WI: Force Z sights 7th Cruiser Squadron

[RLBH]

On the evening of 9th December 1941, Force Z was within five miles of the IJN's 7th Cruiser Squadron, comprising five heavy cruisers and three destroyers. An IJN reconnaissance flight dropped a flare having misidentified the cruiser CHOKAI as the PRINCE OF WALES; this prompted Admiral Philips to abandon the operation on the grounds that surprise had been lost.

The two forces were actually within gunnery range of one another - just ten thousand yards, comparable to the North Sea actions of twenty-five years previously. What if the flare had given the British just enough light to identify the Japanese cruisers?

See here for a map of the forces and movements. Note the rather ominous Japanese force to the northeast of the proposed encounter. Barring extreme good luck on the part of the British forces, this ends badly - but they'll die with their boots on and facing the enemy. That should have major consequences.

 

[nbcman]

If Force Z moves to engage, the 7th Cruiser Squadron would probably evade after firing a series of torpedos at them. They have a 9 knot speed advantage over the PoW and can decide whether to turn back after the results of the torpedo attack or continue northward to meet up with the Kongo/Haruna force. If Force Z follows, they would probably meet up with the combined Japanese force early on the 10th before dawn which would not go well for Force Z.

 

[Trevayne]

On the evening of 9th December 1941, Force Z was within five miles of the IJN's 7th Cruiser Squadron, comprising five heavy cruisers and three destroyers. An IJN reconnaissance flight dropped a flare having misidentified the cruiser CHOKAI as the PRINCE OF WALES; this prompted Admiral Philips to abandon the operation on the grounds that surprise had been lost.

The two forces were actually within gunnery range of one another - just ten thousand yards, comparable to the North Sea actions of twenty-five years previously. What if the flare had given the British just enough light to identify the Japanese cruisers?

See here for a map of the forces and movements. Note the rather ominous Japanese force to the northeast of the proposed encounter. Barring extreme good luck on the part of the British forces, this ends badly - but they'll die with their boots on and facing the enemy. That should have major consequences.

If they fight, this could go either way. If the Japanese torpedos hit, the British will get wrecked. If they don't, it could get as ugly for the IJN as the Matapan was for the Italians.

This is a modern battleship and a older battlecruiser with 15" guns versus a group of heavy cruisers. With just gunnery, the cruisers are getting sunk with little damage to PoW. Repulse may get torn up by 8" shells, but not critically damaged. It all depends on how well the Long Lances do.

 

[Rubicon]

Depends on who spots who first and where and what course changes have been made to have these forces engage each other. And from that map you posted it looks more like 20-25 miles from each other at 19.30 on the 9th so you're going to need more changes then just "spotting" the flare.

But if they do blunder into each other it really do matter who spots who first and in what position.

If it's the Japanese that spots Force Z first, then there might be two sinking capital ships very shortly. If the opposite then it might still end with two sinking British capital ships, but they have a fighting chance, it depends on Admiral Phillips, what and how much he knows about radar and trusts it. Since the type 271 radar was very recently installed on the PoW, the rest were AA radars.

On the other hand the Japanese have a significant speed advantage and can disengage quite easily and call on nearby reinforcements in the guise of Kongo, Haruna, Atagao and Takao.

I'd say advantage Japanese but not overwhelmingly so.

 

[Cryhavoc101]

On the evening of 9th December 1941, Force Z was within five miles of the IJN's 7th Cruiser Squadron, comprising five heavy cruisers and three destroyers. An IJN reconnaissance flight dropped a flare having misidentified the cruiser CHOKAI as the PRINCE OF WALES; this prompted Admiral Philips to abandon the operation on the grounds that surprise had been lost.

The two forces were actually within gunnery range of one another - just ten thousand yards, comparable to the North Sea actions of twenty-five years previously. What if the flare had given the British just enough light to identify the Japanese cruisers?

See here for a map of the forces and movements. Note the rather ominous Japanese force to the northeast of the proposed encounter. Barring extreme good luck on the part of the British forces, this ends badly - but they'll die with their boots on and facing the enemy. That should have major consequences.

I've written a bare bones scenario where this happens - Force Z sorties with HMS Maurtias (OTL left behind due to an issue with her primary water main) 2 extra DDs and 2 of the D class Crusiers

They run into the battleships Kongō, Haruna, three Takao-class cruisers and eight destroyers and also the 7th Squadron racing in - with Mauritias Radar giving Force Z the oppertunity to get the first torpedo strike in before POW and Repulse get stuck in.

So very similiar to your above scenario.

I had the torpedos on both sides being less than decisive - and before anyone shouts "Long Lance sinkz al da Brits" go here and read this

http://www.navweaps.com/index_tech/tech-067.htm

My results were 1 Kongo sunk (actually beached in sinking state 1 initial Torp Hit and multiple 14" Hits) another Kongo badly damaged (Single 15 inch pentrating near aft turrets causes internal fires and knocks out half her guns - ship withdraws)

2 Crusiers damaged by Torpedos and 1 sunk mainly by 6" from Maritiaus and 5.25" fire from

2 more Cruisers badly damaged while attempting counter attack - Main Force Z turns away and withdraws at this point

HMS Dragon is crippled by a Long Lance - most of her crew taken off by HMS Tenedos - who goes on to have an interesting 24 hours after losng the rest of Force Z and being subjected to the rude attention of 2 Air Groups after being mistaken for a battleship.

The upshot?

IJN Command having lost contact with the British force fears that it has all or in part broken through and is now threatening the landings bottles it and orders the landing fleet to abandon its landing ops and return to Thiland

This effectively delays the landings for over a week

But a KGV and Repulse vs some 4 Mogami Heavy Cruisers?

Short some lucky long range Long Lance Hits those Cruisers are in a bad place.

 

[Riain]

The PoW would mostly shrug off the 8" hits, the Repulse less so but still in general would be able to put up a good fight. Both ships would be vulnerable to powerful LL torpedoes, but as that navweps article points out early in the war the IJN was only getting about hits 12% of the time. From what I can ascertain the group of ships that got within 5 miles of Force Z was 4 Mogami cruisers (48 LL torps), Chokai (8 LL torps), Sendai (4 LL torps) and 4 destroyers (dunno, maybe 32 LL torps) for a grand total of 10 ships with 92 torps, of which 11 or so will be hits if all ships fire all their torps.

However the PoW or Repulse's main armament will be enough to deal with any single IJN ship very quickly, and the British torpedos are also very effective at shorter ranges.

I think that it would depend on who got the first shots in as to the particulars of the result. However there is little to no chance that the IJN is going to come out unscathed from such an engagement, if Force Z is destroyed the IJN is going to lose some ships in the process and they can't afford that. How will the battles in the South West Pacific fare if the IJN has 3 less heavy cruisers?

 

[Rubicon]

4 Mogami cruisers (48 LL torps), Chokai (8 LL torps), Sendai (4 LL torps) and 4 destroyers (dunno, maybe 32 LL torps) for a grand total of 10 ships with 92 torps, of which 11 or so will be hits if all ships fire all their torps.

Hold on, where did you get those numbers because they're some mistakes in them, the Takao-class which Chokai was one of carried 4x4 Type 93 24" (LL) torpedoes and the Sendai-class carried 4x2 Type 93 24" (LL). They had 8 and 4 tubes on each broadside. You're also forgetting that they all carry reloads.

And depending on which Japanese destroyers, if it's the four with the Mogami TF, they all had 2x4 tubes each with a full reload, if it's the five with Sendai of the Fubuki-class they all carried 3x3 with 6 reloads each. And what of the destroyer with Chokai (Sagiri?) she was also of the Fubuki-class

 

[Saphroneth]

The PoW would mostly shrug off the 8" hits, the Repulse less so but still in general would be able to put up a good fight. Both ships would be vulnerable to powerful LL torpedoes, but as that navweps article points out early in the war the IJN was only getting about hits 12% of the time. From what I can ascertain the group of ships that got within 5 miles of Force Z was 4 Mogami cruisers (48 LL torps), Chokai (8 LL torps), Sendai (4 LL torps) and 4 destroyers (dunno, maybe 32 LL torps) for a grand total of 10 ships with 92 torps, of which 11 or so will be hits if all ships fire all their torps.

However the PoW or Repulse's main armament will be enough to deal with any single IJN ship very quickly, and the British torpedos are also very effective at shorter ranges.

I think that it would depend on who got the first shots in as to the particulars of the result. However there is little to no chance that the IJN is going to come out unscathed from such an engagement, if Force Z is destroyed the IJN is going to lose some ships in the process and they can't afford that. How will the battles in the South West Pacific fare if the IJN has 3 less heavy cruisers?

12% of the time?
Doesn't it average to more like 6%?
At Java Sea they flushed over 150 tubes and got about three hits, and that really hammers any average

 

[Riain]

Hold on, where did you get those numbers because they're some mistakes in them, the Takao-class which Chokai was one of carried 4x4 Type 93 24" (LL) torpedoes and the Sendai-class carried 4x2 Type 93 24" (LL). They had 8 and 4 tubes on each broadside. You're also forgetting that they all carry reloads.

And depending on which Japanese destroyers, if it's the four with the Mogami TF, they all had 2x4 tubes each with a full reload, if it's the five with Sendai of the Fubuki-class they all carried 3x3 with 6 reloads each. And what of the destroyer with Chokai (Sagiri?) she was also of the Fubuki-class

A quick Wiki and in no way definitive, I'm more than happy to go with your numbers, either way its a hell of a lot of torpedos.

 

[Riain]

12% of the time?
Doesn't it average to more like 6%?
At Java Sea they flushed over 150 tubes and got about three hits, and that really hammers any average

Yes over the longer course of the war, but in 42 the chances of getting a hit was quite good. After radar became widespread and tactics such as long range 6" barrages were adopted to keep IJN ships at bay the previously decent numbers dropped away drastically, by the end of the war a hit was virtually a fluke.

Engagement ANTFPH

Percentage ​

3) 19-20 Feb 42 The Battle of Badung Strait 8:1

12.5%​

4) 27 Feb 42 The Battle of the Java Sea 54.67:1

1.8%​

6) 1 Mar 42 The Battle of Sunda Strait 7.4:1

13.5%​

7) 9 Aug 42 The Battle of Savo Island 7.6:1

13.1%​

8) 21 Aug 42 The loss of USS Blue 4:1

25%​

9) 11-12 Oct 42 The Battle of Cape Esperence 2:0

0%​

10) 13 Nov 42 The First Naval Battle of Guadalcanal 8:1

12.5%​

11) 14-15 Nov 42 The Second Naval Battle of Guadalcanal 25.5:1

3.9%​

12) 29-30 Nov 42 The Battle of Tassafaronga 7.8:1

12.7%​

13) 26 Mar 43 The Battle of the Komandorski Islands 42:0

0%​

14) 6 Jul 43 The Battle of Kula Gulf 12:1

8.3%​

15) 13 Jul 43 The Battle of Kolombangara 16:1

6.25%​

16) 6-7 Aug 43 The Battle of Vella Gulf 8:0

0%​

17) 18 Aug 43 The Battle of Horaniu 26:0

0%​

18) 6 Oct 43 The Battle of Vella Lavella 24:1

4.1%​

19) 2 Nov 43 The Battle of Empress Augusta Bay 44:1

2.2%​

20) 26 Nov 43 The Battle of Cape St. George 9:0

0%​

21) 7 Jun 44 The Battle off Biak 42:0

0%​

22) 24-25 Oct 44 The Battle of Surigao Strait 20:0

0%​

23) 25 Oct 44 The Battle off Samar 7:0

0%​

26) 3 Dec 44 The Battle of Ormoc Bay 4:1

25%​

Averages ​

16.76:1

6.71%​

 

[Saphroneth]

And engagement 4 on the list? The one where they fired over 150 torpedoes and got three hits?

If you sum up the number of torpedoes fired in all the engagements in the region you pick, and the number of hits - and bearing in mind that you've essentially cherry-picked it - then we get:

422 torpedoes launched
32 hits

7.5% average

If we add Kommandorski Islands then it becomes
464:32

6.9% average


You can't just ignore the single largest torpedo launch of the war.

Even if you averaged the percentages (statistically "completely stupid" since you can't mean means) then you get 10.5%, falling to 9.5% if Kommandorski Islands is used.

 

[King Augeas]

AIUI - and this may well be wrong...

The British may not know about the LL, but they do know about torpedoes. If they find themselves in what they perceive as torpedo range of the IJN cruisers, then they'll shoot for a few minutes then turn away in expectation of incoming torpedoes. On the face of it, this should protect them against an aimed LL attack if they initiated the battle by shooting first and they judge the torpedoes' speed and distance correctly.

Alternatively, however, the Japanese might spot them first and launch their torpedoes, which would mean that they arrive early before the turn away, with very serious consequences.

 

[Saphroneth]

With my stathead head on, that analysis actually makes the Japanese torpedoes sound better than warranted because it means the means.

Total number of torpedoes launched: 741.
Total hits (telling or dud): 38.

Ratio of hits to shots fired is 1:19.5, not 1:16.76.

So the 280 torpedo salvo would get only about 15 hits, not 18.


In addition, it's noted that the weapon is not good at long range - and this would be a long range engagement.

 

[takerma]

Once Japanese become aware of what they are fighting would they not flush all their tubes and try to disengage as fast as the can?

 

[Cryhavoc101]

Once Japanese become aware of what they are fighting would they not flush all their tubes and try to disengage as fast as the can?

Night fight + confusion/fog of war - the IJN might not necessarily know where their Friendly's are etc - probably not a good idea to start dumping dozens of torps into the sea unless they are pretty sure they are not about to sink Admiral Kondos 2nd fleet (Comprising Battleships Kongo & Haruna, 3 Takoe Class Cruisers and 8 Destroyers) which had sortied south in search of Force Z or Vice Admiral Ozawa's Takeo class Cruiser Chokai which had also sortied south.

Lots of a potential for fratricide on the high seas

Also it being night, bad weather and their being 3 differing IJN forces in the area there is not going to be a combined mass salvo of torps (well IJN doctrine at the time suggested half salvo assessing the results then repeating with a 2nd half salvo) - as I suggested earlier - torpedo results are going to be disappointing.

 

[Riain]

And engagement 4 on the list? The one where they fired over 150 torpedoes and got three hits?

If you sum up the number of torpedoes fired in all the engagements in the region you pick, and the number of hits - and bearing in mind that you've essentially cherry-picked it - then we get:

422 torpedoes launched
32 hits

7.5% average

If we add Kommandorski Islands then it becomes
464:32

6.9% average


You can't just ignore the single largest torpedo launch of the war.

Even if you averaged the percentages (statistically "completely stupid" since you can't mean means) then you get 10.5%, falling to 9.5% if Kommandorski Islands is used.

I didn't want to be too optimistic and predict an RN walkover based on major torpedo misses and duds. But hey, I'm all for that result if it's plausible.

 

[marathag]

Plus if the IJN is doing reloads under combat, too bad if the fish get hit from RN shell fragments

 

[takerma]

Night fight + confusion/fog of war - the IJN might not necessarily know where their Friendly's are etc - probably not a good idea to start dumping dozens of torps into the sea unless they are pretty sure they are not about to sink Admiral Kondos 2nd fleet (Comprising Battleships Kongo & Haruna, 3 Takoe Class Cruisers and 8 Destroyers) which had sortied south in search of Force Z or Vice Admiral Ozawa's Takeo class Cruiser Chokai which had also sortied south.

Lots of a potential for fratricide on the high seas

Also it being night, bad weather and their being 3 differing IJN forces in the area there is not going to be a combined mass salvo of torps (well IJN doctrine at the time suggested half salvo assessing the results then repeating with a 2nd half salvo) - as I suggested earlier - torpedo results are going to be disappointing.

Thats true my point is that if they know that they are facing a battleship and they have speed advantage, would they not just run for it? I mean fighting cruiser vs modern battleship is kindof suicide.

 

[RLBH]

he British may not know about the LL, but they do know about torpedoes. If they find themselves in what they perceive as torpedo range of the IJN cruisers, then they'll shoot for a few minutes then turn away in expectation of incoming torpedoes. On the face of it, this should protect them against an aimed LL attack if they initiated the battle by shooting first and they judge the torpedoes' speed and distance correctly.

Alternatively, however, the Japanese might spot them first and launch their torpedoes, which would mean that they arrive early before the turn away, with very serious consequences.

IJN doctrine was very much in the British mould - the RN taught the IJN about night fighting and torpedoes, for example. I would fully expect the British destroyers to attack the Japanese cruisers with torpedoes.

Depends on who spots who first and where and what course changes have been made to have these forces engage each other. And from that map you posted it looks more like 20-25 miles from each other at 19.30 on the 9th so you're going to need more changes then just "spotting" the flare.

But if they do blunder into each other it really do matter who spots who first and in what position.

The Admiralty staff history - the source of that map, which I really should have checked in the first place - puts it at 15 miles, and notes that 'had the two forces maintained their original courses a quarter of an hour longer, Matapan might well have been repeated or Savo Island anticipated, according to which sighted the other first.'

I think that it would depend on who got the first shots in as to the particulars of the result. However there is little to no chance that the IJN is going to come out unscathed from such an engagement, if Force Z is destroyed the IJN is going to lose some ships in the process and they can't afford that. How will the battles in the South West Pacific fare if the IJN has 3 less heavy cruisers?

Ultimately, any night surface action is going to be followed up by an air strike by the forces that historically accounted for PRINCE OF WALES and REPULSE. It's difficult to imagine them faring better after intense action - so the question is how much they take with them.

How the IJN then copes with a significant part of their cruiser force chewed up is where it gets interesting.

 

[Matt Wiser]

VADM Ozawa (the Gargoyle to his peers) commanded the covering force for the invasion convoy, and according to John Prados' book Combined Fleet Decoded, had orders from Admiral Kondo not to seek a night surface battle, but to lure Force Z north, where Kongo and Haruna could fight them at dawn. CruDiv 7's commander, RADM Takeo Kurita (the same Kurita at Leyte) would've done just that.

Did the British ships have any surface-search radar installed? The IJN sent divers to the wrecks a few weeks after the actual sinkings and found radar equipment on the ships-and actually recovered the gear. Was it air-search, or surface search equipment?