Armoured Aircraft Carriers in World War II

Examining the battle damage suffered by HMS Illustrious can be a confusing affair. A key example is the sequence in which bombs hit, and what bomb sizes they were.

This confusion is the result of there being two separate reports with the same archival reference, ADM 267/83.

One was produced by the captain in the days immediately after the carrier’s epic struggle for survival on January 10 (reproduced HERE), and conveyed to an anxious Admiralty on January 26. This report is the one most often cited by naval historians. The evocative and comprehensive account was compiled from the recollections and interpretations of events of command staff in Malta while struggling to get Illustrious back to sea while under X Fliegerkorps’ bombs. While inherently accurate, the devil is in the detail. For example, the order in which damage was reported to the bridge was not necessarily the order in which that damage was sustained.

The second report was compiled by naval intelligence officers and constructors (reproduced HERE) in the calmer months following HMS Illustrious’ arrival at the US Norfolk naval base for repairs.

GERMAN AIR FORCE ACTIVITIES IN THE MEDITERRANEAN.
TACTICS AND LESSONS LEARNED 1941 - 1943

5. Course of Events

A supply convoy sailing from Gibraltar to Malta and consisting of 23 ships, among them the aircraft carrier “Illustrious" and two battleships, sighted by our reconnaissance aircraft north of Bougie on 7th January, 1941. Fighter bombers and torpedo-carrying aircraft delivered a low-level and dive-bombing attack on the convoy south of Sardinia. Carrier aircraft presented no danger worth mentioning since they were of an obsolete type. Naval flak caused slight losses. Fighters based on Malta found the distance to the target area too great. Bad weather helped the sea operations so that parts of the convoy, including the "Illustrious”, reached Malta. There followed a series of day and night attacks by Ju88’s and HeIII's and day attacks by Ju87's and Me110's on ships in the harbour of Valetta and on airfields on Malta, Dive bombing and level flight attacks made from a medium height, in which escorting aircraft also took part, achieved on the whole good results. Several hits on the aircraft carrier by S.C. 1000 and 500 bombs were reported and confirmed in aerial photographs but she did not sink and on the 24th of January, under cover of bad weather, she left port for Alexandria. Our own losses were tolerable and were caused mainly by accurate flak and, to a lesser extent, by Hurricanes. Air supremacy over the Island was won in February, 1941.

NEAR MISS No.1: STARBOARD, AFT

Exactly when a near-miss actually caused this damage is uncertain. Illustrious had been repeatedly tossed about by detonations in the water alongside. But, at some point early in the attack, a near-miss had caused flooding which would eventually affect the electrical steering gear.

NEAR MISS NO.2: STARBOARD, FORWARD

This large bomb burst close alongside Illustrious' forward lift about the same moment the second bomb detonated in her aft lift at 1242. The shockwave buckled the lift in an upward arc, causing it to direct onrushing air down into the burning hangar. The whip-lash also appears to have caused a section of the forward hangar floor to sag several inches.

NEAR MISS NO 3: PORT SIDE, Malta dock

A heavy bomb passed within a few feet of the hull of Illustrious to detonate in the water alongside.

The blast pushed in the bottom edge of the side belt armour inward 3in, and the shell plating beneath that some 5ft. A dish some 75ft long was hammered into the hull, with flooding in the torpedo protection and fuel spaces causing a immediate list of about 5 degrees.

The port boiler room was temporarily put out of action as brickwork tumbled, and the sliding feet to the port turbines fractured.

OTHER NEAR MISSES

During the fourth attack, one bomb detonated in the water very close to the island. A single splinter hole penetrated the ship’s steel skin.

Another heavy bomb burst close to the starboard quarter deck which was being used as an emergency hospital. Splinter damage was sustained and many of the wounded – and those tending them – killed. 

Illustrious' Fight For Life
Kenneth Poolman

THE STUKAS CAME in from three bearings, port and starboard bows and starboard quarter, all at the same time. Bill Banham watched them, diving in groups of three from each direction, dove-tailed neatly together, clover-leaf fashion. Down they hurled through the 4.5 barrage and into the pompom screen.

Nothing could stop them. In a terrifying crescendo of crashing sound Illustrious disappeared in spray and smoke. All was bursting bombs, bursting shells, the racket of the guns and the roar and scream of aircraft.

They knocked the broadcasting system out of action and shattered the radar. A bomb hit P1 pompom on the port side for’ard, smashing the gun, killing two of its crew as it passed through the gun platform and exploded on hitting the water, sending jagged pieces flying upwards to kill and wound more men...

Damage Control HQ reported all the damage to Captain Boyd on the bridge, who was taking avoiding action with his eye on the diving Stukas...

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.

"I returned to my action station in the hangar. The ship continued to rock and sway. I looked up with fear and apprehension. Then there was an almighty flash as a 1,000 lb (sic) bomb pierced the 4 inch (sic) armoured deck and exploded. I was only aware of a great wind, of bits of aircraft, debris, all blowing out to the forward lift shaft of 300 tons which was also blown out.
There were dead and wounded around, my overalls were blown off, I had small wounds to the back of my head and shoulder. I was probably 10-15 feet away from the bomb when it exploded. Luck I survived? I prefer the thought of someone looking out for me.
The hanger by then was burning all over. The ship’s commander came and said ‘Come on lads close the armoured doors.’ The overhead sprays then flooded the hanger. The ship started to sink by the stern and everyone had to blow up lifebelts. Then, a spot of humour in all that chaos. Poor old Corporal Gater came through a side door white as a sheet saying ‘I wish I hadn’t bloody joined.’
The battering carried on for six to seven hours.
There were many wounded piled up; the aft surgeons station had been destroyed, the forward station was unable to cope quickly with so many casualties.
Captain Boyd finally steered with the engines into Malta; the ship was quiet at last."

- Memories of the Fleet Air Arm, Richard Griffin

HIT NO.S 4, 5 & 7

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.

Fulmar Observer Lt
Desmond Vincent-Jones

Soon we were away down the deck and starting to climb off the bow of the ship. When we had reached a few hundred feet we found ourselves surrounded by Ju87s as they were pulling out of their dives and some of them were very close, one hundred yards or so, and I could see clearly the rear gunners firing at us... I looked down and saw the poor Illustrious passing through huge columns of water, her guns blazing and a fire and smoke coming from the after end of the flight deck. The first 500kg bomb had scored a direct hit on the Fulmar which had failed to start – no sign of it or its crew was ever seen again. The bomb went on down the after lift well and exploded on the main deck killing about 30 of the maintenance crews of 806 Squadron who had been allocated the after end of the hangar. The blast went through the hangar and buckled the foremost lift, thus putting an end to any further chance of flying off other aircraft.

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 an 1000kg “Esau”.  

DNC would later determine that the bomb had only just managed to defeat the armour plate:  The impact had not dished the 3in hardened steel and the structural joints were not seriously distorted.

The warhead went on to burst in 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.

Illustrious' Fight For Life
Kenneth Poolman

Jago had dashed into a spraying room at the side of the hangar to get the sprayers working. When he got back into the hangar it was a ghastly shambles. Dead and badly wounded men lay on the deck, some hit by pieces of steel from the hangar fire-screens which had shattered to pieces and flung sharp slivers like scythe blades through the hangar. He saw an officer he knew looking straight at him. The man had no top to his head. He immediately had all access doors to the hangar closed and got the sprayers going.  Ammunition was exploding all over the hangar and planes were burning. Down one side of the hangar were six swordfish with depth-charges attached, and another six armed with torpedoes.

‘Don’t worry,’ said the Gunner (T), ‘they won’t cook off.’ 

Then there was a blinding, staggering crash and a great (two) thousand-pounder struck the flight-deck right on the centre-line. It burst through the armoured deck and the hangar-deck below, hit the after ammunition conveyor and exploded, killing and badly wounding everybody in the wardroom flat. All the officers taking a hasty meal in the wardroom were wiped out. The whole after part of the ship went dark and dead. The fire took hold everywhere and raged through the torn and shattered compartments where men lay trapped. A smashed petrol-pipe sprayed streams of liquid flame through the dark, smoke-filled passages.

Bill Banham found that the after bulkhead door was partially open. Peering into the wardroom flat through the thick, acrid haze, he saw the flare from a burning petrol-pipe roaring like a huge blowlamp. Ammunition near the shattered conveyor started to go up. Flame suddenly appeared through the openings in the conveyor.

The SC1800 (General Purpose 4000lb) was deployed in limited numbers against Operation Excess. Nicknamed “Satan”, it had a recorded diameter of 26in.

The PC1000 (Armour Piercing 2200lb) had the nickname “Esau”. Its body diameter was 19.8in and warhead 160kg. But it was not listed by the X Fliegerkorps “overview” report as among the bombs used on January 10.

The SC1000 (General Purpose 2200lb) was nicknamed “Hermann” by the Germans. It came in three variants of 26in, 25.5in and 25.6in wide. Warhead weights were 620kg, 530kg and 600kg.

The SD1000 (Semi Armour Piercing 2200lb) is also a possibility. I’ve not yet found specifications for the type, though some accounts say it is designation misapplied to the PC1000. X Fliegerkorps reports having deployed more than 60 against the British convoy and its escorts that day.

The SC250 (General Purpose 550lb) is among X Fliegerkorps listed bomb loads. It was 14.5in wide with a 130kg warhead.

The SD250 (Semi Armour Piercing 550lb) had the same diameter, but a 79kg warhead. X Fliegerkorps overview report (bottom of this page) states Illustrious was hit by two of these bombs. But that same report’s Appendix summary did not list the SD250 as among those deployed.

LUFTWAFFE BOMBS
AND DESIGNATIONS

The Luftwaffe was equipped with standardised categories of bombs.
These were designated SC, SD and PC. This was used as a prefix, followed by a number which represented their weight in kilograms. A third “tag” could be applied to designate the type of fuse fitted: For example, mV (mit Verzgerung) was a short delay action, LZZ (LangZeitZnder) was a long delay fuse.
Sprengbombe Cylmdnsch (SC): Thin-walled free-fall high-explosive bombs. These were “general purpose” or “burster” bombs, intended to produce maximum blast effect against lightly protected targets. Denoted by a yellow stripe on the tail cone.
Sprengbombe Dickwandig (SD): Medium-cased semi-armour piercing fragmentation bombs. These were available in 50, 70, 250, 500 and 1700 kg versions. Their penetration abilities make them useful against ships, harbours and fortified positions. Denoted by a red stripe on the tail cone.
Panzersprengbombe Cylmdnsch (PC): Extra-thick hardened-steel walled armour-piercing bombs. These were available only in 500, 1000 and 1400kg versions. Their specific purpose was to attack shipping and fortifications. Denoted by a blue stripe on the tail cone.
Many of the bombs were given nicknames – though these often seem confused. For example, the term “Esau” applies to the PC variant which is often incorrectly termed the SD1000. The “Herman” was the SC variant.
The common SD500 bomb does not appear to have had a nickname.

Overview: Hangar

Illustrious’ War Damage Report lists the hangar as holding nine Swordfish and four Fulmars at the time of the attack. The Swordfish were armed with either SAP or anti-submarine bombs while six torpedoes were stored in readiness for any rapid-response strike force.

Three of the four metal fire-curtains were down. Only that at frame 78.5 was likely to have still been up. These fragmented and were sent flying through the hangar when the bombs burst in the aft lift-well and the heavy 2200lb bomb penetrated into “C” hangar.

Among those killed by this shrapnel were men positioned to access the emergency controls for the hangar-fire sprayers. 

Only “B” hangar’s sprayers were immediately activated. “C” hangar’s spray controller was dead, and the starboard control valves were later found to have been jammed. The port control valves were able to be opened half-way before the heat from the fire forced the damage control team to retreat.

Later it was found the “C” hangar salt-water ring main had been pierced and the sprayers were unlikely to have operated at all.

In “A” hangar, while there was no visible fire, the space was filled with smoke. The sprayers were activated  over the Swordfish there as a precaution.

Letter from Commander-in-Chief, Mediterranean
to Secretary of Admiralty 
[ADM 267/ 83]  27 February 1941 

AIR ATTACKS ON HMS ILLUSTRIOUS, 10 January 1941 

Forwarded for the information of Their Lordships, concurring with the remarks of the Rear-Admiral, Mediterranean Aircraft Carriers. 
(2) The circumstances surrounding these attacks on H.M.S. ILLUSTRIOUS will be recorded separately in the report of Operation M.C. 4, of which this episode formed a part. 
(3) There can be no doubt that the German Air Force operating from Sicily made a most strenuous effort to destroy ILLUSTRIOUS. The dive bombing attacks on her, WARSPITE and VALIANT, were pressed home with great determination and were brilliantly executed. 
(4) It was very unfortunate that the 6 fighters up were not over the Fleet at the time for the reasons given in ILLUSTRIOUS’ report. Had they been, the results might have been very different. However, they were able to intervene with effect later on. 
(5) The apparent effect of the A.A. gunfire of the Fleet was disappointing and the fire discipline of the short range weapons was not good. This matter is receiving urgent attention. The need for realistic dive bomber targets for practices is very evident...
(7) I concur with the Rear-Admiral, Mediterranean Aircraft Carriers, that the bearing of the Officers and men of H.M.S. ILLUSTRIOUS under the stress of these attacks and subsequently was exemplary and in accordance with the highest traditions of the Service. 
(8) A separate report regarding damage in H.M.S. ILLUSTRIOUS and damage control will be forwarded in due course.