
I'd settle for an alt-Comet
Agreed. BTW, does anyone have any stats for the 3" HV?
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Given Calais and some extra days before the LW get its act together, they can pull out a lot of the support troops and some of the more valuable kit that wont be needed for defence. Calais can take ships. The RAF can defend it better - its closer - so while eventually the LW and artillery will degrade the port, but these things take time, and they can still pull out a lot of men at night.
Actually I don't see too much of kit like artillery, AA guns or tanks coming back, these will be in the front line. But with troops embarking from a port, the light and personal weapons will come back, which will be a big help in reducing panic about an invasion. A more deliberate evacuation will also mean left-behind kit is properly wrecked, so much less for the germans to aquire.
Actually a defence of the port, even if, as would be expected, it doesn't last too long - its basically doomed when France surrenders - will givethe British more confidence they can handle any invasion that happens.
Actually I don't see too much of kit like artillery, AA guns or tanks coming back, these will be in the front line. But with troops embarking from a port, the light and personal weapons will come back, which will be a big help in reducing panic about an invasion. A more deliberate evacuation will also mean left-behind kit is properly wrecked, so much less for the germans to aquire.
Actually a defence of the port, even if, as would be expected, it doesn't last too long - its basically doomed when France surrenders - will givethe British more confidence they can handle any invasion that happens.
Derek Pullem
Donor
Irritatingly no sources but sounds reasonable.
Vickers 75Mm L/50 High Velocity Tank Gun Of Ww2
I recently assembled some information which was new to me about this obscure gun, so I thought it might be of interest to Tanknetters: Vickers proposed the 75mm L/50 High Velocity tank gun early in 1942 as a replacement for the 6 pdr (57mm) gun. It was intended to be used in the Cromwell tank and...
www.tanknet.org
You're not getting to keep much weaponry, sure, but you're likely to get back soft-skinned vehicles, carriers, maybe even some light tanks (they wouldn't be much use in defence). Plus, you're getting back at least some of the (to quote wikipedia):
That will help immensely.
In addition, Dunkirk is ~45 miles from Dover as the crow flies, and the channel they had to use didn't allow them to travel directly, while Calais is one ~25 miles, and direct travel is possible. So ships can turn around faster. Big ships can get in closer too, which will allow the RN to provide more direct fire support. Finally if it is Calais, you can, as a final act, wreck the port on your way out, preventing its use to the Germans for a few months, reducing further the risk of invasion.
Well if Carden can design a tank to take that gun somewhat earlier than the Comet (which shouldn't be that difficult to pull off, since Carden is thinking ahead already), then they might be ready in time for D-Day, which will give the Germans a rather nasty surprise.
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The gun in question is a new design for TTL. Its not entered production or even full development yet. I was assuming similar performance to the 77mm HV. That article would seem to confirm that as the rough ballpark for the gun.
The post it's mentioned in says that Carden is looking at a weapon with a muzzle velocity somewhere in the region of 2,000-2,500 ft/s, a little lower than the 2,580 ft/s of the 77mm. Not quite as good a hole-puncher (directly at least, though a shaped charge or APDS could help), but likely with a more respectable HE round.
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Derek Pullem
Donor
The post was in response to MattII's question.
I think it's not a bad point to extrapolate the kind of performance we might expect from a M1931 starting point. And the question on 75mm vs 3" is going to be very interesting. Vickers can do either - totally down to allied logistics
For now if the new Vickers gun keeps the ballistics of the AA version it should be somewhat comparable to the German long 75 on Pz IV and slightly better/equivalent to the 6pdr, which is fairly balanced especially for a gun that might enter service in 1942. This should be enough to face uparmoured Pz IVs and Stugs, defeat a Tiger I at reasonable, if still a bit short range as long as APBC is used, and might be even somewhat capable against the turret front of the Panther. The 17 pdr remains much better against the Panther and Tiger in particular, and would still be useful if a suitable tank using it is developped.
I'd say that better Cruiser tank development is fairly plausible here, as the Perkins Lion line allows mass production of a better engine than the Liberty and experience with the Valiant Mk I* will help with making the specs for the post Covenanter/Crusader Cruisers. Mass production of the Valiant will maybe eat all Lion production however, unless it is extended to more companies. I'd say it depends a lot on what happens with the Churchill and Bedford.
If I recall Harland and Wolff was involved in development of the A20. Was it involved in A9 production OTL or is it only ITTL? In that case the A20 may not exist.
My dream timeline would be that the War Office finally sees reason and leaves free development of a heavy infantry tank to the SVDC (aka TOG). The only reason that TOG was forced to make huge and especially long designs (sometimes with sponson guns) is because the War Office asked for ridiculous trench crossing abilities. If it was allowed to work on the tank it wanted we would probably see a more sensible "Churchill".
I'd say that better Cruiser tank development is fairly plausible here, as the Perkins Lion line allows mass production of a better engine than the Liberty and experience with the Valiant Mk I* will help with making the specs for the post Covenanter/Crusader Cruisers. Mass production of the Valiant will maybe eat all Lion production however, unless it is extended to more companies. I'd say it depends a lot on what happens with the Churchill and Bedford.
If I recall Harland and Wolff was involved in development of the A20. Was it involved in A9 production OTL or is it only ITTL? In that case the A20 may not exist.
My dream timeline would be that the War Office finally sees reason and leaves free development of a heavy infantry tank to the SVDC (aka TOG). The only reason that TOG was forced to make huge and especially long designs (sometimes with sponson guns) is because the War Office asked for ridiculous trench crossing abilities. If it was allowed to work on the tank it wanted we would probably see a more sensible "Churchill".
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I think Carden is more likely to design around the Vickers 75mm AA gun for a number of reasons.
Its already been supplied in 3" calibre (for the Finns, iirc). 3" is a standard calibre in British use, with ammo production lines already in place, so I wouldn't see any reason to use 75mm.
Its got the penetration needed in 1939 (assuming its going to need to take on the german equivalent of the Valiant, which is a sensible benchmark to start from); the HE shell looks OK on paper. If when they test it they find the HE shell is burying itself in the ground, there is no huge technical issue from using a lower velocity (and thinner walled) HEround except the need for a dual sight for the gunner. Granted the British seemed to have an issue with these, but the faster shell will still do the job, and if the complaints get too strident the lover velocity shell is pretty straightforward to implement.
The AA gun is already in production at Vickers; while an improved version could be made, or possible one with a shorter recoil, its available for testing and prototype work, speeding up the tank development
Its already been supplied in 3" calibre (for the Finns, iirc). 3" is a standard calibre in British use, with ammo production lines already in place, so I wouldn't see any reason to use 75mm.
Its got the penetration needed in 1939 (assuming its going to need to take on the german equivalent of the Valiant, which is a sensible benchmark to start from); the HE shell looks OK on paper. If when they test it they find the HE shell is burying itself in the ground, there is no huge technical issue from using a lower velocity (and thinner walled) HEround except the need for a dual sight for the gunner. Granted the British seemed to have an issue with these, but the faster shell will still do the job, and if the complaints get too strident the lover velocity shell is pretty straightforward to implement.
The AA gun is already in production at Vickers; while an improved version could be made, or possible one with a shorter recoil, its available for testing and prototype work, speeding up the tank development
Ballistics :
Vickers 75mm L43 AA gun - shell 6.5kg, m/v 750m/s
7.5cm KwK 40 (L48) - shell 6.8kg, m/v 750 m/s
So basically very similar. I wonder if the Vickers gun could be upgraded later in the war with a longer barrel length? The 6pdr went up from L43 to L50, with a 5% increase in MV, so 10% more energy.
I don't remember any issues with the Germans using HE shells with that gun; did they use a different shell loading?
Vickers 75mm L43 AA gun - shell 6.5kg, m/v 750m/s
7.5cm KwK 40 (L48) - shell 6.8kg, m/v 750 m/s
So basically very similar. I wonder if the Vickers gun could be upgraded later in the war with a longer barrel length? The 6pdr went up from L43 to L50, with a 5% increase in MV, so 10% more energy.
I don't remember any issues with the Germans using HE shells with that gun; did they use a different shell loading?
Derek Pullem
Donor
Ideally the British end up with a Valiant 1 / II line which ends up competing with the Pz IVH and Panthers of this world and a Churchill tank which ends up meeting the same role as the StuG
Just did some looking at the 6-pdr.
Apparently they fired test guns in 1939, but didn't think it was needed yet so put it back on the shelf.
Now I see no reason why Carden cant borrow a couple to fit into a Valiant and test. The Army may still decide they don't need it yet, but even so it means that as soon as they do it can pretty much go into production, or even have existing Valiants modified to take it, all the design work will have been done and proven.
If Carden is persuasive enough, maybe some 6-pdr armed Valiants in France to test them out?
Pz III, might penetrate a Valiant at 100 yards
Valiant 6-pdr, can penetrate a Pz III at 1,500yds.
Oops.
Apparently they fired test guns in 1939, but didn't think it was needed yet so put it back on the shelf.
Now I see no reason why Carden cant borrow a couple to fit into a Valiant and test. The Army may still decide they don't need it yet, but even so it means that as soon as they do it can pretty much go into production, or even have existing Valiants modified to take it, all the design work will have been done and proven.
If Carden is persuasive enough, maybe some 6-pdr armed Valiants in France to test them out?
Pz III, might penetrate a Valiant at 100 yards
Valiant 6-pdr, can penetrate a Pz III at 1,500yds.
Oops.
They had a number of "assault tank" designs similar to the Churchill. Personally, I like the Excelsior. Similar armour to the Churchill but larger gun and faster. I think it had the Merritt-Brown gearbox as well, so climbing ability should be pretty good as well
Glyndwr01
Banned
But how could America make the show "Rat Patrol" and claim they won the North African Campaign then?
It's Hollywood, they'll think of something. If history gets in the way of a story they'll make something up. How else do they have American volunteers winning the Battle of Britain before fighting at Pearl Harbour and taking part in the Doolittle Raid?
1: Mussolini doesn't declare on France but prepares for an invasion of Yugoslavia/Grece.
2: Brits, having guaranteed Grece, declare on Italy when they invade
3: Brits are now fighting in NA and Grece
4: Hollywood profits
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