I tend to agree with most of Colombamike's assertions, but I'd say that in any scenario where the Mackensen's being converted to CV's is plausible, there are a few more changes that should be made to the design to keep it within the realm of reality. First we must assume that WW1 goes well enough for Germany they can negotiate equal terms with the Entente for the peace treaty, but the Entente powers must still hold enough influence that post war treaties such as the Washington Naval Treaty come to be. If there is no WNT, then there's no reason to not just simply complete the Mackensens as planned with some post war wisdom retrofitted.
May I offer an alternative route to bringing about the KMS Mackensen (FZT-1)? My speculations are based on my opinion that the counterfactual history has to overcome so many hurdles to trends and events that some rather profound implications would result.
1. To get to SMS Ausonia, General Ludendorff must not go insane in October 1918 so that his staff has to countermand some of his crazier orders, Ebert must suppress the Kiel Mutiny on 3 November 1918. Both will of course be necessary so that Hindenburg has no political reason to go to the Kaiser to tell him that the army ist kaput and so is he. The war will go on. However, attendant to the army/navy side of things...
2. The Kaiser directive to prioritize U-boats in October 1917 must be reversed. Ditto the unrestricted U-boat campaign in late 1916, so that Wilson does not have a convenient excuse to ask for war against Germany in that year. The Germans need six to twelve additional months to realistically have Leutnant Reimpall complete his work on Ausonia and for the conversion to be rushed through into 1919.
(Schenk, Peter (2008). "German Aircraft Carrier Developments". Warship International. Toledo: International Naval Research Organization.)
3. As the allies go into 1919, from the historical record of what the allies planned, it appears that it would have been an Anglo American offensive right up to the Rhine, mainly based on British technology and American troops. France would certainly have been finished as a world power as would be Germany. This has opportunities and shattering consequences^d for what I like to call the Treaty of Cologne.
a. Clemenceau and Foch would be far less influential in the armistice negotiations, Lloyd George and Woodrow Wilson would be calling the tune along with Haig and Pershing. On the German side of it, Kaiser Wilhelm would be one touring car ahead of the German socialist posse and I doubt that Hindenburg would have escaped Ebert either.
b. Britain and America would have dictated the peace, not France. Based in retrospect on what happened post WWII but set in the 1919-1920 timeframe, the balkanization of eastern Europe would still have happened, but with an Ebert socialist Germany and the civil war in Russia, Washington and London will be looking on Germany with somewhat more leniency as they will want a buffer state against Russia. The Bolshevik scare in America and Britain in the immediate post WWI environment makes McCarthyism look like commie coddling.
c. In those terms and conditions, Ebert's Germany could have renounced U-boats and limited the Herr to "defensive" measures. The German navy would have been hard hit with reparations in tonnage turned over. Just not as severely as at Versailles. The beneficiaries would be Britain and the United States. France to a greater extent than was true in the RTL will be given the naval shaft.
d. Admiral Sims (USN), with the exception of Jellicoe, (RN) was considerably smarter and far more capable than his British, German, and French naval counterparts who served at the conclusion of the war and into 1919 RTL. He will look over the list of German ships to be asked for as US war reparations. In this case, Ostfreisland and her fellows would be left to Germany along with the incomplete Ersatz Yorcks and the pre-dreadnoughts to give Russia the Baltic Sea kibosh and to also (US intention) give the brass at Admiralty House something to worry them. Wilson will have Sims' advice and Pershing's AEF to jam that one down Lloyd George's throat. The USN and the RN despite the top leadership's amity had officer corps which did not like each other at all.
e. Derflinger, Lutzow and Hindenberg might be America's asking price to Ebert's Germany. I wonder why?^1
^1 Moffett wanted aircraft carriers to compete with all those "ious" class British battlecruiser flattop conversions. Lexington and Saratoga and their four sisters were post 1916 and were less further along than the Ersatz Yorks. People forget that up until the Japanese program post London treaty in the RTL, it was Great Britain who led the world in numbers and tonnage of aircraft carriers. The USN would not catch up until 1940; Japan not until 1941. More on this situation after I discuss what I think the Germans will find with Ausonia.
So with the premise needed for this ship to exist in mind, the conversion would have to begin in 1922. Presumably the conversion would take place on a similar timetable to the USS Lexington or HMS Furious so she'd be completed 1925-27. This gives the Ausonia plenty of time to be converted at a much faster pace in the interim since her design is probably complete by the time the armistice hits and her conversion can begin in 1919-20. Thus, I believe the Germans would have some time to experiment on Ausonia and make many discoveries about the operation of aircraft on carriers and how their designs work out in reality. One very obvious thing would be the complete superiority of wheeled aircraft to seaplanes. Thus on future aircraft carriers, there would not be two hangars of different heights intended to embark different crafts, but two hangars of similar dimensions both built around housing and handling wheeled aircraft (so, the top hangar would be taller than it is atm and the bottom one a little shorter) I also think that using a single medium sized funnel wouldn't evacuate enough smoke for a ship initially designed with two large funnels so I'd recommend more or bigger funnels.
Some technical factors might come into play. By the time the Ausonia actually is razed and refitted with her new superstructure (1919-1920), the Americans and the British will have far more experience with naval aviation that is wheeled as opposed to floatplane than Germany. That means these two powers will be more aware of the technical needs they have to build into new carriers. In numbers, since the British will have the most operational combat experience, this works out to the UK Gloster Nighthawk (Soon to be Sparrowhawk in Japanese service aboard the Hosho) and the US Vought SE-7 (First fighter/attack plane aboard the USS Langley). The British used the Beardmore WB.III during WWI. All of these planes required 165 by 15 meter clear through flight decks to operate effectively. Ausonia, even refit with a continuous flight deck will not work. The ship is not long enough at the wl plimsol mark.
Add to the German woes that their best candidate aircraft the HB W-12 and HB W-29, both competent seaplane designs for Hansa Brandenburg by Ernst Heinkel, are long rollers on land. Also the inverted tailfin he used does not allow the fitting of a landing hook to those aircraft for arrested landings aboard ship at sea. A better choice might be some of the Pfalz DII-DV aircraft that were being phased out in favor of the Fokkers.
Assuming that the Germans select the correct fighter/attack planes for that era that they do make, they will have to await the conversion of a warship at least 160 meters long to get a true "carrier". Until then, they will have a poorly designed seaplane tender, As the US did with the USS Langley.^2
^2 The planes were just too underpowered to make shorter true flattops work without catapults.
Thus on future aircraft carriers, there would not be two hangars of different heights intended to embark different crafts, but two hangars of similar dimensions both built around housing and handling wheeled aircraft (so, the top hangar would be taller than it is at [now] and the bottom one a little shorter) I also think that using a single medium sized funnel wouldn't evacuate enough smoke for a ship initially designed with two large funnels so I'd recommend more or bigger funnels.
From the carrier conversion point of view, a wide beamy hull kind of makes sense. Deep draft ocean liners built for speed and fuel economy do not fit that criteria. British shallow draft battlecruisers do. Taking into account that the funnels have to be ducted to starboard and the uptakes have to be tall enough to keep smoke off the flight deck, there will be some serious problems counter-massing to port to offset starboard weight and trunking the runs so that they do not interfere with the hanger. So... two or three stacked hangers are a non-starter. Pipe runs, access side panels, and the need for storage and work space in the superstructure above the strength deck is not going to help hanger design either. A deck lift which the Germans will realize soon enough is better than a crane and gantry system, plus bomb and torpedo stowage and aviation fuel tanks separate from the ship's fuel bunkers equals more problems for the small Ausonia that cannot be lessons learned directly applied to the Mackensen. For example; the Americans were fortunate that they had not framed in the barbettes for the Lexington and Saratoga yet when the decision was made to convert. What would have happened if those barbettes were integral build as they would have to be on at least the Mackensen?
There was a reason the American carriers were built with open hangers and a flight deck as quite lightweight superstructure over the strength deck. Top weight which did not bother the Americans in a cruiser or battleship became a real roll concern for their bird farms in a Pacific swell. The Germans would have learned this the hard way as they tried out Ausonia in the North Sea. That is one lesson that would have been applied to Mackensen.
Interesting what two speculative views of a potential foreign carrier might look like The top one is an American view.
The bottom one is a more "British" view.
It's a very interesting speculation and one that has come up in my ideas revolving around Imperial Germany in WW2. So that's just my thoughts on it.
Given what I speculated above, the interesting implications Post WWI from a "US point of view" might be startling.^3
I don't know that the USN would be as eager to bomb a ship like SMS Hindenburg or SMS Lutzow as that service was willing to give up the badly designed Ostfreisland. With Fisher's Courageous class shallow draft "odd" battle cruisers converted turned into "interesting" aircraft carriers as a done deal (Strictly in hindsight, the Sempill mission to Japan
shows that the British were quick to learn but slow to apply the lessons, that resulted into HIJMS Hosho. With all that British traitor Sempill knew about the British carrier program's WWI mistakes, it gave the Japanese a huge head start on the USN.), the AU USN still had to figure that she was a decade behind in the aircraft carrier game. So what is a hard charging Yankee navy to do to close the gap in a hurry?
Two or three Derflingers in hand and Wilson rather Navy friendly before his stroke, would be the prevailing trends. Conversions could begin immediately before any Washington naval conference and this would take in US observations as to what was happening to British ships post war like HMS Argus.
^3 Hmm. Instead of Langley? Might be a different Washington Conference with Uncle and John Bull in a carrier building race instead of launching battleships willy-nilly.
And of course Germany, still able to participate in this AU, with four unfinished hulls would have her chance, too. Ebert might get two flattops. Japan did.