Plan Z

Discussions on all (non-biographical) aspects of the Kriegsmarine except those dealing with the U-Boat forces.
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Takao
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Re: Plan Z

Post by Takao » 07 Dec 2010 05:42

Well, they had similar armament and dimensions. However, the O-class had about half the armor tonnage of the Twins (8,000 tons - 14,000 tons), but had a much greater range (14,000nm@19knots vs. 8,000-10,000nm@19knots). The lack of armor is why the Germans intended the O-class to engage nothing larger than a heavy cruiser.

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mescal
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Re: Plan Z

Post by mescal » 07 Dec 2010 10:21

Takao wrote: they [Gneisenau & O-class] had similar armament and dimensions.

The O-class was supposed to carry the 38 cm/52 SK C/34, whereas the S&G had the 28cm/54 SK C/34.
Looks like a typo ...
That is, if you were not dealing with the envisionned reconstruction of the S & G.

Moreover, O-class was significantly longer (~+25 meters) with the same beam - raising the L/B ratio from 7.6 to 8.5.
Which was consistent with the very high speed requirement.
Takao wrote: The lack of armor is why the Germans intended the O-class to engage nothing larger than a heavy cruiser.
And why they gave her such high speed (175,000 SHP) - even if I doubt they would have reached their intended speed (35 knots) in any conditions other than trials.

Actually, with a belt 180mm (7") thick (as a comparison Tiger had a belt up to 9" thick), their vitals were not immune to CA gunfire.
Quickly browsing through Navweaps' penetration figures, the IZ of O-class was :
* Against UK 8" (256lbs) : 13,000-28,000 yards
* Against US 8" (260lbs) : 13,000-30,000 yards
* against US 8" superheavy (335lbs) : 16,000-27,000 yards

Hardly comfortable if she cannot dictate the range. So I think the high speed was not only to outrun Dunkerques of Renowns, but also to outrun the Allied CAs.

Actually, I can only see these BC as the heirs of Fischer's white elephants (Large light cruisers).
Olivier

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Takao
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Re: Plan Z

Post by Takao » 07 Dec 2010 12:36

Wasn't a typo, but posting while sleepy. I was looking at the Gneisenau 15-inch reconstruction., but never properly posted as such.

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LWD
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Re: Plan Z

Post by LWD » 07 Dec 2010 14:01

Takao wrote:... The lack of armor is why the Germans intended the O-class to engage nothing larger than a heavy cruiser.
Also may be why they considered the O-class to be battlecruisers and the twins to be battleships.

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Re: Plan Z

Post by nebelwerferXXX » 25 Jan 2011 07:55

What's the total cost estimates (roughly) in building the 1,150 ft x 130 ft Dry Dock 'Elbe 17'?

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Re: Plan Z

Post by nebelwerferXXX » 06 Feb 2011 13:57

Plan Z plus Nazi propaganda made the World's Navies uneasy...

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Tim Smith
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Re: Plan Z

Post by Tim Smith » 07 Feb 2011 19:06

'O' class is similiar to Scharnhorst and Gneisenau, but with 6 x 15" guns instead of 9 x 11" guns, and more lightly armoured.

However, the German designers got it wrong again. Scharnhorst and Gneisenau needed 6 x 15" guns to counter the armour of the French and British battlecruisers, the Dunkerque and Repulse classes. But the 'O' class, which was designed only to fight 8" gunned heavy cruisers and run away from anything larger, really needed the 9 x 11" gun armament - for the faster rate of fire and also the 3 extra barrels. Basically a 9 x 11" gunned ship could put at least twice as many shells in the air in five minutes than a 6 x 15" gunned ship, maybe more. Against a small, agile target like a cruiser, more shells per salvo, and more salvos per minute, are better. And 11" shells were quite sufficient to penetrate heavy cruiser armour.

http://www.german-navy.de/kriegsmarine/ ... index.html

Still, had Germany actually built a couple of 'O' class ships, she could have taken the gun turrets off Scharnhorst and Gneisenau (since they were due to be upgraded to 15" anyway) and put them on the two new 'O' class ships, saving the cost and construction time of building new guns and turrets. (This would be assuming that WW2 started several years later than historically, of course, since Germany could never build the 'O's in wartime anyway.)

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Re: Plan Z

Post by Paul Lakowski » 12 Feb 2011 08:57

Hitler was against rebuilding a large “Tirpitz Navy”, since it represented a large investment for a country that was primarily a continental power and this was seen as one of the mistakes of WW-I. Hitler only wanted a coastal defense fleet, however in the Hitler years before WW-II, the German navy laid down 21 large naval vessels [average 29,000 tons each] plus 99 smaller naval vessels [average 1,900 tons each;] and another 152 ‘coastal craft’, [not including Uboats] The total tonnage involved in this building would have required ~ 800,000 tons of construction to complete, but at most 500,000 had been invested up to the end of 1939, plus another 160,000 tons warship tonnage was invested through 1940-41,

A dozen of these large naval vessels were laid down in 1934/36 and should have been completed by the late 1930s. Another 5 were laid down in 1938/39 and could not have been completed before 1942. The rest were laid down in between these extremes and ought to be commissioned in 1939/1940-time period. Had all these large warships been Panzerschiff [Armored ship] type warships, while the bulk of the smaller warships built as Zerstörer’s, then the potential DID exist to build a sizable fleet, able to challenge the Royal Navy, under the right circumstances.

The end of 1939 only 8 Large ships were completed and ½ of those were fleet auxiliary oil tankers. By the end of 1941 another 4 were completed, of which ½ were Capital ships. That’s 12 out of 21, of which only 4 were battleships and no aircraft carriers were completed despite the fact two were laid down in the 1930s.

Using the displacement tonnage as a yardstick, ¾ of the large & small naval vessels should have been completed by the end of 1941 and yet by that date the only German warships completed were 4 battleships; 3 Cruisers; 22 destroyers and 21 Torpedoboot.

German naval planning included a mobilization plan with the following annual builds to be completed two years after the war begins. Every year after this point the following warships were to be completed.

24 Zerstörer [~ 3000tons]
48 Torpedoboot [~ 1000-2000 tons]
135 Mineboot [~ 800 tons]
105 Uboats [¼ coastal + ½ Atlantic + ¼ long range] [average 760 tons]

On average this represents about 1/3 million tons warship construction per year. While many may believe this to be impossible based on historical patterns, infact it was less tonnage than what was actually built.

The historical tonnage of naval/warship displacement built up to the end of 1939 was approximately…502,861 tons of warship displacement and 5216 tons composite plus 18192 tons built to general ship standards. The break down of historical shipbuilding was as follows

75,231 ton =22 Zerstörer & 4+ 8 TBoot
104, 550 ton =3 + 3 Auxiliary tankers [built to warship standards]
44,972 ton =10 FBoot/ 19+36MBoot / 0+5 tenders [26,780 ton to warship standards]
296,300 ton 2+2 BB / 2+3 CA / 0 +2 CV [including 82,900 tons armored steel]
5216 ton 32+ 50 RBoot / 23 + 47 SBoot [Steel frame & wooden construction]
31,791 tons = 32 coastal +20 Atlantic + 11 Large U-Boats [121,190 hp diesel & 37,500hp Generator]


The 1940/41 breakdown of historical shipbuilding was as follows
51,672 STS = 8 Zerstörer + 17 TBoot [1.2 million hp Turbine]
32,800 STS + 34,810 ton = 36 MBoot + 44 Geleitboote [182,145 hp VTE]
28,000 STS = 2 + ii BB & 1 + ii CA & 0 + ii CV [including 9126 tons armored steel]
13,241 Composite = 50 RBoot + 47 SBoot [356,784 hp Diesel]
219,830 STS = 18 coastal +169 Atlantic & 63 large Uboats [193,000hp Generator & 828,768hp Diesel]
53,890 ton Composite = 375/600 Landing Craft [93,400hp diesel & 36,325hp Petrol]
17,000 STS + 24,975ton = 1+ ii Auxiliary tankers + 5 tender [44,180hp diesel]
i = incomplete ship

Already in this transitional phase, the annual warship tonnage is already around ¼ million tons each year.

The 1942/43 breakdown of historical shipbuilding was as follows
62,773 STS = 9+ 8 Zerstörer / 9+8 TBoot [1.23 million hp Turbine]
463,040 STS = 2 coastal + 396 Atlantic & 125 large Uboats [421,500hp Gen & 1,826,360 hp Diesel]
84,259 tons + 4200 NC+ 48,003 Composite = 117 MBoot + 45 Geleitboote [391,010 hp VTE]
60, 572 tons Composite = 170 R/S Boot + 286 KFK [681,203 hp Diesel]
226,000 ton Composite = 583/100 Landing Craft [350,840hp diesel & 159,000hp petrol]
17,000 STS + 24,975ton = 1+i Auxiliary tankers + 1 seaplane tender [44,180hp diesel]
35,700 STS = misc BB, CA & CV work [including 9838 tons armored steel]

That’s nearly ½ million tons warship construction in each year 1942 & 1943. However a good deal of this was composite construction for coastal craft. If only the steel construction is used the figure is still 346,000 tons each year.

The 1944 breakdown of historical shipbuilding was as follows
71,676 STS = 8+19 Zerstörer / 8+20 TBoot [1.2 million hp Turbine]
352,359STS = 2079 mini + 68 coastal + 115 Atlantic & 143 large Uboats [773,545hp Gen & 1,026,501 hp Diesel]
34,259 tons + 5000 NC+ 27,247 Composite = 47 MBoot + 23 Geleitboote [170,805 hp VTE]
74, 324 Composite = 147 R/S Boot + 327 KFK [691,803 hp Diesel]
163,790 ton Composite = 736 Landing Craft [384,690hp diesel & 117,320hp petrol]
10,000 STS + 4838 tons armored steel = misc work

STS = STS naval warship steel tonnage
NC = Nocemented naval steel tonnage

This is almost ½ million tons steel construction plus ¼ million tons composite construction. The figures for 1944 include the spring of 1945, since not much shipbuilding happened in 1945 due to the collapsing German war economy. Notational figures for 1945 & 1946 with out allies over running Europe, should be roughly the same as the 1944 figures.

The Maximum displacement for 1934-1944 is over 1.8 million tons.

All figures are “maximum displacement” from Gröner’s “German Warships 1815-1945” and the following sites
http://www.navypedia.org/ships_index.htm
http://www.warshipsww2.eu/typy.php?lang ... =&stat=GER
http://www.german-navy.de/kriegsmarine/ships/index.html

Rossler "The UBoat"

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LWD
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Re: Plan Z

Post by LWD » 14 Feb 2011 13:44

Mixing "maximum" displacement of warships and tankers is rather misleading.

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Capital ships -vs- Smaller ships

Post by nebelwerferXXX » 20 Feb 2011 01:47

Keith Langley wrote:In answer to the question "Why Plan Z and not Plan X or A or C? " there was initially a plan X which was rejected followed by a plan Y which was also rejected. Finally there were two Plan Zs, one based around smaller ships including U-Boats and one around big ships. Admiral Raeder correctly guessed that Hitler would prefer the latter.

I have a question of my own about the Z-Plan, most books and web site talk about the H-class battleships, the Graf Zeppelin and the O-class battle-cruisers. A few also give information about the M-class cruisers and the Spahkreuzer but what about the destroyers, submarines and smaller craft?

For example the 68 destroyers, this figure probably included the existing ones but was there a definite design for the new construction. Was the Narvik-class part of the Z-Plan? What type of U-Boats were envisaged in the Z-Plan, were they all going to be type VIIs? How many Schnellboote were planned? Also, I assume the escort vessels F1-10 and G1-24 were part of the plan. Is there a really good book with detailed information about the ships planned? I've just bought a book advertised on the internet and it is more about the politics of Raeder and says virtually nothing about the ships planned
I have a listing of two versions of the Z-plan. Based upon Capital ships and Smaller ships. The listing in the book, German Weapons of World War II, have 8 battleships, 5 battle-cruisers, 4 aircraft carriers, 8 heavy cruisers, 68 destroyers and 249 submarines. Basing again, the statement of Keith Langley, I sub-divided the listing from the book by making two versions of the Z-plan into Capital and Smaller ships. So, I made a conclusion, that the Z-plan ships would be like this and are enumerated below. Correct me if my assumptions are wrong.

Plan Z: Capital ships
---8 battleships
---5 battle-cruisers
---4 aircraft carriers

Plan Z: Smaller ships
---8 heavy cruisers
---68 destroyers
---249 submarines

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LWD
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Re: Plan Z

Post by LWD » 22 Feb 2011 21:32

http://www.german-navy.de/kriegsmarine/zplan/index.html
lists 6 battleships, 3 battle cruisers, and 5 carriers
This doesn't includ existing ships so with the twins and Bismarcks and two carriers under construction you'd have
10 battleships and 3 battle cruisers and 7 carrirers although most if not all the carriers would be somewhere between a US CVE and CVL in capablity if that good.
The same source list 12 panzershiffe and 6 cruisers. Or if you go with the German reclassification of the former 18 cruisers. 6 hybrid cruisers are also included in this list.
This site http://www.germanmilitaryhistory.com/bl ... he-z-plan/ lists
In January 1939 Raeder presented both schemes to Hitler, who chose the big-ship, big-gun option - the "Z-Plan" - which called for eight battleships, 12 battlecruisers, 17 light cruisers, two aircraft carriers, 50 destroyers, 64 torpedo boats and 22 submarines by 1945.
And this site has yet again different numbers: http://www.acepilots.com/ships/germany.html
In 1938, German naval planners drew up Plan Z, a construction program that envisaged an 800-ship navy, built up over the next eight years (1939-1947). It would have included 10 battleships and battlecruisers, 4 aircraft carriers, 15 "pocket" battleships (Panzerschiffe), 5 heavy cruisers, 44 light cruisers, 158 destroyers and torpedo boats, 249 u-boats
This site http://books.google.com/books?id=bJBMBv ... ny&f=false
Agrees with your numbers up to heavy cruisers but lists some light cruisers as well.

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Re: Plan Z

Post by nebelwerferXXX » 23 Feb 2011 10:23

@LWD...
Very good site. The discussions about the Z-plan are all here. Thanks!

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800-ship Plan Z

Post by nebelwerferXXX » 24 Feb 2011 06:21

nebelwerferXXX wrote:The Z-plan schedule of work program:

The 1941 Program:
---2 x 30,000-ton aircraft carriers...60,000 tons

The 1943 Program:
---4 x 10,000-ton heavy cruisers...40,000 tons
---128 x 750-ton submarines...96,000 tons

The 1944 Program:
---6 x 56,000-ton battleships...336,000 tons

The 1947 Program:
---2 x 30,000-ton aircraft carriers...60,000 tons
---95 x 750-ton submarines...71,250 tons

The 1948 Program:
---4 x 10,000-ton heavy cruisers...40,000 tons

Cost: RM 33-billion
Crew: 201,000
Fuel: 8,000,000 tons
The Plan Z looks impressive on paper. It surpasses even the combined strength of the Siamese and Chinese Navies in numbers. Imagine 800 units of Plan Z ships that were programmed to rule the high seas of the world. How Uncle Adolf would wish to see it operationally and sink millions of tons of shipping. The USN responded by building in 1943...
---23 Essex-class fleet carriers of 100 aircraft each
---7 great battleships
---100 cruisers
---300 destroyers

source:
Pacific Onslaught, 7th Dec. 1941 to 7th Feb. 1943, Paul Kennedy
Last edited by nebelwerferXXX on 24 Feb 2011 11:58, edited 1 time in total.

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Ironmachine
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Re: Plan Z

Post by Ironmachine » 24 Feb 2011 08:58

nebelwerferXXX wrote:The Plan Z looks impressive on paper. It surpasses even the combined strength of the Siamese and Chinese Navies in numbers.
That's a rather odd comparison, isn't it?

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mescal
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Re: Plan Z

Post by mescal » 24 Feb 2011 12:25

Well, your figures are somewhat off, and your sentence "The USN responded by building in 1943" is unclear : do you mean ships started in 43 ? commissioned in 43 ? or being built on 1st Jan 1943 (or 31 Dec ?) ?

Anyway, I did a quick counting of the USN major warships started after January 1940 and before August 1945


9 BB & CB
6 Iowa-class
3 Alaska Class (Yes, I stil have trouble counting them with cruisers ...)
Notes :
-Alabama was started after Jan 1940, but was authorized by an earlier program
- one may consider counting the reconstructions of West Virginia and California

40 Carriers :
26 Essex-Class
3 Midway-Class
9 Independence Class
2 Saipan-Class
(Not counting the 100+ CVE)

78 Cruisers :
27 CA (14 Baltimore, 10 Oregon City, 3 Des Moines)
11 CLAA
40 CL (28 Cleveland, 9 Fargo, 3 Worcester)

Destroyers :
I don't have an exact count, but I have 320 destroyers commissionned in the USN early enough to see front line duty before August 1945.
Hence your 300 DD figure must be an underestimation.

And that's not taking into account the minor warships and the huge fleet train

On another note it was not simply an answer to the Z-plan. This was a "Two-Oceans Navy", that is a Navy to take on any opponent on both the Atlantic and the Pacific.

Imagine 800 units of Plan Z ships that were programmed to rule the high seas of the world
err, not all of those 800 ships were supposed to be blue-water capable. Many would have been small ships for coastal work.
Olivier

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