How would history have changed if HMSIndomitable had successfully joined Force Z?

[HMSIndomitable_92]

I asked the Korean Alternative History Community and Raddit to solve this question, but I didn't get the right income, so I'm asking here about it.

How would history have changed if HMS Indomitable had succeeded in joining Force Z in Simonstown or Scapa Flow?

 

[sparky42]

I asked the Korean Alternative History Community and Reddit to solve this question, but I didn't get the right income, so I'm asking here about it.

How would history have changed if HMS Indomitable had succeeded in joining Force Z in Simonstown or Scapa Flow?

I would imagine that the Japanese might increase the forces planned for the attack towards Singapore, but given the limitations of the FAA at this stage I can’t see a carrier being present radically altering the outcome?

Edit: Well it is the Japanese, given some of their “planning” who knows…

 

[naraic]

I would imagine that the Japanese might increase the forces planned for the attack towards Singapore, but given the limitations of the FAA at this stage I can’t see a carrier being present radically altering the outcome?

Edit: Well it is the Japanese, given some of their “planning” who knows…

The moment where Force Z sank was out of range of land based fighters. Any FAA presence would radically change the outcome.

Personally I feel that the carrier based scouting attached to Force Z might have resulted in the night time passing of Force Z and (IIRC) Cruiser Division 7 being a night fighting naval battle with heavy losses on both sides with a damaged Battleship and Battlecruiser withdrawing to Ceylon for patchup repairs before returning to the UK or to the USA for more extensive repairs.

Just a guess.

 

[Peg Leg Pom]

Having Indomitable with them will save Force Z on 10th December 1941. Beyond that if it stays east of the Malay Barrier it's not going to survive past February 1942. Singapore is not viable as a base of operations so they will need to retire to Ceylon.

 

[Riain]

This map gives an idea of what else is out there, most notably 2 surface task forces; one centered on a pair of fast battleships and another on 4 heavy cruisers. Also in theatre, supporting another operation, was a light carrier and its escorts.

The carrier aircraft doing searches might preclude the ludicrous blundering about that OTL Force Z did before being sunk. However the IJN did not lack resources to support the invasion, I seriously doubt Force Z could prevail against both of those IJN task forces, although it might strike a blow against one or even both before sucumbing to the IJN counter-attacks.

 

[Navigator]

Even with HMS Indomitable, Force Z was only a token. Can you also butterfly Tom Philips?

In TTL you've at least got air reconnaissance, so the Japanese forces can't get so close undetected. Also, any change whatsoever reduces the statistical probability of the single lucky shot. For Bismarck it was rudder, for Prince of Wales a shaft gland.

The Japanese forces are numerically too strong in December, head for Australia and wait until the American carriers head west. A pair of 28 knot (plus) big gun platforms would be very welcome with most of their own underwater.

 

[Sekhmet_D]

My partner is of the opinion that this changed scenario ends with all three ships at the bottom of the South China Sea, on account of Indomitable's fighter strength not being enough to completely neutralise the very large Japanese bomber force.

I disagree with her; I see only one vessel (Prince of Wales, perhaps) being lost thanks to Indomitable's fighters disrupting the strikes, the other two being at least moderately damaged and forced to withdraw to Ceylon (my model is the 4th Kokutai's attack on Lexington in February 1942).

One thing we can agree upon, however, is minimum Japanese bomber losses of 25 percent.

 

[Peg Leg Pom]

I disagree with her; I see only one vessel (Prince of Wales, perhaps) being lost thanks to Indomitable's fighters disrupting the strikes, the other two being at least moderately damaged and forced to withdraw to Ceylon (my model is the 4th Kokutai's attack on Lexington in February 1942).

You're right, the Japanese torpedo bombers attacked piecemeal rather than en-mass. Indomitable's fighters would be able to land and re-arm between attacks while maintaining a standing cap aided by radar searching the skies. However Force Z cannot remain in the South China or Java Seas and survive for long. Their detterance mission has failed they must withdraw to Ceylon or perish.

 

[Navigator]

You're right, the Japanese torpedo bombers attacked piecemeal rather than en-mass. Indomitable's fighters would be able to land and re-arm between attacks while maintaining a standing cap aided by radar searching the skies. However Force Z cannot remain in the South China or Java Seas and survive for long. Their detterance mission has failed they must withdraw to Ceylon or perish.

Other options include Perth, Darwin, Sydney or Hawai'i.

 

[HMSIndomitable_92]

This map gives an idea of what else is out there, most notably 2 surface task forces; one centered on a pair of fast battleships and another on 4 heavy cruisers. Also in theatre, supporting another operation, was a light carrier and its escorts.

The carrier aircraft doing searches might preclude the ludicrous blundering about that OTL Force Z did before being sunk. However the IJN did not lack resources to support the invasion, I seriously doubt Force Z could prevail against both of those IJN task forces, although it might strike a blow against one or even both before sucumbing to the IJN counter-attacks.

View attachment 831296

Thank you for the good data! Can I refer to it when I write later?

 

[HMSIndomitable_92]

Personally I feel that the carrier based scouting attached to Force Z might have resulted in the night time passing of Force Z and (IIRC) Cruiser Division 7 being a night fighting naval battle with heavy losses on both sides with a damaged Battleship and Battlecruiser withdrawing to Ceylon for patchup repairs before returning to the UK or to the USA for more extensive repairs.

Come to think of it, your argument is also highly likely too. Anyway, thank you very much for your advice!

 

[Riain]

Thank you for the good data! Can I refer to it when I write later?

Go nuts, you can find it online if you search along the lines of Force Z movements or something like that.

 

[mack8]

What was the airgroup composition of Indomitable in this timeframe?

Ignoring other aspects/effects for the moment, if Indomitable was there she would absolutely be the main target of the japanese strikes. It would also take much fewer torpedo hits to disable or sink it compared to the BBs, 2-3 hits and she's gone imo.

 

[HMSIndomitable_92]

What was the airgroup composition of Indomitable in this timeframe?

Ignoring other aspects/effects for the moment, if Indomitable was there she would absolutely be the main target of the japanese strikes. It would also take much fewer torpedo hits to disable or sink it compared to the BBs, 2-3 hits and she's gone imo.

According to Mr. Armoured Carrier's site (https://www.armouredcarriers.com/hms-indomitable-lessons-learned), there're 21 fighters(9 Sea Hurricane, 12 Fulmer) deployed in the HMS Indomitable at that time.

 

[Post]

Apart from the obvious effect a CAP has on the attackers*, there are several other things to consider:
- a CAP may notice seaplanes or submarines which are following Force Z and may chase them off or attack them, which decreases the amount of time the Japanese know where Force Z is. This even makes it possible the Japanese miss it alltogether, because in OTL they atttacked on the return while low on fuel
- flight operations may lead to an attacksolution for one of the Japanese subs in the area
- searchplanes may locate the Japanese surface fleet
- Force Z changed course to investigate something they saw on the radar, which turned out to be a trawler. They may now send a plane to investigate instead
- if possible the Japanese will send in more attacks as long as the carrier and battleships aren't sunk, although losses may make this impossible

* I reckon you can expect 20% of the attackers to be shot down, the big question however if the British will have time to send up more CAP between the waves of attacks. AFAIK know in general torpedobombers had very little success if they were attacked during their approach. The first Japanese attackwave was with bombs however, and had no succes. From that wave several planes will be shot down. From the next waves, out of 49 torpedos 8 hit. If there is a functioning CAP the number of hits will go down a lot.

 

[Sekhmet_D]

- if possible the Japanese will send in more attacks as long as the carrier and battleships aren't sunk, although losses may make this impossible

* I reckon you can expect 20% of the attackers to be shot down, the big question however if the British will have time to send up more CAP between the waves of attacks. AFAIK know in general torpedobombers had very little success if they were attacked during their approach. The first Japanese attackwave was with bombs however, and had no succes. From that wave several planes will be shot down. From the next waves, out of 49 torpedos 8 hit. If there is a functioning CAP the number of hits will go down a lot.

I have a hazy recollection that the Indochina-based bomber squadrons had a finite number of aerial torpedoes available, which, if true, would preclude them throwing more and more aircraft into the fray until the desired result was obtained. This is far likelier to be the limiting factor, rather than any concern about casualties on the part of the high command.

We can expect Indomitable to shrug off the bombs from the initial attack waves with little to no trouble given her armoured flight deck, I think.

 

[Sekhmet_D]

Ignoring other aspects/effects for the moment, if Indomitable was there she would absolutely be the main target of the japanese strikes. It would also take much fewer torpedo hits to disable or sink it compared to the BBs, 2-3 hits and she's gone imo.

She took a pretty bad hit in the port boiler spaces from Italian torpedo planes during Operation Husky, but managed to recover from a 12 degree list and make harbour under her own steam. To be fair, this attack was not on the scale of what happened to Force Z.

 

[HMSIndomitable_92]

I have a hazy recollection that the Indochina-based bomber squadrons had a finite number of aerial torpedoes available, which, if true, would preclude them throwing more and more aircraft into the fray until the desired result was obtained. This is far likelier to be the limiting factor, rather than any concern about casualties on the part of the high command.

We can expect Indomitable to shrug off the bombs from the initial attack waves with little to no trouble given her armoured flight deck, I think.

I think I saw a similar article on the Korean web.

As far as I remember, the Imperial Japanese Navy at the time had a hard time finding Task Force Z because of communication problems. And because of that, the Japanese Imperial Naval Air Force's bombers were almost out of fuel.

 

[white crowe]

I have a hazy recollection that the Indochina-based bomber squadrons had a finite number of aerial torpedoes available, which, if true, would preclude them throwing more and more aircraft into the fray until the desired result was obtained. This is far likelier to be the limiting factor, rather than any concern about casualties on the part of the high command.

We can expect Indomitable to shrug off the bombs from the initial attack waves with little to no trouble given her armoured flight deck, I think.

Didn't bomb hits tend to warp the flight deck and make it unusable, even if the ship otherwise survived?

 

[mack8]

According to Mr. Armoured Carrier's site (https://www.armouredcarriers.com/hms-indomitable-lessons-learned), there're 21 fighters(9 Sea Hurricane, 12 Fulmer) deployed in the HMS Indomitable at that time.

Thanks for the info. So 21 not very effective fighters in total (the G4M is almost as fast as a Fulmar and as i understand most Sea Hurricanes were only good for about 300mph?), but one can be sure they won't all be operational, or even all in the air at the same time.

Again ignoring for the moment potential major alterations to the course of events, looking at the sequence of OTL attacks it seems likely that most or all airborne fighters would be "soaked in" by the first bomber waves, ie the level bombers which didn't hit much anyway. So it's possible most of the torpedo bombers might still attack unmolested.

Plus don't forget that the japanese bombers have 20mm defensive guns, i imagine the Hurricanes and Fulmars must get quite close to hit with their .303s which are nowhere near as destructive as the US .50 cals (unless there were any cannon equipped Hurricanes?)

It also seems that if the first japanese attack wave encounters significant resistance and/or does not manage to sink the targets, there will be another attack.