Better German naval strategy 1930-1945?

[GrauGeist]

The FA223 was capable of ASW, but early helicopters were slow, short-ranged and were sensitive to weather conditions.
Add to this, many types had difficulty with CoG distribution.

 

[SaparotRob]

Unsure what the argument here is? In order to force the UK out of the war, the subs would have to on average cause unsustainable losses.

That they maybe achieved that for some brief moments doesn't win them the battle of the Atlantic. At best it might prove that without appropriate Allied countermeasures they had the capability to do it.



Absolutely. In general, not only for subs vs ASW, with some certainly notable exceptions, the Allies out-innovated the Germans.



I agree, and that does present the Germans with quite a conundrum how to efficiently find the convoys.



That's certainly a good point. And indeed they had many great radials to choose from. Say, if the R-1340 is too weak for a full-featured ASW chopper, there's, say, the R-1820 & R-1830.

Maybe not Wright or P&W. What about from the stash of LeRhone engines they used on the Me-323?

 

[marathag]

This was a major advantage of German U-boats - it allowed subs to much more-reliably take advantage of differing temperature water layers to break up Allied sonar signals, and to attenuate sub-generated noise below what ASDIC could usefully detect.

Unlike the US Boats, the Germans didn't have a bathythermograph onboard to measure it properly and typically couldn't plan on that

View: https://youtu.be/n3SnaDZomws

2nd, That's a great Sir Robin move, being able to run away better. Nice, but you don't win with retreats

Having the humidity controlled allowed the TDC and Radars to be fitted and far more reliable, that increased the real reason the Sub was there, put a torpedo into the side of a moving enemy ship.

Better habitability and good chow keeps crew efficiency and morale high. Not just eating canned sauerkraut twice a day. Fresh food.

 

[marathag]

Kayaba Ka-1 Autogyro.

From the Imperial Japanese Army, used for spotting USN Subs from the Army's Escort carrier

Because the IJN was so bad at that job and Interservice cooperation all but dead halfway thru the War

 

[GrauGeist]

The IJA had it's own fleet because there was little cooperation between the two services as well as the Army's operational requirements were often outside of the IJN's sphere of support.

The IJA's fleet not only consisted of Carriers and Submarines, but gunboats, tankers, supply ships, cargo ships, troop transports, landing craft and other types.

However, the U.S. Army also had a considerable fleet during the war, though subs and carriers were solely U.S. Navy assets.

 

[Thumpalumpacus]

View attachment 792515Kayaba Ka-1 Autogyro.

From the Imperial Japanese Army, used for spotting USN Subs from the Army's Escort carrier
View attachment 792517

Because the IJN was so bad at that job and Interservice cooperation all but dead halfway thru the War

A precursor to the modern amphibious assault ship. It had no hangar, that space used to house fighting troops and some Daihatsus to land them. Airplanes kept in deck park to land ashore once a landing ground was taken.

Mostly used to transport airplanes to garrisons and not for combat operations or ASW.

 

[GrauGeist]

The IJA did have a couple full length carriers, but they were late war and never able to fully conduct their mission.
One was the Kumano Maru, another was the Yamashio Maru.

The "depot ships" which were escort carrier sized, such as the Akitsa Maru, did maintain a compliment of eight aircraft (for ASW), while able to ferry up to thirty aircraft.

These "depot ships" would be sort of a forerunner of the USN's LHA class.

 

[EwenS]

Link here to ship histories for IJA vessels.

RIKUGUN-SEN

While Yamashio Maru was completed in Jan 1945 she never became operational. Tanker conversion. The planned air group was 8 Ki-76 Stella aircraft. No hangar, and only 351ft of flight deck.Two sister ships never completed.

Japanese Oilers/Escort Carriers

Kokusai Ki-76 - Wikipedia

en.m.wikipedia.org

Akitsu Maru was laid down as a merchantman and acquired by the IJA in June 1941 and fitted out with a flight deck before completion in Jan 1942. Her acquisition had nothing to do with the IJN's ASW abilities.It was about boosting the IJA's amphibious capabilities, providing the landing force with spotter aircraft like the Ki-76 & Ka-1.

Kumano Maru was never completed during WW2. Post war she became a repatriation ship, taking Japanese personnel home. The equivalent ofbthe US Magic Carpet operation.

Details of the various IJA Landing Craft Depot Ships here

IJA Landing Craft Depot Ships

The IJA built a specialised amphibious assault ship as far back as 1933/34. The Shinshu Maru

Edit
Details of US Army vessels here

NavSource Online: US Army Ships Photo Archive

 

[GrauGeist]

Ewen, I don't have my books available, but weren't the larger Marus equipped with atresting gear?

 

[Thumpalumpacus]

One was the Kumano Maru, another was the Yamashio Maru.

Even those were essentially Japanese versions of merchant aircraft carriers.

 

[Shortround6]

Well the thread is about a better German naval strategy. Given what was known at the time (much of the 1930s) we could get one answer. Using what was know in the late 40s with all the collected data we could very well get a different answer.

Unsure what the argument here is? In order to force the UK out of the war, the subs would have to on average cause unsustainable losses.

That they maybe achieved that for some brief moments doesn't win them the battle of the Atlantic. At best it might prove that without appropriate Allied countermeasures they had the capability to do it.

Absolutely. In general, not only for subs vs ASW, with some certainly notable exceptions, the Allies out-innovated the Germans.

One strategy was Plan Z that was ordered 1939 for completion in 1948 so that was one extreme. Other extremes from modern thinking (post WW II) claim the Germans should only have built U-Boats or perhaps just used small craft (mine sweepers and coastal escorts?).

Without revamping history too much things would be in the middle. I would note that Plan Z was doomed as the planners don't seem to have taken radar or long range search aircraft into account. Why would they as radar was only being fitted for trials in most navies in 1938-39 and long range aircraft (flying 1000 miles, patrolling for several hours and flying 1000 miles back) were not operational. Prototypes yes.
The No (or smaller ) Navy ideas needs the Weimar Republic to squash the Navy either before the Emden or after the Kolns or somewhere in the Deutschland cycle (ship 1 or 2 or 3?) .

The British had suffered enough from German Subs in WW I that the Weimar Republic was banned from having any subs at all and development/design even for foreign sales was also banned. Germans got around this by opening a design office in Holland and selling plans to Turkey and Finland. Germans don't announce the construction of U-boats until 1935?
Work on the two Type Is (U-25-26) started in 1934 but they completed after a number of the smaller Type II's.

Creating a U-boat force from scratch in 4-5 years would be difficult but with old Adolf in charge, good planning often took a back seat. Thinking the war would not start until sometime between 1942 and 1948 (plan Z in early 1939) meant there was time to build up the ship yards, design and build training subs (the Type IIs) and train and expand the crews and officers for a bigger force. War starting in fall of 1939 caught the navy short both for surface ships and effective subs. The Type IIs could operate in British waters but they were slow (13kts on the surface) and about 7kts underwater. Type VIIs could do about 8 kts underwater and while that doesn't sound like much being 14% faster when you are trying to dodge a depth charge attack might make the crew feel better Type IIs also had 3 tubes and 2 reloads for a total of 5 torpedoes which meant that they spent a lot of time going back and forth to base to reload/rearm. Early Type VIIs carried 11 torpedoes or 22 mines compared to the 12 mines of the Type IIs.
The Type IIs were about 1/2 of the U-boats in the fall of 1939.

We also have to consider what the British/French response to any major change in German strategy/building program/s.
The British were not as slow as some people think.
Hunt class escort destroyers, from Wiki.
"The first ten of the following were ordered on 21 March 1939, and the other ten on 11 April 1939. Three more were ordered on 4 September 1939 (see below) were intended to be of Type II, but were actually completed to the Type I design"
"Eighteen were ordered on 4 September 1939 and two more (Lauderdale and Ledbury) on the following day. Three of these were completed with the same armament as the Type I – Blencathra, Brocklesby and Liddesdale. A final batch of sixteen were ordered on 20 December 1939."
Flower class corvettes
"The RN ordered 145 Flower-class corvettes in 1939, the first 26 on 25 July with a further batch of 30 on 31 August, all under the 1939 Pre-War Programme"

The start of hundreds of escort type ships. The Flowers were designed for coastal use and the loss of France meant they got pushed out into the Atlantic. The Loss of France meant that not only did the 1939/40 allies loose scores of escort ships but the German use of French bases made the U-boats much more effective being able to speed days longer on patrol vs transiting back and forth. Trying to figure that into German navy 1935-39 thinking is hard.

German type IX boats were sort of a mixed bag. They had a lot range, but crew comforts were not good and the torpedo capacity is something of an illusion.
Germans did an awful lot with refueling/replenishing at sea but this meant they were subject to having the supply/replenishment subject to Murphy's law and it's corollary.
This is one reason that things went wrong for the Germans in 1943, not the only reason by far, but part of it. Using short range/endurance boats and extending range by using supply ships instead of building proper long range boats (at least some) means you run out of options if the resupply operations don't go well.

However not contesting the RN at sea, somehow, releases an awful lot of Allied war capacity to be used in other ways.

 

[Thumpalumpacus]

Without revamping history too much things would be in the middle. I would note that Plan Z was doomed as the planners don't seem to have taken radar or long range search aircraft into account.

Nor oil, for that matter. Ask the Italians about battleships swinging at anchor for want of fuel.

 

[z42]

Well the thread is about a better German naval strategy. Given what was known at the time (much of the 1930s) we could get one answer. Using what was know in the late 40s with all the collected data we could very well get a different answer.

I think in order to be meaningful, what-if scenarios must be plausible in light of what the people at the time knew. Then when analyzing such scenarios we are of course allowed to use hindsight to say "If they had done X instead of Y, the result might have been Z". Anyway, with that philosophy side-track out of the way, on with the show..

One strategy was Plan Z that was ordered 1939 for completion in 1948 so that was one extreme. Other extremes from modern thinking (post WW II) claim the Germans should only have built U-Boats or perhaps just used small craft (mine sweepers and coastal escorts?).

Without revamping history too much things would be in the middle. I would note that Plan Z was doomed as the planners don't seem to have taken radar or long range search aircraft into account. Why would they as radar was only being fitted for trials in most navies in 1938-39 and long range aircraft (flying 1000 miles, patrolling for several hours and flying 1000 miles back) were not operational. Prototypes yes.
The No (or smaller ) Navy ideas needs the Weimar Republic to squash the Navy either before the Emden or after the Kolns or somewhere in the Deutschland cycle (ship 1 or 2 or 3?) .

Radar was probably a bit of a black swan event that couldn't have been foreseen, particularly how quickly they were able to miniaturize it sufficiently to mount it on said search aircraft. But aircraft? Sure, such long range patrol aircraft didn't exist then, but they should have been able to extrapolate the range, speed, and load carrying capacity of aircraft over time and see that (potentially!) long range patrol aircraft could cover quite a lot of ocean in a few years time.

As for the Weimar naval building program, I wouldn't worry about it too much. If, hypothetically, the nazis decide to go all in on u-boats the capital outlay so far on the Weimar surface fleet program is in the grand scheme of things quite modest. The door is still mostly wide open for pivoting in all kinds of wild directions, if they so wished for whatever reasons.

We also have to consider what the British/French response to any major change in German strategy/building program/s.
The British were not as slow as some people think.
Hunt class escort destroyers, from Wiki.
Flower class corvettes

They also got 50 US WWI-era destroyers (rechristened the Town class). Obviously not as capable as a then modern fleet destroyer, but with some modest modifications adequate for convoy escort duty.

The Loss of France meant that not only did the 1939/40 allies loose scores of escort ships but the German use of French bases made the U-boats much more effective being able to speed days longer on patrol vs transiting back and forth. Trying to figure that into German navy 1935-39 thinking is hard.

Indeed. And they probably didn't count on conquering Norway either. Which sort of makes Plan Z even more bizarre; what where they going to do with all those surface ships, sitting there in Wilhelmshafen or Kiel, boxed in like in WWI?

German type IX boats were sort of a mixed bag. They had a lot range, but crew comforts were not good and the torpedo capacity is something of an illusion.

To put it mildly. From wiki:

Twelve torpedoes were stowed internally and ten were in the topside deck containers.[1] In order to get the torpedoes into the forward or bow torpedo room, the torpedoes were lifted over the U-boat by a crane. The crew would then pull the torpedo inside the vessel using a cradle that was set at an angle to allow the torpedo to slide into position inside the torpedo room. To reload a torpedo tube with a torpedo from one of the above-deck canisters, the submarine would have to surface in calm water. Then the torpedo would be pulled out of the compartment with winches and lowered into the forward or bow torpedo room. This process could take several hours for just one torpedo, during which the U-boat was unable to dive, making it an easy target for Allied aircraft.

Oof.

That being said, after the initial successes with the surface raiders, long-range u-boats were probably their best bet for raiding further away than the north Atlantic. They might have needed a better next generation long range boat to replace the Type IX. In any case, such long range raids are more of a nuisance thing rather than a war-winning strategy (which doesn't mean it wasn't worth it for them to do it, few things are war-winning by themselves, but many small streams etc.).

However not contesting the RN at sea, somehow, releases an awful lot of Allied war capacity to be used in other ways.

Indeed. So, put down your stake and say what you think the Germans could have done better (given what they knew then)?

 

[ThomasP]

I still think the best bet is listen to Donitz and give him the 300+ hulls he asked for, along with the supporting logistics ships and long-range maritime aircraft. It would (I think) significantly slow down the US getting over to Europe in any strength, and might allow the Germans and Italians to win in the MTO. In the original timeline the US adopted the Europe First strategy and treated the PTO as secondary, but would that have been the decision if the choice had meant that most of the shipbuilding effort built had to be deployed in the Atlantic and ETO/MTO to counter the U-boat threat? There is a good chance the US would have to allow the Japanese to consolidate their conquests in the PTO if they still went with the Europe First idea. Would the US be willing to give up its holdings in the Western Pacific?

 

[Thumpalumpacus]

There is a good chance the US would have to allow the Japanese to consolidate their conquests in the PTO if they still went with the Europe First idea. Would the US be willing to give up its holdings in the Western Pacific?

Even once consolidated, once the Vinson Act ships came into service, I think control of both oceans was going to be secured.

Of course, Germany-first meant that in the Pacific it would become a race between winning the Pacific Front and losing on the home front as war weariness set in (which was already happening by 1945). I'm not sure Germany-first had any inevitability, though, when we consider Adm King's unwillingness to let USN assets sit idle, as shown historically. The year or two required to make Overlord a success meant that idle combat resources could still be used in the meantime.

But that notwithstanding, once the atomic bomb was known to work and then deployed in action, I'm not sure all that Japanese consolidation means diddley-squat. Aside from the Bomb, take into account the sub blockade and B-29 mining ops, which already laid the table for a massive famine in '46 had the Japanese not surrendered when they did.

I don't think America would have to give up anything in the WestPac. Donitz's 300 subs would have been very, very bad for us, but escort carriers and more importantly B-24s made the mid-Atlantic dangerous. More U-boat targets? More Allied shipping losses? Probably both. And meanwhile the CVs, BBs, and a million or so troops -- who can't fight subs anyway -- are going to be hitting at Japan's perimeter all the same.

My opinion, worth every penny you paid for it.

 

[don4331]

I still think the best bet is listen to Donitz and give him the 300+ hulls he asked for, along with the supporting logistics ships and long-range maritime aircraft. It would (I think) significantly slow down the US getting over to Europe in any strength, and might allow the Germans and Italians to win in the MTO. In the original timeline the US adopted the Europe First strategy and treated the PTO as secondary, but would that have been the decision if the choice had meant that most of the shipbuilding effort built had to be deployed in the Atlantic and ETO/MTO to counter the U-boat threat? There is a good chance the US would have to allow the Japanese to consolidate their conquests in the PTO if they still went with the Europe First idea. Would the US be willing to give up its holdings in the Western Pacific?

But you can't give Donitz the 300+ hulls he wants until '41 at best because Germany doesn't have the lead smelting capacity until then. So, if Hitler goes to war against Poland in Sept '39 you'll never get there because UK goes to war again Germany (As S Shortround6 says UK wasn't too stupid - they knew if they left the Kriegsmarine's U-boat construction unhindered, they would have the ability to strangle British Isles. So, UK declaring war on Germany upon the invasion of Poland has to happen).

This is what is causing me so much indecision - do I ignore U-boats and hope that as a result UK doesn't declare war when Poland is attacked? Or will they declare war anyways??​

There needs to be sufficient forces to take Norway - otherwise UK mines the North Sea from Scotland to Norway like they did in late WWI and KM is restricted to Baltic.

Unless France falls, the distances to great for '30s MPA to fly around British Isles to get into Atlantic and still have useful payload/time on station. (More/less same issue as U-boats, cruisers & destroyers). As the technology of the day didn't allow it, Goring didn't waste significant resources having Luftwaffe develop the functionality. If you're planning for both Poland and France to fold like houses of cards, they have padded rooms for you.

Developing air to air refueling is probably important to KM. No idea on how to rearm in addition to refuel, so combat planes may stay on station longer/attach more.​

The MTO is probably as important for Germany as strangling UK in Atlantic - getting the critical minerals from North Africa e.g. Cobalt is vitally important to the war economy.

Closing Suez Canal can probably be done with block ships. What does it take for Axis airpower/Italian navy make it logistically impossible to operate from Gibraltar in MTO?​

​

I'm also looking at what doesn't it take from KM to close Murmansk and Arkhangelsk/open a "Northern Front" for Heer.

Escort type carrier(s) with CL for close protection/BB for distant protection?? If Heer may be supplied by Naval forces but Russian force must be supplied by rail, Germans can win the logistics battle.​

Navy's are still "big gun" so especially Hitler will need is "wonder toys". So, there's pressure to build battleships and they act as 'force in being'.

But do they assist with the strategy??​

 

[Shortround6]

Radar was probably a bit of a black swan event that couldn't have been foreseen, particularly how quickly they were able to miniaturize it sufficiently to mount it on said search aircraft. But aircraft? Sure, such long range patrol aircraft didn't exist then, but they should have been able to extrapolate the range, speed, and load carrying capacity of aircraft over time and see that (potentially!) long range patrol aircraft could cover quite a lot of ocean in a few years time.

As for the Weimar naval building program, I wouldn't worry about it too much. If, hypothetically, the nazis decide to go all in on u-boats the capital outlay so far on the Weimar surface fleet program is in the grand scheme of things quite modest. The door is still mostly wide open for pivoting in all kinds of wild directions, if they so wished for whatever reasons.

The Weimar light cruisers and other light stuff (steam torpedo boats and destroyers) are still going to be very useful. They did a lot of mine laying for one thing. The 3 armored ships also gave the British a lot of heartburn during the 30s and into 1940. Something like 19 ships to chase down the Graf Spee alone. It is in the 30s that they seem to have come off the rails. How many times did they have to refuel the Prinz Eugen during the Operation Rheinübung? Twice after leaving the Bismarck? An ocean raider it was not. And the early bow on the Hipper and Blucher? Again, where were they going to operate it? In the Baltic? And the Machinery was crap. It may have had the most powerful 8in guns of any WW II cruiser (or 2nd) and it may have had the most armor but it couldn't operate in bad weather and need a fleet of tankers to even run around in the North Atlantic? Long range light cruisers with 6-9 15cm guns might have been a better bet. The ugly twins were a better deal. They force the French to reply and they need a lot more attention than simply adding an extra couple of cruisers to the hunters. Is a Hipper worth 2 or 3 Countys if you don't have BC handy? Scharnhorst forced deployment of capital ships. B & T maybe more questionable. Anything past the Tirpitz is a waste. The British can out build the Germans, Forcing them into certain path is one thing. Making the path a little wider or thicker may not give good return on investment.

They also got 50 US WWI-era destroyers (rechristened the Town class). Obviously not as capable as a then modern fleet destroyer, but with some modest modifications adequate for convoy escort duty.

They were a stop gap and they really were not that good. They needed a lot of repairs/refitting and they had lousy sea keeping. Deal was made because many of the Escorts the British ordered back in 1939 were still under construction. Of the 20 Hunts ordered in March April of 1939 only about 8 had been "completed" as of the signing of the "Destroyer deal". And most of them were only under 8 weeks old, crews were still training/making maiden voyages. Much like the Buffalo fighters, the British needed something/anything to hold them over while the things they really wanted were built. And much like Buffaloes, the Towns were running late and needed work before use.

Indeed. And they probably didn't count on conquering Norway either. Which sort of makes Plan Z even more bizarre; what where they going to do with all those surface ships, sitting there in Wilhelmshafen or Kiel, boxed in like in WWI?

Plan Z required a fleet of tankers/supply ships floating around in the North Atlantic invisible to search planes, Old cruisers scouting around and/or RN submarines patrolling the NA looking for them. RN subs attached to the home fleet ( but not based in Scapa) were actually tasked with scouting in the North Sea and close to the Norwegian and Danish coasts. Perhaps their tactics were not the best (tended not to fire full salvos) but they put torpedoes into quite a few German ships in or at the end of the Norwegian campaign. I think the Germans had a rather exaggerated idea of what could you hide in the North Atlantic for long periods of time.

That being said, after the initial successes with the surface raiders, long-range u-boats were probably their best bet for raiding further away than the north Atlantic. They might have needed a better next generation long range boat to replace the Type IX. In any case, such long range raids are more of a nuisance thing rather than a war-winning strategy (which doesn't mean it wasn't worth it for them to do it, few things are war-winning by themselves, but many small streams etc.).

long range (or even medium range ) boats with more tubes/internal torpedoes. Why the Germans waited for the Type XXI to put 6 tubes in the bow is something of a mystery.
The Long Range boats force the distant areas to use convoys, and the time needed to organize and form up convoys slowed down shipping by around 30%, many ship sat at anchor for days waiting for the last ship/s to arrive before the convoy left. Not operating in certain areas is like giving the allies about 30% more ships to use in that area if they don't have to convoy.

Indeed. So, put down your stake and say what you think the Germans could have done better (given what they knew then)?

Easiest thing is to can the carrier before it is laid down. It was more a case of "keeping up the the Jones's " than a real operational need.
Get machinery that actually works, even if larger and heavier.
forget the idea of blasting your way into a protected convoy. The Hippers were both too expensive and yet not armed and armored well enough to duke it out with even British 8in Cruisers. British can afford to loose cruisers. The existing Germans cannot.
Ramp up Sub construction sooner or at least swap some of the Type IIC & D for type VIIs in 1938-39.
That and/or build something like the British U class. 4 tubes in the bow with 4 reloads. But they are slow.
Germans operated in the early part of the war like submersible torpedo boats. At night they fought on the surface and used their speed to attack the convoys and evade many of the early British escorts (11-12knt trawlers).

 

[z42]

I don't think America would have to give up anything in the WestPac. Donitz's 300 subs would have been very, very bad for us, but escort carriers and more importantly B-24s made the mid-Atlantic dangerous. More U-boat targets? More Allied shipping losses? Probably both. And meanwhile the CVs, BBs, and a million or so troops -- who can't fight subs anyway -- are going to be hitting at Japan's perimeter all the same.

Germany going all-in on u-boats means the UK home fleet can be mostly deployed to the MTO, and the US capital ships can all be deployed to the Pacific. Still, there would be a great demand for escort carriers and corvettes/DEs/frigates/whatever. So sacrifice, say, the Iowas and Alaskas, some Liberty ships, and instead churn out an extra 100 CVE's, 500 corvettes, and deploy B-24's for patrol duties rather than to bombing Europe. Germany might succeed in delaying D-day until 1945, though is the invasion needed by then or are the Soviets already in Paris? And of course with the home fleet supporting the MTO, North Africa collapses and Italy probably drops out of the war sooner.

 

[z42]

But you can't give Donitz the 300+ hulls he wants until '41 at best because Germany doesn't have the lead smelting capacity until then.

Is there any chance of hurrying up this project?

Unless France falls, the distances to great for '30s MPA to fly around British Isles to get into Atlantic and still have useful payload/time on station. (More/less same issue as U-boats, cruisers & destroyers). As the technology of the day didn't allow it, Goring didn't waste significant resources having Luftwaffe develop the functionality. If you're planning for both Poland and France to fold like houses of cards, they have padded rooms for you.

Developing air to air refueling is probably important to KM. No idea on how to rearm in addition to refuel, so combat planes may stay on station longer/attach more.​

Even with aerial refueling I don't see operating in the Atlantic as feasible without bases in France.

The MTO is probably as important for Germany as strangling UK in Atlantic - getting the critical minerals from North Africa e.g. Cobalt is vitally important to the war economy.

Closing Suez Canal can probably be done with block ships. What does it take for Axis airpower/Italian navy make it logistically impossible to operate from Gibraltar in MTO?​

Winning the MTO would have been a major accomplishment for the Axis. They might have been able to access petroleum in the middle east, and prevent the Allies from using the Suez. And with Malta falling, their fleet & air power could concentrate on blocking Allied forces from breaking into the Med from Gibraltar.

But, considering the effort they put into the MTO and their logistics capability, all this seems incredibly far-fetched.

I'm also looking at what doesn't it take from KM to close Murmansk and Arkhangelsk/open a "Northern Front" for Heer.

Escort type carrier(s) with CL for close protection/BB for distant protection?? If Heer may be supplied by Naval forces but Russian force must be supplied by rail, Germans can win the logistics battle.​

They did have a "Northern Front". German troops where mostly responsible for the northern part of Finland (the Finnish army was mostly concentrated on the southern part of the country). I'm not sure how those troops were supplied, maybe partially via Norway and partially via the Baltic and then using rail from the northern end (Kemi maybe?)? But the problem, apart from lack of resources & manpower, preventing them from capturing Murmansk is that the terrain is very difficult (lots of bogs), you can't rofflestomp all over the place with tanks like on the Russian plains. Also biting cold winters, and very little infrastructure like roads or rail lines.

 

[WARSPITER]

The other possibility is that another assault is being prepared to cut access to Crimea through Ukraine once forces are drawn
off to the Kursk area. This would leave a well known bridge as the only way in for Russia.