What if the Shokaku and Zuikaku were at Midway: Revisited

Some may remember I posed this same question 7-8 months ago on the old forum, and I thought it might be worth revisiting. 

The scenario is simple: Shokaku and Zuikaku are not impeded from their ability to join the Kido Butai in the Midway Operation as result of the Battle of the Coral Sea. We will assume that not other factors are altered on either American or Japanese sides in terms of ships present, simply just adding the Shokaku's.

To begin, let us look at the capabilities of the Shokaku's in 1942:

Shokaku Class Aircraft Carrier
Displacement: 32,105 t (31,598 long tons) (deep load)

Length: 257.5 m (844 ft 10 in)

Beam: 29 m (95 ft 2 in)

Draft: 9.32 m (30 ft 7 in) (deep load)

Depth: 23 m (75 ft 6 in)

Installed power:

160,000 shp (120,000 kW)

8 × water-tube boilers

Propulsion: 4 × shafts; 4 × Kampon geared steam turbines

Speed: 34.5 knots (63.9 km/h; 39.7 mph)

Range: 9,700 nmi (18,000 km; 11,200 mi) at 18 knots (33 km/h; 21 mph)

Complement: 1660 officers and crewmen

Armament:

4 × twin 127 mm (5 in) Type 89 dual-purpose guns

12 × triple 25 mm (1 in) Type 96 AA guns

Armor:

Waterline belt: 46–165 mm (1.8–6.5 in)

Deck: 65–132 mm (2.6–5.2 in)

Aircraft carried:

72 (+12 spares)

7 December 1941:

18 × Mitsubishi A6M Zeros

27 Aichi D3A "Val"s

27 Nakajima B5N "Kate"s
(Credit on this section to wikipedia)

The Shokaku's would be arguably the most modern and powerful carriers present in the Kido Butai, perhaps even at the battle. They were fast (34.5 knots top speed), well armored, had a powerful, but after further assessment, relatively questionable AA suite, but most importantly, together they would bring an additional 144 (plus 24 spares) aircraft to the battle, taking the IJN total aircraft strike power from 248 to 392 (plus the 24 spares making the grand total 416), compared to the American 233 carrier based and 127 land based. Now the Japanese hold a numerical superiority in terms of aircraft to the U.S., 416 to 360. 

However, these numbers veil the true strength of the forces. With these additional aircraft, the IJN would go to battle with a total of:
144 A6M "Zeros" (Fighter)
163 D3A "Vals" (Dive Bomber)
173 B5N "Kates" (Torpedo Bomber)

The numbers of types aircraft will crucial in our analysis. Now let us examine the composition of the planes used by the U.S.:
88 F4F-4 "Wildcat" (Fighter)
129 SBD-3 "Dauntless" (Dive Bomber)
44 TBD-1 "Devastator" (Torpedo Bomber)
32 PBY-5/A "Catalina" (Patrol Bomber)
6 TBF "Avenger" (Torpedo Bomber)
4 B-26 "Marauder" (Patrol Bomber)
19 B-17 "Flying Fortress" (Patrol Bomber)

As the U.S. has many more aircraft of different makes, I will simplify the composition into the respective categories, so as to better analyze them:
88 Fighters
129 Dive Bombers
50 Torpedo Bombers
55 Patrol Bombers

Now comparing the composition of the IJN air units to the USN air units we find that the IJN possesses an advantage in the following categories:
Fighters (144 > 88)
Dive Bombers (163 > 129)
Torpedo Bombers (173 > 50)

The only advantage possessed by the USN is in patrol bombers (55 > 0). 

Now having examined the situation, with the Shokaku and Zuikaku, the USN is vastly outnumbered in terms of airpower. 

But having numerical superiority is useless unless it is used properly. Now if we turn our attention to the IJN's shortcomings at Midway, we will find that to put it in a very simplified version, the IJN had poor reconnaissance and rotation of fighters to protect the carriers, in addition to the shortcomings of Admiral Chuichi Nagumo and his inability to make quick decisions, which is what left the IJN fleet carriers in that vulnerable position with their decks a strewn with ammunition and fuel. So which if any problems do having these two additional carriers solve?

It is hard to know what decisions would have been made differently. One can imagine millions of different scenarios. I start by stating which change I believe is the most likely to occur regardless of "re-fighting the battle Monday morning", so to speak. I believe at the bare-most minimum one can conclude that the problems of having poor rotation of fighters would be resolved. It was such poor rotation of fighters that resulted in the U.S.'s success with the dive bomber attack at 10:25 AM. Now, some of the many fighters (36 active ones to be exact) would likely be preparing for the carrier strike that would be headed to hit the USS Yorktown, that up until now had been in reserve. Despite this I believe that some of these aircraft, perhaps say 1/3, would be flying combat-air-patrol. This and other combat air patrol forces active would have helped to at least stop more of the Dauntless's, likely saving at least one or two carriers. I do not combat-air-patrol of this size would have torn apart the attacking dive bombers, but I do think that it would have taken out quite a few of them, at least impeding their ability to land accurate hits. 

Let us assume then that one carrier was hit, say the Kaga, as she was struck by the most bombs and had the most aircraft attacking her. The Kaga would likely be out-of-order, if not possibly finished (as Akagi only took one direct hit and that did the job). So without Kaga, the IJN would lose a sizable chunk of their strike power. But there is a key difference between this, and the loss of the three carriers in the actual battle. With only one carrier hit, Nagumo would order the remainder of his force to attack Yorktown's task force. And with his additional aircraft, I believe that the Yorktown would not survive this attack as she had in real life, albeit there would likely be serious cost to the striking arm of the Kido Butai. 

Now both the IJN and USN have lost 1 carrier, and additional aircraft. But the USN loss would be far more damaging. Yorktown would lose a good portion of her airgroup, and this would be far too costly. Yorktown would have at least some quantity of aircraft aboard, and would have lost some either to the battle or to aircraft that had to ditch and couldn't make it to Enterprise and Hornet. 

At this stage, Admiral Fletcher (in overall tactical command) would have been hard pressed to remain in the battle with another carrier lost, as Nimitz had instructed him that if he could not inflict losses upon the enemy without risking further loss to himself, he ought to retreat. Whether Fletcher would have been willing to risk his two remaining carriers to protect Midway, no one knows. As the location of Enteprise and Hornet was still unknown to the IJN, there is a possibility that he would have ordered the two to remain in the area until detected. However, I think that this is unlikely, and Fletcher would order his two flattops still afloat out. One last scenario that could result in Enterprise and Hornet staying at Midway would be Admiral Spruance in direct command of Enterprise and Hornet. The Kido Butai would be on a heightened state of alert now, as they probably would have figured out that there were more than the one detected U.S. carriers in the area. Thus, I do not think an attack by Enterprise and Hornet would be able to knock out any more than one carrier if they remain in the battle area. And if the scouts of the Kido Butai find the two USN carriers, there would be trouble for Spruance. All this aside, I think Fletcher and Spruance would pull back from Midway with another 1-1 carrier loss (Kaga and Yorktown). 




That is what I feel to be the most likely scenario if the IJN had the Shokaku and Zuikaku at Midway.




What are your thoughts? Did I make too many leaps? Or was I too generous to the IJN or USN losses? As with anytime we play "what-if" with history, we are bound to make errors based on opinion, as we can never truly determine how the people who fought these battles would have reacted to the changes we propose. Nonetheless, it makes for a very entertaining discussion!

Sources:

combinedfleet.com/ships/shokaku
en.wikipedia.org/wiki/Battle_of_Midway
en.wikipedia.org/wiki/Sh%C5%8Dkaku-class_aircraft_carrier
en.wikipedia.org/wiki/Midway_order_of_battle