Potential German Carrier conversions WW2

[Rubicon]

I've been looking through various ships the Germans might have decided to convert into carriers (like the Japanese Jun'yō and Hiyō) in case the Germans decided for carrier aviation, and if so, it might be a better idea to start out converting existing ships and work our the flaws, before embarking on carriers built from the keel up *cough* Graf Zeppelin *cough*

This is not really meant for serious discussion. Just to see what might have been possible to convert.
Yes I know the Germans lacked strategic resources for such a conversion and if they so had to take them from elsewhere, yes I know the Germans lacked decent carrier capable planes.

First up:
SS Vaterland (SS as in Steam Ship, not Schutzstaffel)

http://www.thegreatoceanliners.com/intendedgiants.html

[FONT=Arial,Helvetica][SIZE=-1] But in the late 1930s, they commissioned their first large liner since the Bismarck from the Blohm & Voss shipyard in Hamburg. She was to be named Vaterland and have a gross tonnage of 41,000. Her length would be an astonishing 824 feet and her turboelectric engines would [/SIZE][/FONT][FONT=Arial,Helvetica][SIZE=-1]drive her at a service speed of 23.5 knots. She would be very streamlined and actually have some of the Normandie’s lean grace. The Vaterland was launched in 1940 but laid up because of the war. Before fitting out could commence, the great liner was bombed during Allied raids in Hamburg on July 25, 1943. The wreckage of the liner had been entirely scrapped by 1948.[/SIZE][/FONT]

From the looks and from the writing might be a possiblity. But might have been a quite expensive conversion.

2nd possibility: MV Strassburg

MS BALOERAN was built 1930 by the Schelde, Vlissingen for the Koninklijke Rotterdamsche Lloyd. Rott NGJS. Dimensions: 168,8x21,4x9,1 , 16.981 tons. 10 cyl diesel Engine 14.000 hp Sulzer Maiden voyage on 16th April 1930 Rotterdam to India. During WWII the ship was taken by the Germans. Renamed as MS STRASSBURG 1941 she was used as a generator. She was then rebuilt to a hospitalship and used from 20 -07-1941 till 30-05-1943 as a hospitalship.

Might be tad to old, slow and small, but not an impossibility for a CVE.

3rd possibility: SS Berlin

But might definitely be to slow

4th possibility: SS Bremen
5th possibility: SS Europa
Good speed, good size, might even be to large for a converted carrier....


Thoughts?

 

[sharlin]

Possible but what you get is a generally inferior carrier, and a very expensive conversion at that.

 

[Rubicon]

Possible but what you get is a generally inferior carrier, and a very expensive conversion at that.

Granted, however it takes much shorter time to convert then to build a new one. Jun'yō was converted in 14 months at the Mitsubishi shipyard in Nagasaki, the Essex class 20 months and the shipbuilding industry of Newport News working round the clock, a feat the German shipbuilding industry probably wouldn't be capable of duplicating.

 

[BlairWitch749]

Granted, however it takes much shorter time to convert then to build a new one. Jun'yō was converted in 14 months at the Mitsubishi shipyard in Nagasaki, the Essex class 20 months and the shipbuilding industry of Newport News working round the clock, a feat the German shipbuilding industry probably wouldn't be capable of duplicating.

Doesn't change that Germany didn't have an aircraft suited for carrier ops till 1941 (FW-190)

 

[Rubicon]

Doesn't change that Germany didn't have an aircraft suited for carrier ops till 1941 (FW-190)

BW I usully like your posts but for once I'm a bit annoyed at you because it's quite impolite not to read the first post to see what it's all about.

To quote myself

Yes I know the Germans lacked strategic resources for such a conversion and if they so had to take them from elsewhere, yes I know the Germans lacked decent carrier capable planes.

 

[BlairWitch749]

BW I usully like your posts but for once I'm a bit annoyed at you because it's quite impolite not to read the first post to see what it's all about.

To quote myself

Apology for incomplete reading; the broken up nature of your post made me miss that

I don't think they would be super cost effective, and even with effective aircraft; Germany at the end is a land power

 

[CalBear]

Granted, however it takes much shorter time to convert then to build a new one. Jun'yō was converted in 14 months at the Mitsubishi shipyard in Nagasaki, the Essex class 20 months and the shipbuilding industry of Newport News working round the clock, a feat the German shipbuilding industry probably wouldn't be capable of duplicating.

The IJN already knew what a carrier needed to be and how to build one. KM didn't have that advantage.

 

[Rubicon]

Apology for incomplete reading; the broken up nature of your post made me miss that

I don't think they would be super cost effective, and even with effective aircraft; Germany at the end is a land power

Apology accepted, I'll try to write less fragmentary in the future.

Absolutely, but in case Barbarossa succeeds ( I think we've discussed this prior: Italy does better or worse, two more Panzer divisions, a fliegerkorps and some 5000+ trucks available on June 22nd leading to Leningrads fall in late July and then all kinds of butterflies) Germany would have to look towards defeating Great Britain, can submarines do it alone? Maybe, but it might be a good idea to start planning ahead (yes I know almost ASB with the carpet chewer in command, but still)

The IJN already knew what a carrier needed to be and how to build one. KM didn't have that advantage.

Good point.

But then the Germans never managed to finish the Graf Zeppelin to begin with, talk about wasted resources.

Though I still believe in case the Germans would need to turn to carrier aviation, a conversion of a smaller 10-15.000 ton passenger ship would be better for training purposes then a purpose built ship from the keel up.

 

[BlairWitch749]

I've liked the idea for preplanned warship conversions (germany's cruisers were largely useless anyway)... taking the hippers or pb's and building them with the intention of flipping them to carriers at a certain point in their construction

 

[AdA]

German shadow fleet

This was extensively discussed in the "attack on scapa flow if..." Thread a few weeks ago. At the time I suggested a german shadow fleet program modelled on the IJN model, with seaplane tenders and fast oilers designed in a way that they could be converted to carriers when needed. The IJN chitose or shoho are potential role models, but the USN Sangamom class is another.
Real cooperation with japan and a totally different german naval staff are required for this to be plausible...

 

[Rubicon]

I've liked the idea for preplanned warship conversions (germany's cruisers were largely useless anyway)... taking the hippers or pb's and building them with the intention of flipping them to carriers at a certain point in their construction

To be honest most the German surface fleet was useless, not just the heavy cruisers. The only part that did well would be the S-boots I think.

Constructing the cruisers to be easily be converted into carriers would require almost hindsight amounts of knowledge I think, not sure how such an idea can be pulled off or sold to Hitler.

 

[BlairWitch749]

This was extensively discussed in the "attack on scapa flow if..." Thread a few weeks ago. At the time I suggested a german shadow fleet program modelled on the IJN model, with seaplane tenders and fast oilers designed in a way that they could be converted to carriers when needed. The IJN chitose or shoho are potential role models, but the USN Sangamom class is another.
Real cooperation with japan and a totally different german naval staff are required for this to be plausible...

My proposed idea (give or take) is for the germans to secretly buy the plans for the ryjuo; and then lay down 3 "cruisers" for arguments sake say they replace the PB's... these would be built with the express intent that the moment germany renounces versailles that their construction would shift and go about immediately completing them as ryjuo's; making them ready for commission in 1937 or so

To go hand in hand with that; have Germany pay or trade something to Japan to send several dozens of their pilots to Japan for carrier training and certification with the actual ryjuo so that when the German ones come online they already have a crop of pilots ready to fly on her; saving critical time from her work up so the three ships can be in full fleet service perhaps with a patrol or two to their credit in 1939

Ryjuo fits the bill in a lot of ways

1. design is not complicated; and the ship existed already in the time frame the germans would want to buy it
2. it is moderated sized and could be traded almost 1 for 1 with the pocket battleships
3. it is of medium speed/range/utility which is about the best the germans could possibly hope for
4. the japanese have one in service for the germans to pre train pilots on

 

[Astrodragon]

The Japanese converted carriers were part of a 'shadow carrier' program, built with the intention of converting to a carrier quickly.
Given that the Kriegsmarine had no idea how to design a carrier in the first place (Graf Zepellin, *cough*), it would be quite difficult to arrange this. Then of course its the air group, the training, and the 10 years of operating carrier experience they lack...

It could be done, but I dont think it would work very well...

 

[Astrodragon]

My proposed idea (give or take) is for the germans to secretly buy the plans for the ryjuo; and then lay down 3 "cruisers" for arguments sake say they replace the PB's... these would be built with the express intent that the moment germany renounces versailles that their construction would shift and go about immediately completing them as ryjuo's; making them ready for commission in 1937 or so

To go hand in hand with that; have Germany pay or trade something to Japan to send several dozens of their pilots to Japan for carrier training and certification with the actual ryjuo so that when the German ones come online they already have a crop of pilots ready to fly on her; saving critical time from her work up so the three ships can be in full fleet service perhaps with a patrol or two to their credit in 1939

That would probably work (if they can get the plans off Japan, the Japanese plans are going to be for a different ship, they'd basically have to do a new design unless you want a replica of Ryjuo, in which case its going to be rather obvious what she is... a carrier has quite a different design from a PB)

Its not just aving carrier-trained pilots, though, its teh accumulated years of trial, development, experience and carrier doctrine that the Germans will lack - the carriers will probably work, but they probably wont work that well...

 

[BlairWitch749]

To be honest most the German surface fleet was useless, not just the heavy cruisers. The only part that did well would be the S-boots I think.

Constructing the cruisers to be easily be converted into carriers would require almost hindsight amounts of knowledge I think, not sure how such an idea can be pulled off or sold to Hitler.

I don't think it's that hindsitish... it's just another thing that Germany ducks around the treaty on

Look at what they did with aircraft and tanks; and the Bismarck and Tirpitz... they were always ducking the treaty... plus the Germans were at least sort of interested in carriers; after all they built one and planned to build two more

Hitler just has to decide he wants them in 1933; and just apply german treaty ducking to the idea; it's actually pretty plausible; although it could draw a pretty furious response of counter building on the part of the french and british once they renounce, but that is a separate issue

 

[BlairWitch749]

That would probably work (if they can get the plans off Japan, the Japanese plans are going to be for a different ship, they'd basically have to do a new design unless you want a replica of Ryjuo, in which case its going to be rather obvious what she is... a carrier has quite a different design from a PB)

Its not just aving carrier-trained pilots, though, its teh accumulated years of trial, development, experience and carrier doctrine that the Germans will lack - the carriers will probably work, but they probably wont work that well...

I was suggesting an exact replica more or less with the "pocket battleships" being laid down in such a way as some work can be done till renunciation

Basically the Germans take 18 months or so to do some work on the ship, then take the mask off and take another 24 to finish her as a copy (or 3 copies) of ryjuo

Obviously many items will still be in the infant stage by 1939; however, my proposed scenario would probably see the ships at least have functioning crews; especially the air crews; with 1 or 2 shake down patrols to their credit

so they may not be quite as functional as say the hermes or courageous battlegroup; but they would still be of some utility

 

[Rubicon]

My proposed idea (give or take) is for the germans to secretly buy the plans for the ryjuo; and then lay down 3 "cruisers" for arguments sake say they replace the PB's... these would be built with the express intent that the moment germany renounces versailles that their construction would shift and go about immediately completing them as ryjuo's; making them ready for commission in 1937 or so

To go hand in hand with that; have Germany pay or trade something to Japan to send several dozens of their pilots to Japan for carrier training and certification with the actual ryjuo so that when the German ones come online they already have a crop of pilots ready to fly on her; saving critical time from her work up so the three ships can be in full fleet service perhaps with a patrol or two to their credit in 1939

Ryjuo fits the bill in a lot of ways

1. design is not complicated; and the ship existed already in the time frame the germans would want to buy it
2. it is moderated sized and could be traded almost 1 for 1 with the pocket battleships
3. it is of medium speed/range/utility which is about the best the germans could possibly hope for
4. the japanese have one in service for the germans to pre train pilots on

There are some problems with the Ryūjō though. Primarily in that it was a pretty crappy design. Only reason Japan built it was that there existed a loophole in the Washington Naval Treaty in where a carrier below 10.000 tons didn't count towards the tonnage limit of carriers.

To be honest Japan ought to have gone: Hōshō>Sōryū>Hiryū>Shōkaku
And completely skipped Ryūjō, Zuihō and Shōhō. Saving the money and materiel for regular fleet carriers. I've seen estimates that the Ryūjō with all her reconstructions cost as much as the Hiryū but with half the air complement.

 

[BlairWitch749]

There are some problems with the Ryūjō though. Primarily in that it was a pretty crappy design. Only reason Japan built it was that there existed a loophole in the Washington Naval Treaty in where a carrier below 10.000 tons didn't count towards the tonnage limit of carriers.

To be honest Japan ought to have gone: Hōshō>Sōryū>Hiryū>Shōkaku
And completely skipped Ryūjō, Zuihō and Shōhō. Saving the money and materiel for regular fleet carriers. I've seen estimates that the Ryūjō with all her reconstructions cost as much as the Hiryū but with half the air complement.

I don't disagree with Ryjuo's lack of utility... my selecting her is based on simplicity, size and existence at the proper time; plus it wouldn't hurt Japan to keep her in home waters in the 30's to use her for training German pilots for a period

The scenario would be even more effective if the Germans could just buy the Ryjuo at that point; but it's not possible till the mask is off at the earliest; which by then is too late to achieve the desired effect

 

[Matt Wiser]

The Kreigsmarine in 1942 actually produced plans for three liners to be converted into carriers: Europa, Potsdam, and one named for Scharnhorst's sister ship....(the liner Scharnhorst was stuck in Japan at the outbreak of war, and the IJN purchased her for conversion: she became the CVE Shinyo. Sunk by a USN submarine in Nov 44). The nearly complete CA Seydlitz was also earmarked for conversion to a carrier.

 

[Astrodragon]

I was suggesting an exact replica more or less with the "pocket battleships" being laid down in such a way as some work can be done till renunciation

Basically the Germans take 18 months or so to do some work on the ship, then take the mask off and take another 24 to finish her as a copy (or 3 copies) of ryjuo

Obviously many items will still be in the infant stage by 1939; however, my proposed scenario would probably see the ships at least have functioning crews; especially the air crews; with 1 or 2 shake down patrols to their credit

so they may not be quite as functional as say the hermes or courageous battlegroup; but they would still be of some utility

The real trouble with 'disguising' a carrier as a PB is that the hull structure is completely different, and you dont have those big barbettes that are an early and integral part of the PB structure. British naval intelligence had pwnd the German shipbuilding program, one report of what the hull looks like and they will know whats being built.

Mind, they wouldnt breach the treaty, so the likely response is either a few more RN carriers, or changing the design to put more planes on the armoured ones. Your scheme as such is doable, I just dont think it would help the germans much..and of course, you still have to persuead Goering....