Could obsolete M3 Lees be converted into proto-IFVs?

[Alamo]

The last thread this was in went a bit off-topic, so this is a cross-posting of the content:

The ideal way to have a 1942 IFV in a hurry would be to just use a M3 Medium tank, remove the 75mm and all the related stuff, widen the side doors and keep the 37mm in the turret.

The Soviets apparently used some of their M3s in such a fashion (though I'm not sure if they removed the 75mm gun).

But do you know how Soviet crews called M3s? Grave for 5 brothers.

Found the reference - apparently they fit 10 infantrymen into the Lee:

The inside of the tank comfortably accommodate 7 crewmen, and also can carry 10 soldiers armed with submachineguns in summer conditions. The tank can be used this way to transport submachinegunners. While carrying troops, all tank guns can fire. Dropping off the 10 soldiers through the side hatches takes 25-30 seconds. Side hatches provide convenient entry and exit for the crew and soldiers.

http://tankarchives.blogspot.com/2014/03/lend-lease-impressions-m3-lee.html

Wow. like packing kids into a Volkswagen Beetle

Thanks Alamo. Since the allies had a lot of redundant M3 in good condition in 43/44, removing the main gun and ammo racks should allow for a full squad.
The ideal IFV configuration would probably be driver plus two men crew with a seven men squad. With a 37mm and MG, it would have been a 1944 IFV, capable of transporting infantry and providing fire support.
I once did a drawing for the alternate AFV thread in chat, but can't seem to find it...

You posted that on the Speculative Armour thread.

Thanks Cortz

here's the M3 "Komodo" IFV Looks the part, doesn't it?

In place of the 37mm, I'd rather have the 75mm pack howitzer used in the M8 GMC

The M8 had a turret ring diameter of 1380mm, a few mm of the M3 Lee

Just put a lid on that turret, and fire a really useful round for supporting infantry

I'd say have one howitzer M3 for every three with the 37.mm gun.

I'd go for IFV for the rifle coy, and since they would be operating as part of armoured divisions within the US Combat Command system, they could rely on M4s for fire support.
If you have a unit using a M3 based IFV, it's more logical to team them with M4 than to put a lighter weapon on a chassis in the same class as the M4.
Within the combat command, you could mix IFV platoons with Sherman platoons (both 76 and 105 versions) to form flexible company sized units.

Thanks Alamo. Since the allies had a lot of redundant M3 in good condition in 43/44, removing the main gun and ammo racks should allow for a full squad.
The ideal IFV configuration would probably be driver plus two men crew with a seven men squad. With a 37mm and MG, it would have been a 1944 IFV, capable of transporting infantry and providing fire support.
I once did a drawing for the alternate AFV thread in chat, but can't seem to find it...

Hmmm. I think you could take that one step further. Instead of just ripping out the gun and welding the port over, why not cut out the sponson assembly entirely, and weld a four-plate section into the gap, creating a flush front? That would significantly increase the internal space. Combine that with moving the radio out of the hull (either into the turret due to it only possessing a two-man crew now, or an armored box welded to the turret rear) and you could likely fit an eight to nine man squad.

The resulting vehicle might look something like this:

(Yeah, I know it's a pretty ugly looking manipulation. It's just to get a rough idea of what it would look like.)



The problem with that is, you'd have to divert pack-howitzer production, and increase (modified) turret production for the M8. Either that or start taking apart Scotts. If you stick with the M3's original turret and 37mm gun, you don't have to worry about interfering with existing demand for M8s, and you're using equipment that's deemed obsolete (assuming that modifications into APCs start sometime in 1943). By the tail end of the war, the M8s were getting replaced by heavier self-propelled guns, and you saw their turrets getting mounted on things like the LVT(A)-4. But that was only later on, starting in '44.

On top of that, you're going to run into ammo storage issues rapidly with the 75mm howitzer - the shells are so much larger than the 37mm rounds that if you want the vehicle to carry a decent amount of them, you'd need to start storing them in the lower hull, eating into space for the infantry dismounts.

US made 2592 pack howitzers during the war, half of them in 1943, and ending production in 1944

Making more won't be a problem. around 1500 were lend leased. Or use the older M1 guns that didn't go overseas.

I want safer ammo storage, something the M3 didn't have with the 37mm

It's very ilustrative. The seating inside wouldn't be very conventional in modern IFV tems, sicne the troop compartment is wide rather than long. I would remove the top MG turret, which I think it's an overkill, and the hull MG station, like you did. Since this is an adaptation, I'm not sure how easy it would be to fit bigger doors, but since that would require cutting armour plate, I'd think they would have to stick with the original doors.
This would be an ideal IFV for the infantry battalions in the Armoured divisions. Assuming non rifleman platoons (Mortars, AA, etc) stick with halftracks, you'd need at least 4 IFV for each Platoon (more likely 5) plus a couple for the Coy command group, meaning 42 to 57 IFV per Batt, roughly 150 per Division.

I couldn't resist having a play with Alamo's idea, so I did a line drawing version. I'm not sure about all the angles here but its as close as I could get it.
I added some gun ports to the front and sides.

Great work as usual Cortz. A few sugestions

Instead of three portholes on the front right, just a driver vision port and periscopes.
Delete the small top MG turret.
If you really want the IFV look, add lunch rails for aicraft type AT rockets on the side of the turret. Not the most obvious mod, but not impossible and certanly badass

Take two for M3 APC. Used most of your suggestions but unfortunately could only do the AT rockets on the side view of the APC.

 

[cortz#9]

So over at the AH-AFV thread eltf177 posted-

Wow, that bow... Can anything be done with that, it really spoils the look!

Any suggestions for improvements?

 

[Delta Force]

That actually did happen. The Canadians built the Kangaroo using surplus M7 Priest self-propelled artillery guns. The M7 Priest used the M3 Lee chassis.

 

[cortz#9]

That actually did happen. The Canadians built the Kangaroo using surplus M7 Priest self-propelled artillery guns. The M7 Priest used the M3 Lee chassis.

I think most of us here already know about the Kangaroo but the version were discussing here is closer to a modern IFV, while the Kangaroo was just a makeshift APC - hauler vehicle.

 

[Alamo]

Alright, a slightly revised manip:

The commander's machine-gun has been removed, and the roof hatch in the front section has been rotated. Before, it couldn't have been opened fully without getting in the way of of the other hatch. Now that shouldn't be a problem. A lot of modern and historic APCs and IFVs have multiple hatches on the roof, both to increase situational awareness and for additional egress points in an emergency.

One more thing - after looking at some photos of the M3's turret interior, I think that there's actually space to fit the radio into the position the commander used to be located without interfering with turret operations. That should free up space in the hull to the right and rear of the driver.

Having looked at some other internal pictures and trying to figure out the space freed up by removing the 75mm gun and ammo, I think you can fit eight infantry - nine if you're willing to squeeze them in.

Sans radio and hull-machine guns, I think you can seat two people to the left of the driver, backs against the hull side (though the one near the front will be pretty uncomfortable). A third can sit behind and partially to the left of the driver, in a position similar to that of the radio-man.

With the extension of the right-front section of the hull, you might be able to seat two rows - two people with seat-backs facing the hull, from the glacis to the door, and another three across from them, backs to the driver and turret basket. There should be room for a sixth man in a jump seat to the left of the door, in front of one of the 37mm ammunition stowage racks.

Passengers are in red, vehicle crew in gold

I would remove the top MG turret, which I think it's an overkill, and the hull MG station, like you did.

The problem with removing the commander's MG turret/cupola is that's where most of the optics are located (2-3, depending on the version). You can't just rip it off and drop a hatch in place - you'll need to find substitute optics, periscopes and mounts to fit into place, and then modify your new hatch to hold them. Seems like more bother than it's worth. Just remove the superfluous additional machine-gun and weld over the port. I don't think the additional 10-inches or so in silhouette you gain is worth the bother of trying to replace it, unless existing parts from the M4 are already compatible with the size of the M3's cupola - I'm not sure if they are.


cortz#9 - One of the reasons I was trying to just remove the entire sponson assembly, including the roof section, is because it's a rather large and unnecessarily heavy piece of metal. Keeping the existing roof section would complicate adding the remainder of the roof area, and add weight. By removing it, hopefully the additional plating added would equal out, and prevent the modified vehicle from being unbalanced towards the front-right corner.

That actually did happen. The Canadians built the Kangaroo using surplus M7 Priest self-propelled artillery guns. The M7 Priest used the M3 Lee chassis.

Those weren't fully enclosed vehicles, and they didn't mount anything heavier than a machine-gun, so that would make them more proto-APCs than IFVs.

 

[marathag]

I would also remove the turret basket, just have seats attached to drop down brackets from the turret itself to open up space.

This way both doors are useable for faster egress than crawling the the basket to get out on that side

 

[Alamo]

I would also remove the turret basket, just have seats attached to drop down brackets from the turret itself to open up space.

This way both doors are useable for faster egress than crawling the the basket to get out on that side

Where would the ready ammunition be stored?

 

[marathag]

Where would the ready ammunition be stored?

I'd weld a bustle to the rear of the turret. or have those 37 clips around the turret roof. reachable since the basket is gone

 

[marathag]

Also, there were these made up for D-Day, the Sherman BARV

Beach Armored Recovery vehicle

Oz made one from am M3

If you want other ideas on how to rework the Hull

 

[Admiral Beez]

Would it be best to switch the trannie and drive so that it could drive fastest in reverse, thus using the engine block to protect the personnel?

Some pics, courtesy of http://smg.photobucket.com/user/Panzerserra/media/M3 Grant Command Tank/GrantCommand050.jpg.html

 

[Delta Force]

Why not retain a hull machine gun? It can help cover the assault by forcing enemy soldiers into more defensive positions while friendly infantry dismount and advance.

 

[cortz#9]

Interesting stuff. I like the pics of the model that Admiral Beez posted, I'm going to try do a pic based on it and add a hull MG like Delta Force suggested.
Still open to suggestions.

 

[cortz#9]

Alright, a slightly revised manip:

<snip>


cortz#9 - One of the reasons I was trying to just remove the entire sponson assembly, including the roof section, is because it's a rather large and unnecessarily heavy piece of metal. Keeping the existing roof section would complicate adding the remainder of the roof area, and add weight. By removing it, hopefully the additional plating added would equal out, and prevent the modified vehicle from being unbalanced towards the front-right corner.

<snip>

I see what your saying, I'm going to try to find a line drawing of the M3 that shows both left and right sides of the tank and do a better pic.

 

[AdA]

Why not retain a hull machine gun? It can help cover the assault by forcing enemy soldiers into more defensive positions while friendly infantry dismount and advance.

It's a matter of internal space vs mounted firepower. even in a IFV, the primary "weapon" is the dismounted squad.

Regarding the turret(s), why not use the british Grant turret? Relocates the Radio and solves the height vs optics problem.

Since this would be a modification, anything too extensive might make it more worthwhile to design a new AFV.

And the most interesting point would be that if it worked, and was proved to be an ideal infantry AFV for the infantry componet of armoured divisions, it would lead to the IFV concept being adopted a lot earlier than OTL, with the possibility of a dedicated IFV design in time for Korea (probably based on the M24 chassis)

 

[cortz#9]

It's a matter of internal space vs mounted firepower. even in a IFV, the primary "weapon" is the dismounted squad.

Regarding the turret(s), why not use the british Grant turret? Relocates the Radio and solves the height vs optics problem.

Since this would be a modification, anything too extensive might make it more worthwhile to design a new AFV.

And the most interesting point would be that if it worked, and was proved to be an ideal infantry AFV for the infantry componet of armoured divisions, it would lead to the IFV concept being adopted a lot earlier than OTL, with the possibility of a dedicated IFV design in time for Korea (probably based on the M24 chassis)

Find me a decently large pic of the Grant and I'll use it, because all I've been able to find so far are pics that are too small.

 

[cortz#9]

Find me a decently large pic of the Grant and I'll use it, because all I've been able to find so far are pics that are too small.

Never mind I think I found something I can use.
maybe.

 

[Delta Force]

Some of these proposals are rather ambitious. Isn't the concept to use existing American Army M3 Lee vehicles?

 

[cortz#9]

M3 with bow section removed and hull MG. I know the hull MG takes up a bit of room but I liked the way it looked.
Grant version coming up, still open to suggestions and critiques.

 

[cortz#9]

Some of these proposals are rather ambitious. Isn't the concept to use existing American Army M3 Lee vehicles?

I don't think the versions I've done are too much, they would just involve a bit of cutting and bolting on new metal plates, not that different than the Kangaroo or some of the other variants of the M3 that were done during the war IMO.

 

[pdf27]

I did this in A Blunted Sickle, although as APCs rather than IFVs - shift the engine to the front, delete the turrets (everything but a commander's MG, in fact) and fit rear doors where the engine was. The problem with IFVs is that they're ferociously expensive for what they do, which is to provide infantry with a bit more fire support under their own control.

At the time when the M3 chassis is available, the infantry don't even have any form of protected mobility (often no cross-country mobility in fact, being carried in lorries which are road-bound in most circumstances). That means you gain an awful lot from an APC conversion, and not a lot more from an IFV conversion - but you can have two or three APCs for the cost of one IFV, at least in new build. Turrets and guns are expensive, chassis units and machine gun rings are cheap.