Better German naval strategy 1930-1945?

As a thread drift, the three I-400 class boats completed by Japan were the largest subs ever floated until the USS Nautilus atomic boat 1953. The three operated without incident in the Pacific and were only discovered by the Allies at surrender. I-403 was completed as a resupply ship to provide supplies to the bypassed islands and was never spotted.

I find those boats fascinating. I read an account of USN personnel touring the engine room and one asked "where does this hatch go?" He was amazed to learn it went to the other engine room. "There's another engine room?"

Better German Naval strategy phase 1:

1. Do not cancel Panzerschiffe D.
2. Instead of Panzerschiffe E, lay down 2 additional repeat Leipzig class (Kreuzers G & H). Versailles requires using naval yards for construction - there are 3 slips available. Panzerschiffe D is in one so building G & H is possible (Grey on violation of Versailles; RM is just building additional cruisers using the Panzerschiffe allotment; somehow I doubt France/UK lose sleep over that). Technically with issues on K class, couple could be demilitarized for reconstruction so RM wouldn't have more than allotted 6 in service.
3. Instead of building 22 Zerstörer 1934/34a/36 boats and 10 Type 37/39 boats, build 32 Zerstörers of ~1938B class size: 2k tons std.)/4 x 1 - 12.7 guns/50k hp.
4. Lay down the 1st Type II U-boats as per historic.

Laying down the U-boats, mass production of destroyers and demonstrating plans to start building battleships should be enough to ensure the historic AGNT - allowing Germany to build up to France's level. Remember, in '35, the enemy is France. If you think Poland and/or France will fold in 6 weeks, we've a padded room for you.

Panzerschiffe D and Kreuzers would still be fitting out when AGNT is signed so:

5. While Kreuzer G is completed as gun boat; convert Kreuzer H to Kleiner Flugzeugträger. Leipzig class hull in more/less same size as IJN Hōshō. KM needs carrier in '36 to learn what they don't know. Hōshō has enough 'interesting features' for KM figure out what they want in their future fleet boats (two level hanger aft, turrets/casements for surface defense, 2nd hanger for fighters, control tower/lack there of, etc.) The aft hanger on Hōshō is large enough to support 3 torpedo bombers <Fi-167> (wings folded) on each level/if Messerschmitt has Bf.108 wing fold added to Bf.109 v15 (Jumo engine with under cowl radiator, extended wings and other naval equipment), the forward hanger supports 6 fighters (Hōshō fit 9 Mitsubishi 1MF planes) For better/worse, this keeps KM from wasting 20k+ tons on Graf Zeppelin (Should keep both Goering and Raeder equally unhappy) Can always be converted back to gun boat when tonnage needed for fleet boats.

I'm still working on strategy for Battleships/Submarines (I've put the historic number of submarines down).

Correction:
I thought about it overnight, while Panzerschiffe D was planned for 18k tons std., its probably going to come in heavy - there's no passing a ship off as a cruiser. Beside it passes duck test for capital ship: guns over 10", over 17k tons and capital expenditure by country. Getting an exception for the 28cm guns on PBBs should be possible - there are exemption for Hood, Lexingtons and not worth France going to war over.

Very good, I like it. PBB/Panzerschiffe is a hair-raising thing for the RN, because they understood Zenker's intentions ie disruption of trade routes. (which was shown at the beginning of the war). It is much easier to reduce Germany to one of the signatories of international agreements than to give them space to think outside the box. (the purpose of this thread ).
Minor complaint - PBB/Panzerschiffe tonnage is included in the AGNA agreement as capital ships.

don4331 said:

Correction:
I thought about it overnight, while Panzerschiffe D was planned for 18k tons std., its probably going to come in heavy - there's no passing a ship off as a cruiser. Beside it passes duck test for capital ship: guns over 10", over 17k tons and capital expenditure by country. Getting an exception for the 28cm guns on PBBs should be possible - there are exemption for Hood, Lexingtons and not worth France going to war over.

Click to expand...

Zmauky said:

Minor complaint - PBB/Panzerschiffe tonnage is included in the AGNA agreement as capital ships.

Click to expand...

Yes, I'm quite sure there's no way they'd be able to negotiate the PBB's to be classified as cruisers. Hood got the exemption largely because she was a pre-Jutland design not taking advantages of lessons thereof, and was to some extent considered obsolete already at launch. Being able to classify a newish 28cm armed ship as a cruiser would never have been accepted, just compare the shell weights and ranges of the 28cm gun with a heavy cruiser 20cm gun.

But, in a way it's all moot anyway. British estimates were that even if Germany built as fast as she could with no major hiccups, she would be able to reach the 35% limit of the AGNA by 1942 or 43. Germany kicked AGNA to the curb in 1939(?), and by that point they were nowhere close to the tonnage limits in any of the categories.

Returning to this thread that has been dormant for a while, and thinking of the plan above by D don4331 , an AH German naval strategy for the surface part that is substantially more focused on naval aviation than historically, using about the same total tonnage as historical:

1. A crucial element is getting experience of naval aviation ASAP. Thus, as part of the various (semi-)clandestine rearmament efforts that the Weimar republic engages in, around 1930 or so a liner or fast transport under construction is converted to a carrier (similar to other early carriers like Hosho, Langley, Argus, ...). Make it unarmed, and call it a fast mail ship or something equally silly, with the idea that mail aircraft can takeoff/land when sufficiently close to shore to deliver mail faster than having to steam all the way to port. This gives the Germans time to develop carrier doctrine without flagrantly violating the Versailles treaty.
2. Scharnhorst and Gneisenau are built as historically. Yes, it's a waste to cancel the Panzerschiffe D's, but at that time the potential enemy is France, and the D's are too weak to counter the Dunkerques.
3. Subsequent to the AGNA being signed, Germany has 47kton of carrier tonnage available. The first carrier from point 1. above can be classified as an aircraft ferry, or even for the time being be left unarmed operated by an "officially" civilian crew (hey, the UK managed to build the Unicorn and classify it as a "aviation support ship", so...). To fit this tonnage, two 23kton fleet carriers are laid down. The idea behind them is that in a potential conflict with France carrier task forces will break out into the open sea, and harass French shipping or even launch air strikes on French foreign territories.
4. Hitler sneezes on some magic pixie dust and gives the KM full control over their own aviation. Goering is of course furious but has to stuff it. Due to limited R&D resources the KM still has to do with mostly navalized versions of land based aircraft rather than bespoke carrier aircraft. The mainstay will be a navalized Bf 109 fighter, and a navalized Stuka dive bomber. A project to develop a suitable torpedo bomber is ongoing but never reaches maturity and widespread deployment.
5. To support the carriers, design a ~10kton light cruiser of an improved Leipzig design, and a longer range destroyer type of say around 2000 tons (yes, forget the 15cm guns on the destroyers!).
6. The big sacrifices here compared to historical are the two Bismarck's and the three Hippers. That gives about 130kton to use for other things. Say, 3 23kton carriers, 3 10kton light cruisers, and 15 2kton destroyers.

So how could these, hypothetically, have been used? By the Norway invasion, maybe 1 fleet carrier, two CL's, and a bunch of destroyers might be ready. Instead of Blucher, send in a few destroyers up the Oslo fjord. Sucks to lose one, but less a disaster than losing a heavy cruiser. Moving up Norway, the fleet carrier launches strikes on Norwegian positions, and maintains situational awareness so the invasion fleet isn't caught with their pants down. The older carrier can help, or if nothing else help ferry planes up to Norwegian airfields to quickly consolidate positions. For the battle of Britain, maybe the second fleet carrier is ready too, and they can launch hit and run raids against North-East UK. Or maybe team up with the Luftwaffe to provide fighter cover for LW bombers coming from Norway? I'm not sure breaking out into the Atlantic is feasible. Maybe they try with one carrier (+ escorts) and it gets sunk similarly to Bismarck historically. So the rest of the war the carriers spend mostly in Norwegian waters, occasionally launching some air strikes on, say, Scapa flow or Iceland, and of course against the Arctic convoys. Eventually of course their luck runs out and the Allies catch them, be it with Tallboys, submarines, carrier launched air strikes or whatever.

z42 said:

Returning to this thread that has been dormant for a while, and thinking of the plan above by D don4331 , an AH German naval strategy for the surface part that is substantially more focused on naval aviation than historically, using about the same total tonnage as historical:

1. A crucial element is getting experience of naval aviation ASAP. Thus, as part of the various (semi-)clandestine rearmament efforts that the Weimar republic engages in, around 1930 or so a liner or fast transport under construction is converted to a carrier (similar to other early carriers like Hosho, Langley, Argus, ...). Make it unarmed, and call it a fast mail ship or something equally silly, with the idea that mail aircraft can takeoff/land when sufficiently close to shore to deliver mail faster than having to steam all the way to port. This gives the Germans time to develop carrier doctrine without flagrantly violating the Versailles treaty.
2. Scharnhorst and Gneisenau are built as historically. Yes, it's a waste to cancel the Panzerschiffe D's, but at that time the potential enemy is France, and the D's are too weak to counter the Dunkerques.
3. Subsequent to the AGNA being signed, Germany has 47kton of carrier tonnage available. The first carrier from point 1. above can be classified as an aircraft ferry, or even for the time being be left unarmed operated by an "officially" civilian crew (hey, the UK managed to build the Unicorn and classify it as a "aviation support ship", so...). To fit this tonnage, two 23kton fleet carriers are laid down. The idea behind them is that in a potential conflict with France carrier task forces will break out into the open sea, and harass French shipping or even launch air strikes on French foreign territories.
4. Hitler sneezes on some magic pixie dust and gives the KM full control over their own aviation. Goering is of course furious but has to stuff it. Due to limited R&D resources the KM still has to do with mostly navalized versions of land based aircraft rather than bespoke carrier aircraft. The mainstay will be a navalized Bf 109 fighter, and a navalized Stuka dive bomber. A project to develop a suitable torpedo bomber is ongoing but never reaches maturity and widespread deployment.
5. To support the carriers, design a ~10kton light cruiser of an improved Leipzig design, and a longer range destroyer type of say around 2000 tons (yes, forget the 15cm guns on the destroyers!).
6. The big sacrifices here compared to historical are the two Bismarck's and the three Hippers. That gives about 130kton to use for other things. Say, 3 23kton carriers, 3 10kton light cruisers, and 15 2kton destroyers.

So how could these, hypothetically, have been used? By the Norway invasion, maybe 1 fleet carrier, two CL's, and a bunch of destroyers might be ready. Instead of Blucher, send in a few destroyers up the Oslo fjord. Sucks to lose one, but less a disaster than losing a heavy cruiser. Moving up Norway, the fleet carrier launches strikes on Norwegian positions, and maintains situational awareness so the invasion fleet isn't caught with their pants down. The older carrier can help, or if nothing else help ferry planes up to Norwegian airfields to quickly consolidate positions. For the battle of Britain, maybe the second fleet carrier is ready too, and they can launch hit and run raids against North-East UK. Or maybe team up with the Luftwaffe to provide fighter cover for LW bombers coming from Norway? I'm not sure breaking out into the Atlantic is feasible. Maybe they try with one carrier (+ escorts) and it gets sunk similarly to Bismarck historically. So the rest of the war the carriers spend mostly in Norwegian waters, occasionally launching some air strikes on, say, Scapa flow or Iceland, and of course against the Arctic convoys. Eventually of course their luck runs out and the Allies catch them, be it with Tallboys, submarines, carrier launched air strikes or whatever.

Click to expand...

A navalized BF 109? They had enough problems landing without waves moving the runway.

And where do they train? In the Baltic, where they won't face sea states as per North Sea ops? And to get them to waters off France. Maybe get them through the Dover Straits where French land-based air gets a crack?

If it's only Germany v France, Army and LW should get the resources. If it's Germany v UK as well as France, any German carrier will get sunk before it sinks Hood.

z42 said:

1. To support the carriers, design a ~10kton light cruiser of an improved Leipzig design, and a longer range destroyer type of say around 2000 tons (yes, forget the 15cm guns on the destroyers!).
2. The big sacrifices here compared to historical are the two Bismarck's and the three Hippers. That gives about 130kton to use for other things. Say, 3 23kton carriers, 3 10kton light cruisers, and 15 2kton destroyers.

Click to expand...

A major problem for the Kriegsmarine is that a lot of their ships were just plain bad designs compounded by bad designs of machinery. Then they squared the problems by trying to do too much, armament/speed or combinations.

Leipzig was and improved Koln and the Kolns were among the worst cruisers built between the wars. Not hard to improve them but what do you get in the end?
The British town classes are not impressive on paper but they worked. Germans spent too much tonnage on trick propulsion and leading edge guns/armament.
German 5.9s out ranged the British 6in guns by around 4000yds? trouble is that nobodies 6in guns could hit at max range. Germans paid for long range with short barrel life, they also had less magazine capacity. They carried about 50% more torpedoes. and so on.

Same with the Destroyers, it wasn't the 15cm guns so much as the roughly 70,000hp engines needed for the 36-38kt speeds. British Tribal class had 44,000hp and 1/2 the boilers (not quite fair the British boilers were not the high pressure steam type).
Only 18 destroyers were completed with 5.9in guns.

The Big German ships scared the British. A few 10kton 6in cruisers and 15 2kton destroyers would not even have been a decent lunch for the RN.

Looking at displacement to broadside weight, the Bismarcks must be the one of lightest armed, or unbalanced dreadnought battleships. Anyone else would have put nine, ten or even twelve 15" guns, or nine 16" guns on a similar displacement. Only the one-off Vanguard comes close with her four second hand twin 15" turrets.

Shortround6 said:

A major problem for the Kriegsmarine is that a lot of their ships were just plain bad designs compounded by bad designs of machinery. Then they squared the problems by trying to do too much, armament/speed or combinations.

Leipzig was and improved Koln and the Kolns were among the worst cruisers built between the wars. Not hard to improve them but what do you get in the end?
The British town classes are not impressive on paper but they worked. Germans spent too much tonnage on trick propulsion and leading edge guns/armament.
German 5.9s out ranged the British 6in guns by around 4000yds? trouble is that nobodies 6in guns could hit at max range. Germans paid for long range with short barrel life, they also had less magazine capacity. They carried about 50% more torpedoes. and so on.

Same with the Destroyers, it wasn't the 15cm guns so much as the roughly 70,000hp engines needed for the 36-38kt speeds. British Tribal class had 44,000hp and 1/2 the boilers (not quite fair the British boilers were not the high pressure steam type).
Only 18 destroyers were completed with 5.9in guns.

The Big German ships scared the British. A few 10kton 6in cruisers and 15 2kton destroyers would not even have been a decent lunch for the RN.

Click to expand...

Not to mention that many of those German cruisers couldn't face into the weather, many of their destroyers required oil retained for ballast which reduced their range, and even the Ugly Sisters took beatings from -- yikes! -- the weather, much less shells, mines, and so forth.

Admiral Beez said:

Looking at displacement to broadside weight, the Bismarcks must be the one of lightest armed, or unbalanced dreadnought battleships. Anyone else would have put nine, ten or even twelve 15" guns, or nine 16" guns on a similar displacement. Only the one-off Vanguard comes close with her four second hand twin 15" turrets.

Click to expand...

Drachinifel points out this engineering inefficiency. The Americans put 9x16" guns onto a hull 7,000 tons lighter, with arguably better armor and similar speed.

Thumpalumpacus said:

Drachinifel points out this engineering inefficiency. The Americans put 9x16" guns onto a hull 7,000 tons lighter, with arguably better armor and similar speed.

Click to expand...

The Germans had planned 8x16" for their H-class, similar to the IJN's Nagatos from decades earlier. 9x16" is a good layout that only Britain (just NelRods) and the US made use of.

In 1933, Germany could have aporoached the Japanese for assistance in building up their Navy on the down-low.

Thumpalumpacus said:

A navalized BF 109? They had enough problems landing without waves moving the runway.

Click to expand...

Indeed. But that was what they historically were planning for their naval aviation. Would it have worked, no idea. Potentially if the fuselage is strengthened sufficiently?

And where do they train? In the Baltic, where they won't face sea states as per North Sea ops? And to get them to waters off France. Maybe get them through the Dover Straits where French land-based air gets a crack?

Click to expand...

Before the war, wherever. After the outbreak of the war, yes the Baltic as they historically trained the KM.

For a hypothetical war against France where the UK stays out of it, they can go around the UK.

If it's only Germany v France, Army and LW should get the resources. If it's Germany v UK as well as France, any German carrier will get sunk before it sinks Hood.

Click to expand...

In retrospect, yes obviously they don't need a blue water navy to beat France. But historically, they still built the PBB's and the Scharnhorsts as counters to French naval power. For this scenario I'm assuming they still think like this, silly as it is.

As for a German carrier vs Hood, just like a golden shell sunk the Hood historically, a golden bomb from a Stuka could sink it. Then again, the UK response to a German Atlantic breakout attempt with a carrier strike force wouldn't likely be the Hood and PoW, but rather some kind of carrier force of their own. So we might instead have seen the carrier battle of Denmark Strait. Outcome not certain, but my money would be on the RN.

z42 said:

Indeed. But that was what they historically were planning for their naval aviation. Would it have worked, no idea. Potentially if the fuselage is strengthened sufficiently?

Click to expand...

A potential rival for the Bf109E (T) may have been the He112B - history may never know, but their performance profiles (the Bf109E) were comparable.

Thumpalumpacus said:

Not to mention that many of those German cruisers couldn't face into the weather, many of their destroyers required oil retained for ballast which reduced their range, and even the Ugly Sisters took beatings from -- yikes! -- the weather, much less shells, mines, and so forth.

Click to expand...

Yes, hence I suggested new designs. Even the Germans should be able to come up with a seaworthy light cruiser if they have 10ktons to work with. Of course that might also require a kind of back to basics design and not use the extra tonnage for more gizmos.

Thumpalumpacus said:

Drachinifel points out this engineering inefficiency. The Americans put 9x16" guns onto a hull 7,000 tons lighter, with arguably better armor and similar speed.

Click to expand...

IIRC Drach's argument is that there's two main reasons for this. First, losing a lot of the institutional memory for warship design due to the Versailles treaty and the subsequent economic crash. Secondly, a dysfunctional Nazi bureocracy with a design by committee where each department needs to show their importance by cramming their feature into the design.

As for the Americans, it has been claimed (by Friedman?) that the South Dakotas were the finest treaty compliant battleships. Lots of room for Germany to improve before unseating them from the throne.

Admiral Beez said:

The Germans had planned 8x16" for their H-class, similar to the IJN's Nagatos from decades earlier. 9x16" is a good layout that only Britain (just NelRods) and the US made use of.

Click to expand...

Yes, more guns per turret helps save weight, both by needing fewer turrets and by keeping the citadel length shorter. But more guns per turret also presents more (much more!?) engineering challenges. Would the Germans have been left with a white elephant had they tried to go for triple 15" turrets?

As for the 9x16" layout, it seems there was a consensus it was very difficult, if not impossible, to make a well balanced battleship with that armament at the 35kton treaty limit.

Arguably the British would have been better served by doubling down on their excellent 15" gun. Make the Nelrods 9x15" ships, use the leftover tonnage for speed (see the F3 design). And similarly arm the KGV's with 9x15", using the same turret design as the F3-Nelrods, and they might have functional turrets in time for Denmark Strait.

Thumpalumpacus said:

Drachinifel points out this engineering inefficiency. The Americans put 9x16" guns onto a hull 7,000 tons lighter, with arguably better armor and similar speed.

Click to expand...

Admiral Beez said:

The Germans had planned 8x16" for their H-class, similar to the IJN's Nagatos from decades earlier. 9x16" is a good layout that only Britain (just NelRods) and the US made use of.

Click to expand...

In addition to the turret layout, a major aspect that is different between the Bismarck and other capital ships of the era is the armor layout. The turtleback scheme Bismarck and other German big warships had, while there were a few advantages to it, were pretty inefficient on a protection per weight basis, and also had several other major downsides compared to the box type citadels everyone else was building in that timeframe.

Here's Nathan Okun's analysis and comparison to other contemporary capital ships: ARMOR PROTECTION OF KM BISMARCK by Nathan Okun 9/6/91

z42 said:

Here's Nathan Okun's analysis and comparison to other contemporary capital ships: ARMOR PROTECTION OF KM BISMARCK by Nathan Okun 9/6/91

Click to expand...

It's impressive how a single piece of armoured steel can be both hard and soft at different thicknesses.