Graf Zeppelin vs HMS Ark Royal and Victorious

[Bgile]

Ultimately the USN decided to adopt an armoured flight deck on the Midway class CVs.

The problem for the US was how to get an armored flight deck AND the air wing size they felt they needed. To get both, they ended up with a 45,000 ton ship (the Midway class), which in spite of their large displacement had problems operating aircraft in moderately heavy seas. With the advent of heavier jet aircraft, it wasn't until the ships approached 100,000 tons that the combination was really satisfactory.

[dunmunro]

Ultimately the USN decided to adopt an armoured flight deck on the Midway class CVs.

The problem for the US was how to get an armored flight deck AND the air wing size they felt they needed. To get both, they ended up with a 45,000 ton ship (the Midway class), which in spite of their large displacement had problems operating aircraft in moderately heavy seas. With the advent of heavier jet aircraft, it wasn't until the ships approached 100,000 tons that the combination was really satisfactory.

Well, that's debatable...the Implacable class had a standard displacement of 24000 tons and were operating 80 aircraft by 1945. The Essex class operated about 100 with a 27000 ton standard displacement. I think it is reasonable to conclude that by redesigning Implacable to 27000 tons standard, that the capacity could have been increased to 100 aircraft as well. The Midway's were increased in size because of the AFD but also because USN designers were realizing that much heavier and larger aircraft would be needed in the near future, in part because of the need to carry aircraft with the speed and range needed to attack AFD carriers in the face of increasingly effective AA systems.

[Bgile]

dunmunro,

The Impacables had a designed complement of 45 aircraft, right? How did they manage to get 85 on it? Or are we talking apples and oranges?

[dunmunro]

dunmunro,

The Implacables had a designed complement of 45 aircraft, right? How did they manage to get 85 on it? Or are we talking apples and oranges?

Well you can see what they were carrying in comparison to USN carriers here:

http://www.navweaps.com/index_oob/OOB_W ... slands.htm

The Essex has a hanger deck size of 654' x 70' = 45780 sq ft
Implacable has a hanger deck size of 468' x 62' plus a lower hanger of 208' x 62' = 41912 sq ft

Now the Implacable hanger height was only 14' versus 17.5' in Essex which restricted the use of certain aircraft types, but the actual deck areas are not much different, and a redesigned Implacable with an extra 3000 tons would probably have been able to match Essex in hanger size and height. The Essex might still carry a larger compliment due to her larger FD area, for a larger permanent deck park, but the differences would be minimal.

[Tiornu]

If the Americans wanted to accept the limited speed, range, hangar height and ventilation, and avgas stores of the British design, they might have found Implacable acceptable. But in actuality, they would have found the suggestion ridiculous.

[dunmunro]

If the Americans wanted to accept the limited speed, range, hangar height and ventilation, and avgas stores of the British design, they might have found Implacable acceptable. But in actuality, they would have found the suggestion ridiculous.

Yeah, after watching Franklin light up like a torch, I bet they couldn't stop laughing at those silly AFD carriers and their elaborate avgas stowage systems that limited their Avgas stowage. Implacable carried about 115000 US gallons versus about 230,000 for Essex but this was reduced to about 209,000 gallons after safety mandated redesigns. However to put this perspective, 230000 US gals is equal to about 640 tons. Implacable had her fuel stowage increased by 50% over Illustrious and it would not have been too difficult to increase it further, especially in an enlarged design, but the USN carriers were probably designed with excessive fuel capacity for their tonnage. Essex could carry about 6100tons versus about 4500 for Implacable.

The Implacables and Essex class made about the same speed on trials, but by 1945 the Essex class were dangerously overweight and were probably slower than the Implacables. However, a USN Implacable would have been built with their lighter HP PPs leaving more room for fuel and avgas, so even on the same tonnage would have been able to carry more fuel and avgas than a UK built ship. As it was the Implacables operational range was more than sufficient for typical operations, but of course I am postulating a 27000 ton UK built implacable, which would allow for more fuel capacity as well.

[Tiornu]

Yeah, after watching Franklin light up like a torch, I bet they couldn't stop laughing at those silly AFD carriers and their elaborate avgas stowage systems that limited their Avgas stowage.

I'm guessing it bothers you to realize that American carriers were better-protected from air attack than the British armored-box carriers.

The Implacables and Essex class made about the same speed on trials, but by 1945 the Essex class were dangerously overweight and were probably slower than the Implacables.
However, a USN Implacable would have been built with their lighter HP PPs leaving more room for fuel and avgas, so even on the same tonnage would have been able to carry more fuel and avgas than a UK built ship.
As it was the Implacables operational range was more than sufficient for typical operations, but of course I am postulating a 27000 ton UK built implacable, which would allow for more fuel capacity as well.

Yes, I enjoy statements without foundation as much as anybody.

[dunmunro]

I'm guessing it bothers you to realize that American carriers were better-protected from air attack than the British armored-box carriers.

I guess that's why Franklin suffered more casualties than all the RN AFD carriers combined.

Yes, I enjoy statements without foundation as much as anybody.

LOL, Implacable = 4 shafts and 148,000 SHP, Essex = 4 shafts and 150,000 SHP.

[Tiornu]

I guess that's why Franklin suffered more casualties than all the RN AFD carriers combined.

Why would you guess that? Was this best effort of your cause-effect reasoning?

LOL, Implacable = 4 shafts and 148,000 SHP, Essex = 4 shafts and 150,000 SHP.

Yes, we can all laugh at stats in a vacuum. Let me know when a point is coming.
I don't anticipate any serious responses ensuing.

[dunmunro]

I guess that's why Franklin suffered more casualties than all the RN AFD carriers combined.

Why would you guess that? Was this best effort of your cause-effect reasoning?

LOL, Implacable = 4 shafts and 148,000 SHP, Essex = 4 shafts and 150,000 SHP.

Yes, we can all laugh at stats in a vacuum. Let me know when a point is coming.
I don't anticipate any serious responses ensuing.

What have you contributed to this discussion? You've demonstrated, once again, that you can't stand to be contradicted and that's about all.

Franklin was hit by two 550lb or smaller bombs and was turned into a burned out hulk and suffered nearly a thousand casualties in the process. Bunker Hill was also hit by two Zero Kamikazes and 1 550lb bomb, and was also turned into a blazing wreck, while suffering 650 casualties, again more than all the RN AFD carriers combined. But of course, again, this is meaningless. Right?

[Tiornu]

What have you contributed to this discussion?

Go back and read it again, if that will help.

You've demonstrated, once again, that you can't stand to be contradicted and that's about all.

As you know, what I can't stand is deliberate distortion. You cite a single anecdote and present it as a valid point. You've made no effort to examine the subject from any angle, even an obvious one, that does not dovetail into your baseless conclusion. You had the option of considering how many bombs did not hit American carriers due to their overwhelming pre-emptive air strength and their massive CAP capability--the very assets that have already been cited as the anti-thesis of the armored flight deck. Why you chose not to do so...is clear.

But of course, again, this is meaningless. Right?

Agreed.

I don't anticipate any serious responses ensuing.

Am I prescient or what?

[dunmunro]

You've demonstrated, once again, that you can't stand to be contradicted and that's about all.

As you know, what I can't stand is deliberate distortion. You cite a single anecdote and present it as a valid point. You've made no effort to examine the subject from any angle, even an obvious one, that does not dovetail into your baseless conclusion. You had the option of considering how many bombs did not hit American carriers due to their overwhelming pre-emptive air strength and their massive CAP capability--the very assets that have already been cited as the anti-thesis of the armored flight deck. Why you chose not to do so...is clear.

The RN AFD carriers were designed before effective GCI or even simple search radar was a reality. Take away Radar and the USN's carriers would have been lighting up the Pacific as did the IJN's. The argument that large air complements prevent attack is false. It is the combination of radar, combined with adequate numbers of aircraft and effective GCI doctrine that allowed the USN to use their numbers effectively. It is also a fact that IJN/IJAAF aircraft had vastly inferior performance to contemporary Luftwaffe aircraft, for example, again creating the illusion of an effective CAP due to the USN carrier's large complement, when it was really a case of meeting a vastly weaker opponent, whose poor performing aircraft allowed effective interception. The USN had the luxury of assessing the combat experience of RN carriers, RN design doctrine including AFD designs with unlimited access to RN files and decided to build their own AFD carriers that fully incorporated both RN and USN combat experience, a luxury that the RN did not have since all their designs were completed pre-war. The RN had to pioneer the development of carrier tactics the hard way. However, the RN did incorporate war experience into their designs to the extent possible, and the result was Implacable. Put Implacables into the 1941/42 Med or Atlantic, with late war RN carrier doctrine and the result would have been the total dominance of those oceans, in that time frame, and the probable destruction of the Kido Butai in April 1942.

However, again we have to come back to the fact that Implacable was a smaller CV than Essex, and a hypothetical USN Implacable would have had a larger air complement, with more fuel, avgas, and munitions stowage than Implacable and probably another elevator. Now, let's replace the Essex class with USN Implacables. Would an AFD CV with say 90-95 aircraft, 150000 gallons of avgas, and say 5000 tons of fuel, have been superior to the historical Essex? I would argue that it would have been and USN carriers could have then advanced farther and faster, in terms of island hopping , than was historically the case, but in any event the differences between the two designs would have been far less than is commonly imagined.

Additionally, the existing RN implacable class could have been improved upon even further, on the same tonnage, by replacing the 4.5" guns with 4" and by reducing the belt armour to say 2". This would probably have allowed one or both of the hanger decks to have been heightened to 16' or more, with no reduction in AA performance and no real reduction in damage resistance.

[lwd]

The point about the armored flight decks forcing the use of heavier bombs seams a bit problematic to me. While a strike vs a CV escorted by DDs might be able to use lighter bombs if the CV didn't have an amored deck a strike against a CV group with cruiser and battleship escorts is going to want to use the heavy bombs anyway in case they engage the escorts. So in most circumstances I don't see the CV deck dominating the choice of what bomb load is carried. And as for dive bombers it's not at all clear to me that carrying additional bombs increases the hit probability much and may actually decrease the probable damage.

[Bgile]

I read quite a bit of Friedman on CV design last night. At least this discussion has done that much for me. What dunmunro has done is cherry pick a small part out of this huge treatise. He left out all the parts where the drawbacks of AFDs were discussed and the back and forth the USN went through trying to improve on the Essex design and zeroed in on the thing about making the enemy use bigger bombs.

Anyway, after all this study they came up with the Midway class of 45,000 tons std displacement and an armored flight deck. It wasn't entirely successful, being a poor landing platform in heavy seas, in part due to the heavy flight deck up high in the ship. It was a big expensive ship though, and the navy needed jet capable fight decks so they hung in there and modified them extensively over the years and got good service out of them. They also modifed at least one Essex (Ticonderoga) which served through the Vietnam war. It may be noteable that the Midway class were not used in Korea, even though they were the largest CVs at the time.

Modern CVs have thick steel fligh decks, but they have to have them to operate the very heavy jets used today. They are huge ships though, and the thick flight decks aren't as much of a burden ... proportional to ship size I don't think they are nearly as thick as the British used in WWII.

[dunmunro]

I read quite a bit of Friedman on CV design last night. At least this discussion has done that much for me. What dunmunro has done is cherry pick a small part out of this huge treatise. He left out all the parts where the drawbacks of AFDs were discussed and the back and forth the USN went through trying to improve on the Essex design and zeroed in on the thing about making the enemy use bigger bombs.

Anyway, after all this study they came up with the Midway class of 45,000 tons std displacement and an armored flight deck. It wasn't entirely successful, being a poor landing platform in heavy seas, in part due to the heavy flight deck up high in the ship. It was a big expensive ship though, and the navy needed jet capable fight decks so they hung in there and modified them extensively over the years and got good service out of them. They also modifed at least one Essex (Ticonderoga) which served through the Vietnam war. It may be noteable that the Midway class were not used in Korea, even though they were the largest CVs at the time.

Modern CVs have thick steel fligh decks, but they have to have them to operate the very heavy jets used today. They are huge ships though, and the thick flight decks aren't as much of a burden ... proportional to ship size I don't think they are nearly as thick as the British used in WWII.

When I made my initial comments on page 5 about the tactical advantages of AFD carriers regarding weapon weight versus conbat radius, I hadn't read Friedman either. I was simply applying armour theory to CVs, so imagine my surprise to read that BuShips was considering such arguments in 1942. I did allude to the USN debate over AFDs but I'm not going to reproduce the whole discussion. The USN had no option but to proceed with the Essex class as unAFD CVs because their design and construction was too far advanced to fully incorporate RN war experience. whether the USN would have built the Essex class as AFD carriers, had that been an option is unclear. However, the USN in their assessment of Illustrious attributed her lower AVgas capacity and small air complement to the AFD design, although they did note that:
"...The direct comparison is obscured by the fact that the Illustrious is of smaller displacement than the CV-9 class and that the British practice of carrier operation differs materially from ours in the number of planes operated..."US Aircraft Carriers p216

I wonder what they would have thought of Illustrious, if she was built to Indomitable or Implacable specs and was operating with late war RN carrier doctrine? Many of Illustrious characteristics, such as Avgas capacity and magazine capacity were driven by the design doctrine calling for a smaller airgroup. That is, the avgas capacity, for example, was a function of doctrine and not an inherent limitation of the AFD design. If the RN had changed operational doctrine the AFD carriers would have had avgas capacity, for example, that reflected greater aircraft complements during the initial design phase.