Tirpitz and Graf Zeppelin 1941

[Paul L]

Actually it was Hitler more than anything that determined naval strategic direction.

If they had wanted to break out in late 1941, a new supply network would have been established without too much difficulty. Since the RN intel was days behind the Actual German naval disposition and movements, then the Germans would have the head start they need to stay ahead. To effectively cover the GIUK gaps would have required a dozen cruisers on patrols to get 100% coverage, and doesn't preclude another reverse manuever to lose the shadowing Cruisers, as was done during the Bismarck/PE break out attempt. Even retreat into the artic for a week or two to refuel and re attempt a break out should get through at high speed dash.

In the Bismarck pursuit the distance involved 1350nm at top speed. Most British Cruisers had endurance of 10100nm @ 12knots and about 1/4 that distance at 30 knots., which means they would need to keep 1/2 there fuel in reserve, reducing the patrol endurance to two weeks at 12knots. When done they have to return to port to refuel as was the case with Operation Rheinübung.

[dunmunro]

In the Bismarck pursuit the distance involved 1350nm at top speed. Most British Cruisers had endurance of 10100nm @ 12knots and about 1/4 that distance at 30 knots., which means they would need to keep 1/2 there fuel in reserve, reducing the patrol endurance to two weeks at 12knots. When done they have to return to port to refuel as was the case with Operation Rheinübung.

Arrangements were often made for patrol cruisers to refuel in the nearest sheltered harbour via tanker, and for Icelandic patrols, this usually meant the nearest fjord.

[RF]

In the Bismarck pursuit the distance involved 1350nm at top speed. Most British Cruisers had endurance of 10100nm @ 12knots and about 1/4 that distance at 30 knots., which means they would need to keep 1/2 there fuel in reserve, reducing the patrol endurance to two weeks at 12knots. When done they have to return to port to refuel as was the case with Operation Rheinübung.

But don't forget that Norfolk stayed it out to the end, to finally answer Bismarck's opening gunfire with a shell hit that knocked out the Bismarck's main gunnery control position......

[Paul L]

No argument on those points other than to point out they are just more variables that could contribute to interception or break out. There are no guarrantees. Alot depends on how much lead time the Admiralty gets on a German raider departure. Clearly with Operation Berlin, they got away fast enough and avoided positive detection and were able to make another break out attempt a week later from the Artic. That was only couple of months before Bismarck.

http://www.scharnhorst-class.dk/scharnh ... erlin.html

[Pandora]

I agree with you Paul.
Scharnhorst/Gneisenau turned back when they where sighted by a cruiser and tried to break out days laters which they did. so I wonder if Bismarck had turned back when she was first sighted by Suffolk and tried later. a thing that people tend to forget is that if the Germans spend X fuel for its ships, the Royal navy has to spend many times more fuel for all her hunting fleet. if the Germans turn back and refuel in the North Sea, the British must return to Scapa to refuel as well.

[srgt rock]

I don't know if you realy need to dig so deep into details, Sgt Rock.
The most probable outcome, IMO, would be that the German raider force breaks into the open waters of the Atlantic, and attacks 1-2 convoys, that are scattered with great losses for the Allies. AFTER THAT however, shortage of fuel and ammo aboard TZ and GS would be greatly felt. AND, considering the response Bismarck triggered, there would be several (4-5 ?) convergent task-forces, with at least 3 carriers and 6 BBs and BCs present. Coastal Command would add to the search efforts, and so would every ship from every convoy the raiders encounter.

The German raiders would play a huge gamble by this time, either trying to refuel/rearm by sea (an operation which takes many hours, during which the ship is most vulnerable) OR trying to race back to Brest, somehow through the net of British task-forces.

Either way, it's a big, big gamble, with a moderate payoff.

Just my opinions, of course...

The ability to refuel and rearm would depend upon how many Trosschiffs were in the mid-Atlantic with the German task forces. If the Support Group ships Nordmarck and Dithmarchen were able to join Uckermarck and Python, the Germans would have had the ability to operate from the Central Atlantic where they would have been difficult to locate.

The goal of Rapier WOULD NOT be to return to Brest but to Norway with ALL German heavy units.

Even if Rapier were only to result in 1 or 2 convoy attacks and a successful return to Norway IMHO it would have been a major payoff. All offensive British operations would have been put on hold during the operation. Would Rommel needed to fall back as far if some more of his supply ships had gotten through? I would also think that even one successful break through by a GZ based task force would have led to a British build up of air units in Iceland. They could only have come from Bomber Command.

As a final thought, the Germans would have needed a training aircraft carrier to keep GZ supplied with air crews. I think Friesenland would have done the job or if they did not want to take Friesenland from her role of seaplane tender, the uncompleted Trosschiff Franken would have been my next choice.

PS: Once the KM starting using aircraft carriers would they consider converting the iron ore ships like the Albert Jensen to MAC ships?

[alecsandros]

The ability to refuel and rearm would depend upon how many Trosschiffs were in the mid-Atlantic with the German task forces. If the Support Group ships Nordmarck and Dithmarchen were able to join Uckermarck and Python, the Germans would have had the ability to operate from the Central Atlantic where they would have been difficult to locate.


The goal of Rapier WOULD NOT be to return to Brest but to Norway with ALL German heavy units.

Even if Rapier were only to result in 1 or 2 convoy attacks and a successful return to Norway IMHO it would have been a major payoff. All offensive British operations would have been put on hold during the operation. Would Rommel needed to fall back as far if some more of his supply ships had gotten through? I would also think that even one successful break through by a GZ based task force would have led to a British build up of air units in Iceland. They could only have come from Bomber Command.

They may have had some successes, but I don't see the logistics necessary to keep those 2 big ships underway for more than 1 sortie. The reason I'm thinking about concerns 38cm shells needed for TZ and various types of aircraft needed by GZ.
Did the Germans had supply ships capable of transporting such ammo and planes far out at sea ? And could a 800kg shell be loaded from the transport ship to Tirpitz, at sea, in the waters of the North Atlantic ?

Indeed, they would have been difficult to locate, but the RN and RAF had considerable more resources available in Nov-Dec 1941 than they had in May the same year. British submarine strength increased, the number of operational carriers also, teh number of destroyers also, etc.

And, if the weather was realy bad, thus hindering search&destroy operations by the RN/RAF, the planes from GZ would also be "grounded", thus cutting the offensive and defensive force of the German squadron.

====

Anyways, the response would almost certainly have been "Sink the Tirpitz and Graf Zeppelin", thus concentrating large sea and air forces against the 2 German raiders. GZ, if it would make it to Norway, or France, or whatever (which I doubt), would be bombed severely and repeatedly, leaving it in repairs for years. Tirpitz, if it would escape destruction/heavy damage, would work in conjunction with Schar/Gneisenau, and maybe Prinz Eugen. It would be a powerfull shock force, but again restricted by the range of their guns to a 20-30km maximum attack radius.

My opinion is that the Germans needed at least 3-4 fleet carriers in 1941 to change the course of the battle of the ATlantic...

[RF]

Scharnhorst/Gneisenau turned back when they where sighted by a cruiser and tried to break out days laters which they did. so I wonder if Bismarck had turned back when she was first sighted by Suffolk and tried later. a thing that people tend to forget is that if the Germans spend X fuel for its ships, the Royal navy has to spend many times more fuel for all her hunting fleet. if the Germans turn back and refuel in the North Sea, the British must return to Scapa to refuel as well.

This does pose an interesting question. If Lutjens had gone into the Arctic and refuelled from the Weissenburg, which the original orders for Rheinubung specified, would they then have easily broken out, with Hood/POW back in Scapa Flow along with KGV? The implied answer here is yes, but there are two crucial differences between the breakouts for Berlin and Rheinubung.
One - Rheinubung was expected by the British because the German ships had been spotted on their way to the break out run. So the patrolling cruisers were on full alert. For Berlin there was no such clear forewarning of German moves.
Two - by the time Rheinubung came round the patrolling cruisers had decent radar so they could shadow the German ships which of course were expected at some time. The Niade did not have the advantage of radar, there was no clear prior indication of an imminent German breakout so when nothing happened in the days after Niades' sighting report it was assumed the report was on a mistaken sighting......
Had Lutjens run north after encountering Suffolk the change in direction would have been reported.... also enigma decripts were beginning to betray the locations of German supply ships, which would have included Weissenburg.

No, any breakout for Rheinubung would have been far more difficult than for Berlin. Indeed one aftermath of Rheinubung was that both raiders and blockade runners were routed through the Channel and Biscay ports to avoid the Iceland passages (except for a brief period in 1943 - when all the runners were intercepted).

[RF]

The ability to refuel and rearm would depend upon how many Trosschiffs were in the mid-Atlantic with the German task forces. If the Support Group ships Nordmarck and Dithmarchen were able to join Uckermarck and Python, the Germans would have had the ability to operate from the Central Atlantic where they would have been difficult to locate.

This overlooks the point that enigma decrypts were starting to betray the positions of the German supply ships. They present the weak point in the German plans - and become a key target for the RN. Indeed the Python was intercepted this way.

[srgt rock]

The ability to refuel and rearm would depend upon how many Trosschiffs were in the mid-Atlantic with the German task forces. If the Support Group ships Nordmarck and Dithmarchen were able to join Uckermarck and Python, the Germans would have had the ability to operate from the Central Atlantic where they would have been difficult to locate.

This overlooks the point that enigma decrypts were starting to betray the positions of the German supply ships. They present the weak point in the German plans - and become a key target for the RN. Indeed the Python was intercepted this way.

The positions of the refueling ships were determined when the U-boat codes were used.

The way I see any chance of success of any operation by the German heavy units after the loss of the Bismarck, would be only if the supply ships moved to stay in approximately the region to the ocean as the heavy striking groups. They would not be waiting in the wings.

The German Naval Supply Ships, (Trosschiffs) were large ships capable of speeds of 22 knots and they carried over 10,000 tons of fuel. They were equipped to carry and transfer the large caliber shells the heavy ships used. The German Navy had been training since 1935 to conduct side-by-side underway replenishment from these ships.

The Germans built 5 of these ships:
Nordmarck
Dithmarchen
Ermland
Altmarck/Uckermarck
Franken

[RF]

Not all five of these ships were completed or brought into service.

The round up of the German supply ships immediately after Rheinubung were not specifically related to U-boat operations. A virtual clean sweep was achieved by a combination of the work at Bletchley Park, intelligence via MI9 from POW's, radio direction finding intercepts and the knowledge of RN officers and naval intelligence as to areas in the Atlantic known for generally calm conditions, away from the normal sealanes, that would be suitable for refuelling rendevous. Indeed HMS London, on one intercept mission quite by chance came across another German supply ship that the RN didn't know was there.

[dunmunro]

Most British Cruisers had endurance of 10100nm @ 12knots and about 1/4 that distance at 30 knots., .

The County class carried 3425 tons of fuel, giving them an actual range (based upon prewar operational experience with clean bottoms but in tropical waters) of ~13000nm @ 12 knots. Range at 30 knots would be about 3600nm.

[srgt rock]

Not all five of these ships were completed or brought into service.
Yes they were. All but Franken were operational at the start of the war. Franken was launched on 8 Jul 1939. You can see pictures of her being completed at an adjacent pier next to Graf Zeppelin. Franken was completed in March of 1943.


The round up of the German supply ships immediately after Rheinubung were not specifically related to U-boat operations. A virtual clean sweep was achieved by a combination of the work at Bletchley Park, intelligence via MI9 from POW's, radio direction finding intercepts and the knowledge of RN officers and naval intelligence as to areas in the Atlantic known for generally calm conditions, away from the normal sealanes, that would be suitable for refuelling rendevous. Indeed HMS London, on one intercept mission quite by chance came across another German supply ship that the RN didn't know was there.

For the operational plan that I would envision for Rapier, the Trosschiff based Supply Group would operate in close proximity of the Surface Strike and Carrier Strike Groups. The Trosschiffs were equipped with 3 15 cm guns and AA guns. They would have been able to fight it out with an intercepting ship or aircraft.

[Paul L]

At this time in the war Germany had 38 fleet tankers with an average cartage of 8600 tons of fuel each.They also had another 41 supply ships that worked in support of the raiding ships as well.These supply ships brough other supplies and limited ammo that included Torpedos. When a Dithmarschen AOE tanker was assigned it added a repair facility was well as refueling at sea and limited other supplies.

The locating of there supply patrols was dependant on very aggressive & risky RN attacks on the German weather ships and other patrol ships to sieze the time critical code books that told where each supply ship was to operate over time. The incident of the HMS London points to just how little sucess the allies had at shutting down this particular network until the code books were aquired. Most of the rest of these supply ships were sunk with critical intell haul from U-100 [or was that U-110?].

The Germans were gaining supply ships faster than they were loosing them, and had the RN not had such success with stealing these code books, the loss of these supply networks would never have happened. At this point in time Germany also had another network operating in the Indian ocean that was not penetrated and shut down until 1944..

BTW there were actually 6 Dithmarschen tankers built and launched.The last tanker "Haverland" was not completed during the war.

[RF]

The Trosschiffs were equipped with 3 15 cm guns and AA guns. They would have been able to fight it out with an intercepting ship or aircraft.

This issue of arming these vessels was carefully considered by the Germans pre-WW2 as they were originally intended for raiding as well as supply operations.

The Germans came to the correct conclusion that these large ships and their dangerous flammable/explodable cargoes made commerce raiding too risky for the ships' safety. So they were assigned as supply vessels only. The armament provided was defensive only, rather like the Allied concept of the DEMS. Such armament would be wholly inadequate against any warship larger than a destroyer. To the best of my knowledge none of these ships used their armament against surface targets. The only exception I can think of was Tannenfels during the Stier/Stephen Hopkins fiasco.