WORK IN PROGRESS
“The life of the Midway also demonstrates the progress of our Navy; the accommodation of our ships to aircraft of high performance; the use of missiles; exploitation of electronics; the capability to employ a whole family of weapons unheard of when her keel was first laid. No other navy, no other service of any country, has a single military unit as powerful, as versatile and as mobile as this great ship.”
“The General Board has taken notice of damage to carriers in this war, has considered the characteristics of our own carriers built and building, and has
studied the characteristics desirable in aircraft carriers of unrestricted tonnage ... it is essential to have some tougher carriers which embody improved power of survival and which can engage in offensive operations without being easily placed out of action by a few light bombs, one or two torpedoes, or medium-sized projectiles. The Board is of the opinion that the advantages to be gained by the considerable increase in standard displacement of this class of carrier outweigh the additional cost involved. . . .”
Rear Admiral E.L. Cochrane, chief of BuShips, 1945.
While the armoured flight deck was still desirable, the British arrangement of armoured sides to the hangar was not desirable in view of the hazards to planes exposed in the hangar in the event the flight deck was penetrated …
The Midway has an armoured flight deck, a heavy hangar deck, and, in addition, heavy transverse bulkheads subdividing the hangar against such casualties as the Franklin later experienced, and with relatively open sides for the hangar so as to prevent the serious damage which the Illustrious suffered of a bomb burst in the hangar …
THE BATTLE CARRIER (CVB)
The Midway Class was no compromise. Its primary purpose was to deploy on its flight deck the largest practical strike group. It was to carry as many aircraft as possible. It did all these things.
The final design was for a 300.5m long, 41,5m wide carrier capable of 33 knots. With three elevators and two catapults, it also had the space and facilities needed to provide the sustained operation of 137 aircraft. Its contentious secondary argument was finally resolved to be 18 of the new 5in/54cal guns.
While not entirely popular among the 1945 navy, the three CVBs completed would prove their true worth postwar. Their internal volume enabled adaptability. Their endurance accommodated global operations. Their strength facilitated new generations of heavier jet-based aircraft.
The open hangar also proved advantageous. Its structural adaptability enabled the Battle Carriers to quickly adopt the new British angled flight deck and steam catapult innovations.
All these advantages led the CVB to become the progenitor of the later the Forrestal and Nimitz class ‘Super Carriers’.
VINDICATION
FLIGHT DECK
While Midway’s stark, angular lines dominate every view of the floating museum, the ship was originally designed with an axial flight deck like that of the Essex and Yorktown before it.
Despite their great size, this gave the CVB’s the same challenges in operating aircraft as their predecessors. They needed enough clear space at the front of the flight deck to suit variable wind-over-deck conditions. The aft lift could not be used during landing operations - nor could the centre-side lift. So aircraft had to be bunched on the forward flight deck until landing was complete.
While the flight deck carried armour, it was not a strength deck as in the RN designs. Instead, it was superstructure. But this presented some challenges of its own.
The flight deck armour was heavy. So it needed extensive structure to prevent it from “racking”, or deforming due to the stresses of the ship’s movements. And having a concentration of weight so high in the ship produced excessive heel under high-speed turns.
HANGAR
“The open hangar is not necessarily a great deal wider than a closed hangar. There are all sorts of obstructions along its sides, including the deep frames for supporting the flight deck; access ladders to the gallery deck above; hatches to give access to the decks below and even winches, bollards etc.”
“HMS Illustrious in an action off Malta on 1 January 1941 was hit by several bombs, three of which detonated in the hangar spaces. Large fires swept fore and aft among parked planes thereby demonstrating the desirability of attempting to confine the limits of such explosions and fires by structural sectionalization of the hangar space. On the CVB Class the hangar was therefore divided into five compartments ...”
The blast from a 2200lb bomb in HMS Illustrious’ armoured-box hangar in 1941 created a pressure pulse that buckled the forward lift and has been implicated in the sagging of the forward hangar deck. In the case of the IJN Taiho, its unarmoured - but enclosed - hangar became a massive fuel-air bomb that cracked the 3.5in armorued flight deck and blew out portions of the ship’s sides.
It was argued open hangars would allow such blasts to vent with minimal effect. But compression was not limited to enclosed hangars, as photos of Enterprise’s lift rocketing skyward on a plume of smoke attest to. And open sides allowed air to fan fires - something HMS Illustrious and Formidable were able to limit.
But BuAer was adamant carriers needed to have open sided hangars to allow aircraft to warm up. Only this way, they argued, could multiple strikes be ranged and launched from deck as rapidly as possible.
The vast hangar deck was divided into four sections by three fire doors.
The hangar, while open, was less so than an Essex. There were no bays through which aircraft could be loaded. As a result, the ships large flight-deck crane had to be used to haul them up to the flight deck.
LIFTS
As originally completed, the Midways had two centreline elevators and one deck edge elevator.
Before the war, elevator speed was the primary requirement. This is why pre-war designs had aluminum tops. Lighter meant faster. But it also meant the structure was prone to splinter damage and offered no resistance to bomb hits that could carry further down into the ship.
AIRCRAFT EQUIPMENT
A pair of hydraulic powered catapults (H4-1s) were fitted to the bow. The idea of a side-launch catapult having proven impractical in the Essexes. The H4-1s were a lengthened version of those found on the Essex class catapults. They proved capable of accelerating a 28,000 lb aircraft to 90mph.
The arresting gear as fitted was fourteen Mk 5 Mod 0 engines
Six barricades were arrayed across the centre of the flight deck.
FIRE SUPPRESSION
“It is hoped that this sectionalization, in conjunction with sprinkler and fog foam systems, will effectively prevent fires from spreading throughout the hangar spaces, as occurred on Franklin on 30 October and 19 March. ”
PROTECTION
“The experiences of several British carriers, which unlike our own were fitted with armored flight decks, demonstrated the effectiveness of such armor in shielding hangar spaces from GP bombs and vital spaces below the hangar deck from SAP bombs. ”
But not everybody was convinced. Even a 45,000 ton carrier had its limits. And manufacturers were promising a new 1750lb bomb could breach 7in of armour.
Ultimately, the availability of the Montana-class building blocks set aside any concerns that production of Essex hulls would suffer if the CVBs went ahead.
Midway was completed with three layers of horizontal protection - the most extensive of her era. The space between her two centreline lifts on the Flight Deck had 3.5in armour plate. The Hangar Deck was of 2in steel. There was a further 2in on the Third Deck.
Side protection was equally significant. And it reflected the root-cause of the armoured carrier’s original concept: the need to survive marauding Japanese 8in cruisers. A 7.6in armoured belt lined the port side of the ship. The starboard side belt was 7in in order to counterbalance the weight of the island.
Armour wasn’t the only protection built into the CVBs.
Hull plating was of thicker steel. There were more transverse bulkheads (26 in all). And the number of subdivided compartments was much greater than any other carrier class.
While of great benefit when it came to surviving battle damage, this extensive subdivision gave the class a reputation of being uncomfortable for their crews.
ARMAMENT
The debate over the CVB’s gun armament had been intense. Were dual-purpose mounts sufficient? Or did the threat of Japanese cruisers make 8in weapons necessary? Eventually, the USN settled on a new type of 5in DP gun - the 5”/54.
Each 40 ton single-gun mount had a crew of 17, with a total of 18 mounts recessed into the hull outboard of the Hangar Deck. This isolated the guns from flight deck operations.
The 5”/54 performance was a significant improvement over the 5”/38. They could reach out to 23,000m as opposed to 16,000m. And they fired a heavier 70lb shell (against 55lb).
Midway was completed with an armoured pilot house on her bridge. But Coral Sea had this weight removed to allow the forward 5in Mk37 Fire Control System director to be fitted on top of the island instead of immediately in front of it. This cleared further deck space for flight operations.
As delivered, Midway carried 21 40mm quad mounts (for a total of 84 barrels). Each mount had a crew of 11 and were provided with radar fire control.
Exactly how many 20mm guns were originally intended to be installed is a matter of debate. Some sources put it at 28 barrels, others at 68. Either way, 10 twin 20mm mounts were actually fitted to Midway in 1945. These, along with the quad 40mm guns, were gone by the 1950s as they proved ineffective against fast jets.
AMMUNITION & STORES
RADAR
MACHINERY
Armoured flight deck critics were adamant: speed and maneuverability were a much better defence against bombs and torpedoes.
But war damage report after war damage report put paid to this argument.
What was needed was balance.
STABILITY & SEAKEEPING
The CVB’s hull design was based upon that of the cancelled Montana class battleships. It was a relatively slim design for its great length. This produced excellent speed and maneuvrability. But it also permitted significant pitch and roll in any kind of seaway.
Combined with the weight of the armoured flight deck high up in the ship, the Midways quickly developed a reputation for plunging in even moderate seas. This reduced her ability to operate aircraft in any kind of serious weather.
Every effort had been made to improve the stability of the CVBs.
The long hull had a relatively low freeboard when put alongside an Essex. Internal deck heights were also reduced to 8ft.
But the ships would have a reputation of being ‘wet’ ships for their entire careers.
AIR GROUP
The CVB’s 1945 air group configuration was specified as 132:
64x F4U-4 Corsairs
64x SB2C-5 Helldivers
4x F6F5P (photo reconnaissance) Hellcats
But, still, not everybody was happy. And - at least initially - they had cause.
It was argued the 1945 CVB could not operate their very large air groups efficiently. Put simply, the bigger ship with its bigger air group was not actually capable of delivering more aircraft on target.
At the centre of the argument was the USN concept of “complete carrier evolution”. This is the time it takes to launch and land an airgroup. At anassumed 20 second launch and a 40-30 second landing intervals, this would inevitably be a significant amount of time for 130-140 aircraft.
Further delaying matters was that not all aircraft could be ranged on deck at any one time. So no more than half the air group could be cycled. Making matters even more difficult was the axial-alignment of the World War II era flight deck. Take-off and landing-on operations could not be conducted simultaneously.
The consequence of so many aircraft operating from one deck meant the CVB would have to spend at least six hours of a day sailing into the wind in order to operate the expected six deck-load strikes. And this almost always led the carrier away from the desired direction of travel.
This would only be overcome with the advent of the angled flight deck. Simultaneous launch and landing would reduce the time need for the six-strike requirement to four hours.
By this time the size of the Midway came into its own. Aircraft sizes were growing dramatically. And the CVBs could easily be modified to accommodate them.