WesWorld

Drawn up primarily to provide a baseline for future aircraft carrier design, the CVA 50 is constrained by Germany's current infrastructure, and is thus smaller than foreign design sketches. However, the design represents the Kriegsmarine's basic doctrine that an aircraft carrier is meant to operate aircraft; thus her defensive armament is no different than the earlier Spaun-class. Speed has been much enhanced, as well as operating radius. It is unclear whether construction of this design will be pursued or superseded by other proposals.

Ersatz Zeppelin, German Fleet Aircraft Carrier laid down 1950

Displacement: 53,148 t light; 54,639 t standard; 62,977 t normal; 69,647 t full load

Dimensions: Length overall / water x beam x draught

909.94 ft / 885.83 ft x 134.51 ft (Bulges 141.08 ft) x 34.45 ft (normal load) [277.35 m / 270.00 m x 41.00 m (Bulges 43.00 m) x 10.50 m]

Armament:

32 - 2.17" / 55.0 mm guns (16x2 guns), 5.08lbs / 2.30kg shells, 1950 Model Anti-aircraft guns in deck mounts on side, evenly spread, all raised mounts
8 - 0.79" / 20.0 mm guns (4x2 guns), 0.24lbs / 0.11kg shells, 1950 Model Anti-aircraft guns in deck mounts on side, evenly spread, all raised mounts
Weight of broadside 164 lbs / 75 kg
Shells per gun, main battery: 2,500

Armour:

Belts: Width (max) Length (avg) Height (avg)

Main: 4.72" / 120 mm 820.21 ft / 250.00 m 16.40 ft / 5.00 m
Ends: Unarmoured
Upper: 1.97" / 50 mm 820.21 ft / 250.00 m 16.40 ft / 5.00 m
Main Belt covers 142 % of normal length

Torpedo Bulkhead and Bulges: 1.18" / 30 mm 820.21 ft / 250.00 m 24.08 ft / 7.34 m

Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)’

Main: 0.98" / 25 mm 0.59" / 15 mm -
2nd: 0.39" / 10 mm - -

Armour deck: 3.15" / 80 mm, Conning tower: 3.94" / 100 mm

Machinery:

Oil fired boilers, steam turbines plus diesel motors, Geared drive, 4 shafts, 288,938 shp / 215,548 Kw = 35.00 kts
Range 18,500nm at 18.00 kts
Bunker at max displacement = 15,008 tons

Complement: 1,987 - 2,584

Cost: £22.244 million / $88.976 million

Distribution of weights at normal displacement:

Armament: 21 tons, 0.0 %
Armour: 9,476 tons, 15.0 %
- Belts: 3,584 tons, 5.7 %
- Torpedo bulkhead: 863 tons, 1.4 %
- Armament: 29 tons, 0.0 %
- Armour Deck: 4,865 tons, 7.7 %
- Conning Tower: 134 tons, 0.2 %
Machinery: 6,912 tons, 11.0 %
Hull, fittings & equipment: 18,739 tons, 29.8 %
Fuel, ammunition & stores: 9,829 tons, 15.6 %
Miscellaneous weights: 18,000 tons, 28.6 %

Overall survivability and seakeeping ability:

Survivability (Non-critical penetrating hits needed to sink ship): 110,523 lbs / 50,132 Kg = 21,771.9 x 2.2 " / 55 mm shells or 16.7 torpedoes
Stability (Unstable if below 1.00): 1.15
Metacentric height 10.1 ft / 3.1 m
Roll period: 18.6 seconds
Steadiness - As gun platform (Average = 50 %): 69 %
- Recoil effect (Restricted arc if above 1.00): 0.00
Seaboat quality (Average = 1.00): 1.26

Hull form characteristics:

Hull has raised forecastle and transom stern
Block coefficient: 0.512
Length to Beam Ratio: 6.28: 1
'Natural speed' for length: 35.31 kts
Power going to wave formation at top speed: 57 %
Trim (Max stability = 0, Max steadiness = 100): 55
Bow angle (Positive = bow angles forward): 30.00 degrees
Stern overhang: 3.28 ft / 1.00 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 36.09 ft / 11.00 m
- Forecastle (20 %): 36.09 ft / 11.00 m (32.81 ft / 10.00 m aft of break)
- Mid (50 %): 32.81 ft / 10.00 m
- Quarterdeck (15 %): 32.81 ft / 10.00 m
- Stern: 32.81 ft / 10.00 m
- Average freeboard: 33.46 ft / 10.20 m

Ship space, strength and comments:

Space - Hull below water (magazines/engines, low = better): 80.1 %
- Above water (accommodation/working, high = better): 262.6 %
Waterplane Area: 83,495 Square feet or 7,757 Square metres
Displacement factor (Displacement / loading): 152 %
Structure weight / hull surface area: 162 lbs/sq ft or 792 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.95
- Longitudinal: 1.49
- Overall: 1.00
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent
Good seaboat, rides out heavy weather easily

Breakdown of miscellaneous weight

14,400 tons for up to 120 conventional or 80 jet aircraft
20 spare aircraft @ 25 tons each - 500 tons
Air and surface warning radars - 400 tons
Fire control radars and integrated gun directors - 300 tons
Flight operations center - 400 tons
Flag bridge and associated accommodations - 200 tons
Enhanced damage control system (CO2 flooding, etc.) - 400 tons
Aviation equipment - catapults etc. - 1400 tons

Ship is fitted with two catapults for aircraft launch and has three elevators, including one deck edge elevator.

Looks to me like a fairly decent follow-up on the Spaun design even if Germany is limited by its infrastructure, though it has its flaws. The speed probably eats up a bit too much hull strength to my liking. BC is probably a bit on the low side for a vessel of this size and dimensions. I expect it to be more around 0.6 like Spaun. I would also move the trim a notch to get to 70% and the "steady gun platform" remark in the report. That 69% seems rather sinful to me even if there is not much difference between that and 70% except for a few words extra in your report.

I suspect the Ersatz Zeppelin is designed to make use of a steam catapult given the steam and diesel propulsion (which seems a bit odd and wasteful for a carrier) and the high speed (probably too high to be worth it) is more of an artefact of having lots of steam pressure.
The RN notes it still has a major lead of steam catapult technology, and unlike OTL its had no compulsion to share its secrets with the US and so retains a monopoly for the time being.

The armament still feels too light to me, a complaint I had about the Spaun. Until the point-defence SAM becomes a reality (another 5-8 sim years away) then a medium calibre gun at least provides some hitting power, especially against the small rocket-glide bombs likely to be developed in this period.

Hood wrote,

Quoted

I suspect the Ersatz Zeppelin is designed to make use of a steam catapult given the steam and diesel propulsion (which seems a bit odd and wasteful for a carrier)…

CODAS powerplants have been pretty much standard on major KM combatants since Hrolf’s day. The CVA 50 design merely follows the trend

Walter commented,

Quoted

The speed probably eats up a bit too much hull strength to my liking… I would also move the trim a notch to get to 70% and the "steady gun platform" remark in the report….

The speed may be higher than it needs to be, and there are a couple of ways to increase the ship’s steadiness – I am still considering options there.

Hood also wrote,

Quoted

The armament still feels too light to me, a complaint I had about the Spaun. Until the point-defence SAM becomes a reality (another 5-8 sim years away) then a medium calibre gun at least provides some hitting power, especially against the small rocket-glide bombs likely to be developed in this period.

If the Kriegsmarine operated its aircraft carriers as lone wolves (as the RN seems to do at times) this might be a concern. However, with the number of escorts available, KM doctrine calls for them to provide the principal firepower.

As for glide bombs – the KM is quite familiar with the limitations of them – the Luftwaffe having operated the Hs293 for years. The principal means of dealing with them is to kill the carrier aircraft before they can launch their payloads – and that is why the CVA 50 is designed to operate the number of aircraft it does.

Quoted from "Hood"

The RN notes it still has a major lead of steam catapult technology, and unlike OTL its had no compulsion to share its secrets with the US and so retains a monopoly for the time being.

For the time being, yes. I'll note in turn that the Russians have been developing steam catapults for the large carriers Reval and Kerch, which shall complete in November 1948, while France's Foudroyant is also very likely to have steam catapults. The RN definitely is getting their stuff out first, but the monopoly is only going to last until I commission my next CVs.

Quoted

Quoted

I suspect the Ersatz Zeppelin is designed to make use of a steam catapult given the steam and diesel propulsion (which seems a bit odd and wasteful for a carrier)…

CODAS powerplants have been pretty much standard on major KM combatants since Hrolf’s day. The CVA 50 design merely follows the trend

Yes, that was something I noticed when looking at the previous carriers. If it works then it would make sense to keep on using it.

Quoted

The speed may be higher than it needs to be,

Well, it really depends on whether you think it is important. I thought that the 30 knots on my design was good enough so that I could use the hull strength that would normally be used to get a greater speed for other things that I think are more important for a carrier than speed.

Quoted

and there are a couple of ways to increase the ship’s steadiness

Changing trim from 55 to 56 is the only thing that is needed to get the "steady gun platform" if you keep the rest of the sim unchanged.

Quoted

If the Kriegsmarine operated its aircraft carriers as lone wolves (as the RN seems to do at times) this might be a concern. However, with the number of escorts available, KM doctrine calls for them to provide the principal firepower.

As for glide bombs – the KM is quite familiar with the limitations of them – the Luftwaffe having operated the Hs293 for years. The principal means of dealing with them is to kill the carrier aircraft before they can launch their payloads – and that is why the CVA 50 is designed to operate the number of aircraft it does.

To me what you mentioned here as well as in the thread with the Spaun design, it made sense to me and more confident regarding my choice to use the 75mm as main armament on the Ishinagenjo even though it has more AA guns than the Spaun and Ersatz Zeppelin combined. That's just in case any threat might threaten to get through the protective circle around the carriers. Otherwise the escort ships should do what they are supposed to do (protect the carrier) so the carrier can focus on what it is supposed to do (launch/recover aircraft).

Quoted

For the time being, yes. I'll note in turn that the Russians have been developing steam catapults for the large carriers Reval and Kerch, which shall complete in November 1948, while France's Foudroyant is also very likely to have steam catapults. The RN definitely is getting their stuff out first, but the monopoly is only going to last until I commission my next CVs.

Won't be until the mid 50s when Japan will have them operational. At least the RN can enjoy their monopoly until the Russian/French carriers are completed. That'll keep them happy for a short while.

I just find a steam-diesel set up odd for carriers, especially large ones. The diesels are useful for cruising in peacetime but are probably not enough to allow safe take-off operations if the main steam system was inoperable due to damage etc. in wartime. Also, I'd think in wartime the fleet cruising speed would be higher and perhaps not suited to the diesels.

Nice to know I'm not alone. I find it odd though that nobody has ever built a reliable steam catapult (for carriers) other than the British and Americans in OTL (I'm not sure who supplied the catapults for the Clemenceau Class, I can't remember if they are French or foreign design - so that's my caveat). Should be a simple enough bit of kit to produce, maybe its just in OTL those two navies monopolised the building and export of carriers (though the Soviets never went for steam catapults)?

The French wiki page indicates...

Quoted

2 catapultes à vapeur Mitchell-Brown de 50 m type BS 5 pouvant catapulter des avions de 12 à 15 tonnes à 150 nœuds

... so to me the 'Mitchell-Brown' is an indication that the catapults are of foreign design.

Many times foreign wiki pages are a lot more useful than the English wiki pages.

Indeed so, I thought that might have been the case but wasn't sure.

I feel I need to step up my game and design a huge carrier or two.

Quoted from "The Rock Doctor"

I feel I need to step up my game and design a huge carrier or two.

Please don't feel you need to do so on my account. ;)

The CVA 50 is larger than I would really like it to be, but to allow for operating a reasonable number of jet aircraft - according to our rules - the miscellaneous weight has to be increased and an overall larger ship to permit it.

And then there is the time factor - even a 'small' super carrier like the CVA-50 is going to take more than five years to build.

Quoted from "Hood"

Nice to know I'm not alone. I find it odd though that nobody has ever built a reliable steam catapult (for carriers) other than the British and Americans in OTL (I'm not sure who supplied the catapults for the Clemenceau Class, I can't remember if they are French or foreign design - so that's my caveat). Should be a simple enough bit of kit to produce, maybe its just in OTL those two navies monopolised the building and export of carriers (though the Soviets never went for steam catapults)?

Yeah, nobody else built a CATOBAR carrier other than the NATO powers - and for France, just building two carriers, it was probably easier to buy a British or US catapult rather than sinking a bunch of money into a local design...

If I recall correctly, I think the Soviets put some design work into a regular style (non-ski-jump) carrier which probably *could* have had steam catapults, if it'd been built... so maybe they put some design effort into it? But I can't say that for certain.

Quoted

The CVA 50 is larger than I would really like it to be, but to allow for operating a reasonable number of jet aircraft - according to our rules - the miscellaneous weight has to be increased and an overall larger ship to permit it.

Yes, that is the square root in the formula at work.

Something I mentioned a bit in the British 1948 ship thread with the normal planes, if you double the number of planes then you will need 4x the miscellaneous weights, if you triple the number of planes then you will need 9x the miscellaneous weights, if you quadruple the number of planes then you will need 16x the miscellaneous weights, etc. If you work with 30 planes (20 jets), you need 900 tons. If you step it up, you have 3600 tons for 60 planes (40 jets), 8100 tons for 90 planes (60 jets), 14400 tons for 120 planes ( 80 jets) and 22500 tons for 150 planes (100 jets).

Originally I was thinking of 80 jets as well, but due to how much miscellaneous weights is needed with those high number of planes, I decided to drop it to 70 as I still consider that to be a good amount of jets to have on my carrier and I had more than 3300 tons which I could put into the armor that was needed...