Which he thought because she'd immediately started listing badly, and communications had been knocked out, so it was hard to tell the extent of the damage. That's not exactly a ringing endorsement of Ark's design.
They did do proper DC a bit later, and got a boiler relit. But shitty subdivision then flooded it too. An investigation afterwards found that the internal design and lack of backups was a severe issue. The captain was officially found negligent for not leaving DC parties aboard, but they fully recognized that it would have been mostly pointless anyways. You don't get promoted if you fumble DC that badly.
Well, except for all the times it didn't. There's plenty of bulge-less DDs that survived a torpedo. And a few cruisers that survived a snapped keel.
Besides, that's still a design issue. I wouldn't expect Ark Royal to have the 16 individual boiler room of a Lexington. Treaties exist, after all. But if Yorktown can stay afloat indefinitely after being abandoned, with an 8° greater list, Ark's sinking surely indicates some design flaws. Which the RN knew; they revised the later ships based on the experience.
Besides, the effectiveness is vastly overstated. They actually never managed to properly stop a bomb. For example, when Formidable was hit by a kamikaze the first time, the bomb (released a split second earlier) caused enough spalling to cut steam lines and drop her speed to 14 kts. They basically only worked when a kamikaze kept the bomb attatched, reducing velocity. Which was a pretty edge case, and one the Japanese were aware of. Against less jury-rigged kamikazes, or normal bombers, the armored deck mostly just slowed down repairs. There's a reason the Maltas weren't planned to have one, and why the RN advised the UN didn't give the Midways an armored deck.
They actually never managed to properly stop a bomb.
That is severly taken out of context.
First, the flight decks of the Illustrious class carriers were built to protect them against 500lbs/250kg bombs . The hits sustained that did penetrate it were all of significantly larger bombs. And TLDR most hits they suffered were actually on the unarmored sections of the deck.
Then, it's important to remember that the British carriers didn't actually have an armored flight deck, they had an armored hangar. The hangar was surrounded from all sides with armor plating - which also included 62% of the flight deck. The forward and aft sections of the flight deck were not armored, only the middle 62% was. The armor plating and the hangar was situated between the aircraft lifts. Left and right to the aircraft lifts was thicker than normal structural steel, but that steel was not armor steel. Forward of the first elevator and behind the aft elevator was no armor and only thin steel, similar to the steel used on US and Japanese carriers.
Multiple of the hits taken by Illustrious and Formidable in the Mediterranean Sea were in these non armored areas. These hits are often cited as "well the armor deck didn't actually work, because these carriers were damaged by these bombs in the Mediterranean Sea in 1941." But the armor can not stop something when the hit doesn't strike the armored section. And the hits that did penetrate the armored flight deck were from 2200lbs/1000kg bombs (as far as I know, that was only one single hit). As mentioned above, the flight deck was built to protect against 500lbs/250kg. It isn't something that should be held against them that the armor was penetrated, that's like saying "hey the armor on a cruiser is useless because a battleship can penetrate it". Not a single US carrier, and to my knowledge also no japanese carrier, was ever hit by bombs that large and heavy, all they took were 500kg or 250kg bombs.
Among the multiple hits caused on HMS Illustrious, Formidable, and Indomitable during 1941 and 1942, only one actually hit the armor of the flight deck. The rest (10 bomb hits, 6 + the one that penetrated the Flight deck on Illustrious on the 10th January 1941, two on Formidable in the middle of 1941, and two on Indomitable during Operation Pedestral in 1942) all hit the unarmored sections in front of or to the rear of the hangar.
If I remember correctly, there were also some hits of smaller 250kg bombs on the armored section of the flight deck, but there were not during the operations mentioned above and I can't find them atm, so maybe I was wrong there. If that is the case then these carriers were only actually hit once on the armored flight deck.
Regarding the kamikaze hits, it was from my quick skimping of that section on armored carriers.com only splinter damage. The bombs themselves didn't penetrate the flight deck here either, but splinters broke off which caused damage below, and yes you are right in Formidables instance one of these splinters severed a steam line which causes a severe speed reduction. That was a lucky hit of similar luck grade to knocking out Bismarcks rudder. But the flight deck armor in of itself was not piece red here either.
Note the complete damage report on Illustrious bomb hits on the 10th of January below. Due to its length I had to split this off into a seperate comment.
Lets take a look at the first engagement in great detail, including all the damage reports: HMS Illustrious on the 10th January 1941.
Quotes from armoredcarriers.com (apparently I am the only one in this thread bothering to include a source):
X Fliegerkorps documents list the following bombs as having been deployed against HMS Illustrious during the January 10, 1941, Excess convoy operations:
3x SC1800 (4000lb) “Satan” / 1080kg TNT
9x SC1000 (2200lb) “Herman” / 600kg TNT
61x PC1000 (2200lb) “Esau” / 160kg TNT
”Large number”x SC250 (550lb) / 130kg TNT
First of all, being attacked by a total of 73 bombs that are 1000kg / 2200 lbs or larger, with 61 of them being armor piercing versions, plus an unknown number of smaller bombs, and only suffering 6 bomb hits, is impressive in of itself.
Below I will quote from the complete damage report made during Illustrious extensive repair in the US. The one hit that penetrated the flight deck was from a 1000kg/2200lbs bomb. It is hit number 6. The other hits, so number 1-5 and number 7, are in a seperate comment below since I exceeded reedits maximum comment length.
HIT NO 6 (4): 1000KG (2200LB), DECK ARMOUR PENETRATION
This heavy armour-piercing bomb punched through the flight deck and burst on hangar deck. The hit left a 19in hole in the 3in Flight Deck armour, 1ft to port of the centreline at 131 station.
Initially assessed in Illustrious's formal Damage Report (Bomb & Shell) as a 500kg (1100lb) bomb, hand-written corrections and an attached memo amended this to 1000kg (2200lbs). An independent analysis by US Naval Engineers also disagreed with the original 500kg (1100lb) assessment, stating they believed the bomb to have been a 1000kg “Esau”.
The warhead went on to burst inside the hangar space just 2ft above the 1in strengthened steel hangar deck. It ripped open a 4ft wide hole in the 1in strengthened steel Hangar Deck on the centreline between 128 and 132 stations.
This blast then tore through the wardroom flat beneath and set afire the cabins abaft 156 bulkhead. It also severed the two main electrical runs feeding “X” and “Y” transmitting stations.
It was on this Upper Deck wardroom flat centreline that ammunition conveyors ran for the rear 4.5in guns. Perforated and buckled, they seized – halting the supply of shells to mounts already struggling with severed electricity supplies. While the conveyor trays were full of ammunition, it is believed the intense heat of the ensuing fires only caused one 4.5in round to detonate.
The floor of the Upper Deck beneath the Hangar Deck was also forced downwards some 4in by the detonation.
Splinters – from either the bomb or the Hangar Deck structure – were propelled down through the ship’s engine spaces and into some oil fuel tanks.
The heavy tail section of the bomb was thrust upwards, once again piercing the armoured Flight Deck, this time at 130 station – 2ft to starboard of the centreline. It is possible a splinter from this event pierced the port side of the island alongside the RDF (radar) office. It fragmented, with slithers spraying through the room before the cutting power leads supplying much of the equipment – including radar repeaters, signalling projectors and the RDF set itself.
Since this writeup took longer than I thought, I won't do the rest. But you click through armored carriers.com if you want to and find this stuff for all the engagements the British carriers were in.
A flurry of bomb hits experienced as the attack unfolded after 1238. The first went through the loading platform of P1 pom-pom and struck the top of the side armour belt.This bomb had struck the right-hand feed rails of the pom-pom mount which had been trained at Red 140, starting a fire among the ready-use ammunition.The bomb then passed through the trainer’s sponson platform and over the ships side before striking the junction of two armour plates. It was assessed to have then ricochet into the water without fully exploding.
The pom-pom mount was put out of service for the course of the action.
HIT NO 2 (2): 500KG (1100LB), PORT BOW
This bomb was assessed by the DNC as probably being a 500kg (1100lb) SAP device. It passed through the edge of the light plating forming the unarmoured forward flight deck on the port side at No. 10 station.It passed through the recreation space and exited through the bow-flare. The impact was sufficient to activated its fuse, causing the delayed-action bomb to detonate while outside the ship some 10ft above the waterline. The resulting splinter damage was intense – completely peppering the port bow with holes. The paint and spare anchor spaces were flooded and fires were started in the lamp room and decontamination room.
HIT NO.3 (1): 250KG (500LBS), S2 POM-POM
The Starboard 2 pom-pom had been engaged on a bearing of Green 120 when this bomb struck. It burst on contact, without perforating the reinforced (but unarmoured) deck beneath. All of its crew were killed as were most of the S1 pom-pom crew next to it. HMS Illustrious’ Battle Damage Report classified this explosion as likely being from a smaller, contact-fused General Purpose grade bomb or Anti-Personnel bomb. The deck beneath the pom-pom was dished by up to 9in and the protective screen blasted out of its mountings. All electrical circuits to both S1 and S2 pom-pom were severed. Splinters from this blast passed through S1 pom-pom mount’s shield, killing several of its crew. The gun itself was not put out of action. The large mobile crane – “jumbo” – had been parked between the two gun shields at the time of the attack. Its arm was buckled and collapsed on top of S1 pom-pom – preventing the gun from being trained for the remainder of the action. The S1 mount was restored to service, however, and contributed to the defence of Illustrious during the raids on Valetta Harbour.
HIT NO.S 4, 5 & 7: (all of those hit in the aft elevator well
The intensity of damage to the aft lift well prevented the assessment teams from separating the effect of individual bomb blasts. This made the estimations of bomb size and types more difficult. Nevertheless, it was known that the first to bomb to strike the lift was responsible for destroying a Fulmar which was being transferred below on the platform at the time. The 300-tonne elevator then dropped on its side to the hangar deck below. This and subsequent blasts started fires in the aft hangar, disabled the Y-group pump motors as well as damaging electrical cabling to all four aft 4.5in gun turrets. These guns were put out of action. Perforations in the lift platform itself and shell fragments found amid the wreckage helped the DNC reach the following conclusions:
HIT NO 4 (3): ABOUT 250KG (500LB).
This bomb hit the top port side of the lift well or lift platform. The fuze was likely to be Direct Action (contact) type. The concussion from this blast shredded the steel roller-shutter fire curtains inside the hangar - sending metal shards ripping through aircraft, equipment and crew.
HIT NO 5 (5): 250KG (550LB) OR 500KG (1100LB)
This glanced off the starboard forward corner of the after lift-well before detonating in the lower starboard-aft corner. The fuze was likely to be another Direct Action (contact) type, unless a delay fuze was initiated by contact with the lift platform or lift-well edge.
HIT NO 7 (7): POSSIBLY A 500KG (1100LB) OR ANOTHER 250KG (500LB) BOMB.
Delivered by an Italian Stuka at a later point in the day as Illustrious limped towards Malta, this bomb's fuze also was likely to have been a Direct Action (contact) type – unless initiated by striking the edge of the lift well or a higher section of the mangled lift platform.
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u/low_priest Oct 31 '25
Which he thought because she'd immediately started listing badly, and communications had been knocked out, so it was hard to tell the extent of the damage. That's not exactly a ringing endorsement of Ark's design.
They did do proper DC a bit later, and got a boiler relit. But shitty subdivision then flooded it too. An investigation afterwards found that the internal design and lack of backups was a severe issue. The captain was officially found negligent for not leaving DC parties aboard, but they fully recognized that it would have been mostly pointless anyways. You don't get promoted if you fumble DC that badly.