Mechanization

[tomo pauk]

The ww2 saw many of the tecnical developments, one of those was a strong trend towards mechanization of ground forces (for the countries that could afford such thing, of course). Starting with tanks, introducing SP artillery, AAA, infantry transporters, amphibious vehicles, logistical vehicles - all based on either full- or half-tracked platforms.
Could the things be sped up? British were experimenting with 'Birch gun', an SP piece that combined hull of medium tank and armed with 'all elevation' 18pdr cannon. Soviets were experimenting with APCs based on the T-26. Early in ww2, Germans used 15cm infantry gun and the 4,7cm ATG on the Pz-I chassis, and 7,5cm gun on the Pz-III chassis (StuG-III). So lets see, in an alternate history layout, what could happen when, say, British don't discard the 'Birch gun' concept and decide to explore it further.

to be continued

 

[davebender]

Certainly. It's just a matter of how a nation decides to spend their military budget. Spend the money for mechanized equipment plus logistical support and you will have it. Something else will get a budget cut at the same time.

 

[tomo pauk]

To start with alt history time line:
In 1936, the idea of a 'regular' artillery piece carried on tracked chassis was embraced once again, this time with determination to really introduce the new equipment to the Army.
The gun to be carried was the 18pdr, while companies offered their tracked hulls as the platforms. In 1937, the 3 proposals that were chosen for pre-series production of 6 vehicles each were the Bren Carrier, Vickers LT Mk VI and the modification of the Vickers 6 ton tank. The trials revealed shortcomings: Carrier was judged as a too light vehicle, not allowing for any useful numbers of round to be carried, the LT Mk VI was also far away from a comfortable vehicle, while the 6 ton tank conversion was not that fast as the LT conversion, and absence of the tank from the British Army ranks was weighted also against it. So it was decided to install wider combat compartment at the rear hull of the Mk VI , providing the more room for crew and ammo, and the Bren MG is to be installed to provide a form of self-defense. In order to provide more ammo, each SP piece can tow a limber from the towed 18pdr.

Picture, you say? This is a historical conversion of a captured Mk VI, sporting the German 10,5cm LefH 16 howitzer ( a ww1 left-over); note the ground brake:

 

[davebender]

What is being cut from the RAF and/or RN to pay for an increase of the British Army budget?

 

[davebender]

France probably has the best chance for SP howitzers at the start of WWII. By the mid 1930s they had a mature tank industry and they had a newly installed communist government that voted a massive increase in military spending. With different spending decisions a large portion of French Army 105mm light howitzers could be mounted on a tracked chassis. They could also produce APCs based on one of their existing light tank chassis.

 

[tomo pauk]

What is being cut from the FAF Marine Nationale to get such stuff?

What is being cut from the RAF and/or RN to pay for an increase of the British Army budget?

Nothing - part of the the hulls of the LT Mk VI is used for the SP artillery (= less light tanks), the Britain is awash with 18 pdr guns in the 1930s.

 

[Shortround6]

What is being cut from the FAF Marine Nationale to get such stuff?



Nothing - part of the the hulls of the LT Mk VI is used for the SP artillery (= less light tanks), the Britain is awash with 18 pdr guns in the 1930s.

Please Tomo, I expect better of you. Britain is awash is not a phrase I would have thought you would use

Britain hasn't made an 18pdr since about 1919. There are two rather distinctive 18pdrs. The older ones with the recoil system on top of the barrel have rather limited elevation and traverse and are the older style, meaning that if any large number have not already been scrapped they are due for it. Mounting barrels with a good part of their useful life already gone on new tracked carriages in peace time is a sure way to start a scandal in the press.
many of the newer ones with the recoil system under the barrel are slated to be rebored/relined from 83.4mm to 87.5mm to make 18/25pdr guns as the treasury is too cheap to buy new 25pdr field guns.

Mounting the guns on the MK VI chassis is also a mark of desperation. Better than using a team of horses perhaps but putting the barrels on a tracked chassis is just the start of the equation. You need ammo, and battery command posts, and radio links and wire parties and so on. Standard British doctrine was to have 142 rounds of 25pdr ammo in the first line of supply for towed guns, 114HE 16 smoke and 12 AP. More ammo is in the 2nd and 3rd echelons of supply. Please note that the German Wespe is not as "efficient" as some people make it out to be. Every 4 gun battery had another two chassis acting as ammo carriers.

 

[tomo pauk]

--continuation--

When the trials of the modified SP piece were conducted in 1938, the Army had more confidence to continue.
It was decided to move on with larger heavier vehicle, the one that would be as armored as tanks the Army was purchasing, bolstering their punch when used together. For a short time it was considered to build tank's versions that would've featured short howitzer in turrets, but that was discarded since it was felt that a shell of decent both weight and muzzle would come in handy. With the new gun, the 25pdr, wanted as main armament, arming the turret of the tanks in production was out of question, so the designers proposed a more refined gun layout of the French Char B1 for the new 'tank'. In 1939, the boxy superstructure (called 'ugly' by many of the people that saw it) was added instead of the turret at the hull of the A9 tank. Hull MG turret were deleted, one MG mounted at the roof. Superstructure was featuring overhangs above tool boxes, and was armed with 18pdr instead of planned 25pdr.
Another hull considered for the same role was from the Matilda II.
A rough sketch how should the A9 version looked:

--tbc--

 

[davebender]

The Wespe was a dirt cheap wartime improvisation to take the place of the cancelled Sd.Kfz.165/1. Without the desperate wartime need for lots of low cost equipment the Marder SP AT gun and Wespe SP 10.5cm howitzer would not have produced.

Peacetime production should plan for something better.

 

[tomo pauk]

Please Tomo, I expect better of you. Britain is awash is not a phrase I would have thought you would use

May I plead to be a non-original speaker?

Britain hasn't made an 18pdr since about 1919. There are two rather distinctive 18pdrs. The older ones with the recoil system on top of the barrel have rather limited elevation and traverse and are the older style, meaning that if any large number have not already been scrapped they are due for it. Mounting barrels with a good part of their useful life already gone on new tracked carriages in peace time is a sure way to start a scandal in the press.
many of the newer ones with the recoil system under the barrel are slated to be rebored/relined from 83.4mm to 87.5mm to make 18/25pdr guns as the treasury is too cheap to buy new 25pdr field guns.

Well, it could go this way: not everyone (that was in charge for this or that) was a 'true believer' into the SP artillery case, so not many of those were built, maybe one hundred by the time UK declared the war?

Mounting the guns on the MK VI chassis is also a mark of desperation. Better than using a team of horses perhaps but putting the barrels on a tracked chassis is just the start of the equation. You need ammo, and battery command posts, and radio links and wire parties and so on. Standard British doctrine was to have 142 rounds of 25pdr ammo in the first line of supply for towed guns, 114HE 16 smoke and 12 AP. More ammo is in the 2nd and 3rd echelons of supply. Please note that the German Wespe is not as "efficient" as some people make it out to be. Every 4 gun battery had another two chassis acting as ammo carriers.

Not a 'mark of desperation', but more of 'the war might be starting; if works in real combat - fine, we'll build more (and/or better stuff); if not - we did not spent too much of money, and the hulls guns can be reused'.
I've already stated that the limber would be towed behind (80 rounds, if I've counted correctly), and some quantity of the ammo can be carried on board. The dedicated ammo vehicle could be used, and it was used in German units operating the 10,5/Mk VI combo; it was based upon the Mk IV itself, and was also towing a trailer. The German version was not towing a limber, so the separate ammo vehicle was necessity; the 10,5cm ammo being more voluminous anyway.
The artillery units will get what it takes to be proper units: command posts, radio links etc.

 

[Shortround6]

Well, it could go this way: not everyone (that was in charge for this or that) was a 'true believer' into the SP artillery case, so not many of those were built, maybe one hundred by the time UK declared the war?



Not a 'mark of desperation', but more of 'the war might be starting; if works in real combat - fine, we'll build more (and/or better stuff); if not - we did not spent too much of money, and the hulls guns can be reused'.
I've already stated that the limber would be towed behind (80 rounds, if I've counted correctly), and some quantity of the ammo can be carried on board. The dedicated ammo vehicle could be used, and it was used in German units operating the 10,5/Mk VI combo; it was based upon the Mk IV itself, and was also towing a trailer. The German version was not towing a limber, so the separate ammo vehicle was necessity; the 10,5cm ammo being more voluminous anyway.
The artillery units will get what it takes to be proper units: command posts, radio links etc.

If you haven't seen it yet try this web site;

British Artillery in World War 2

Many pages and while you might not agree with everything it does provide a very good over view of artillery in general.

There is a distinct difference between an armored gun used for direct fire assaults and self propelled artillery or "mechanized" artillery. For an artillery battery or battalion to be truly "mechanized" not just the guns but a very large part of the battery/battalion must be mechanized. It does no good to get the guns across 20 miles of sandy dessert if half of the radios, field phones, and meteorological section are left behind. Every sub unit or section in the Battery/battalion needs the same mobility.

Somebody once said the shells are the weapon, the guns are just the delivery system. An artillery howitzer or gun is expected to fire 5000-10,000 rounds before needing a new liner. Towing un-armored trailers of ammo behind the tracked armored SP gun is a sure indicator that something wasn't planned well. Granted proper use of even armored SP guns calls for them to thousands of yards from the front lines.
Artillery fire often calls for time fuses and in the case of howitzers instead of guns, zone charges. towed guns have 6 or more in the gun crew in order to handle all the tasks, A GOOD SP artillery piece is going to have room for a gun crew of 4-6 men to work and serve the gun including ammo preparation. This means more than one loader. One man cannot unpack, fuse, adjust fuse timing and load the gun while keeping up any sort of rapid fire rate. Having to adjust the zone charges on Howitzers just adds to the confusion/slows the rate of fire.

Armored boxes on the top of tank hulls are fine for putzing around but as the British found with the Bishop: Bishop (artillery) - Wikipedia, the free encyclopedia

They are far, far from ideal. The Sexton may have been less than ideal ( no top cover, not as much ammo as desired, height made bombing up difficult, more?) but a battery of Sextons could provide fire to a much, much larger area than even several batteries of Bishops. Which is the better buy?

In peace time take the time to get it right, To much time,effort, and money was spent on half-**sed solutions that were "cheap" but of dangerously limited actual ability.

 

[tomo pauk]

There is a distinct difference between an armored gun used for direct fire assaults and self propelled artillery or "mechanized" artillery. For an artillery battery or battalion to be truly "mechanized" not just the guns but a very large part of the battery/battalion must be mechanized. It does no good to get the guns across 20 miles of sandy dessert if half of the radios, field phones, and meteorological section are left behind. Every sub unit or section in the Battery/battalion needs the same mobility.

I've tried to respond to the similar question raised, by:
-The artillery units will get what it takes to be proper units: command posts, radio links etc.-
That means that the supporting parts of the unit will travel either by gun-less SP gun platforms, and part of them can travel on the 'Bren' carriers.

Somebody once said the shells are the weapon, the guns are just the delivery system. An artillery howitzer or gun is expected to fire 5000-10,000 rounds before needing a new liner. Towing un-armored trailers of ammo behind the tracked armored SP gun is a sure indicator that something wasn't planned well. Granted proper use of even armored SP guns calls for them to thousands of yards from the front lines.

Good call on the unarmored trailer being a fair game to threats that would not harm the vehicle towing it (the SP in question gun should provide horizontal protection vs. artillery splinters up to the rifle/LMG fire). The cure might be the trailer with same level of protection (even if it need to carry only 60 rds, to allow for weight of the armor), while introducing a dedicated ammo carrier (based on same vehicle as the SP gun).

Artillery fire often calls for time fuses and in the case of howitzers instead of guns, zone charges. towed guns have 6 or more in the gun crew in order to handle all the tasks, A GOOD SP artillery piece is going to have room for a gun crew of 4-6 men to work and serve the gun including ammo preparation. This means more than one loader. One man cannot unpack, fuse, adjust fuse timing and load the gun while keeping up any sort of rapid fire rate. Having to adjust the zone charges on Howitzers just adds to the confusion/slows the rate of fire.

The German version was served with 4 men (+ driver).

Armored boxes on the top of tank hulls are fine for putzing around but as the British found with the Bishop: Bishop (artillery) - Wikipedia, the free encyclopedia

They are far, far from ideal.

I'm gearing the A9 'Stug' more towards direct fire role (they would serve instead of historical CS tanks).

The Sexton may have been less than ideal ( no top cover, not as much ammo as desired, height made bombing up difficult, more?) but a battery of Sextons could provide fire to a much, much larger area than even several batteries of Bishops. Which is the better buy?

Hold your horses, we are still in 1939 here. The LT Mk VI based SP gun will serve in artillery units, not the A9 based one.

In peace time take the time to get it right, To much time,effort, and money was spent on half-**sed solutions that were "cheap" but of dangerously limited actual ability.

I could not agree more.


If I was not clear above, this time line is not about the 'ideal SP artillery' for different countries, but a time line that would include trial and error, ups and downs, while some ideas would be adopted by other coutries. If I was to propose 'ideal' stuff, I'd went with 15-20 ton 75-105mm SP artillery, and 25-30 ton 115-155mm stuff.

 

[yulzari]

The German army had less of a trend to mechanisation and more of a trend to equitation with horse power remaining a crucial large part of their transport and artillery.

The British army began the war as the most committed to mechanisation, having all but eliminated horses in european operations. Though it found a worthwhile role for mules in poor ground conditions such as french mud, italian mountains and burmese jungle and was grateful for indian and cypriot muleteers amongst others.

The russians would have been hard pressed to mechanise their transport without american lorries which were the most vital support sent to russia.

 

[davebender]

Not so sure about this.

The BEF was mechanized but that was only a small part of the total British / UK army. For instance I doubt the large British controlled Indian Army was mechanized.

 

[Shortround6]

Tomo, a more "practical" SP gun for 1938-39 would be to take the A9, and much like the Archer 17pdr, turn it around so that the gun is pointed back over the engine deck. Use the 18pdr MK V Mount so you have 25 degrees traverse each way (or within vehicle limits) without moving the vehicle. 8 degrees of traverse is a joke. Now you have the room from the turret and mg turrets (and driver vacating his seat) for the gun crew to work. Much more room than a MK IV light tank lashup. More ammo on the vehicle.
When the Germans were converting those left over British and French chassis, not only did they not have enough tracked chassis of their own, or trucks, they didn't even have enough horses go around. Any way of moving a gun was an improvement over not moving it.
Much artillery fire is not done at the maximum rate of fire but limiting your peak rate of fire because of a too small vehicle is a problem that CAN be avoided in peace time.

While the entire ammunition supply doesn't need the same mobility as the guns there is usually a lot more ammunition than people think. In 1914 the "official" ammo supply for an 18pdr gun was 24 rounds on the gun limber, 152 rounds on ammo wagons in the battery, 76 rounds in the Brigade ammunition column, 126 rounds in the Division ammunition column for a total of 378 rounds on transport. A further 150 rounds were in Divisional ammunition parks and another 472 rounds in ordnance depots. These was supposed to be the allotment per gun in the field and not including storage in home depots or factories. How close they came I have no idea and a number of revisions happened as to what ammo was kept were as the war went on.

 

[davebender]

That would be useless for direct fire and the 18 pounder shell is too small for effective indirect fire. You would be further ahead to install an inexpensive 120mm mortar on an outdated tank chassis.

 

[Shortround6]

Yes it would be useless for direct fire but if you are using the divisional artillery assets for direct fire the situation has gone to pot in a big way and total disaster is imminent.

The M7 Priest and the Sexton were never intended for the direct fire role. Like wise the US M37 self propelled 105 was never intended for the direct fire role nor the post war M-108. The M-12 155mm was only intended for the direct fire role in the rarest of circumstances, as was the M-40. The M-55 and M-109s are not direct fire weapons. The M-41 was not a direct fire weapon.

As far as further ahead????

The 18pdr could range to 11,000yds with 38 degrees of elevation, given an observer in a good position (or aerial) it could sit thousands of yards out of range of the 120mm mortar and pound it to destruction.

If you want rebore/reline the the gun to take 25pdr ammunition as was done to around 1000 towed guns, not quite the range of a regular 25pdr (due to elevation limit) but th e traverse of the 18pdr MK V mount may make up for it.

18pdr HE shells of WW II weighed 18.5 lbs and carried 1.1 lbs of explosive. While not 105 howitzer rounds they are a step above 75mm rounds.

Your a bit too obsessed with cheap weapons. Cheap is good in some cases but carried too far results in the loss of capability. Russians equipped entire battalions with stamped sheet metal sub-machine guns and hand grenades, worked in cities and in the open with lots of t-34 tanks as close support. In the open without the tanks???
How much do the tanks cost in relation to the "normal" battalions heavy weapons?

Somebody once claimed the Germans would run from "cold steel" (bayonet charge) on the Russian front. A cynic replied they only ran after the machine gun ran out of ammunition.
Bayonets are really cheap. Machine guns are expensive. We know how most armies wound up voting.

 

[davebender]

If you are going to that trouble why not just develop a modern 105mm light howitzer?

 

[Shortround6]

Just maybe because were talking about the British army before WW II. Developing special guns "just" for the mechanized troops that took different ammo was a luxury nobody could afford.

The British did rebore/reline 1422 18pdrs to 25pdrs from 1937 to1941 while production of the "modern" 25pdr was organized and under taken, First "modern" 25pdr being made in 1940.

 

[tomo pauk]

Tomo, a more "practical" SP gun for 1938-39 would be to take the A9, and much like the Archer 17pdr, turn it around so that the gun is pointed back over the engine deck. Use the 18pdr MK V Mount so you have 25 degrees traverse each way (or within vehicle limits) without moving the vehicle. 8 degrees of traverse is a joke. Now you have the room from the turret and mg turrets (and driver vacating his seat) for the gun crew to work. Much more room than a MK IV light tank lashup. More ammo on the vehicle.
When the Germans were converting those left over British and French chassis, not only did they not have enough tracked chassis of their own, or trucks, they didn't even have enough horses go around. Any way of moving a gun was an improvement over not moving it.
Much artillery fire is not done at the maximum rate of fire but limiting your peak rate of fire because of a too small vehicle is a problem that CAN be avoided in peace time.

I have a vehicle like you're describing on the pipeline, it would not take much for the British to come out with one
IIRC the cause for artillery not firing on max rate was the barrel's imminent overheating, after a minute or two of firing at max rate?

While the entire ammunition supply doesn't need the same mobility as the guns there is usually a lot more ammunition than people think. In 1914 the "official" ammo supply for an 18pdr gun was 24 rounds on the gun limber, 152 rounds on ammo wagons in the battery, 76 rounds in the Brigade ammunition column, 126 rounds in the Division ammunition column for a total of 378 rounds on transport. A further 150 rounds were in Divisional ammunition parks and another 472 rounds in ordnance depots. These was supposed to be the allotment per gun in the field and not including storage in home depots or factories. How close they came I have no idea and a number of revisions happened as to what ammo was kept were as the war went on.

Thanks; as they say, logistics is the key