The Kaiser's Toy Fleet and the Real German Army

[Deleted member 1487]

Furthermore, I am also suggesting that these additional troops would be used in East Prussia, which means that they will have 12 corps instead of the historical 4. That is likely to mean that the variant G of Plan 19 is likely to be used, meaning that the Russian 4th army deploys up north, further slowing Russian mobilization. The Russian 1st and 2nd armies were essentially based in Poland and the Baltic area pre-war anyway and did not need to be moved much to prepare for war. They were actually ready before the Germans.

However, the German mobilization is going to be slower too, as there are more trains needed and using the rather cramped lines in Prussia to deploy. Perhaps that will allow the Russians to advance first, catching the Germans off guard...

 

[Grimm Reaper]

Where are all these units coming from? Total eradication of the Kriegsmarine wouldn't add that many divisions worth of manpower.

 

[Deleted member 1487]

Where are all these units coming from? Total eradication of the Kriegsmarine wouldn't add that many divisions worth of manpower.

For Germany, manpower isn't the issue, it was funding for it. They conscripted less than the French did and had plenty of room for sustainable growth in their military had the funds been there. There was just more pressure for the fleet to be built, which was significantly less cost effective vis-a-vis what can be purchased for the amount of money invest. "The Kaiser's Army" by Eric Dorn Brose covers the politics around investing in the military, as well as the resistance by the "powers that be" to modernizing the military and further opening up the technical branches to the middle class. The change was coming, but it required a sponsor in the manner of Tirpitz to create. A Kaiser more interested in army toys instead of naval ones would fit the bill nicely. In fact, historically the Kaiser was a major proponent of the machine gun being adopted in large numbers, which was resisted by many traditionalists. So something like this certainly was possible with the right pressure.

 

[BlairWitch749]

By changing Willie's very character its possible the GO WEST idea gets scrapped. Perhaps the Germans adopt a strategy of staying put in the west using the Belgians and their own excellent border fortifications as a shield and sending the striking power of their army against the russians where the force to space ratio was low enough where general trench warfare wouldn't lead to strategic stalemate

 

[Deleted member 1487]

The only problem with that is that the Kaiser had nothing to do with war planning. In fact, he was kept out specifically because the military wanted to have a free hand it what they considered 'their' realm. They heavily resented that the Kaiser would come in and give them orders to change things in the military, like with the machine gun issue. No branch, outside a few forward thinking individuals, really wanted anything to do with the machine gun even after the Kaiser demanded they have it.

But the major problem for Germany is the two front long war. Moltke considered that the long war was inevitable, which is why he didn't invade Holland for the Maastricht area's rail lines; he wanted to keep the Dutch neutral so that he could use them as a trading front with the world. Also, Moltke correctly realized that HIS plan (I am of the school that the Schlieffen plan really didn't exist other than as a funding ploy and the real plan was of Moltke's design) would not result in victory at 40 days. Really, he expected to hurt the French army badly enough that he could then transfer large numbers of troops East while mopping up the West.

Attacking Russia, while diplomatically logical, would only result in Germany's greatest fear: being stuck in Russia's vast wilderness with no strategic victories or plan to get out, while an undiminished and industrially intact France pounds at Germany's back door. He knew that the French would be the first to develop heavy artillery large enough to break through the Metz, Thionville, Strasbourg forts. With the vast land to hold down in Russia and with a weak ally (yes the German military realized that the Austro-Hungarians were not very useful as an ally), they will not have extra forces to use in the West, or at least not enough to hold back the French indefinitely while still trying to land a knock out blow against the Russians.

In hindsight we know that the Russians could not have politically lasted long with the Germans kicking in their front door, but the German military had their perspective changed when Russia made its rapid recovery after the Russo-Japanese war. Fearing that the Russians would be much tougher than they proved to be, the German high command assumed that they could not defeat Russia in an all out move like they could the French. They thought the French would capitulate quickly after losing an army or more.

It turns out they overestimated the Russians and underestimated the French, a situation to be reversed in WW2 based on experiences in WW1. The point is that even with the Kaiser more involved in getting extra funding for the army and pushing more technology on them, Moltke would be even more resistant to the Kaiser trying to butt his nose into military planning.

Historically even when the Kaiser ordered Moltke to change the thrust of the army East in early August 1914, he was ignored. Here that situation would be worse, what with Moltke resenting the Kaiser's input, but the general military situation better, as then Moltke can leave the Eastern Front comfortably in the hands of his 3 Eastern armies and keep all the West Heer in France. It would have interesting knock on effects for the conduct of the Marne campaign as there would be an extra two corps present for the battle, which was 2/3's the number of corps that were in the new 7th army that plugged the gap between the 1st and 2nd armies after that battle. That could very well mean that there is no need to pull back to the Aisne line, as the Marne river would be far enough to close the breech thanks to these corps, which could be reinforced by the historic 7th army. Also the Entente did not follow very hard on the heels of the retreating Germans, which means that they have breathing room to regroup and continue the offensive with reinforcements from the left wing...

 

[BlairWitch749]

The only problem with that is that the Kaiser had nothing to do with war planning. In fact, he was kept out specifically because the military wanted to have a free hand it what they considered 'their' realm. They heavily resented that the Kaiser would come in and give them orders to change things in the military, like with the machine gun issue. No branch, outside a few forward thinking individuals, really wanted anything to do with the machine gun even after the Kaiser demanded they have it.

But the major problem for Germany is the two front long war. Moltke considered that the long war was inevitable, which is why he didn't invade Holland for the Maastricht area's rail lines; he wanted to keep the Dutch neutral so that he could use them as a trading front with the world. Also, Moltke correctly realized that HIS plan (I am of the school that the Schlieffen plan really didn't exist other than as a funding ploy and the real plan was of Moltke's design) would not result in victory at 40 days. Really, he expected to hurt the French army badly enough that he could then transfer large numbers of troops East while mopping up the West.

Attacking Russia, while diplomatically logical, would only result in Germany's greatest fear: being stuck in Russia's vast wilderness with no strategic victories or plan to get out, while an undiminished and industrially intact France pounds at Germany's back door. He knew that the French would be the first to develop heavy artillery large enough to break through the Metz, Thionville, Strasbourg forts. With the vast land to hold down in Russia and with a weak ally (yes the German military realized that the Austro-Hungarians were not very useful as an ally), they will not have extra forces to use in the West, or at least not enough to hold back the French indefinitely while still trying to land a knock out blow against the Russians.

In hindsight we know that the Russians could not have politically lasted long with the Germans kicking in their front door, but the German military had their perspective changed when Russia made its rapid recovery after the Russo-Japanese war. Fearing that the Russians would be much tougher than they proved to be, the German high command assumed that they could not defeat Russia in an all out move like they could the French. They thought the French would capitulate quickly after losing an army or more.

It turns out they overestimated the Russians and underestimated the French, a situation to be reversed in WW2 based on experiences in WW1. The point is that even with the Kaiser more involved in getting extra funding for the army and pushing more technology on them, Moltke would be even more resistant to the Kaiser trying to butt his nose into military planning.

Historically even when the Kaiser ordered Moltke to change the thrust of the army East in early August 1914, he was ignored. Here that situation would be worse, what with Moltke resenting the Kaiser's input, but the general military situation better, as then Moltke can leave the Eastern Front comfortably in the hands of his 3 Eastern armies and keep all the West Heer in France. It would have interesting knock on effects for the conduct of the Marne campaign as there would be an extra two corps present for the battle, which was 2/3's the number of corps that were in the new 7th army that plugged the gap between the 1st and 2nd armies after that battle. That could very well mean that there is no need to pull back to the Aisne line, as the Marne river would be far enough to close the breech thanks to these corps, which could be reinforced by the historic 7th army. Also the Entente did not follow very hard on the heels of the retreating Germans, which means that they have breathing room to regroup and continue the offensive with reinforcements from the left wing...

France had almost ZERO "heavy" artillery in 1914... they where releying on the 75mm which had too flat of a trajectory and too small a payload for work against forts especially one as advanced as Metz. The majority of the guns France had in 1914 above 105mm where Debange guns from 1877-1880 that lacked a recoil mechanism (essentially franco prussian war pieces except breach loaders) France didn't even mint the monsterous 520mm metz buster howitzers till late 1917 and they didn't even have the good Schneider 155mm in any appreciable quantity till Petain's Verdun counter offensive in 1917. That gives Germany an awfully long time to beat up the Russians... plus France is going to get roughly handled attacking the metz forts over and over again

 

[Deleted member 1487]

The French had about 300 pieces of heavy artillery ready to deploy in 1914, not counting the fortress artillery, which could be removed and used provided gun carriages could be made. Without a quarter of French industry being captured and 80% of their steel and coal industry being taken or rendered useless by German actions, the French are in a much much better place to produce heavy artillery. One cannot compare historical France with this France, as it would also have another 3 million citizens not under German control. France also had 9 regiments of "foot" artillery, which were their siege guns. If given free reign to attack Germany at will, these could be brought to bear on German forts one by one. Also, with none of their forts under attack the French could take the heavy caliber guns out of their mountings and use them in the field. Granted this would take time, but by 1915, with unimpeded work by a complete French industry, these guns will all be ready for use at the front. Granted, they would also be out of date, but when France is the one dictating when and where engagements are being fought, they can concentrate their artillery to make it as effective as possible. This is a situation that Germany was dreading, as France was a modern, western nation with modern industry. If not disrupted, they could bring some nasty firepower to bear after the initial battles.

Moltke and the German staff were also worried that during this period of perhaps up to one year they would not have decisively defeated Russia and would in fact be further committed in the depths of the country, something that Russian planners counted on. Add to that the fear of Russian manpower and the impression that the Russians could take unlimited casualties, and the words quagmire ring loud and true. Like I stated before, the Russians were not the Russians of WW2, but the Germans thought they had that kind of staying power. This was also something Russian planners thought, so the Germans weren't that off base thinking so, but one cannot assume the German war planning would suddenly be changed because the Kaiser had a different personality.

Edit:
http://www.landships.freeservers.com/fivestar_305mm_m06_rrgun_kitreview.htm
adopted in 1906

 

[stevep]

Guys

I think they key points would be what way the Germans seek to use the resources freed up by not having a massive fleet and how the various countries respond to the differing circumstances. Mainly Britain without a German naval threat but there will be other effects as well.

Germany wouldn't recruit many more troops initially because they wanted to keep the army politically reliable, recruited largely from conservative agricultural areas. However without the large fleet they have a lot of skilled manpower, money and potential other resources freed up. Some of this will go into a more heavily developed army but others might go into the general economy, whether productively or not. Interesting point raised that the change might increase social tension by limiting the outlets for the middle class. The other option when war comes is that Germany doesn't over-moblise and keeps [or more likely when it realises the problem] returns some manpower to the civilian economy, especially agriculture.

The big factor is what does Britain do? Does the mistrust of Edward VII and the concerns about German military domination of Europe still mean Britain joins the entente powers. Or does the continued naval build-ups by France and Russia, coupled with colonial tensions and the fear that Russia especially is getting too strong, plus possibly better German diplomacy mean Britain sides with the central powers. Alternatively Britain could stay neutral, especially if the war doesn't involve a massive invasion of Belgium. In that case Britain might stay neutral and trade with both sides. [Or the great war might be a mainly colonial conflict with Britain, probably allied with Japan and possibly Turkey clashing with France and Russia.]

If Britain sides with the entente a lot of butterflies will still happen but likely the allies still win, although only after a long war. If Britain sides with the central powers then they almost certainly win. If Britain stays neutral then depends on the circumstances but probably a limited German victory. [As Viking said there were a lot of fears about a German advance deep into Russia and they might well have come true without the Russians spending several years attacking to take the pressure off France]. However any victory in the west for Germany is likely to be costly for all involved.

Steve

 

[Campbell1004]

The French had about 300 pieces of heavy artillery ready to deploy in 1914, not counting the fortress artillery, which could be removed and used provided gun carriages could be made. Without a quarter of French industry being captured and 80% of their steel and coal industry being taken or rendered useless by German actions, the French are in a much much better place to produce heavy artillery. One cannot compare historical France with this France, as it would also have another 3 million citizens not under German control. France also had 9 regiments of "foot" artillery, which were their siege guns. If given free reign to attack Germany at will, these could be brought to bear on German forts one by one. Also, with none of their forts under attack the French could take the heavy caliber guns out of their mountings and use them in the field. Granted this would take time, but by 1915, with unimpeded work by a complete French industry, these guns will all be ready for use at the front. Granted, they would also be out of date, but when France is the one dictating when and where engagements are being fought, they can concentrate their artillery to make it as effective as possible. This is a situation that Germany was dreading, as France was a modern, western nation with modern industry. If not disrupted, they could bring some nasty firepower to bear after the initial battles.

Moltke and the German staff were also worried that during this period of perhaps up to one year they would not have decisively defeated Russia and would in fact be further committed in the depths of the country, something that Russian planners counted on. Add to that the fear of Russian manpower and the impression that the Russians could take unlimited casualties, and the words quagmire ring loud and true. Like I stated before, the Russians were not the Russians of WW2, but the Germans thought they had that kind of staying power. This was also something Russian planners thought, so the Germans weren't that off base thinking so, but one cannot assume the German war planning would suddenly be changed because the Kaiser had a different personality.

Edit:
http://www.landships.freeservers.com/fivestar_305mm_m06_rrgun_kitreview.htm
adopted in 1906

Wiking, you are an incredible fountain of wealth and your posts are full of key information. What are your sources? If you wouldn't mind passing the names of a few to me, id be very appreciative.

 

[Deleted member 1487]

Wiking, you are an incredible fountain of wealth and your posts are full of key information. What are your sources? If you wouldn't mind passing the names of a few to me, id be very appreciative.

Osprey's book on the French army and landships about some artillery. Also the economics of WW1- its a compilation work inexpensive on amazon, but quite technical.

 

[BlairWitch749]

The French had about 300 pieces of heavy artillery ready to deploy in 1914, not counting the fortress artillery, which could be removed and used provided gun carriages could be made. Without a quarter of French industry being captured and 80% of their steel and coal industry being taken or rendered useless by German actions, the French are in a much much better place to produce heavy artillery. One cannot compare historical France with this France, as it would also have another 3 million citizens not under German control. France also had 9 regiments of "foot" artillery, which were their siege guns. If given free reign to attack Germany at will, these could be brought to bear on German forts one by one. Also, with none of their forts under attack the French could take the heavy caliber guns out of their mountings and use them in the field. Granted this would take time, but by 1915, with unimpeded work by a complete French industry, these guns will all be ready for use at the front. Granted, they would also be out of date, but when France is the one dictating when and where engagements are being fought, they can concentrate their artillery to make it as effective as possible. This is a situation that Germany was dreading, as France was a modern, western nation with modern industry. If not disrupted, they could bring some nasty firepower to bear after the initial battles.

Moltke and the German staff were also worried that during this period of perhaps up to one year they would not have decisively defeated Russia and would in fact be further committed in the depths of the country, something that Russian planners counted on. Add to that the fear of Russian manpower and the impression that the Russians could take unlimited casualties, and the words quagmire ring loud and true. Like I stated before, the Russians were not the Russians of WW2, but the Germans thought they had that kind of staying power. This was also something Russian planners thought, so the Germans weren't that off base thinking so, but one cannot assume the German war planning would suddenly be changed because the Kaiser had a different personality.

Edit:
http://www.landships.freeservers.com/fivestar_305mm_m06_rrgun_kitreview.htm
adopted in 1906

Wiking... those 300 guns didn't have recoil mechanisms... making them useless on the modern battlefield. Lets assume france makes two or three disasterous lunges at metz before they realize that they can't crack forts without heavy howitzers... it would probably take them at least a year to produce a viable number of guns to saturate the forts and try to storm them and even if they fall the germans can retire to the rhine which is a strong positions

 

[Deleted member 1487]

Wiking... those 300 guns didn't have recoil mechanisms... making them useless on the modern battlefield. Lets assume france makes two or three disasterous lunges at metz before they realize that they can't crack forts without heavy howitzers... it would probably take them at least a year to produce a viable number of guns to saturate the forts and try to storm them and even if they fall the germans can retire to the rhine which is a strong positions

That is just factually wrong. There were several batteries of the modern French 122mm and 150mm howitzers. Beyond that, the lack of a modern recoil mechanism does NOT make them useless. Sure, they cannot fire as quickly, but a heavy shell will kill you dead regardless of the recoil mechanism of the weapon that fired it. As to the claim that the French lacked useful siege guns, the 305mm rail artillery guns would be effective is smashing through the Metz or Thionville forts. Though lacking the same level of heavy artillery the French would wise up quickly, especially when they are dictating the pace of the campaign. Eventually massed heavy artillery, from dismounted fortress guns, would be concentrated enough to counter the German advantage at some point of the line. Then its just a short step to the 'grignoter' strategy of limited battle, a la the Champagne battles, where the French started using heavy artillery effectively. Sure they lost there, but initially they effectively annihilated several German divisions. When they moved beyond the heavy guns' support, they lost heavily themselves.

But in the meantime, the French can afford such losses in learning, while the Germans are not able to do anything about it but hope the Russians collapse as they advance deeper and deeper into Russia. As this goes on, the French are then able to build more and better guns, raining down hails of artillery on the Germans, wrecking the Metz-Thionville forts, which were not as well upgraded as the Verdun complex that survived the heavy German shelling. Soon the border defenses are gone and it becomes an ugly grinding scenario, where the French learn to fight like they did in 1917, advancing only to a limited point and moving up their artillery and repeating until they are grinding out the Germans. Historically the Germans never developed a successful counter to this method. It is slow, but the Germans don't have strategic depth in the Alsace region. Their important mines of the Saar become immediately vulnerable both to artillery and air attack, thanks to strategic bombing, which can also hit the Ruhrgebiet.

 

[The Sandman]

In the absence of a significant fleet, here's somewhere the Germans could open up for middle-class military service: the engineering and logistics wing. Anything that lets the Germans manage their supply train and war industry better can only aid the war effort. Even on a local scale, better planning and an engineering corps that can rebuild the rail/road infrastructure more quickly behind the German advance would let the Germans get farther into northern France before running out of steam.

Also, the lack of a significant German navy coupled with the likelihood of Britain joining on the side of France in any general European war might force the Germans to make more deliberate preparation for the effects of a British blockade, as they will know from the outset that they have no chance of breaking it.

 

[Deleted member 1487]

In the absence of a significant fleet, here's somewhere the Germans could open up for middle-class military service: the engineering and logistics wing. Anything that lets the Germans manage their supply train and war industry better can only aid the war effort. Even on a local scale, better planning and an engineering corps that can rebuild the rail/road infrastructure more quickly behind the German advance would let the Germans get farther into northern France before running out of steam.

Also, the lack of a significant German navy coupled with the likelihood of Britain joining on the side of France in any general European war might force the Germans to make more deliberate preparation for the effects of a British blockade, as they will know from the outset that they have no chance of breaking it.

Couple of interesting discoveries. The German army league was only founded in 1912 (december 1911) and it only had 90,000 members (though nearly every army officer!) compared to 380,000 or so members to the naval league (founded in 1897). Perhaps if it is founded earlier with the Kaiser's backing, the 1913 army bill, which was heavily cut down (only raised the army by 117,000 instead of the 300,000 requested and didn't include provisioning for heavy artillery thanks to Falkenhayn's predecessor von Heeringen). So the will was there, just that it was stifled by the conservatives clinging to tradition and not trusting the middle class and liberals in the army.

With an earlier army league and the replacement of the naval law of 1912 with an earlier, full army bill of 1913, then what I have suggested is very possible. Of course this would mean the victory of the technocrats, which changes the army and training substantially. No more bayonet charges, but rather open order manuever and fire superiority. Falkenhayn would have to rise earlier and Ludendorff, one of the major proponents of modernization and expansion, who incidently was demoted for his efforts on the 1913 bill, would have to be promoted too.

Of course the effects would be huge and a major boon for the German army.

As to the prepartions for a blockade, Germany did start planning with the famous Walther Rathenau pre-war (he headed up German economic planning during the war), but his recommendations were rejected because stockpiling resources was seen as a provocation and that Germany was planning on launching a war soon. It would have to be clandestine, but that is going to be hard to hide...

 

[jkay]

Arrogance like Willy II's, I fear, is a pretty big barrier to innovation. You have to have the honesty to always look at your own which bits of your ideas aren't working. I could go on for depressing pages on successful people of all sorts who grew arrogant from success and did little else after success went to their heads.

It's one of the wonders of the world that the delaying effort outside Antwerp made by a mere two British brigades with armored cars in 1914 didn't get serious attention sooner.

It got plenty of attention from Churchill, who'd put them there as an experiment, and was hoping they'd be able to move fronts forward as the armored knights of old had, only at motorcar speed. They did, in fact, outperform regular infantry, but they needed treads and more size to cross trenches. Tanks also had better armor and integral cannon.

I rather doubt the Ottomans would be calm at the robbery of their battleships even without a replacement at hand. After all, they didn't dominate much even with the German ships.

It had been true, by the way, since the American Civil War that military fronts moved slowly, if at all, and would stay that way until the tank was invented at the end of the war. That's because rifles' rates of fire had risen high enough that most of an army would be mowed down from trenches before it could get far. Meanwhile, those trenches could be dug in one desperate night.

 

[Monty Burns]

As to the prepartions for a blockade, Germany did start planning with the famous Walther Rathenau pre-war (he headed up German economic planning during the war), but his recommendations were rejected because stockpiling resources was seen as a provocation and that Germany was planning on launching a war soon. It would have to be clandestine, but that is going to be hard to hide...

This, again, brings us back to the major factor to be considered here: Britain. Only Britain can impose a blockade on either side. With Britain allied to the central powers, France will be blocked without Haber-Bosch. With Britain neutral neither side will be effectively blocked.

 

[Riain]

I'd like to point out that the HSF forced the RN to adopt a distant blockade, it being impossible for the RN to mount a close blockade in the face of 2 dozen capital ships. With no HSF a close blackade would have been far more uncomfortable for Germany.

 

[larpsidekick]

I'd like to point out that the HSF forced the RN to adopt a distant blockade, it being impossible for the RN to mount a close blockade in the face of 2 dozen capital ships. With no HSF a close blackade would have been far more uncomfortable for Germany.

It wasn't the capital ships that stopped close blockade, it was submarines, mines and torpedo carrying destroyers - plus the realisation that it wasn't necessary (distant blockade was sooo much easier on the logistics chain). Essentially, the Admiralty couldn't afford to loose Dreadnoughts (battleships or battlecruisers) to those threats, as it would reduce the number active in the fleet to close to parity (or less than parity) with the HSF, giving the HSF the ability to try for a decisive battle.

If it had just been the 2 dozen battleships, the Admiralty would have happily have posted a close blockade, or gone through into the baltic, or any number of Jackie Fishers madcap schemes, to draw those two dozen into the next trafalgar.

 

[stevep]

I'd like to point out that the HSF forced the RN to adopt a distant blockade, it being impossible for the RN to mount a close blockade in the face of 2 dozen capital ships. With no HSF a close blackade would have been far more uncomfortable for Germany.

Riain

Not sure that's right. For one thing a more distant blockade was pretty damned effective, at least for Germany because of the simple geography.

More to the point there were a number of factors that made a close blockade more difficult and expensive whether or not the target had a powerful battlefleet:
a) The change from wind to steam meant that ships at sea, while they had more reliability in movement also meant that they no longer had potentially infinite fuel.

b) Improvements in communications, along with steam power giving reliable propulsion, meant it was easier to coordinate separate forces. This works for both sides to a degree but especially with radio still very much in its infancy the blockaded state has the advantage of land lines i.e. telegraphs.

c) The general increase in range of weapons while they make naval guns more powerful also make coastal batteries far more formidable. Again ship-based guns will tend to lose against well established and organised batteries so this forces the ships to stand further off.

d) A range of other new weapons, most especially the mine and torpedo, make operating large ships more difficult and dangerous is close and coastal waters. Especially with fast light torpedo boats and even more early subs, which unlike in Nelson's time, have a real chance of damaging and destroying capital ships.

e) The much greater cost and complexity of modern [by the time] ships also means they are scarer. Even Britain in WWI only had about 50-60 dreadnoughts as compared to ~200 ship of the line a century before. This means they can't be in as many places and are more difficult to replace. Also their greater complexity means its more likely they will need time in the dockyards.

As such, even if Britain went to war with a Germany that had say only 6-10 old coastal battleships but a lot of modern light vessels and defences I doubt a close blockade would be practical. Its definitely likely to be a lot more costly.

What would be the saving grace is that if Germany has a much smaller battlefleet Britain - other threats allowed for - needs a smaller force itself and can concentrate on more smaller ships.

All this presumes that Britain is on the opposite side to Germany in a big conflict. Which could be an highly debatable point.

Steve

 

[BlairWitch749]

That is just factually wrong. There were several batteries of the modern French 122mm and 150mm howitzers. Beyond that, the lack of a modern recoil mechanism does NOT make them useless. Sure, they cannot fire as quickly, but a heavy shell will kill you dead regardless of the recoil mechanism of the weapon that fired it. As to the claim that the French lacked useful siege guns, the 305mm rail artillery guns would be effective is smashing through the Metz or Thionville forts. Though lacking the same level of heavy artillery the French would wise up quickly, especially when they are dictating the pace of the campaign. Eventually massed heavy artillery, from dismounted fortress guns, would be concentrated enough to counter the German advantage at some point of the line. Then its just a short step to the 'grignoter' strategy of limited battle, a la the Champagne battles, where the French started using heavy artillery effectively. Sure they lost there, but initially they effectively annihilated several German divisions. When they moved beyond the heavy guns' support, they lost heavily themselves.

But in the meantime, the French can afford such losses in learning, while the Germans are not able to do anything about it but hope the Russians collapse as they advance deeper and deeper into Russia. As this goes on, the French are then able to build more and better guns, raining down hails of artillery on the Germans, wrecking the Metz-Thionville forts, which were not as well upgraded as the Verdun complex that survived the heavy German shelling. Soon the border defenses are gone and it becomes an ugly grinding scenario, where the French learn to fight like they did in 1917, advancing only to a limited point and moving up their artillery and repeating until they are grinding out the Germans. Historically the Germans never developed a successful counter to this method. It is slow, but the Germans don't have strategic depth in the Alsace region. Their important mines of the Saar become immediately vulnerable both to artillery and air attack, thanks to strategic bombing, which can also hit the Ruhrgebiet.

A debange gun has to be repositioned after every single shot... they would be horribly vulnerable to rapid firing german 150mm guns which could fire from superior angles

Also it should be noted that the Germans where able to beat the Russian's in otl without ever employing more than 55ish of their divisions in the theater. By concentrating at Metz and using Belgium as a shield they could still have 70 divisions guarding the west with their appropriate artillery componets and send another 85 to go beat up the Russians