Indian Ocean scenario

[weasel_airlift]

The 1942 scenario that pits Admiral Somerville's Eastern Fleet against Admiral Nagumo's carrier force in the Indian Ocean has already been discussed to death, I propose the following

Say Nagumo's carriers were busy engaged in a carrier vs. carrier engagement against Somerville's Force A, which included the carriers Indomitable and Formidable, not to mention HMS Warspite for AA protection, 2 E class cruisers and 6 destroyers, and do not come further into this discussion.


In this scenario, Nagumo had detached Mikawa's 4 Kongo class battleships plus some escorts to bombard the RN base at Addu Atoll, only to run smack into Admiral Willis' Force B, which included the four surviving "R" class battleships, 3 cruisers and 7 destroyers.

The IJN BB's escorts are limited to one destroyer squadron and Kurita's 4 Mogami class cruisers, let’s discuss the outcome. Let's assume the weather conditions were perfect with the IJN getting advance warning from scout planes while the RN surface radar also detects the Japanese ships.

So, we have the British fleet:


Battleships

Resolution
Royal Sovereign
Revenge
Ramillies

Cruisers

Caledon
Dragon
Jacob Van Heemskerck (Dutch)

Destroyers:
Griffin
Norman (RAN)
Arrow
Decoy
Fortune
Scout
Isaac Sweers (Dutch)

And the Japanese fleet:

Battlecruisers

Kongo
Haruna
Kirishima
Hiei

Cruisers
Mogami
Mikuma
Suzuya
Kumano

Destroyer Squadron
Abukuma (Light cruiser)
Urakaza
Tanikaze
Isokaze
Hamakaze
Kasumi
Arare
Kagero
Shiranui
Akigumo

 

[CV12Hornet]

This is liable to go poorly for the Brits. If the Japanese stay at long range like they’d trained to do, and given the speed gap they can, the British battleships won’t be able to do much. Worse, that screen is not going to stand up to four CAs punching through and letting destroyers at the battleships. We could very well see total annihilation of the British fleet with minimal losses for the Japanese.

 

[HMS St.Lawrence]

IMHO the best (and probably only) shot the Royal Navy has at victory in an hypothetical engagement against the IJN during the Indian Ocean Raid is at night.

In daylight, the four Kongos vs four Rs scenario is not looking so good for the Royal Navy. The British have in theory the firepower advantage but the Japanese have the speed and better torpedoes. I don't believe the Kongos alone could take out the Rs, but like CV12Hornet mentionned, the Japanese screen is likely to be able to overcome the British escorts and launch a spread of Long Lances at the unsuspecting battleships. Meanwhile, the Fleet Air Arm will have a very hard time conducting offensive operations against the Kido Butai: their Fulmars are not suited for escort missions where they need to take on enemy figthers head-on. That leaves them with Martlets and Sea Hurricanes, but the numbers will be strongly in favor of the Japanese. In a full fleet daylight engagement, my money is on the Japanese navy.

However the biggest problem with this scenario is that, as far as I'm aware, these is no indications that the IJN knew of Port T at that time. And this, is in my opinion the best advantage the British had during the raid. Port T gave them a safe(ish) harbour where they could fall back and reorganize. I truly think that, at night, Somerville stands a reasonable chance to blood the vanguard of the Kido Butai using his ASV-equipped Albacores to guide a strike. If all goes well that night, then comes the morning of Easter Monday the Kido Butai will have two carriers out of action and the Eastern Fleet will be going west at full pelt. The IJN meanwhile will still have the number advantage, but their superiority will be reduced and they will still have to find the British, not to mention that their destroyers will be due to be refueled on that day, What then happens on April 6th is another conversation.

 

[Coulsdon Eagle]

This is liable to go poorly for the Brits. If the Japanese stay at long range like they’d trained to do, and given the speed gap they can, the British battleships won’t be able to do much. Worse, that screen is not going to stand up to four CAs punching through and letting destroyers at the battleships. We could very well see total annihilation of the British fleet with minimal losses for the Japanese.

The Japanese also had superior optics compared to the tired old R-class. Radar may be a factor in any night fighting.

The Kongo's armour is poor in comparison, but I agree with CV12 Hornet that the most likely outcome is a sudden & mystifying torpedoeing of the floating coffins (cf. Winston) at unusually long ranges.

 

[weasel_airlift]

This is liable to go poorly for the Brits. If the Japanese stay at long range like they’d trained to do, and given the speed gap they can, the British battleships won’t be able to do much. Worse, that screen is not going to stand up to four CAs punching through and letting destroyers at the battleships. We could very well see total annihilation of the British fleet with minimal losses for the Japanese.

I would think that the Kongos staying at range will result in emptying of magazines with no major damage.

Anyone know how good the shooting of the Rs was? They're third tier by 1942, so I can't imagine they have the cream of the RN, nor even the milk. Probably just the skim milk. Mechanically I know they were in poor shape, and to maintain cohesion could probably not steam faster than 18 knots for any extended period.

 

[CalBear]

The Japanese have a series of enormous advantages.

They can dictate the engagement at will as their capital ships have a 9 knot speed advantage, and with CAVU conditions their will be able to engage at range both using the utterly superb optics their heavies mount, as well as multiple spotting aircraft to provide real time correction (each of the Mogami carry three float planes, while the "fast BB carry two each); only two of the RN ships (Resolution and Ramilies) carry any float planes, with each embarking a single aircraft. This alone presents an almost unrecoverable advantage to the IJN.

The British cruisers are WW I holdovers, meant more to be fast scouts and destroyer flotilla leaders. Relatively little fire power and a basic torpedo set up (2x4 21" tubes). Jacob Van Heemskerck is a CLAA, with no torpedo capability of any kind. The RN destroyer forces it a mix of ships from different classes (and navies) with most carrying 2x4 21" torpedoes. The forces have never exercised together and their crews are a mix of "convoy battles" and surface warfare veterans.

The IJN heavy cruisers are, by contrast, over gunned and overarmed (with the inevitable weight issues that implies, but in the conditions noted this isn't really an issue). 2x5 20.3cm guns that demonstrated themselves to be a formidable weapon, and the typical Japanese massive torpedo armament of 4x3 24" Type 93 (Long Lance) torpedo tubes AND a full set of reloads. The IJN DD carry 4x2 24" tubes (no reloads) and are all, excepting Arare, of the same class (Kagerō), as was relatively standard practice of the Japanese. About the only break the British have gotten is that Abukuma is an immediate post WW I design and lacks the prodigious torpedo armament of later Japanese cruiser classes.

In summary, the Japanese can hot far harder, with torpedoes of a range beyond the wildest fantasies of the British* and at lower ranges with extremely fast (50 knots) weapons that carry unusually large (490kg/1080 lb) wartheads that caused enormous damage to ships over any class (Given the age, various torpedo bulge designs and displacement (~30,000 tons) of the British R class ships, it is unlikely that any of them could survive three hits, even two might be enough to put them on the bottom, with a single hit likely to produce a mission kill/5-8 knot cripple.

British will be fortunate to get most of their destroyers away, They may well sink one of the Kongo in a gun duel, and/or one or two of the Japanese CA, but on balance it will be a slaughter.


*The long range is really only useful in that it allows the Japanese to fill the water with extremely effective torpedoes at a distance beyond anything the British though even possible, with vast majority of very long range shots being misses. It is, nonetheless, a very dangerous issue if a number of torpedoes are fired into the likely direction of the enemy while that enemy remains entirely unaware that they are even under attack.

 

[CV12Hornet]

I would think that the Kongos staying at range will result in emptying of magazines with no major damage.

Anyone know how good the shooting of the Rs was? They're third tier by 1942, so I can't imagine they have the cream of the RN, nor even the milk. Probably just the skim milk. Mechanically I know they were in poor shape, and to maintain cohesion could probably not steam faster than 18 knots for any extended period.

Japanese practice was to fight at long range, and they were the only fleet to plan to fight the decisive phase of any battleship gunnery action at long (21,000-27,000 yards). Their optimum range was 21,000-24,000 yards, and in battle practice achieved a 21% hit rate at 22,000 yards and a 12% hit rate at 35,000, albeit the latter with the 16" guns of the Nagatos, not the 14" guns of the Kongos.

Even pessimistically assuming a third of that hit rate in actual combat, the Kongos should be able to land 30-40 hits before running dry on 14" shells; while at preferred ranges the belt should keep out Japanese shells most of the hits would be against the thin decks and underwater, where only the TDS protects from flooding, and the Rs are about as poorly designed to handle delay-fuzed shells as Kirishima was. Thus, 30-40 hits should be more than enough to sink or disable an R. Conversely, British fire is unlikely to be effective past 20,000 yards, as it took until the 1930s for the British to even practice gunnery past that range and effective shooting beyond that required new fire control that the Rs never got.

Toss in CalBear's point about spotter aircraft and Japanese optics, and yeah, I do think that the Kongos could sink the Rs by themselves if they had to. But, of course, they have all those lovely torpedo vessels on hand...

 

[naraic]

I'm pretty sure that IJN didn't like battleships doing shore bombardment. So if the cruisers go to do shore bombardment and the battlecruisers are distant cover maybe the R class can get the jump on the cruisers and inflict some damage before being sunk.

That said its much more likely (given Japanese spotting planes) that the Japanese get an advantage over the slow R classes and they are sunk by a combination of gunnery and torpedoes without managing to do significant damage.

 

[Riain]

As others have pointed out Sommerville's fleet was woefully inadequate to deal the the forces the IJN bought to bear in the Indian Ocean.

There was a 5 month long thread that ended in March about optimising the RN for WW2 that goes into what needed to be done to fight the early years of WW2. The R class doesn't come off too well.

Optimize the RN for WWII

Congratulations you've been made 3rd Sea Lord at the beginning of 1923 and will hold the post till the beginning of 1939. Your objective is to optimize the RN especially its new designs and refits of existing ships for WWII. Assume you get around a 10 to 15% larger budget than otl and slightly...

www.alternatehistory.com

 

[Cryhavoc101]

If its in the day time - advantage IJN

If its at night - advantage RN

The Japanese might have been good at night fighting - the British were also good at it and had actually done it!

Chuck in flashless cordite for everything 6" or less, working torpedoes, aggressive DD captains and radar and war experienced British crews and the Japanese are in for a rough night that would likely make the as then unfought "battle of Guadalcanal" a more desirable outcome