The Case For (Or Against) Armoured Flight Decks in WW2

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The Case For (Or Against) Armoured Flight Decks in WW2

Post by aurora » Sun Dec 07, 2014 12:47 pm

The Royal Navy of the 1930s resolved to build a carrier not merely capable of surviving sustained air attacks, but of continuing air operations after taking a measure of battle damage.Such a carrier needed to be able to protect its aircraft, to provide fleet reconnaissance and trade protection, as well as offer air patrol and combat strike functions.

The challenge was to provide this within restrictions defined by Washington Treaty limits.This was achieved by an ingenious – and for some considerable time Top Secret - design which incorporated an “armoured box” hangar into a strength deck that was also the flight deck.It was an innovation which provided considerable weight savings for such a heavily armoured structure. But it came with a cost.To maintain stability, the second hangar had to be discarded. As a result, the Illustrious Class would have to be limited to 33 internal stowage spaces for aircraft.

FLIGHT DECK
That the Illustrious Class had an “armoured flight-deck” is something of a misstatement.What made the class so unique was an armoured box incorporating the centre of the flight deck between the lifts which enclosed the aircraft and machinery spaces within a protective “cocoon”. The lifts themselves were not armoured and nor was the flight deck fore and aft. In effect, the 3in armour covered 62 per cent of the flight deck and weighed 1500 tons. Much of the remainder was 1.5in toughened structural steel.

The United States Navy built its flight decks as though they were part of the vessels superstructure. British carriers, including Ark Royal, incorporated them as their primary strength deck. As a result the flight decks were an integral part of the ship’s hull. This is why the flight deck around the fore and aft lifts was rated as 1.5in armour – for strength reasons, not as protection.While of roughly similar weight to their United States Washington Treaty contemporary (the USS Yorktown Class) and HMS Ark Royal , the Illustrious Class were smaller ships. This was compounded during the early war years by the provision of extensive “round downs” on the bow and stern to improve air flow over the deck.

All three ships underwent flight deck rebuilds to improve the operational flight deck space during the war years. Eventually, the usable length of HMS Illustrious herself was boosted to 740ft. Initially, only 620ft had been available.Where Ark Royal had a freeboard to the flight deck of some 60ft, the deletion of the second hangar deck from the Illustrious class in order to preserve stability reduced this height above the water to 38ft.The flight deck and aircraft facilities of the class were initially designed to operate 11,000lbs aircraft with an maximum take-off weight of 14,000lbs. This was steadily upgraded throughout the war.

HANGAR

The Royal Navy regarded the hangar as a place of refuge for aircraft, not just as a place for maintenance, rearming and repair.But it was even more than this.
Instead of a simple garage, the Royal Navy was extremely aware the hangar held large amounts of flammable and explosive fuels, oils and ordinance. As such it regarded the vast 458ft x 62ft vault to be in the same category as an ammunition magazine: A space to be well protected and contained.This attitude reached its height with the “closed box” concept of fully armoured hangar.

The intention was for the carrier and its aircraft operating facilities to be immune from 6in cruiser gunfire and standard airborne armour-piercing bombs.To achieve this, the “armoured box” walls were given 4.5in C grade armour plate and the hangar deck was 3in C grade plate.

The ends of the hangar were likewise protected with 4.5in armoured bulkheads. The vulnerable space between the unarmoured lifts and the hangar could be closed off by 4.5in C grade armoured shutters when in action. The hangar itself could be divided into thirds (one squadron each section) by two heavy steel fire shutters inside the hangar itself, and another shutter at the entrance to each of the lift wells.

A 3in NC grade armoured deck was expected to resist a 500lb semi-armour piercing bomb dropped from below 7000ft and 250lb SAP bombs from below 11,500ft. It was calculated the deck could resist a 1000lb armour-piercing bomb only if it was dropped beneath 4500ft.The 4.5in C grade armoured hangar sides were designed to stop 4.7in shellfire from all ranges and block 6in fire between 7000 and 19,000 yards.

The armoured hangar was intended from the outset to contain the blast of any bomb or shell that penetrated to prevent further damage to the vital machinery and magazines beneath. It was for this reason access was only through double-blast-door lobbies. Workshops were accessible only via the hangar, and nowhere was the hangar wall the side of the ship.
Source (edited) as shown by link
http://www.armouredcarriers.com/design/
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Re: The Case For (Or Against) Armoured Flight Decks in WW2

Post by aurora » Sun Dec 07, 2014 2:47 pm

AIR GROUP

Britain operated squadrons of an optimal twelve aircraft, divided into four “sections” of three aircraft. Each “section” had a designated colour and each section aircraft a number.Illustrious was designed with stowage allocated for 33 aircraft. Many reports state this was 36, but a look at the original lash-down arrangements shows provision for 12 aircraft in hangars A and C (named divisions based on the fire curtain compartments), and only 9 in Hangar B.Ark Royal’s intended total stowage capacity was 72 aircraft (though fewer could be operated). The Illustrious’ US contemporary, USS Enterprise, was carrying more than 70.

At first glance, these figures are misleading.The British capacity designations are only for numbers of operational aircraft capable of being stowed in hangars under peacetime conditions. The United States counted deck-parks and disassembled spares as part of their standard complement from the outset.

For example: USS Yorktown was carrying 53 operational (non-spare) aircraft at Coral Sea. At the same time as Coral Sea HMS Victorious was deploying with 40. Later, Yorktown operated 66 aircraft - though her official complement was 88 (including disassembled spares). Victorious at this time was operating 53 machines.By 1941 US-style deck-parks were becoming a feature of the British carriers – as much because of the hurried adoption of non-folding Martlets, Hurricanes and Spitfires to the naval role as for any need to boost aircraft numbers.

A range parked at the forward end of the flight deck of HMS ILLUSTRIOUS in the Indian Ocean. In the immediate foreground are Grumman Hellcats and Grumman Wildcats and further forward are Fairey Fulmars and Fairey Swordfish.
A range parked at the forward end of the flight deck of HMS ILLUSTRIOUS in the Indian Ocean. In the immediate foreground are Grumman Hellcats and Grumman Wildcats and further forward are Fairey Fulmars and Fairey Swordfish.

In the late 1930s, tactical thinking had been that the armoured carriers should carry two strike squadrons of TSR (Torpedo Strike Reconnaissance) aircraft and a mixed squadron of six fighters and six fighter bombers.Experience off Norway and in the Mediterranean quickly emphasised the practical role of fighters in fleet defence. The number carried began to creep up steadily until, in 1945, they formed on average more than two thirds of a carrier’s air wing.

But the problems related to the class’ small aircraft capacity became obvious even before the first ship was completed. This was addressed with the modification of the fourth Illustrious Class vessel, Indomitable, while she was still in the builder’s yard.
The final two armoured carriers – laid down before the war but much delayed by political and supply issues during the early war years – were to emerge somewhat redesigned.

Nevertheless, the Illustrious, Formidable and Victorious quickly had their aircraft load increased by relaxing stowage spacing standards and adopting outrigger parks - essentially pylons upon which the tail wheel of a fighter could be suspended out over the side of the ship to keep the bulk of the aircraft off the busy deck.With the adoption of deck parks came the need to constantly shift aircraft forward and aft to allow landing and takeoff operations. While this required larger deck handling parties, it allowed the ship's air groups to be boosted to a much more useful 55-57 Corsairs and Avengers in 1945.
Source (edited)as before -see link

http://www.armouredcarriers.com/design/
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Re: The Case For (Or Against) Armoured Flight Decks in WW2

Post by Steve Crandell » Sun Dec 07, 2014 10:28 pm

This has been debated endlessly. Friedman's volume on USN Carriers describes the USN's decision making process and why they didn't go with armored flight decks until they built much larger CVs post war. I think today it's more a question of being able to support the weight and heat generated by modern jet aircraft than it is of protection from damage.

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Re: The Case For (Or Against) Armoured Flight Decks in WW2

Post by dunmunro » Mon Dec 08, 2014 12:11 am

Steve Crandell wrote:This has been debated endlessly. Friedman's volume on USN Carriers describes the USN's decision making process and why they didn't go with armored flight decks until they built much larger CVs post war. I think today it's more a question of being able to support the weight and heat generated by modern jet aircraft than it is of protection from damage.
There has been a lot of heat and smoke generated on this topic:

Here's what the US Defence Dept has to say on this issue:
The modern carrier is the only surface ship now in the U.S. Navy designed
and built to be survivable. The ship design encompasses many features (such
as armored flight deck, double hull, magazine location, and shock-absorbing
structures) intended to allow the ship to sustain multiple hits by missiles or
torpedoes, yet survive.
Automation is improving damage control effectiveness
and response speed. The features now incorporated in carriers are effective
against current threats but continuous improvement is necessary to keep up
with advances in adversary weaponry.
Defense Science Board
Task Force on
FUTURE OF THE
AIRCRAFT CARRIER

October 2002
Office of the Undersecretary of Defense
For Acquisition, Technology, and Logistics
Washington, D.C. 20301-3140

Let's cut out the b*llsh*t that somehow the USN adopted armoured flight decks for any reason other than protection. Why people can't just admit that the USN made a mistake in not adopting armoured flight decks on the Essex class is beyond me.
Some features of the Nimitz class:

...Given the lessons of the Korean War, and the shortfalls of the current
carrier fleet composition, the Navy once again pushed for development of
a new carrier, essentially a scaled-down version of the canceled United
States. This time the Navy was successful. Named in honor of the first US
Secretary of Defense and World War I naval aviator, James Vincent
Forrestal, the USS Forrestal (CV 59) displaced 59,000 tons (53,523 tonnes)
and measured 1,039ft 9in (316.9m) in length and 129ft 6in (39.5m) in
beam. The flight deck incorporated several British innovations, including
the armored, angled flight deck and steam catapults
, and also introduced
the Fresnel Lens landing system. Forrestal represented a multi-generational
leap forward in carrier design. Indeed, as carrier historian Norman
Friedman stated in his work, US Aircraft Carriers: An Illustrated Design
History, the Forrestal was so successful that it formed the basis for all
subsequent US Navy carrier designs...

The Hangar Bay
The hangar bay is located just below the flight deck and runs approximately
two-thirds of the length of the carrier. Overall, the hangar measures 684ft
(208.5m) long and 108ft (33m) wide, and stands 25ft (7.6m) high – almost
three stories. The bay is divided into three equal-sized areas and separated
by a series of massive, armored, power-sliding doors that, together with an
elaborate fire-suppression system, serve to limit damage caused by fire or
explosions.
The hangar bay, while huge, can only store about 50 of the air
wing’s aircraft; thus, some aircraft are always parked on the flight deck. The
hangars are used for maintenance and repair work and for storage of parts,
spare engines, and aerial drop tanks (kept in overhead storage racks). The
Aircraft Intermediate Maintenance Division (AIMD) is located just aft of
the hangar bay.
NIMITZ-CLASS AIRCRAFT CARRIERS, Edward.
The USN continues planning to incorporate armoured flight decks and armored hanger protection to allow their carriers to operate in a high threat environment, just as the RN's AFD design team planned for a similar enviroment in the 1930s.
Summary
The new technologies on the CVN 21 carriers will improve their
operational capabilities, increase their survivability, and result in
smaller crew sizes and lower maintenance costs compared to Nimitzclass
carriers. Sortie generation rates will increase by more than 15
percent. New systems will allow the launch and recovery of both
heavier aircraft and unmanned vehicles and will require less manpower
and maintenance. They will also place less stress on airframes,
increasing the life of aircraft and reducing aircraft maintenance costs.
New structural improvements and advanced forms of armor will pro-
tect the ship from both torpedoes and missiles. The new propulsion
and new electrical distribution systems will enhance battle-damage
control and require less maintenance, thus providing more time for
operational missions. Eventually, they could allow the ship to defy
new threats through upgraded defense systems and energy-absorbing
dynamic armor.
Combined weight and space reductions will increase
munitions, aircraft fuels, and stores capacity while improving the
habitability of the ship. The CVN 21–class ships will require 500 to
800 fewer sailors than a Nimitz-class ship and the quality of life for
those sailors will be improved. Overall, the CVN 21 class is projected
to have an 11 to 20 percent reduction in carrier LCC.
Modernizing the U.S. Aircraft Carrier Fleet. Accelerating CVN 21
Production Versus Mid-Life Refueling.
Rand Corporation 2005 prepared for the USN.

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Re: The Case For (Or Against) Armoured Flight Decks in WW2

Post by Steve Crandell » Mon Dec 08, 2014 2:24 am

Dunmunro, I am convinced that absolutely anything the USN did in WWII, you would think was a bad idea unless the RN had already done it. It is always a fruitless exercise to attempt to convince you otherwise.

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Re: The Case For (Or Against) Armoured Flight Decks in WW2

Post by alecsandros » Mon Dec 08, 2014 6:10 am

... My impression is that armoured deck was one of the many defensive features the British carriers had , while the American carriers didn't.

The reverse was that the USN carriers had much more planes on board, and longer range, on a considerably smaller displacement (see Yorktown vs Illustrious).

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Re: The Case For (Or Against) Armoured Flight Decks in WW2

Post by aurora » Mon Dec 08, 2014 9:15 am

My sincere thanks gentlemen for your interest and input-I am aware that there was much discussion immediate post WW2-the period covering this thread is WW2-about the relative values of RN and USN type of carrier.One factor sticks in my mind-a USN carrier would not have survived the hammering that both Illustrious and Formidable took in the Mediterranean Theatre in 1941/42; and it was here that the RN's decision to build almost indestructable bomb proof carriers with armoured flight decks was proven.The downside ,of course was the significant reduction in the number of aircraft carried.The American Essex Class was constructed conventionally; and they were built in large numbers-almost like shelling peas 29 in all- because America could do so,and they had much larger Air Groups.In the meantime cash strapped GB was constructing only two new carriers-

The Implacable-class aircraft carrier was a class of two aircraft carriers built for the Royal Navy during World War II. Derived from the design of the Illustrious class, they were faster and carried more aircraft than the older ships. They were initially assigned to the Home Fleet when completed in 1944 and attacked targets in Norway as well as the German battleship Tirpitz. Subsequently they were assigned to the British Pacific Fleet (BPF)-and I am disinclined to discuss the controversial BPF
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Re: The Case For (Or Against) Armoured Flight Decks in WW2

Post by alecsandros » Mon Dec 08, 2014 10:14 am

aurora wrote:My sincere thanks gentlemen for your interest and input-I am aware that there was much discussion immediate post WW2-the period covering this thread is WW2-about the relative values of RN and USN type of carrier.One factor sticks in my mind-a USN carrier would not have survived the hammering that both Illustrious and Formidable took in the Mediterranean Theatre in 1941/42; and it was here that the RN's decision to build almost indestructable bomb proof carriers with armoured flight decks was proven.The downside ,of course was the significant reduction in the number of aircraft carried.The American Essex Class was constructed conventionally; and they were built in large numbers-almost like shelling peas 29 in all- because America could do so,and they had much larger Air Groups.In the meantime cash strapped GB was constructing only two new carriers-

The Implacable-class aircraft carrier was a class of two aircraft carriers built for the Royal Navy during World War II. Derived from the design of the Illustrious class, they were faster and carried more aircraft than the older ships. They were initially assigned to the Home Fleet when completed in 1944 and attacked targets in Norway as well as the German battleship Tirpitz. Subsequently they were assigned to the British Pacific Fleet (BPF)-and I am disinclined to discuss the controversial BPF
... One interesting idea would be to hypotheticaly replace the British carriers that formed the escort for Pedestal with contemporary USN carriers.
VIctorious, Eagle, Iloustrious, with 77 fighters on board (historically) , replaced by , say, Enterprise, Hornet, Saratoga, with maybe 90-100 fighters on board.

My opinion is that things would not be much different - as the weight of the Axis air + sea attacks was simply to much to be seriously disrupted by an extra ~20 fighters.

The USN carriers would have poorer protection and would possibly suffer more serious damage then the British ones (historically - Eagle sunk, Illustrious badly damaged and out of action, Victorious lightly damaged, but with a devastated air group - only 19 of the original 77 fighters being operational on Victorious - the last operational carrier - at the time the heavy escort withdrew)

=====

The USN carriers woudl have the edge , IMHO, in terms of strike capability over an enemy battle fleet and/or enemy shore installations , beacuse their normal complement of 30+ fighters, 36+ dive bombers and 15-20 torpedo bombers.

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Re: The Case For (Or Against) Armoured Flight Decks in WW2

Post by dunmunro » Mon Dec 08, 2014 10:26 am

aurora wrote:My sincere thanks gentlemen for your interest and input-I am aware that there was much discussion immediate post WW2-the period covering this thread is WW2-about the relative values of RN and USN type of carrier.One factor sticks in my mind-a USN carrier would not have survived the hammering that both Illustrious and Formidable took in the Mediterranean Theatre in 1941/42; and it was here that the RN's decision to build almost indestructable bomb proof carriers with armoured flight decks was proven.The downside ,of course was the significant reduction in the number of aircraft carried.The American Essex Class was constructed conventionally; and they were built in large numbers-almost like shelling peas 29 in all- because America could do so,and they had much larger Air Groups.In the meantime cash strapped GB was constructing only two new carriers-

The Implacable-class aircraft carrier was a class of two aircraft carriers built for the Royal Navy during World War II. Derived from the design of the Illustrious class, they were faster and carried more aircraft than the older ships. They were initially assigned to the Home Fleet when completed in 1944 and attacked targets in Norway as well as the German battleship Tirpitz. Subsequently they were assigned to the British Pacific Fleet (BPF)-and I am disinclined to discuss the controversial BPF
There's a couple of factors to consider. One is that by adopting deck parks, as per the USN, RN AFD carriers considerably narrowed the gap in aircraft capacity. 2ndly, While Enterprise carried more aircraft than Illustrious, she did not carry more than Implacable, and by the time Implacable appeared Enterprise had had to be blistered to enable her to cope with the additional weight of increased armament and heavier aircraft, and as blistered Enterprise was as heavy as Illustrious at standard displacement and her full load was almost identical to Implacable, yet Enterprise was not nearly as well armed or armoured. The Essex class were much heavier than any RN WW2 carrier, and they also suffered from being overweight and by war's end their standard displacement was nearly 5000 tons more than Implacable. A 27500 ton standard displacement RN AFD would have operated almost the same number of aircraft as an Essex and would have been far more survivable design.

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Re: The Case For (Or Against) Armoured Flight Decks in WW2

Post by aurora » Mon Dec 08, 2014 11:26 am

alecsandros wrote:
aurora wrote:My sincere thanks gentlemen for your interest and input-I am aware that there was much discussion immediate post WW2-the period covering this thread is WW2-about the relative values of RN and USN type of carrier.One factor sticks in my mind-a USN carrier would not have survived the hammering that both Illustrious and Formidable took in the Mediterranean Theatre in 1941/42; and it was here that the RN's decision to build almost indestructable bomb proof carriers with armoured flight decks was proven.The downside ,of course was the significant reduction in the number of aircraft carried.The American Essex Class was constructed conventionally; and they were built in large numbers-almost like shelling peas 29 in all- because America could do so,and they had much larger Air Groups.In the meantime cash strapped GB was constructing only two new carriers-

The Implacable-class aircraft carrier was a class of two aircraft carriers built for the Royal Navy during World War II. Derived from the design of the Illustrious class, they were faster and carried more aircraft than the older ships. They were initially assigned to the Home Fleet when completed in 1944 and attacked targets in Norway as well as the German battleship Tirpitz. Subsequently they were assigned to the British Pacific Fleet (BPF)-and I am disinclined to discuss the controversial BPF
... One interesting idea would be to hypotheticaly replace the British carriers that formed the escort for Pedestal with contemporary USN carriers.
VIctorious, Eagle, Iloustrious, with 77 fighters on board (historically) , replaced by , say, Enterprise, Hornet, Saratoga, with maybe 90-100 fighters on board.

My opinion is that things would not be much different - as the weight of the Axis air + sea attacks was simply to much to be seriously disrupted by an extra ~20 fighters.
The USN carriers would have poorer protection and would possibly suffer more serious damage then the British ones (historically - Eagle sunk, Illustrious badly damaged and out of action, Victorious lightly damaged, but with a devastated air group - only 19 of the original 77 fighters being operational on Victorious - the last operational carrier - at the time the heavy escort withdrew)


The USN carriers woudl have the edge , IMHO, in terms of strike capability over an enemy battle fleet and/or enemy shore installations , beacuse their normal complement of 30+ fighters, 36+ dive bombers and 15-20 torpedo bombers.
I could not agree more dunmunro-firstly the difference in the battlegrounds-goldfish bowl and inland sea-secondly the Mediterranean convoy battles in which the enemy land based airceaft pressed home their attacks with savage diligence and accuracy-would have been a Test to Destruction for the USN carriers.Thirdly-their carrier war in the Pacific was played out over vast areas of ocean-the USN carriers latterly- rarely seen.However it was the Pacific where the RN carriers were found wanting vis a vis the insignificant size of the Air Groups; and some of the aircraft the RN were stuck with-were found wanting eg.the Seafire-- with it's short range and landing on difficulties-more losses in landing than in combat says it all.
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Re: The Case For (Or Against) Armoured Flight Decks in WW2

Post by alecsandros » Mon Dec 08, 2014 3:07 pm

@Duncan,
Enterprise and Essex class carried up to 100 aircraft.
Implacablee carried around 80.

The USN carriers had lomger range in exchange for poorer protection
AA systems were comparable, at least in size.

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Re: The Case For (Or Against) Armoured Flight Decks in WW2

Post by aurora » Mon Dec 08, 2014 3:29 pm

Implacable's war service was very short indeed-making little impact of any significance. She arrived at the BPF's main operating base at Manus Island, in the Admiralty Islands, on 29 May. A week later Rear Admiral Sir Patrick Brind hoisted his flag in preparation for Operation Inmate, an attack on the Japanese naval base at Truk in the Caroline Islands that began on 14 June. Having flown 113 offensive sorties over the two days of the attack, with only one loss of a Seafire to enemy action, the carrier and her escorts returned to Manus Island on 17 June. On 30 June No. 8 Carrier Air Group was formed, absorbing No. 24 Naval Fighter Wing, to control all of the air units aboard Implacable.

After working up, she sailed to join the main body of the BPF off the Japanese coast on 6 July, and rendezvoused with them ten days later. Implacable flew off eight Fireflies and a dozen Seafires against targets north of Tokyo on 17 July, but only the Fireflies were able to locate their targets because of bad weather. Eight near obsolescent Fireflies and twenty Seafires attacked targets near Tokyo the next day, before more bad weather halted flying operations until 24–25 July, when the BPF's aircraft attacked targets near Osaka and the Inland Sea, crippling the escort carrier Kaiyo. After replenishing, airstrikes resumed on 28 and 30 July, the British sinking the escort Okinawa near Maizuru.

A combination of bad weather, refuelling requirements and the atomic bombing of Hiroshima delayed the resumption of air operations until 9 August. During the day, Implacable '​s Seafires flew 94 sorties and her Fireflies flew 14 against targets in northern Honshu and southern Hokkaido for the loss of two Seafires. The attacks were repeated the next day, sinking two warships, numerous small merchantmen and destroying numerous railroad locomotives and parked aircraft.

The BPF had been scheduled to withdraw after 10 August to prepare for Operation Olympic, the invasion of Kyushu scheduled for November, and the bulk of the force, including Implacable, departed for Manus on 12 August. Her aircraft flew over 1,000 sorties since her arrival the previous month.
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Re: The Case For (Or Against) Armoured Flight Decks in WW2

Post by dunmunro » Mon Dec 08, 2014 7:27 pm

alecsandros wrote:@Duncan,
Enterprise and Essex class carried up to 100 aircraft.
Implacablee carried around 80.

The USN carriers had lomger range in exchange for poorer protection
AA systems were comparable, at least in size.
Enterprise class never operated with 100 aircraft. Typical 1942 mix was ~72 plus spares and typical mix after her 1943 refit was ~60 plus spares. AA armament as designed was 8 x 5"/38 (open mounts), 16 x 1.1" and 24 x .5". Illustrious/Implacable design armament was 16 x 4.5in (twin turrets), 48 x 40mm pom-pom and 32 x .5". At the end of the war both carriers had much increased automatic armament, but to do so Enterprise had to be widened via a blister (bulge) which considerably increased her displacement. Enterprise as designed had a very weak AA armament.

Range was never an issue with RN carriers but the first 3 did have insufficient avgas capacity when their airgroups were enlarged via a deck park.

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Re: The Case For (Or Against) Armoured Flight Decks in WW2

Post by aurora » Mon Dec 08, 2014 8:05 pm

dunmunro wrote:
alecsandros wrote:@Duncan,
Enterprise and Essex class carried up to 100 aircraft.
Implacable carried around 80.

The USN carriers had longer range in exchange for poorer protection
AA systems were comparable, at least in size.
Enterprise class never operated with 100 aircraft. Typical 1942 mix was ~72 plus spares and typical mix after her 1943 refit was ~60 plus spares. AA armament as designed was 8 x 5"/38 (open mounts), 16 x 1.1" and 24 x .5". Illustrious/Implacable design armament was 16 x 4.5in (twin turrets), 48 x 40mm pom-pom and 32 x .5". At the end of the war both carriers had much increased automatic armament, but to do so Enterprise had to be widened via a blister (bulge) which considerably increased her displacement. Enterprise as designed had a very weak AA armament.

Range was never an issue with RN carriers but the first 3 did have insufficient avgas capacity when their airgroups were enlarged via a deck park.
Illustrious,Formidable and "Victorious"(Robin) or was it Indomitable; did have insufficient avgas capacity; but it was more secure-this must be a throwback to the Mediterranean-where flight ranges were not great; but certainly a killer in the Pacific.but their AA defence was formidable,ie 96 guns all calibres.The only issue which could affect their range was the "rinkydink" Fleet Train-almost totally unfit for purpose :kaput:

Two RN carriers-Illustrious and Formidable were badly damaged in the Med by dive bombers,but managed to remain intact under Kamikaze attack in the Pacific; whereas two Essex Class Franklin and Bunker Hill were severely damaged by Kamikaze attack
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Re: The Case For (Or Against) Armoured Flight Decks in WW2

Post by Steve Crandell » Mon Dec 08, 2014 10:13 pm

Which Essex class CVs were sunk by bombs?

Which British CVs were sunk by torpedoes?

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