How can a "better" Kriegsmarine be built?

[ValiantHeart]

I’m not sure if this topic has been discussed before, but I’d like to hear your ideas for building a "better" Kriegsmarine than the one that existed irl.

I am not saying that "if Hitler had ordered the construction of [A, B, C...], Germany could have won the Battle of the Atlantic," but I do expect that a "better" Kriegsmarine would have adopted a more rational strategy and shipbuilding plan (Plan Z was pure fantasy/madness), leading to a better performance than what actually occurred?

From the moment I began to find this topic interesting - something surprising to me, as I am not typically a fan of alternate history - I delved into various forums and gathered a wealth of noteworthy opinions:

• Focusing solely on U-boats would not work, as the Anglo-German Naval Agreement restricted the construction of additional vessels, and any attempt to "spam" U-boats would inevitably draw the attention of the Allies. Although U-boats - as in real life - should be prioritized for resources, the ideal Kriegsmarine remains a balanced fleet across its various branches.
• There is broad agreement that the effort to build a surface fleet capable of competing with Britain was futile... yet the consensus ends there, as opinions differ on how such a fleet should actually be constructed. However, most of the views I have encountered tend to revolve around the concept of scaling back battleship construction in favor of focusing on smaller vessels.
• S-boots and auxiliary cruisers (Hilfskreuzer) were underrated.
• The Germans could have gained more - and reduced their losses - had they invested more in amphibious warfare.
• Perhaps Kriegsmarine should have limited itself to using U-boats and auxiliary cruisers for power projection in the Atlantic and across the globe, while the remaining fleet focused on securing dominance in the Baltic Sea and defending the English Channel?
• Or would the development of naval air power - or at least better coordination with the Luftwaffe - compensate for the lack of naval strength?

I also wonder whether closer and more extensive cooperation with Italy and Japan would have been of any further benefit to Kriegsmarine?

...as you might guess, many of the assumptions involved here would require more than just "abandoning one thing to build another"; they would necessitate a "profound shift" in the power structure and strategic mindset of the Nazi leadership. For instance, unless Göring had died prematurely from illness or an accident, there would have been no better coordination with the Luftwaffe. Hitler himself would have needed a better understanding of naval affairs - or at least the decisiveness to strip Göring of his absolute authority and cede some of it to Raeder. Something like this, something like that, yada yada...

 

[tomo pauk]

What is the starting date?

 

[ValiantHeart]

By 1939, it would be too late to start anything; you would simply have to make do with whatever you already had.

Most people tend to use 1933 - the year the Nazi Party came to power - as the starting point. After all, the most impressive aspects of the Kriegsmarine emerged from that time onwards.

But there is no "Law of Alternate History" preventing me from doing anything, and in any case, Germany's rearmament efforts had already begun in the 1920s under the Weimar Republic.

In that case... I'll pick a point far back in time. How about 1921? The first thing I want to do is find a way to get close to Hitler and become one of his Inner Circle, and then—

 

[tomo pauk]

In that case... I'll pick a point far back in time. How about 1921? The first thing I want to do is find a way to get close to Hitler and become one of his Inner Circle, and then—

Before the early 1930s, the historical development is probably okay. What might be useful for the next 10+ years is to keep the keen eye on foreign developements wrt. the carrier aviation, submarine and anti-submarine warfare, as well as to test different armor schemes (like the British usage of water between the plates to improve underwater protection). The development of low-drag shells, from the high length/diameter ratio, to the shells with aerodynamic caps. Do the work on different radio devices: radars, radio detectors, underwater sensors etc. All of this requires time, and can be done without provoking the Entente.
For the early 1930s, the carrier aviatino needs to take form, 1st in order to learn the tricks of the trade, then to make that aviation a real weapon of the war. After the Panzeshiffe, make the aricraft carriers before the 38cm guns are ready.
Supoport the Lufthansa in buying the diesel-powered 4-engined aircraft for the immense range, later have these outfitted with radio devices of different kinds to act the fleet eyes at far distances.
Have the automatic 37mm AA gun procured - the single-shot 37mm Flak was a bad joke.
Submarines should have the means to breath air without announcing themselves to the enemy miles away.
Wired guide bombs might've been interesting, keeping the lumbering aircraft in the safe altitudes/distances.

 

[builder396]

Well, if I wanted to be a party pooper Id say Germany should start with not losing WWI. But that wouldnt be any fun.

Have the automatic 37mm AA gun procured - the single-shot 37mm Flak was a bad joke.

This is certainly a good point, since the 3.7cm Flak 36 was a decent enough gun, even if it combined the firepower of a 40mm Bofors with less effective range, but the later 3.7cm Flak 43 gave it double the rate of fire at least, and it got adopted by the KM. But in 1943 it was too little too late. Only big downside I can see on those guns is that they are not well suited to multiple mounts, certainly won't ever have a sextuple mount like the Bofors.

A 5cm Flak 41 would also be a decent candidate. It's pretty obscure, but imagine the ballistics of a 5cm Pak 38 combined with the clip feed and mount of the 3.7cm Flak 36, except bigger. On land it was considered pretty useless, because it closed a performance gap between the 3.7cm Flak and the 8.8cm Flak, but on land youre either dealing with ground attack aircraft or heavy bombers, but few things in between where the extra range matters. On sea however it's a whole different ballgame, where being able to open fire on approaching planes earlier can be a life-saver. At 180 rpm the fire rate is pretty good, too, so with proper integration into a fire director it would be a pretty amazing if heavy gun.

I got one original point, too, though.

Get rid of these stupid split secondary batteries!

Seriously, splitting the secondary batteries on Battleships and Panzerschiffe and above into 15cm anti-ship guns and 10.5cm (or even 8.8cm) AA guns did neither job any favors. 15cm guns had a time fuze round in theory, but they traversed too slowly and couldnt elevate enough to use them, while the AA guns werent all that great at anti-ship work, but what both batteries have in common is not having enough guns.

I see three solutions to this problem:

Solution 1: Replace all 15cm guns with more 10.5cm twin mounts. Yes, anti-ship firepower takes a nosedive, but youll be firing way more shells at an enemy ship, and if 10.5cm guns are wholly ineffective the target is big enough to involve the main battery, even on a Bismarck.

Solution 2: Develop a unified gun based on the 12.7cm SK C/34 with a high elevation mounting, preferably twin turrets, and good enough traverse speed to track planes. Get the best of both worlds. Z46 turrets are pretty much what Im thinking of.

Solution 3: O-class twin 15cm turrets, a few were used when Germany decided a 15cm-armed destroyer was a good idea, so look at Z32. 60° of elevation isnt all that great, but the turrets rotate and elevate fairly fast, so maybe thatll be good enough if the priority really is on surface firepower. Just dont fumble around with these stupid single 15cm gun mounts.

 

[Rule of cool]

Develop a unified gun based on the 12.7cm SK C/34 with a high elevation mounting, preferably twin turrets, and good enough traverse speed to track planes. Get the best of both worlds. Z46 turrets are pretty much what Im thinking of.

Dual purpose guns was the way the RN and USN were moving, and the Germans cannot afford to waste anything so ruthless efficiency is a must.

 

[ValiantHeart]

Here is an opinion I just came across, quote:

The High Seas Fleet in World War I had one great success - Moon Sound. A perceptive admiralty might have fixed on this and specialized the navy for Baltic operations. Anything that hastens the German advance to Leningrad could have important repercussions.

In my opinion, anything that strengthens the KM for warfare against Britain is missing the point. The Germans cannot defeat the Royal Navy. It's nice to pretend the Germans could become a carrier-based power, but then we have to ignore any British response to that and hope that the fleet is sitting in Scapa at the right time and place to be Pearl-Harbored. And then what?

The Germans need to restrict their westward navy to jeune ecole warfare, scare Britain with subs and raiders, and focus their primary effort to the east where they can be the Big Man on Baltic and reap the benefits of naval superiority. More training ships, more amphibs, more minesweeping sloops.

I don't think changing Scharnhorst's guns will accomplish anything significant except taking the ship out of action long enough to make those extensive changes.

 

[Rule of cool]

Sea Power is a combination of fleet and geography. In WW1 Germany had the fleet but not the geography, in WW2 they had the geography but not the fleet. The ability of Germany to capture superb naval geography really boosts whatever fleet they manage to construct, making capital ship building not a waste of time as has been often asserted.

 

[Ainen]

I am not saying that "if Hitler had ordered the construction of [A, B, C...], Germany could have won the Battle of the Atlantic," but I do expect that a "better" Kriegsmarine would have adopted a more rational strategy and shipbuilding plan (Plan Z was pure fantasy/madness), leading to a better performance than what actually occurred?

There's nothing mad about Plan Z, it began in 1938. Absolutely no decision taken so late will have any impact, Germans failed to complete any heavy vessels from well before that point(since XI.1936).

If you want to get more out of Kriegsmarine - don't begin war in 1939. Navy isn't tanks, the cycles are longer. KM couldn't hold even a single proper summer fleet training cycle before the war, as their first heavy units only arrived in 1939. KM can't be expected to organizationally perform against the UK until 1943, and that they did IRL is already way out of proportion for the size of the force at hand.

Get rid of these stupid split secondary batteries!

All German heavy units until 1940 had a basic belts problem (Encounter with French superdestroyers; they can - and did during the war - reach there in a matter of hours). Sufficient escort force couldn't be expected to arrive in time.
All German battleships other than Tirpitz had to repel multiple determined destroyer torpedo attacks through their career. All 3 same ships had to repel (or at least engage in case of Bismarck) air and surface threats simultaneously.
In most cases they repelled manageable air attacks well enough, and in cases where they did not - more/heavier DP guns would've made matters even worse.
On no German battleship through their career DP gun would've had any additional substantial positive impact. Negative - easily so.
Keep in mind that the basic assumption "bigger=better" doesn't work here.
Before VT fuse and evolved radar GFC, even the great 5"/38 was rather mediocre in its performance; British 5.25" was simply meh, and throughout the war never achieved the level of AA performance SK C/33 had.
Since the active career of German battleships more or less ended in 1942, you'll not just sacrifice ASuV, you'll ironically sacrifice AA performance as well.

 

[ValiantHeart]

Here is another opinion I just came across, quote:

Why not the bastion sea strategy ?

• 200 land based bombers with crew trained to hit warships each with 800kg projectiles
• 20 % more Subs than in OTL
• Cheaper escort vessels , maybe go further with vorpostenboot idea
• S& G with larger caliber twin turrets 14 inch or more
• No raiding sorties by capital ships reclassify panzerschiff as 11inch heavy cruisers
• Full “ fleet in being “ for big ships including destroyers
• No aircraft carriers
• Employ more cheap converted commerce raiders

Commerce raiding force of 8 heavy cruisers plus 3 rebuilt pocket battleships. All of them with diesels and global range plus improved air wing as suggested in my long heavy cruiser post, meaning each has 4 Fi 156 Slepcev Storchs for observation plus two spares and a floatplane fighter. This should prevent mistakes like that of Graf Spee blundering into a task force. Each of these is accompanied by a fast supply ship. Not purpose built, just a large merchant tanker or freighter with upgraded power-plant (4 x 5000 hp diesels, 20 knots). These ships can carry several more Slepcev Storchs plus spares. So, each heavy raider with its supply ship will have 8-10 Fi 156 for short range recon. Only three CA/PBBs deployed at one time - one in the mid Atlantic, one in the South Atlantic, one in the Indian Ocean. Main goal - force the creation of a global system of convoys. Occasionally destroy a poorly escorted convoy. Occasionally a fourth ship deployed to create a dangerous pair of cruisers in a theatre that is harder to counter.

U-boats for the North Atlantic. Occasionally supported by heavy cruiser/PBB plus destroyer sorties. Long-range destroyers deployed in the North Atlantic in support of the U-boats after the fall of France. The mission is mainly to give the Allies something other than U-boats to worry about and create confusion. A U-boat can be countered by a cheap Flower. Three large German destroyers will require more powerful ships to counter.

Fleet-in-being battleships based in Norway, supported by land based aircraft. Occasional sorties to ease the break-outs and returns of raiders. Operations in the area between Norway and Greenland - entirely in poor weather. No convoy raiding. Mission after 1941 - cut the Arctic convoys together with aircraft, U-boats and cruisers. Fast ships like Scharnhorst and Gneisenau should sail on cruiser hunting missions around the GUIK gap in poor weather.

Fleet-in-being carriers. It is somewhat unlikely the Germans will get a functional carrier quickly with no prior experience. Maybe Wilhelm Gustloff and Robert Ley get finished as carriers. Main mission - force perfectly good and functional British carriers to sit in Scapa Flow doing nothing. Graf Zeppelin tied two, so these will probably tie up three. They don't need to even be fully functional, just announced as such.

Cheap minesweepers, S-boats, improved S131 torpedo boats for coastal operations. Emphasis on mine warfare.

Prepared fleet of let's say 16 auxiliary cruisers. Just normal ships with power-plant upgrades sponsored by the KM (4x5000 diesels, 20 knots). These should also get 3-4 Slepcev Storchs for observation.

General idea - create a multi-dimensional threat. Heavy cruisers and PBBs require cruisers/battlecruisers to counter. The British had about 50 light and 20 heavy cruisers at the start of the war. Having them escort convoys and form task forces at the same time won't be easy. Some will be needed in the Mediterranean and others in Home waters. Some won't be operational, some will be in transit. The auxiliary cruisers will also help disperse the British cruiser fleet.

Will this win the war at sea? NO, but it would be better than what the Kriegsmarine did historically.

 

[MichiK]

I’m not sure if this topic has been discussed before, but I’d like to hear your ideas for building a "better" Kriegsmarine than the one that existed irl.

[...]
In that case... I'll pick a point far back in time. How about 1921? The first thing I want to do is find a way to get close to Hitler and become one of his Inner Circle, and then—

Honestly?
Kill Hitler, Göring and the whole bunch, and make sure that no NSDAP nor anything compareable comes to power in Germany. Because, besides obviously being a much healthier timeline for the whole world, the Reichsmarine/Kriegsmarine never had a poltical environment to thrive.

At first this was because of the limitations of the Versaille treaty, followed by the world economic crisis (which in terms of navy building, probably was almost imperceptibly short). But after 1933 it was the Nazis (namely Hitle rhimself - remeber he "promised" the navy not to start a war before 1945!) with their strategic incompetence and insane rush to start a war, that made any attempts of rebuilding the navy futile in the first place.


So no NSDAP, no WW2 in 1939, the "primary" opponent ist still Poland. That leaves basically two scenarios:
- War against and including GB - good luck with that one!
- War against basically France alone.
In that case the main objectives must be
- denying French forces from entering the baltic sea.
- ideally blocking French forces from passing through the English Channel.
- securing own shipping through the north sea, in particular the iron ore trafic from Sweden.
- only if all this is established, cutting of France from overseas supplies (how ever that could be done).

Given that the Versaille treaty is more or less concordially dropped, put the emphasis on destroyers and smaller units (plus training and support, of course).
Technically there's no need to rush the development of high pressure machinery to such an extend as it happen in reality. I.e., there's big chance that most of the ships spend their time in service, not in maintenance.

What happensafterwards is pure unbased speculation - it strongly depends on France's reaction and the general political development...

 

[Avimimus]

I think the best way to look at this question, is from the perspective of the Royal Navy.

- Submarines had been the most effective force in WWI, causing significant food shortages - so putting all resources into their production would make sense. We also know that anti-submarine efforts were expensive and diverted a lot of material from other parts of the war effort.

- Torpedo boats could contest littoral waters. It would be tempting to have a class of destroyers to support them, but it would likely be an unwise use of resources.

- The Fritz-X program could threaten larger capital ships.

I don't think any other program can be justified.

In reality, the development of centimetric radar, jamming capabilities, and the loss of air superiority would doom even these efforts - but it would still be a more painful situation for the Royal Navy than any set of alternative choices.

 

[Dilandu]

The fundamental Kriegsmarine problem was, that they utterly lacked any long-term focus and coherent goals. Initially (then they still were the Reichsmarine), their main goal was deterrence against France - and a bit against Britain - and defense against USSR and Poland on Baltic. Nothing else could be done with limitations both legal & material.

After limitations were lifted, Kriegsmarine was given a new goal - be ready to the possible war with France, but NOT with Britain. They were specifically assured, that Germany would not be fighting Britain, that German government learned WwI lessons and would not risk to make Britain the enemy. The 1936 treaty allowed Germany to create a modest but balanced fleet, comparable with French, and Kriegsmarine started to do exactly that.

(a note about "why submarines weren't given a priority. A - because they were of limited use against France, B - because Kriegsmarine feared that building submarines could provoke Britain, and C - because 1936 treaty limited German submarine tonnage to the same as British, and Royal Navy have relatively few submarines)

Then came 1938, and Kriegsmarine was suddenly given a new goal - to prepare to the possible war against Britain, but not now, somehwere in the future. Admirals were shocked by such change of politics, but at least they were assured that they have time, that war would "certainly" not came before 1944, and "likely" not before 1946. So admirals more or less agreed to build fleet, capable of fighting Britain, but in eight years, and only if naval construction woukd be given absolute priority (on which Hitler readily agreed)

(again, there were no reason to start mass-producing submarines - battleships and cruisers took longer to build, so if the war was not expected soon, it was more logical to concentrate resources on surface fleet)

And then came 1939, and Kriegsmarine were ordered to be prepared to fight against Britain RIGHT NOW. With nothing actually ready for the task.

(at this point they started to crunch out submarines - simply because it was only thing they could build fast!)

What am I trying to demonstrate, is that Kriegsmarine planning was not - and could not - be oriented toward the goal of "war against Britain in 1939". German admirals weren't fools, they were reluctant to oppose Britain - from even worse positions than in 1914 - and while they recognized that such situation MIGHT arise in future, they were repeatedly assured by political leadership that any kind of conflict with Britain is a distant future. So they concentrated on practical goal; preparing the fleet, capable of countering French one.

 

[Dilandu]

- Submarines had been the most effective force in WWI, causing significant food shortages - so putting all resources into their production would make sense. We also know that anti-submarine efforts were expensive and diverted a lot of material from other parts of the war effort.

Problem was, that German navy officers thought otherwise. They recalled how "unrestricted submarine warfare" failed as soon as British introduced convoys, and assumed (correctly) that British would just do the same right from thr beginning now. So from German officers point of view, submarines alone were not a reliable plan, and would likely fail. That's why they put such emphasis on large surface raiders; they envisioned that threat of surface raiders would force British to reduce the number of convoys (since Royal Navy lacked numbers in heavy ships to provide escorts), and thus increase the efficiency of submarines by forcing more merchants to sail outside of convoys.

The logic basically was:

* All-submarine fleet - British just form many convoys with only destroyers and sloops as escorts, and submarines would do nothing;
* Combined submarine & surface fleet - British would be forced to give convoys heavy ships as escorts, and RN did not have much of them. So there would be only a few convoys (because lightly defended convoys could be easily destroyed by heavy raiders, and thus would be impractical), more ships would sail out of convoys, and submarines would hunt them;

That was the logic.

 

[Ainen]

What am I trying to demonstrate, is that Kriegsmarine planning was not - and could not - be oriented toward the goal of "war against Britain in 1939". German admirals weren't fools, they were reluctant to oppose Britain - from even worse positions than in 1914 - and while they recognized that such situation MIGHT arise in future, they were repeatedly assured by political leadership that any kind of conflict with Britain is a distant future. So they concentrated on practical goal; preparing the fleet, capable of countering French one.

"Even worse position than 1914" is a major understatement.
In late 1914 German navy was (and promptly wasted) in it's best position v RN ever, before or after.
1914 position was only possible again if Z plan was to be flawlessly executed.

 

[MichiK]

Furthermore, even if there had been a clear decision to fully rely on subs, this would have required a much broader building program.

Note, that we are still talking about peace time efforts, so it is utterly impossible to plan or even think about having occupied the whole of northern France and Norway.

I.e., the German navy would have to plan and provide for the subs to operate from German bases just like during WW1.
And just like in WW1 the first thing the RN would do is infest the approaches to and from with mines.
And Germany would have to send in the minesweepers to counter the mines...
And the RN would send in destroyers and cruisers to counter the minesweepers...
And Germany would have to send destroyers and cruisers and battleships to back the minesweepers...
Just like in WW1.

 

[tomo pauk]

This is certainly a good point, since the 3.7cm Flak 36 was a decent enough gun, even if it combined the firepower of a 40mm Bofors with less effective range, but the later 3.7cm Flak 43 gave it double the rate of fire at least, and it got adopted by the KM. But in 1943 it was too little too late. Only big downside I can see on those guns is that they are not well suited to multiple mounts, certainly won't ever have a sextuple mount like the Bofors.

Sextuple mount Bofors? Not something to worry about in ww2, and not something that were are sure that it would not be possible to make, knowing the German penchant to sometimes complicate stuff.
Even twin mounts of automatic 37mm guns beat the combo of single-shot 37mm guns and 20mm mounts; I'd favor the 37mm above the 20mm, that should be only installed on the places where the 37mm cannot fit.

Something as powerful as the 40mm Bofors, or the automatic that uses the Navy's powerful 37mm ammo (750g at 1000 m/s, vs. 640g at 840g) would've been even better than a version of teh Luftwaffe's 37mm.

A 5cm Flak 41 would also be a decent candidate. It's pretty obscure, but imagine the ballistics of a 5cm Pak 38 combined with the clip feed and mount of the 3.7cm Flak 36, except bigger. On land it was considered pretty useless, because it closed a performance gap between the 3.7cm Flak and the 8.8cm Flak, but on land youre either dealing with ground attack aircraft or heavy bombers, but few things in between where the extra range matters. On sea however it's a whole different ballgame, where being able to open fire on approaching planes earlier can be a life-saver. At 180 rpm the fire rate is pretty good, too, so with proper integration into a fire director it would be a pretty amazing if heavy gun.

Every 5cm installed means two of the 37-40mm are not, and the very moment the attacking aircraft are ~3500m away from the ship(s), it will do half of RoF vs. the 37-40mm battery (assumes the same RoF of all of the guns in question).

Get rid of these stupid split secondary batteries!

Seriously, splitting the secondary batteries on Battleships and Panzerschiffe and above into 15cm anti-ship guns and 10.5cm (or even 8.8cm) AA guns did neither job any favors. 15cm guns had a time fuze round in theory, but they traversed too slowly and couldnt elevate enough to use them, while the AA guns werent all that great at anti-ship work, but what both batteries have in common is not having enough guns.

I could not agree more: indeed, no secondary batteries.
Start with DP 105mm stuff, and move on the 127-128mm stuff by the mid-1930s. Anything that is a light cruiser or smaller will suffer that wall of fire, and the anything above destroyers will be attacked by the main battery anyway. Of course, the KM cruisers get the 150 or 210mm stuff as the main guns.

 

[builder396]

Sextuple mount Bofors? Not something to worry about in ww2, and not something that were are sure that it would not be possible to make, knowing the German penchant to sometimes complicate stuff.
Even twin mounts of automatic 37mm guns beat the combo of single-shot 37mm guns and 20mm mounts; I'd favor the 37mm above the 20mm, that should be only installed on the places where the 37mm cannot fit.

Something as powerful as the 40mm Bofors, or the automatic that uses the Navy's powerful 37mm ammo (750g at 1000 m/s, vs. 640g at 840g) would've been even better than a version of teh Luftwaffe's 37mm.

The sextuple was just an extreme example to illustrate that the top-feeding clip of the Bofors gun lends itself much better to multiple gun mounts than the German side-feeding 3.7cm Flak guns. Twins of those did exist, but only by awkwardly stacking the guns on top of each other. Quad-mount Bofors guns did exist, but I wouldnt even be sure what a German quad mount would be looking like in that case, except for mirroring the guns on one side like they did on the Flakvierling.

Every 5cm installed means two of the 37-40mm are not, and the very moment the attacking aircraft are ~3500m away from the ship(s), it will do half of RoF vs. the 37-40mm battery (assumes the same RoF of all of the guns in question).

Speaking of the 2cm, generally speaking navies have light, medium and heavy AA, light being approximately 20-25mm, medium approx. 40mm and heavy would be 75mm and up single shot guns with time fuze, and there is a lot of method to that madness, because each have their effective range envelope, with light AA being often shoulder-aimed 20mm mounts used as last ditch against planes that got REALLY close.

Because of that Id be careful saying something about the 3.7cm Flak replacing 2cm mounts entirely, they have very different jobs, and the 3.7cm cant be made to do a 2cm guns job. Especially as the KM employed single and twin 2cm mounts that were shoulder-aimed, and the Flakvierling also outputs a ton of tracer fire in a short time, adding a great deal to the psychological effect.

This argument only gets more important when coupled with my suggestion of using 5cm autocannons, which deal even more target tracking capability for effective range. By the way, the cyclic rate of fire on the 5cm gun is 180rpm, while the 3.7cm Flak 36 only gets up to 160rpm, the later Flak 43 gets 240rpm. So you wouldnt lose much in terms of shell output, most difference would come from 5cm 5-round clips being heavy.

If you want to know what happens when you skip one of the 3 AA gun types look at Japan with their 25mm Type 96 gun combining the pitiful effect on target, short range and bad accuracy of a light AA gun with the (cyclic) rate of fire, unwieldiness and low traverse speed of a medium AA gun, while also hampering the gun by using 15 round magazines, not clips, actual magazines, as in remove old magazine, put on new magazine, pull on charging handle. Practical rate of fire is down in the dumps.

Which is why Im so hesitant about putting the 3.7cm Flak 36 on a pedestal, it has a fairly short effective range, the Pompom being the only similar gun in that regard, but that thing came in octuple mounts with a long belt feed if you wanted. The 3.7cm gun doesnt have anything that offsets its low effective range even, so I think its a bad pick only to be taken if truly nothing better is available.

 

[Dilandu]

"Even worse position than 1914" is a major understatement.
In late 1914 German navy was (and promptly wasted) in it's best position v RN ever, before or after.
1914 position was only possible again if Z plan was to be flawlessly executed.

Exactly. Plan Z, for all its grandiose, was essentially viewed as "minimal sufficient fleet to fight Britain". German admirals weren't optimistic at all; they would certainly prefer war with Britain avoided.

 

[lastdingo]

Keep in mind the foreign policy restrictions regarding fleet and especially submarine fleet size.
https://defense-and-freedom.blogspot.com/2009/06/german-submarine-force-size-of-1939.html


Also keep in mind the ordinary daily work of a navy that's not producing headlines:

- picket boats
- minesweeping and marking lanes with buoys
- netlaying and recovery boats
- torpedo recovery boats for exercises with torpedoes
- coastal ships inspecting incoming cargo ships
- coastal (especially to Norway's territorial waters) escorts, primarily against submarines but also relevant against destroyer and aircraft
- ships to move fuel to bases
- replenishment ships
- training ships
- small and cheap boats (torpedo boats), essential to develop leadership talents
- investment in ports, especially drydocks
- investment in base buildings
- research ships to measure ocean depth, magnetic field, underwater currents and temperature layers

Furthermore, consider that the Kriegsmarine was meant to dominate the Baltic Sea and required to be able to escort blockaderunners in a war with France (including diversionary activity overseas to draw away destroyers and cruisers from the North Sea).
It was not meant to be ready against UK (much less UK+FRA) by 1939/40.


about WW2 AAA calibres:
https://defense-and-freedom.blogspot.com/2026/07/optimal-aaa-calibres-in-ww2-and-today.html
personally, I would go for 14 cm (single on cruiser-accompanying destroyers, twin on cruisers) anti-ship/anti-torpedo bomber guns,
5 cm (single or twin) anti-bomber guns
and 3 cm (single or twin) "don't get that close, or else" guns.

Realistic at the time was a mix of 4 cm/3.7 cm and 2 cm guns. I don't get why they thought 8.8 or 10.5 cm would be effective. HAAA fire control and fusing was as unsatisfactory as was its effect against ships. The few barrels even of a capital ship could not possibly make much of a difference. The only satisfactory services were making sure airships would not come close and firing starshells for night combat illumination.

 

[tomo pauk]

The sextuple was just an extreme example to illustrate that the top-feeding clip of the Bofors gun lends itself much better to multiple gun mounts than the German side-feeding 3.7cm Flak guns. Twins of those did exist, but only by awkwardly stacking the guns on top of each other. Quad-mount Bofors guns did exist, but I wouldnt even be sure what a German quad mount would be looking like in that case, except for mirroring the guns on one side like they did on the Flakvierling.

If an idea looks stupid, but it works, it might not be stupid (or awkward) Put two pairs of mirroring the Zwillings on a big mount and there it is - a Quadruple 37mm.
Czech tilted their side- and clip-loading 30mm M53 gun by 90 deg when they made the top- and magazine loaded M53/59, so there is that option, too. Germans made the top-loading M42 37gun, too.

At any rate, I will not loose too much of a sleep about all of that, my point is that the single-shot 37mm dies a swift death, and that the automatic 37mm is installed as densely as possible.

Speaking of the 2cm, generally speaking navies have light, medium and heavy AA, light being approximately 20-25mm, medium approx. 40mm and heavy would be 75mm and up single shot guns with time fuze, and there is a lot of method to that madness, because each have their effective range envelope, with light AA being often shoulder-aimed 20mm mounts used as last ditch against planes that got REALLY close.

Because of that Id be careful saying something about the 3.7cm Flak replacing 2cm mounts entirely, they have very different jobs, and the 3.7cm cant be made to do a 2cm guns job. Especially as the KM employed single and twin 2cm mounts that were shoulder-aimed, and the Flakvierling also outputs a ton of tracer fire in a short time, adding a great deal to the psychological effect.

20mm is probably unable to provide the covering fire for anything beyond the ship it is installed to, to tackle any kind of 'level' bombers, and will be hard pressed to defend that ship againts the dive-bombing attacks. The shoulder-aimed 20mm guns will be an easy fit on where the 37mm will not, I've noted that already; the Flakvierling is not in the same group.
Against the torpedo-bombers, the 37-40mm will be firing for far longer than the 20mm.

My point is that 37mm gun provides a much better bang for a buck, and on the big ships it will be easy to provide the required deck space and volume for a numerous battery of these. Small ships will make do.

This argument only gets more important when coupled with my suggestion of using 5cm autocannons, which deal even more target tracking capability for effective range. By the way, the cyclic rate of fire on the 5cm gun is 180rpm, while the 3.7cm Flak 36 only gets up to 160rpm, the later Flak 43 gets 240rpm. So you wouldnt lose much in terms of shell output, most difference would come from 5cm 5-round clips being heavy.

The Flak 18 should be the 1st step. Don't wait too much with the next version, this need to be more mass-production friendly (like the Flak 43, and unlike the Flak 18 and 36, that were made in few dozens per month in 1939-41) and have it do better RoF (again, like the Flak 43). Having a better 37mm by the late 1930s removes the need for the M42, too.

The 5cm Flak 41 was a later design than the 37mm Flak 18/36. The 5cm will force the Germans to have 4 types of AA guns in service.

If you want to know what happens when you skip one of the 3 AA gun types look at Japan with their 25mm Type 96 gun combining the pitiful effect on target, short range and bad accuracy of a light AA gun with the (cyclic) rate of fire, unwieldiness and low traverse speed of a medium AA gun, while also hampering the gun by using 15 round magazines, not clips, actual magazines, as in remove old magazine, put on new magazine, pull on charging handle. Practical rate of fire is down in the dumps.

Yes, the IJN mis-calculated badly when they went shopping for the new light AA gun. IMO, adopting the Bofors 40mm and one of the Army's (or European) 20mm for the Navy needs would've been much better.

Which is why Im so hesitant about putting the 3.7cm Flak 36 on a pedestal, it has a fairly short effective range, the Pompom being the only similar gun in that regard, but that thing came in octuple mounts with a long belt feed if you wanted. The 3.7cm gun doesnt have anything that offsets its low effective range even, so I think its a bad pick only to be taken if truly nothing better is available.

Timing is important. When the 37mm Flak 18 emerged, the only better gun was the Bofors 40mm.
The low-velocity ww1 relic pom-pom, used by RN, IJN and Soviets was god-awful for the needs of ww2, and it will take some time for the high-velocity version to emerge. The less we say about the single-shot French, German, Czech and Soviet light AA guns, the better.
Granted, the Flak 36 should've been a much better gun, not just a nip & tuck of the Flak 18.

 

[Ainen]

Yes, the IJN mis-calculated badly when they went shopping for the new light AA gun. IMO, adopting the Bofors 40mm and one of the Army's (or European) 20mm for the Navy needs would've been much better.

Bofors was not available as a product when Japan shopped. Hotchkiss was not just available, it was already a product with available FCS.

But overall, the problem is overblown. No German heavy ships were lost to air attacks at sea, and only one lone ship was disabled by them, in rather specific conditions. When KM was in a position to contest anything (1939-1942), their air defenses clearly held, and they did so better than anyone else during the same period.

 

[tomo pauk]

Bofors was not available as a product when Japan shopped. Hotchkiss was not just available, it was already a product with available FCS.

Sources for the statements? FCS for the French 25mm, apart from the gunsight?

But overall, the problem is overblown. No German heavy ships were lost to air attacks at sea, and only one lone ship was disabled by them.

Crew members of the Bismarck: yeah, we totally were not closely followed by the Catalinas, and we totally didn't gotten the torpedo by Swordfish to hit us.
To what the crew members of Koenigsberg can reply: no bomb from the Skuas, either.

Which is why Im so hesitant about putting the 3.7cm Flak 36 on a pedestal, it has a fairly short effective range, the Pompom being the only similar gun in that regard, but that thing came in octuple mounts with a long belt feed if you wanted. The 3.7cm gun doesnt have anything that offsets its low effective range even, so I think its a bad pick only to be taken if truly nothing better is available.

The ammo update for the 37mm Flak would've been one of the ways to improve it. The BK 3,7, that started as a spin-off from the Flak, ended up firing the ammo with 260g of propellant, vs. the Flak's 185g. Several other ammo types were being designed for the Flak, with 200 to 220g of propellant, so there is a lot of elbow room there.

 

[T. A. Gardner]

This is a massively big "IF" version that would fundamentally make the KM effective versus the RN. It requires such a stretch in so many areas, it is likely undoable, but none of those stretches involves unrealistic production of ships, just the mindsets and politics of Nazi Germany and the top military command is involved.

What happens is about 1936 the top KM admirals realize that they can't win a traditional war at sea against the British. So, they institute a revolutionary substitute: They decide to build a carrier-centric navy instead. They send attaches and such to get as much information on what the British, US, and Japan are doing in carrier design and construction. With that knowledge, they set out to build their own carriers.

They start with laying down one in 1936, then two in 1937, and another two in 1938. They also build several large seaplane tenders that can operate their aircraft at sea in reasonable weather. In addition, they lay down destroyers and light cruisers to escort their carriers with an eye on making these have good range. Aircraft are sought for the carriers, the usual fighter, dive bomber, torpedo plane, combination.

Let's say Hitler comes down on the KM's side against Göring and lets the KM have their own planes and pilots so long as these don't compete with the Luftwaffe's needs. So, companies like Henkel build the fighter, say a He 112 derivative using an engine the Luftwaffe doesn't see as interfering with their own production. The dive bomber is either the Ju 87 which is in mass production, and the KM's numbers are so small that the Luftwaffe sees it more as a benefit to expand production lines than a problem. The naval version has more range built in. The torpedo plane could be the Fi 187 or maybe the He 70 with a BMW radial.

Each carrier is to have an air wing of about 50 to 60 planes aboard divided roughly evenly between the three types. A catapult for floatplanes is fitted so the carrier can operate with the aforementioned seaplane tenders as well.

In addition, the KM chooses 6 to 8 large merchant or passenger ships as potential candidates for conversion and draws up detailed plans to do this if a war is declared.

Surface raiders and U-boats are still built as they were historically. A few heavy cruisers are laid down, say one a year at most. The plan is by 1939 to have 4 carriers with 4 to 6 destroyers and 2 or 3 cruisers as escorts available for operations.

Extensive training of the aircrews starts from land bases. This then moves to the Baltic where they start practicing when a carrier is available.

The RN doesn't see this as too much of a threat. The Admiralty is confident in their ship's ability to provide air defense using guns in AA fire and maneuvering as that's what they've selected as their primary air defense. They have more carriers in a 'bean count' and the FAA is seen as mostly a supplement to battleships for offensive action. By their thinking, the Germans don't have much of a real threat with their smaller carrier fleet.

Overall, by 1939 the KM has 3 or 4 carriers with escorts available each with 50 to 60 planes aboard. If we assume the Germans are halfway competent with their carrier fleet, the RN is in for a rude shock come about 1940 when the two first seriously clash off Norway.

 

[Dilandu]

They start with laying down one in 1936, then two in 1937, and another two in 1938. They also build several large seaplane tenders that can operate their aircraft at sea in reasonable weather. In addition, they lay down destroyers and light cruisers to escort their carriers with an eye on making these have good range. Aircraft are sought for the carriers, the usual fighter, dive bomber, torpedo plane, combination.

They still need the battleships to cover those carrier fleet deployment. North Sea and Baltic aren't exactly very carrier-friendly areas, both in weather & size. So the battleship construction would be required, otherwise carrier fleet would be too risky to deploy from bases.

 

[T. A. Gardner]

They still need the battleships to cover those carrier fleet deployment. North Sea and Baltic aren't exactly very carrier-friendly areas, both in weather & size. So the battleship construction would be required, otherwise carrier fleet would be too risky to deploy from bases.

No, they don't. The carrier(s) can operate once into the North Sea effectively against the RN and even the RAF just as the USN and IJN did in the Pacific. Attacking a carrier or two with 8 to 12 fighters defending it using only twin-engine bombers is going to be a high-cost mission profile. The RAF can't escort a strike with what they have in 1940. Worse, they lack a torpedo bomber other than something the FAA is operating. So, sending a squadron of medium bombers to level bomb a carrier is an exercise in futility.

The FAA, assuming the RN makes the assumption that what they have is "good enough" so they're roughly historical in 1940, is woefully unprepared for a carrier war. The Germans send a strike of say 8 to 10 Stuka, 8 to 10 He 70 torpedo bombers, escorted by 6 to 8 He 112 against a British carrier. Both are operating singly.

The RN carrier has puts up say, 4 Sea Gladiator and some Skuas. The Henkels make short work of the British CAP and then dive bomb and torpedo the carrier. The Skua strike with say 6 planes and another 6 or so Swordfish approach the German carrier. The Henkels on CAP have their way with the British planes that are all but defenseless against them. Between the CAP and AA fire most of the strike is shot down and what isn't is shot to pieces. They might get lucky and score a hit on the German carrier.

Battleships? The Germans do to those what the Japanese did to the PoW and Repulse, or they "Bismarck" them. AA defenses alone won't cut it and the carrier group having much higher speed can avoid a surface action with better scouting available to them.

 

[Rule of cool]

Furthermore, even if there had been a clear decision to fully rely on subs, this would have required a much broader building program.

Note, that we are still talking about peace time efforts, so it is utterly impossible to plan or even think about having occupied the whole of northern France and Norway.

I.e., the German navy would have to plan and provide for the subs to operate from German bases just like during WW1.
And just like in WW1 the first thing the RN would do is infest the approaches to and from with mines.
And Germany would have to send in the minesweepers to counter the mines...
And the RN would send in destroyers and cruisers to counter the minesweepers...
And Germany would have to send destroyers and cruisers and battleships to back the minesweepers...
Just like in WW1.

This is the fundamental problem with the German Navy, it was constrained by geography that it has no chance of changing, but the Army might be able to change that geography. Was the Navy even considered as a beneficiary in the invasions of Norway and France, did the Navy advance campaign plans as prerequisites for greater scope of action.

Perhaps the best thing the German Navy could have done in the 20th century was in 1914 have their Marine division to follow the Army's sweep through Belgium and veer off to capture Calais while the Army was approaching Paris.

 

[tomo pauk]

This is the fundamental problem with the German Navy, it was constrained by geography that it has no chance of changing, but the Army might be able to change that geography. Was the Navy even considered as a beneficiary in the invasions of Norway and France, did the Navy advance campaign plans as prerequisites for greater scope of action.

IIRC the invasion of Norway was the Navy's baby. They certainly counted the Norway under Germany a boon.

 

[Dilandu]

No, they don't. The carrier(s) can operate once into the North Sea effectively against the RN and even the RAF just as the USN and IJN did in the Pacific. Attacking a carrier or two with 8 to 12 fighters defending it using only twin-engine bombers is going to be a high-cost mission profile. The RAF can't escort a strike with what they have in 1940. Worse, they lack a torpedo bomber other than something the FAA is operating. So, sending a squadron of medium bombers to level bomb a carrier is an exercise in futility.

And now let's start to discuss operation tempo, weather gauge, and average weather conditions in North Sea...

After half of German non-protected carriers would be massacred by British battleships coming out of the blue, with the wind blowing from the west - and Western winds prevail in North Sea - the rest would probably be turned into floating barracks.

 

[tomo pauk]

After half of German non-protected carriers would be massacred by British battleships coming out of the blue,

Out of the blue? What are German naval commanders supposed to do at the high seas, twiddle their fingers like the commander of Gloirous did? After they cut off and otherwise disable their radars, and while keeping their aircraft in hangars, war be damned?

 

[Dilandu]

Out of the blue? What are German naval commanders supposed to do at the high seas, twiddle their fingers like the commander of Gloirous did? After they cut off and otherwise disable their radars, and while keeping their aircraft in hangars, war be damned?

Since they would be far less experienced in carrier operations than Royal Navy? Probably worse; they would do something as totally stupid as actually trying to run into the wind & launch planes with British warships coming on them from the wind direction)

 

[Ainen]

Sources for the statements? FCS for the French 25mm, apart from the gunsight?

Le Prieur LPR, bought (licensed) together with Hotchkiss gun as a couple, in 1936. It could be installed on individual twins; it's also at the heart of the Type 95 director, available on most new or updated heavy Japanese ships (i.e. carriers and Yamato-class battleships).

Crew members of the Bismarck: yeah, we totally were not closely followed by the Catalinas, and we totally didn't gotten the torpedo by Swordfish to hit us.

Please read again what you're quoting.

To what the crew members of Koenigsberg can reply: no bomb from the Skuas, either.

Light cruiser is many things, but it is not a heavy ship. In any case, it was sunk in harbor/on anchorage, like almost all German vessels.
Protection of the ship in harbor to a minor degree is provided by onboard means, unless it's an entire fleet at harbor.

 

[tomo pauk]

Le Prieur LPR, bought (licensed) together with Hotchkiss gun as a couple, in 1936. It could be installed on individual twins; it's also at the heart of the Type 95 director, available on most new or updated heavy Japanese ships (i.e. carriers and Yamato-class battleships).

Thank you.
From another site, about the 40mm Bofors:
The British Army first showed interest in these guns in 1933

Light cruiser is many things, but it is not a heavy ship. In any case, it was sunk in harbor/on anchorage, like almost all German vessels.
Protection of the ship in harbor to a minor degree is provided by onboard means, unless it's an entire fleet at harbor.

It was indeed not a heavy ship.
It was also not in a friendly harbor when sunk, the air defenses were pretty much what was on the ship.

 

[tomo pauk]

Since they would be far less experienced in carrier operations than Royal Navy? Probably worse; they would do something as totally stupid as actually trying to run into the wind & launch planes with British warships coming on them from the wind direction)

Waiting for the enemy warships to appear within the visual range so the recon and combat aircraft are launched should not be the modus opearndi for any sane captain of a CV. Particularly for the Germans operating close to UK, where the RN ships can only be expected to appear frequently and in good numbers.

 

[Ainen]

No, they don't. The carrier(s) can operate once into the North Sea effectively against the RN and even the RAF just as the USN and IJN did in the Pacific. Attacking a carrier or two with 8 to 12 fighters defending it using only twin-engine bombers is going to be a high-cost mission profile. The RAF can't escort a strike with what they have in 1940. Worse, they lack a torpedo bomber other than something the FAA is operating. So, sending a squadron of medium bombers to level bomb a carrier is an exercise in futility.

I am sorry to ask, but you're an American, aren't you?
It's honestly an impressive level of ignorance of European geography.
In real life, French destroyers raided Skagerrak at least once. And no, they weren't sunk.

They start with laying down one in 1936, then two in 1937, and another two in 1938. They also build several large seaplane tenders that can operate their aircraft at sea in reasonable weather. In addition, they lay down destroyers and light cruisers to escort their carriers with an eye on making these have good range. Aircraft are sought for the carriers, the usual fighter, dive bomber, torpedo plane, combination.

Real German carriers were laid down in late 1936 and 1938, respectively. Earlier L/D is impossible per your conditions.
As you know, even the unit laid down in 1936 wasn't finished. Here goes your entire revolution.

Battleships? The Germans do to those what the Japanese did to the PoW and Repulse, or they "Bismarck" them. AA defenses alone won't cut it and the carrier group having much higher speed can avoid a surface action with better scouting available to them.

There's a reason Churchill (and RN) were so shocked after the Japanese raid into the Indian Ocean. RN combatants were under German air attacks on many occasions, and despite rather sorry state of RN air defenses and dozens of losses, this was not their experience.
British air threat was generally lower; German AAA and early war coastal air screens were generally better. Which is why, in the end, only one ship was disabled at sea, in very specific conditions.

 

[Ainen]

Thank you.
From another site, about the 40mm Bofors:
The British Army first showed interest in these guns in 1933

Interest is a broad term... Overall, Hotchkiss was available as a product earlier.
And if we look at 1941-42, Japanese AA wasn't especially bad, and while it was indeed worse than american - the american gun we're talking about is 1.1" Chicago Piano, Oerlikon, and .50 Browning. If you go ship by ship of what's installed where, 1st and 3rd are awfully underestimated in public consciousness.

It was also not in a friendly harbor when sunk, the air defenses were pretty much what was on the ship.

Still, it's anchorage. And in any case, it was an older, 1920s cruiser ... there won't be a 5" DP battery on it, unless you're replacing the main battery with it.

 

[Dilandu]

...The (in)famous North Sea Battle of March 1940 is well-known as the worst example of carrier operations in history. It all started when patrol German He 70 from 1st Flugzeugträgerdivision was engaged by British "Gladiator" from HMS Glorious. Noting the presence of British carrier nearby, Grossadmiral von Dummkopfen ordered 1st Flugzeugträgerdivision to engage, while 2nd Flugzeugträgerdivision be ready to press the attack.

The 1st Flugzeugträgerdivision, under command of Oberadmiral von Flügelferkel bravely run into the wind (which was from the West) at top speed. Due to German clumsy deck operations (which weren't perfected due to very short time of German carrier fleet existence) took more than an hour for all three carriers of the 1st Flugzeugträgerdivision to scramble the modest attack group. Bad weather hampered the search operation, but Grossadmiral von Dummkopfen, in a flash of ingenuity, ordered to seek British carrier in the areas of good visibility, assuming that such are required for flight operation.

Indeed, HMS Glorious was found with its destroyer escort, and, after gallant battle, sunk by German aircraft. Encouraged, Grossadmiral von Dummkopfen ordered 2nd Flugzeugträgerdivision to start launching aircraft, expecting to find more British warships. But, as he soon find out, it was not needed; British warships found him first.

All the hour that 1st Flugzeugträgerdivision run to the West (and more to recover the returning planes), the British battle force - HMS Hood, three heavy cruisers and eight destroyers - were running to the East toward them. At full 30 knots speed, both formations were closing at almost 60 knots - i.e. 110 km/h. And the North Sea was just 580 km wide max at the far north...

The 2nd Flugzeugträgerdivision under command of Oberadmiral von Schnapswürstchen was just preparing to launch it first planes, when radars detected surface contact in Western mist. The max range of German FuMo 27 surface search radars was just about 25 km (in perfect conditions), so the Oberadmiral von Schnapswürstchen was informed about possible surface engagement exactly at the moment when HMS Hood guns opened fire.

Engaged from long range, the HHHS (His Hitlership Hitler's Ship) "Karpschwein", proud flagship of 2nd Flugzeugträgerdivision, was straddled15-inch shells. The planes, prepared for action, were fueled and loaded on deck, so the first hit caused immediate catastrophic fire. The British cruisers at this time engaged the HHHS "Unversenkbare Seeluftziegel", causing large carrier to lose power and stop, suffering under rain of shells.

The sole remaining carrier of 2nd Flugzeugträgerdivision - HHHS "Wiener Frankfurter" - managed to turn & run. German escort - consisted of one heavy, two light cruisers and some destroyers - attempted to lay smokescreen and fight the rearguard action, but British destroyers charged, and despire suffering losses, torpedoed the heavy cruiser and forced other escorts to flee. The HHHS "Wiener Frankfurter" was chased, straddled and eventually destroyed, finding herself unable to outrun the Mighty Hood.

At the same time, 1st Flugzeugträgerdivision - which just landed its planes - totally incapable to interfer, done the only reasonable thing, and run to the East as fast as they could. By doing that, they were completely unable to launch any planes, so combat air patrol soon ceased to exist. This opportunity was used by HMS Furious, which launched air strike against retreating Germans. The Swordfish bombers again proved themselves, and HHHS "Das fliegende Halteverbot" was torpedoed and slowed down - enough, to be caught by British destroyers and sunk.

To finish this Very Bad Day for Kriegsmarine, the flagship of 1st Flugzeugträgerdivision - HHHS "Sauerkraut-Bunker" - was torpedoed and crippled by French submarine while entering German coastal waters, reducing German carrier forces to one operable carrier, the HHHS "Der taktische, allwettertaugliche Überschall-Stahlbeton-Pürierstab"...

 

[Ainen]

...The (in)famous North Sea Battle of March 1940 is well-known as the worst example of carrier operations in history. It all started when patrol German He 70 from 1st Flugzeugträgerdivision was engaged by British "Gladiator" from HMS Glorious. Noting the presence of British carrier nearby, Grossadmiral von Dummkopfen ordered 1st Flugzeugträgerdivision to engage, while 2nd Flugzeugträgerdivision be ready to press the attack.

Zepellin won't be ready until mid-to-late 1941, even in very optimistic circumstances; more likely later than that. Carrier has to operate as a coherent unit (even with a certain generosity of mind giving a discount to the significant surface firepower of this ship).

I.e., after normal training and air group testing/evaluation, there will be at least a cycle of maneuvering with escorts (per pre-war plans - Hipper-class heavy cruisers, be it Z or not Z).

Keep in mind the Kriegsmarine (unlike WW1, which gave them Huge advantages) had no time to conduct even a single proper fleet-wide training cycle before the war. They simply had no experienced task force admirals at all. At most, flotilla leaders with experience on smaller units.

Main problem with any German carrier fan fiction is that Zepellin was already laid down as early as humanly possible, and everything was already running on the earliest possible timelines (and collapsed before any actual realistic delays could've started).
Hitler's Kriegsmarine had only a very, very narrow window when they could lay down heavy units which could physically be built; no earlier than the first quarter of 1935, and no later than November 1936.

Everything that could be laid down during that period already was laid down. You just won't be able to add anything. Most you can change is make Hitler less hands-on and get Scharnhorst/Gneisenay built with 33cm rather than 28cm guns, making them actual battleships (and even here there's a big risk it'll lead to big delays with guns, and ships won't be available until 1940).
It's almost impossible to change anything else.

 

[tomo pauk]

Interest is a broad term... Overall, Hotchkiss was available as a product earlier.

I don't think that Hochkiss was available earlier, or at least not in some meaningful number of weeks. At any rate, IJN locking on the 25mm without looking at other options was very short-sighted.

And if we look at 1941-42, Japanese AA wasn't especially bad, and while it was indeed worse than american - the american gun we're talking about is 1.1" Chicago Piano, Oerlikon, and .50 Browning. If you go ship by ship of what's installed where, 1st and 3rd are awfully underestimated in public consciousness.

We're probably straying too much off-topic here. It is about the Germans, and what they can do. Opting for a good automatic 37-40mm gun would've been a much better deal than what they did historically.

Still, it's anchorage. And in any case, it was an older, 1920s cruiser ... there won't be a 5" DP battery on it, unless you're replacing the main battery with it.

See above for the change in light AA.
Anchorages hundreds of miles away from the actual naval bases and in the vicinity of the enemy do not work like the 'home spots' in the "Mensch ärgere Dich nicht" game - there is no immunity just because you are there.

 

[Ainen]

I don't think that Hochkiss was available earlier, or at least not in some meaningful number of weeks. At any rate, IJN locking on the 25mm without looking at other options was very short-sighted.

They did look at other options, and they looked at Bofors specifically.
It wasn't chosen (once again) specifically because it was not available as a product yet.

We're probably straying too much off-topic here. It is about the Germans, and what they can do. Opting for a good automatic 37-40mm gun would've been a much better deal than what they did historically.

They opted for both good 37 and good 40mm guns when they could - keep in mind they had a Bofors factory(MAVAG, Norway), and captured most ground 40mm guns produced to that date. Actual naval Bofors guns in other navies(allied) only start appearing, in small numbers, in 1942(mostly towards the end), but in 1943 at scale(mostly in US; for UK it's much later).
Kriegsmarine is finished by 1943 in any scenario, unless they don't stop Plan Z. There's nothing to change here.
IRL they got quite a few Flak 28(Bofors) in 1944, and they played a substantial role in Baltic operations in 1945.

Replacing 3.7cm sk c/30 won't work - it is from a previous generation of AA gun, predating high mv automatic guns; replacement just won't be available earlier. What was doable in time - proliferation of 20mm automatics - was done by germans, and was done ahead of everyone else.

Once again, keep in mind that in 1940 there were very few naval Bofors operational anywhere. Mostly a few Dutch runaway ships (many - with half-experimental mountings), neutral Swedish ships...and that's it.