An interesting read

Were Armored Flight Decks on British Carriers Worthwhile?

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"Yet it is eyes which blind the man,"....
"Because a man can see, he does not look."

Master Po

Not a naval expert but that report did not make sense nor convince me. I would think it easier to repair an armored deck with dents in it than one that is not armoured with complete holes. also, I would think that you would want to prevent a bomb from going into the ship.

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American by birth, TEXAN by the grace of GOD!

It speaks of the design that no armored flight deck carriers have been built since WWII.

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Best Regards,
Not Slipdigit

Am I having Deja Vu? I seem to remember this being posted already? LOL

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For the first time I have seen "History" at close quarters,and I know that its actual process is very different from what is presented to Posterity. - WWI General Max Hoffman

What I got from it was that in order for it to "repulse" bombs (ever improving/enlarging) it would be to "top heavy" to sail, and when one did go through, the blast was contained and inflicted structural damage. Much worse than a holed flight deck. Having your deck blow off and still floating, is preferable to losing structural integrity.
It was 3" thick (front of a Sherman), but would have to be (?) 8-10 to get bombs to bounce off (so to speak).
It has it pro's & con's. Not unlike someone else telling you what kind of vehicle to drive, or how his is better, yada yada
Along with the smaller air group, which in fact was the best way to prevent damage from arriving, rather than to let it come and absorb it.
What works somewhere, does not work everywhere.

It's called Vuja De...= this kinda $@#% has never happened before!

__________________
"Yet it is eyes which blind the man,"....
"Because a man can see, he does not look."

Master Po

Just a note: Modern US carriers do have an armored flight deck. I can't tell you the thickness because someone would come and arrest me no doubt.

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Truth is stranger than bullshit!

I heard that.

What you see here stays here. A typical orientation.

I'm not looking froward to a second Honeymoon in the "Red-Line" brig !

__________________
"Yet it is eyes which blind the man,"....
"Because a man can see, he does not look."

Master Po

I doubt they woud be made of wood.......if anything it would have to be armoured just to hold up the weight of the asphalt or is it concrete?

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American by birth, TEXAN by the grace of GOD!

Asphalt or concrete ? Not on a naval ship.

Carriers are made of steel, and the flight deck is too, with a covering to reduce slipping in wet weather for the deck crew. WW2 British carriers had a wooden deck surface, which is easier to repair than metal. Remember that metal was in short supply then , while wooden timbers were more available.

Jim B. Toronto.

Oh, that's alright, we'll manage.

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There is an ass in my avatar.

Thanks Jim. I wasn't sure what the surface was made of but was sure that is was not just plain exposed steel. Cheers

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American by birth, TEXAN by the grace of GOD!

The British may have had a shortage of metal, yet they had armored flight decks, where as the IJN and USN used wooden flight decks...perhaps the Akagi, Kaga Hiryu, Soryu might have benefitted at midway but with the number of planes and payloads left on the flightdeck from changing to torpedo's from bombs might not have mattered

During 1945, she saw service against Japanese forces with the British Pacific Fleet, and survived several kamikaze attacks while supporting the landings on Okinawa. On May 4th, Just after 11.30 a.m. a Japanese plane made a steep dive from "a great height" at Formidable and was engaged by AA guns. The kamikaze was hit at close range, but crashed into the flight deck, making a massive dent about 10 feet (3 m) long, two feet (0.6 m) wide and two feet deep in the armoured flight deck. A large steel splinter speared down through the hangar deck and the centre boiler-room, where it ruptured a steam line, and came to rest in a fuel tank, starting a major fire in the aircraft park. Eight crew members were killed and forty-seven were wounded. However, the steel flight deck of Formidable, (and many other British carriers) prevented further damage by Kamikaze attacks. (American carriers had wood-surfaced flight decks, while British carriers had steel ones)HMS Formidable (67) - Wikipedia, the free encyclopedia

bf109 Emil

The only reason the armored flight deck proved useful against Kamikazes was that these had little penetrating power. Where an enemy made more conventional attacks using heavy bombs the British armoring system proved very vulnerable and actually amplified damage greatly.
After the crippling of the Illustrious in the Mediterrainian the RN issued recommendations that carriers with armored flight decks under bombing attack lower one of their elevators to allow bomb blasts to vent from the hanger bay should the (and likely to be) flight deck be penetrated.
The other problem with the armored flight deck on a carrier the size of British ones was that it limited the size of the air wing. Weight restrictions were severe with that much mass so high in the ship. Metacentric heights were harder to obtain where there was little risk of capsizing in the event of uneven damage to the ship.
The US solution appeared to be much better. The flight deck was made from thin plate or armor plate about 1/2" to 3/4" thick. This was enough to generally set off most bomb's fuzes. The actual surface was then planked over with wood as were many weather decks on ships of the period.
The hanger bay was an open superstructure that allowed plenty of ventilation particularly of gasoline fumes, a big danger on the ship. The hanger deck, or the deck below that, was typically about 3 or 4" thick and constituted the main armored deck of the ship. This was deemed sufficent to stop most bombs from penetrating to the main spaces and magazines particularly when combined with the burster deck of the flight deck.
For the British armored carriers a flight deck penetration could mean the death of the ship. An explosion in the confined hanger bay (the sides are armored too) would cause massive damage there. A longer fuzed bomb once through the flight deck faced no further serious armor to stop it from reaching magazines or machinery spaces.
As I pointed out earlier, Kamikazes represent a special case. They had no ability to penetrate armor as such. Instead, they typically squashed themselves like bugs on a windshield when they struck armored portions of ships. Their danger came from the massive fuel fires they created. Armor generally protected the ship from this danger too.
As such, they represent a poor argument for armored flight decks on carriers.

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Truth is stranger than bullshit!

Good point, and absolutely true, as little could be done against armor piercing bombs, but against kamikazi's where speed of the bomb/plane reached maybe 400 mph, and the impact spread throughout the entire aircraft, rather then a focal point of the nose of a bomb/shell led to saving the carrier as opposed to penetrating it, and causing fires in below decks...by late in the Pacific, the chances of a high level bomber dropping an ordinance and hitting a carrier from high altitude was slim....yet any fire that did start below deck was multiplied by armored decking containing heat and fumes adding to the problem...my previous response was mainly directed to lead or point to Canadiancitizen as to maybe not having heard about the decks of British carriers being armored

bf109 Emil

These two posts are essentially correct in detail but miss an important point as to why armored flight decks were particularly disadvantageous on carriers. The British armored flight deck carriers had to be kept within certain displacement ranges because of considerations of repair facilities and ports which could not handle very large ships. There is some evidence, too, that the British were careful to keep their carriers smaller than they could have built them because of manning shortages. In any case, because they wanted armored flight decks which carried considerable weight penalties very high up in the ship's structure, the designers decided to make the armored flight deck the "strength" deck of th ship. this avoided adding more weight by making the hangar deck the strength deck, as it was in US carriers. Thus the flight deck, keel, and frames of the British carriers formed a sort of box girder which held the ship together and counteracted the various stresses which were naturally encountered in any sea-going vessel.

Where the problem comes in is, if there is a serious fire anywhere below the flight deck, it will apply massive amounts of heat to one side of the girder. If enough heat is applied for a sufficient period of time, that side of the girder will deform or warp, any structures (frames) attached to the warped girder will be pulled out of symmetrical alignment, causing the keel and indeed, the entire hull to "wrack" or be twisted out of shape. It would be as if a giant had grabbed the hull and twisted each end in opposite directions; the result is the same as in a car frame that has been involved in a serious accident, everything is out of alignment, nothing works properly, and extreme wear on tires, wheels, drive shaft, etc., is the consequence. With a car, it's usually possible to strip it down to the frame and use a frame alignment device to twist it back into the proper shape. Unfortunately, with a carrier, there is no machine big enough, or powerful enough, to twist the hull back into the proper shape.

Formidable, Indomitable, and Illustrious all suffered hangar deck fires that wracked their hulls so badly that in one case the center propeller shaft froze up and would not turn. The armored flight decks were no guarantee against hangar fires due to penetration by AP bombs, splinters, or even burning gasoline dripping from crashed kamikazes which had not penetrated the flight deck. Hangar fires that Essex class carriers would have shrugged off because of their hangar decks being the strength deck, actually warped the ships girder on the British armored carriers so badly that they were essentially constructive total losses.

The Midway-class, the lead ship of which was commissioned in 1945, did have an armored flight deck, but because the US could afford to build this class without regard to displacement restrictions the weight of the flight deck did not require that it be the strength deck. The hangar deck in the Midway class was the strength deck and the hangar sides were open so that, in the event of a fire or explosion, the heat and force would be vented rather than deforming the ship's girder. If you look at pictures of the Midway, however, you will note that the flight deck appears closer to the water than in the Essex class; it was actually the same height as in the Essex class but the greater length creates that appearance. However, the designers did not add the additional deck which could have been possible without the weight of the Armored flight deck. For this reason the Midways were considered to be rather "wet" in a seaway.

The Japanese also built an armored flight deck carrier, the Taiho, during WW II. At the Battle of the Philippine Sea, the Taiho took a single submarine torpedo which fractured fuel lines and caused leaks in the fuel storage tanks. The Taiho had been fueled with unrefined Tarrakan crude oil which emitted volatile vapors. These vapors were inadvertently spread throughout the ship by inexperienced damage control crews. Eventually, they encountered a spark and exploded. The force of this explosion could not be vented through open hangar sides and instead, blew out the sides and bottom of the hull, sinking the ship in minutes.

Actually, the displacement of British armored carriers was determined by Washington naval treaty limits at the time of their design. 23,000 tons was the maximum allowed treaty weight for a carrier.
As for the armored flight deck, this appears to have been the brain child of just one person in the right place to force it through: Controller of the Royal Navy and Third Sea Lord, Sir Reginald Henderson. He was absolutely against the Admiralty's recommendation that repeat Ark Royals be built under the 1934 construction program.
The Director of Naval Construction was directed to design a 23,000 ton carrier with an armored flight deck proof against 500 lb bombs. This was based on an RAF analysis that this would be the heaviest bomb in use for at least the next ten years! Side armor was to equal that of current cruisers.
WAD Forbes, the leading expert on carrier construction was put in charge of the design and then taken out of the normal channels of the construction process and reported to the Sea Lord directly.
The three screw design was the only way the designers could find to put sufficent power into the ship and fit the machinery within the hull size. The design aircraft complement was to be 36 aircraft, half of what Ark Royal was designed to carry.
Another problem found in service was that the armored flight deck lowered the flight deck height sufficently that in moderately rough seas water was being taken over the deck, particularly at higher speeds.
A measure of how poorly the armored carrier turned out for the British can be seen in the fourth and last Illustrious class vessel, Indomitable having reduced armor and a half second hanger deck inserted into the design. The follow-on Implacable and Indefatigable likewise traded armor for a larger hanger and bigger air wing.
The Boyd committee headed by Admiral Sir Denis Boyd towards the end of the war reviewed the armored carrier design. This committee was clearly disappointed by it and felt that a thinly armored flight deck with more armor deeper in the ship would have been a better combination. They also were not kind about the small size of the air wing and felt that much of the damage that British carriers did take could have been avoided with larger aircraft complements.
Basically, within the size and design features of WW 2 aircraft carriers the heavily armored flight deck carrier was a mistake. Air wing size was far more critical as both the Japanese and US correctly deduced.

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Truth is stranger than bullshit!

You are,of course, correct. My intention was to mention the WNT limitations on carrier displacement and the additional reasons unique to the RN, but I got side-tracked and forgot to include the information. According to my information the Ark Royal itself was built under the 1934 build program and entered service in 1938. The Illustrious was built under the 1936 program, the Victorious and Formidable were both under the 1937 program, By this time the WNT was only being observed by the US and UK. BTW, the Ark Royal also had a double deck hangar. Larger hangars than was the practice in the USN were required not only because of hangar heights being lower due to the armor, but because the RN did not use deck parks.

This was another reason why large air groups made little sense on British carriers; RN doctrine limited the number of planes that could be launched and recovered in a reasonable period of time. For instance, at Taranto, a single British carrier was able to launch a 21-plane strike force, but only in two waves, the second one being about an hour behind the first. USN carriers could launch about twice that number in a single wave.

According to Norman Friedman in his design history volume on US Aircraft Carriers, the USN also had it's armored flight deck advocates though they were in the minority unti the Midways were designed. The philosophy in the USN was that large fighter squadrons and efficient fighter direction doctrine was the best protection and that carriers should be maximized for offensive operations. The RN's FAA, being saddled with the RAF's choice of obsolete fighters for their small carrier fighter squadrons, could not hope to loft enough fighters to provide an adequate air defense strategy.

I agree, however, that armored flight decks, at least in the first part of WW II, were a failure and made little sense even in the context of the kamikaze warfare in the final stages of the Pacific War. The RN ended up, in contrast to the USN's experience with the Essex class, getting poor service out of it's armored flight deck carriers.