Germany forgoes battleships, goes all in on CVs

[SaparotRob]

Not sure what you mean by "taken" but TF58 at it's height was probably going to wreck any single installation they set their sights on. We are talking mustering an 800+ plane strike force after all.

I was exaggerating. It just seems ridiculous to me that the Kreigsmarine could have taken on Gibraltar with whatever it could have come up with in the way of a carrier battle group.

 

[EwenS]

Interesting. Did anyone else drain the oil and heat it separately? Did they have separate oil tanks for each engine? Otherwise it could be potentially disastrous if one engine on the verge of seizing has it's oil drained into a common tank and contaminates everybody's oil with metal shavings or unwanted chemicals (like petrol blown past cylinder rings..)?

AFAIK no one else heated the oil in this way. But then again everyone else operated a system of warming their aircraft engines through before take off, usually while ranged on the flight deck or, in the case of the US carriers with open hangars, occasionally on the hangar deck. The German system was designed to allow engines to be started immediately they were delivered to the flight deck.

All the book I referred to says is

"...the aircraft's engine would be emptied of oil, this being done by operating the ship's oil distribution pumps in reverse. Oil removed from the aircraft would be returned to the four large conjoined storage tanks, where it would be mixed with the ten tons of aircraft engine oilthat were to be carried aboard ship."

It would however seem odd that, having gone to all the trouble of installing this system to warm the oil, that they would not have included some form of filtration system to ensure the oil was not being contaminated in the way you suggest. German efficiency & all that. But the information about GZ and her systems is less than complete as she was never completed.

 

[Barrett]

Years ago I considered a novel based on Graf Zeppelin v. a US/RN CVE force in the North Atlantic.
Then I looked closer.
The KM had the Japanese and British navies as examples of how to build and operate carriers--and inevitably ignored those lessons. Short version: the Germans chose the worst options in what mattered most: handling and launching aircraft. Mounted the planes on launch dollies on the hangar deck and used recessed tracks "on the roof" to move the contraptions into position for a tail-up launch.
And then...
decided on compressed air catapults instead of hydraulic when the CA versions were limited to 18 cycles (including two test shots) before recharging. Which apparently took hours.
Ach du Lieber!

 

[z42]

AFAIK no one else heated the oil in this way. But then again everyone else operated a system of warming their aircraft engines through before take off, usually while ranged on the flight deck or, in the case of the US carriers with open hangars, occasionally on the hangar deck. The German system was designed to allow engines to be started immediately they were delivered to the flight deck.

Guess it can make sense if you're planning to operate during freezing rain in northern waters rather than some cozier southern latitudes.

It would however seem odd that, having gone to all the trouble of installing this system to warm the oil, that they would not have included some form of filtration system to ensure the oil was not being contaminated in the way you suggest. German efficiency & all that.

I've been reading Calum Douglas SHPR book lately, and, well, lets say my trust in German efficiency is being tested.

I'm sure they must had planned to use filters, and while those can filter out solid metal particles, those won't help e.g. with petrol contamination, which was an issue that severely affected the LW during WWII. But presumably those issues weren't foreseen when GZ was being designed, so in a way hard to fault them for it..

 

[Admiral Beez]

This is NOT the trolley used with the hydraulic catapults on the carriers.

Understood. I've got a pic and vid of the carrier trolley above.

 

[Admiral Beez]

I get that hull for capital ship takes time, but Hitler wasn't predicting war until '44, so Raeder had time to build a "training carrier" before committing to the ultimate solution.

How did Hitler expect Germany to economically survive without war until 1944?

 

[SaparotRob]

The Third Reich wasn't necessarily enamored with reality.

 

[EwenS]

Years ago I considered a novel based on Graf Zeppelin v. a US/RN CVE force in the North Atlantic.
Then I looked closer.
The KM had the Japanese and British navies as examples of how to build and operate carriers--and inevitably ignored those lessons. Short version: the Germans chose the worst options in what mattered most: handling and launching aircraft. Mounted the planes on launch dollies on the hangar deck and used recessed tracks "on the roof" to move the contraptions into position for a tail-up launch.
And then...
decided on compressed air catapults instead of hydraulic when the CA versions were limited to 18 cycles (including two test shots) before recharging. Which apparently took hours.
Ach du Lieber!

The original studies for a German carrier were carried out in late 1933 to early 1934 but were hampered by the same question that other navies had, and to which I have referred to before i.e what is the carrier for?

During the 1935 Navy Days (held at the end of July beginning of Aug) a delegation of German naval architects visited HMS Furious but were able to "gain little insight". By then Furious no catapults or crash barrier (and possibly no arrester gear) and still had her 5.5" armament so hardly represented the latest in carrier design.

They followed that up with a visit to Japan where they were able to visit Akagi (this was just before she began her Oct 1935 - Aug 1938 reconstruction). They left "with plans for such items as the central elevator and aircraft arrestor gear, but declined Japanese offers for a long-term study of their carriers."

The orders for the first two ships were then placed in Nov 1935.

So it looks like they left visiting other carriers a bit late in the design process. Maybe Britain was a bit more amenable to showing them Furious given that this was just after the Anglo-German Naval Agreement had been signed in June 1935 and relations between the two nations was more cordial and knowing that she would be of little help.

That brings us to the next problem that the Germans faced in carrier production. Shipyard capacity. The laying down of GZ had to await the launch of Gneisenau, the ships being built on the same slip. The second ship was delayed in part as the yard had to launch Prinz Eugen before making a start. And delays crept into the programme after that due to various shortages.

 

[EwenS]

I'm sure they must had planned to use filters, and while those can filter out solid metal particles, those won't help e.g. with petrol contamination, which was an issue that severely affected the LW during WWII. But presumably those issues weren't foreseen when GZ was being designed, so in a way hard to fault them for it..

Water contamination of petrol supplies was a problem for the RN throughout the war. In the days leading up to Taranto for example Illustrious lost 3 Swordfish due it was thought to this cause. The result was that all her aircraft had to have their tanks flushed & filled using chamois leathers to absorb the water. That water, along with sand and a wierd form of algae, had come from the tanker she had filled that particular petrol tank from. There were other incidents as the war went on, particularly in colder regions where the water seems to have come from condensation IIRC.

 

[don4331]

Years ago I considered a novel based on Graf Zeppelin v. a US/RN CVE force in the North Atlantic.
Then I looked closer.
The KM had the Japanese and British navies as examples of how to build and operate carriers--and inevitably ignored those lessons. Short version: the Germans chose the worst options in what mattered most: handling and launching aircraft. Mounted the planes on launch dollies on the hangar deck and used recessed tracks "on the roof" to move the contraptions into position for a tail-up launch.
And then...
decided on compressed air catapults instead of hydraulic when the CA versions were limited to 18 cycles (including two test shots) before recharging. Which apparently took hours.
Ach du Lieber!

Lufthansa had been using compressed air catapult systems on catapult ships for mail planes for some time. HSwMs Gotland is using German compressed air catapult as do K & Leipzig class cruisers (5) and Deutschland armoured ships (3). Given KM has that knowledge already, another 9 under construction for planned BB/CAs, its really not surprising that they didn't reinvent the wheel for 4 CV catapults.

50 minute recharge time is hardly hours, and not really an issue when all 39 (maybe 41) aircraft have been launched. The joke is more only 41 planes on more tonnage than Ark Royal or Yorktowns. (And a little on the limited range of said aircraft).

The original studies for a German carrier were carried out in late 1933 to early 1934 but were hampered by the same question that other navies had, and to which I have referred to before i.e what is the carrier for?

During the 1935 Navy Days (held at the end of July beginning of Aug) a delegation of German naval architects visited HMS Furious but were able to "gain little insight". By then Furious no catapults or crash barrier (and possibly no arrester gear) and still had her 5.5" armament so hardly represented the latest in carrier design.

They followed that up with a visit to Japan where they were able to visit Akagi (this was just before she began her Oct 1935 - Aug 1938 reconstruction). They left "with plans for such items as the central elevator and aircraft arrestor gear, but declined Japanese offers for a long-term study of their carriers."

The orders for the first two ships were then placed in Nov 1935.

So it looks like they left visiting other carriers a bit late in the design process. Maybe Britain was a bit more amenable to showing them Furious given that this was just after the Anglo-German Naval Agreement had been signed in June 1935 and relations between the two nations was more cordial and knowing that she would be of little help.

That brings us to the next problem that the Germans faced in carrier production. Shipyard capacity. The laying down of GZ had to await the launch of Gneisenau, the ships being built on the same slip. The second ship was delayed in part as the yard had to launch Prinz Eugen before making a start. And delays crept into the programme after that due to various shortages.

How serious were studies in '33-34? Reichmarine did studies in late 20s but there was no hope of building CV, so they were paper exercises.

Things really don't kick off until mid '35 with Anglo-German naval treaty. So, mid 35 visits to RN and late '35 visits to IJN are basically as early as KM got serious. Raeder still wasn't big fan of floating gasoline tankers being warships and Goering wasn't fan of KM having control of aircraft outside LW. We will note that RAF had control of FAA during this planning period. If they had been really serious about CVs, they could have been building GZ instead of PE in Kiel and started a CL at Bremen (Leipzig class CL is more/less same dimensions as Hosho) Based on historic build times, the CL would have commissioned in early '39 allowing almost 2 years operation before fleet carrier was ready.

 

[GreenKnight121]

Graf Zeppelin aircraft handling arrangements (drawn from "Freedom of the Seas. The Story of Hitler's Aircraft Carrier - Graf Zeppelin" chapter titled "Carrier Operations. Deployment of a Kriegsmarine Carrier - Based on Original Operating Plans for the Graf Zeppelin" and other sources.)

Each cat was powered by compressed air with storage to allow a test shot and 8 operational shots before the air reservoir required refilling. Using alternate cats aircraft could be launched every 30 secs. The real weakness in the system was that once the air was exhausted it took 50 mins to replenish.

50 minute recharge time is hardly hours, and not really an issue when all 39 (maybe 41) aircraft have been launched. The joke is more only 41 planes on more tonnage than Ark Royal or Yorktowns. (And a little on the limited range of said aircraft).

Sorry - as pointed out by EwenS the catapults could only launch 8 EACH before needing that 50-minute recharge.

That's 16 aircraft total that could be launched before recharge..

 

[don4331]

Technically, the catapults could do 9 launches each, assuming you use the test shot to launch an aircraft, but 8 each is sufficient.

Graf Zeppelin's air group:
8-10 Bf 109T-1 fighters
13 Ju 87C dive bombers
18 Fi 167 recce/torpedo bomber - we note that the Fi 167s don't even have catapult spools - they are expected to launch on their own; as biplane with several high lift devices, they don't need much airspeed to take off.

Theoretical combat: Saturday, 24/May/'41 GZ in place of PE. KM ships exit the snowstorm aware Suffolk and Norfolk are using radar to trail, so a strike is prepared:

3 Bf.109 & 13 Ju.87 are loaded onto trolleys and arranged for catapult launch; behind are the 18 Fi 167 and at very back are the remaining 3-5 Bf.109s.

GZ turns west into the wind and accelerates to 35kn. Catapult launch of initial 3 fighters and the 13 dive bombers (8 catapult shot each); regular launch of torpedo bombers. That leaves the remaining 3 fighters >200m of deck with >50kn wind over deck (wind on 24/May/'41 was over 15kn). Bf.109Ts have no issue launching without use of catapult. (Although technically, in the 10+ minutes to launch all the torpedo bombers, the catapult would have recovered enough capacity to shoot the remaining fighters.

All 41 aircraft would be in air to attack RN ships.

Bf.109 catapult launches were reserved for cases like 24/May/'41 - Attack by Victorious aircraft.

FAA aircraft are spotted on radar 30nm out (~15 minutes for Swordfish), which leaves GZ no time to turn into wind/accelerate to launch speed. Bf.109 are filled with hot oil and lifted to deck, engine is fired by compressed air. Less than 2 minutes after notice 1st CAP plane is in the air; within 10 minutes all 10 planes are launched in attempt to stop the 15 FAA planes (6 Fulmars and 9 Swordfish). 6 Ju.87 and all Fi.167 could still be launched in counter strike Actually, by time the planes were oiled, fueled, armed, brought to deck and arranged, full charge would be available for catapults.

Given KM inability to operate a Task Force with required oilers to allow GZ to replenish petrol/design was started before Radar was available, I understand the rationale behind catapult launches rather than standing CAP, heating oil versus warming up aircraft on deck. Note: Understand rationale and thinking it was good solution are completely different things. So, they get full marks for ingenuity, but I'm betting it would get failing grade in practice. RN will armoured flight deck is probably better solution.

Aside: The crew of HMS Glorious probably wishes they could have launched 6+ Skuas at Twins before the deck hit. With GZ solution - needing only distance from fore elevator forward, Glorious might have been able to launch every undamaged plane she had.

 

[delcyros]

Interestingly, the SCHWABENLAND in fact used steam catapults to launch heavy seaplanes off the Antarctic. The steam was fed from the ships own boiler system.