KMS Graf Zeppelin (1939)

Nazi Germany (1939)
Aircraft Carrier – 1 unfinished

Germany’s aircraft carrier

Contrary to most European powers, Germany never ventured into the Aircraft carrier genre, but perhaps a few ad hoc conversions as seaplane tenders. The appearance and raid of HMS Furious on Zeppelin’s base in 1918 was duly noted by the German admiralty, but it was way too late then to devise any response. If there was any project of carrying aircraft, it was through these famous airships, for self-defense. That’s perhaps not at random that the first ships of a new ambitious class based on Plan Z, which stated four aircraft carriers, was named after the famous count.

Graf Zeppelin being launched in December 1938
Graf Zeppelin being launched in December 1938

Plan Z

While the initial renewal of the Kriegsmarine included as an objective the control of the Baltic, and a war with France (her fleet was mostly in the Mediterranean) Hitler, increasingly confident, decided in 1938 he wanted also the possibility to take on the Royal Navy in a war scenario with UK in home waters. For this, Plan Z (the third proposed by the Admiralty), the most ambitious, was approved in January 1939. This was a Wagnerian-like endeavour, with a plan for 800 ships, including 4 aircraft carriers, 10 battleships (two, Bismarck class), 12 battlecruisers (none), 3 armored ships (Panzerschiffe, improved Deutschland class, none), 5 heavy cruisers (Hipper class, all built), 44 light cruisers (M-class cruiser, none), 158 destroyers and torpedo boats (about 50 destroyers and 48 TDs), 249 submarines (much more). By the beginning of the war, despite M-class cruisers, H-class battleships and O-class battlecruisers being just started, Plan Z was just 20% advanced. In all that, the Graf Zeppelin was the first of its class, but was also started way before Plan Z was approved, back in 1936.

Genesis of the Graf Zeppelin

Building an aircraft carrier from scratch was not an easy endeavor. At least the first enemy targeted, France, had some experience with seaplane carriers in WW1 and converted a Washington-banned battleship, Bearn, into its first aircraft carrier in the 1920s, gaining a considerable experience. All top three best navies also had many of these in service and planned more. Initial researches for the design could be found in Wilhelm Hadeler, a member of the Kriegsmarine construction department, which followed with attention developments in other countries in particular UK. There were heated discussions as naval aviation technology leaped forward a considerable way in the 1930s, and the lack of anything resembling pilot training for naval operations was a concern too. Everything was to be done from scratch. First sketches were presented to Hitler in 1933 and 1934, planning for a 22,000 tonnes, 35 knots ship with 50 aircraft was agreed. Eventually with the Anglo-German naval agreement, Hitler felt time was come to authorize these ships and fixed the tonnage to 19,250 about 35% of British carrier tonnage.

US Naval intelligence 1942 recoignition plate
US Naval intelligence 1942 recoignition plate.

Design

Design had to be reworked to keep much of the original specs. Eventually before construction started, technical design studies were given to a specially setup Deutsche Werke AG design bureau. Final specs were redacted in close cooperation with the Kriegsmarine’s construction department and assistance by the Luftwaffe, which however was anything but motivated for the project and never specified requirements for their aircraft.

The general opinion of the day was an aircraft carrier was to be able to defend herself, and she was aligned on that of heavy cruiser in terms of armament and protection. Later this also included preventing destroyers night attacks and a battery of quick-firing 150mm guns was added. HMS Furious was visited in 1935 (a waste of time according to the report) and another delegation made a more fruitful trip to see the Akagi, helping to confirm the design path. Eventually the blueprints were ready and construction approved.

Construction

As the cornerstone of a future blue water navy, the lead ship of a class of two sisterships, “A”, was approved in 1935 and on 16 November 1935 a contract was awarded to Deutsche Werke shipyard in Kiel. However at that time the largest slip was occupied by Gneisenau, so construction had to wait for it to be cleared, which left time to refine the blueprints. The navy also tested models of elector-hydraulic lifts while the Luftwaffe constructed and tested an arrestor system at Travemünde. In total 2500 tests were made and the design refined until completion. To cope with wind pressure on such a tall hull, German engineers added retractable Voith-Schneider propellers in the bow for extra handling maneuvers. To prevent for aviation fuel fires, tanks fuelling systems non-liquid filled parts were filled with dry gas while serving pipes were surrounded by inert gas pipes. In addition sprinklers were added in all hangars.

A class aircraft carrier at Kiel
Flugzeugträger “A” keel in Kiel AG, 28.12.1936

Concerning the superstructure, which was rather long to accommodate the staged AA artillery 105 mm batteries, the funnel height was reduced for clearing out the belt bridge near Fredericia. This imposed mast and aerials to be retractable, which was proven later unfeasible and all such height limits were dropped. In 1939 also the hull design was altered, the straight stem be converted as a “clipper” bow. The design was altered again in 1941 and 1942.

Details specifications

The 1938 design planned a 250 m long (820 fts 2 in on the waterline) ship, 31.50 m wide at bulge width (103 feets 4 in) and 7.20 draught (23 feets 7 in). Power comprised four shafts, each propelled by a Brown Boveri turbine, fed by 16 La Mont boilers for a total of 200,000 hp and 35 knots top speed. However 1942 design extra weight and bulges reduced that to 33 knots.
Armor protection comprised a 3.5 in belt, 1.5 in hangar deck, 3,5 in flight deck, and 1.5 in casemates.
Armament included eight double 150 mm guns 55 caliber C28 in casemates, six twin 105 mm/65 C33 dual-purpose guns, twenty-two 37mm/83 C33 AA guns in eleven twin mounts, and twenty-eight single 20 mm C38 mounts and possibly quad mounts C38M.

Aircraft complement
Eventually the Luftwaffe took on the program more seriously and began modifying the three planes intended to make the onboard complement: These were initially 10 Messerschmitt 109T (T for “träger”), 13 Junkers 87G, a navalised version, and 20 Fieseler Fi 167s torpedo reconnaissance bombers. For simplification it was later modified to 12 BF109T and 30 Ju87G acting as dive bombers and torpedo launchers. The choice a the Stuka in general seemed a good one as shown by Mediterranean operations (in Crete and elsewhere). It was also a way to simplify maintenance and supplies. In September 1939, Trägergruppe 186 had been formed and tested by the Luftwaffe at Kiel Holtenau, with the planned final complement, for the pilots to be properly trained to operate from mid-1940.

Fate

On 28 December 1936, Flugzeugträger A keel was laid down and she was launched on 8 December 1938, the 24th anniversary of the Battle of the Falkland Islands. She was christened by Helene von Zeppelin, daughter of the famous Count. At the outbreak of war projected completion by the middle of 1940 was realistic. However, despite all the efforts put into such project, and progresses, the graf Zeppelin was a casualty of war: Whereas construction was almost 85% complete (the “A” being christened “Graf Zeppelin”) U-boat construction priorities saw the project suspended. There were several nails in the coffin, though.


Graf Zeppelin in Stettin 8.12.1938

Norway
The first was linked to the conquest of Norway in April 1940. Whereas priorities to defend the Norwegian coastline asked for coastal guns and anti-aircraft batteries, Raeder also argued that fitting out the ship with the planned fire control system (just sold to USSR) and final guns would take another ten month. Therefore, Hitler suspended work on the aircraft carrier and all the planned guns and FLAK artillery were diverted to Norway.

Moving from places to places and back
In July 1940, Graf Zeppelin hulk was towed from Kiel to Gotenhafen (Gdynia) for a future completion. However when war erupted in the summer of 1941 with the Soviet Union, the ship was towed again this time to Stettin, out of reach of Soviet aviation. This further complicated an hypothetical completion as teams and materials were simply not there. By November, the ship was moved again to Gotenhafen as the German advance pushed back enough the Soviets to stay out of harm’s way. She layed there as a store ship for timber.

1942 design modifications
Raeder meeting with Hitler on naval strategy in April 1942, however, pushed the project again out of obscurity as operations clearly shown the usefulness of such a type of capital ship. Work resumed on 13 May 1942, with Hitler’s authorization. Raeder wanted newer planes, but Göering had him rebuffed due to the meager industrial resources of a hard-pressed Luftwaffe then, and stick to the initial planned provision of modified planes while training of new pilots resumed at Travemünde. But since the planes were heavier than 1938 versions, numerous designs changes had to be made.


In Kiel’s drydock 24.3.43 (Bundesarchiv)

Catapults needed modernization, stronger winches for the arrestor system were also needed, flight deck, elevators and hangar floors required reinforcement, new updated radars and fire control systems were also required, new radio equipment, armored fighter director cabin mounted and new reinforced main mast, better armored bridge, new curved funnel cap, an all-quad Flakvierling 38 guns complement and finally additional bulges fitted to improve stability on a ship that passed from 26.931 tonnes to 28.090 and then nearly 30,000 for this 1942 final design. That was ambitious, but the Kriegsmarine planned completion for April 1943. As sea trials were planned to began in the summer of that years, Chief Engineer Wilhelm Hadeler was reassigned to the prject and worked on a 26-knots capable powerplant. Service was estimated to start in the winter of 1944. Graf Zeppelin was back at Kiel on 5 December 1942, and placed on a drydock for this completion.

Final Cancellation
Although light seemed to be at reach in the tunnel for the unfortunate ship, fate turned again as Hitler became so disenchanted with the surface fleet that in late January 1943 he ordered in one of these famous hot-headed decisions that all large surface ships had to be scrapped and the material recycled to built U-boats. Raeder was relieved of command and Dönitz appointed as C-in-C. Little work was done when the hull in April was towed again to Gotenhafen but she was eventually moored at a back-water wharf in the Parnitz River near Stettin. She layed there without much progress but a guarding 40-man custodial crew until the Soviets reached her in April 1945. The crew scuttled the ship by opening the Kingston valves, preventing any attempt to tow her while demolition and depth charges were placed and detonated by order on 6pm on 25 April 1945. What about her sister ship ? “B” was ordered at Germaniawerft but if work started she was cancelled in March 1940 and broken up in situ. It was envisioned she would be modified during construction after changes made on A design.

Model of the ship at the Aeronauticum
Model of the ship at the Aeronauticum, German maritime aircraft museum

A controversial fate after the war
Attributed to USSR after the war by the allied tripartite commission she was designated “Category C” ship, unable to be retrieved and operated, and therefore had to be broken up. But she was ultimately refloated in March 1946, then towed to Leningrad and according to historian Erich Gröner struck a mine en route off the coast of Finland. According to other sources she survived the hit, made it to Leningrad and was to be broken up in 1948–1949. However declassified Soviet records revealed that on 14 August Graf Zeppelin was towed into Swinemunde harbor to be sunk five series of controlled explosions and torpedo hits at Swinemunde harbor. Her exact position was rediscovered on 12 July 2006 by Polish research vessel RV St. Barbara which made a three days dive campaign and confirmed its identity. All what’s left from this ship is the shipyard’s model, now displayed at the at the Aeronauticum, German maritime aircraft museum located in Nordholz (close to Cuxhaven).


Reconstruction of the initial 1939 design by DG_alpha

Links/src

en.wikipedia.org/wiki/German_aircraft_carrier_Graf_Zeppelin
trumpeter-china.com/Uploads/201701/586def418cc50.jpg (what-if livery)
wardrawings.be/WW2/Images/2-Airplanes/Axis/1-Germany/7-Aeronaval/Ju-87V-25/p1.jpg
(Planned torpedo-bomber v25 by Vincent Bourguignon)
Conway’s all the world fighting ships 1921-1947.

Graf Zeppelin specifications

Dimensions 262.5 x36.2 x8.5 m (861, 118, 27 ft)
Displacement 33.550/34.088t FL
Crew 1760+ aircrew
Propulsion 2 geared turbines, 16 LaMont boilers, 200,000 shaft horsepower (149,140.0 kW)
Speed 33.8 kn (62.6 km/h; 38.9 mph)
Range 8,000 nmi (14,816.0 km; 9,206.2 mi) at 19 kn (35.2 km/h; 21.9 mph)
Armament 16× 15 mm, 12× 10.5 mm, 22× 37 mm, 28× 2 mm FlaK
Aviation 12 M109 fighters & 30 Ju87 Stuka dive bombers
Armor Belt: 100 mm (3.9 in) Flight deck: 45 mm (1.8 in) Main deck: 60 mm (2.4 in)

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