Dec 7, 1941. The USN is at sea. What does IJN do now?

[cammerjeff]

You also have to consider how it would have turned out if the USN BB's were caught in the open sea, yes they have a better chance of dodging bombs & Torpedo's, but it is also much harder to salvage a Sunk BB from the bottom of the Pacific, than from the bottom of a shallow Harbor. Also as no mention of the USN Carriers has been made, are they still off delivering planes to Wake & other more forward bases? Enterprise was very close to Peal Harbor at the time, actually close enough to launch F4F's to Pearl. If the Japanese fleet does start looking for the BB's do they stumble on the Enterprise? If so how do you think a 6 to 1 battle would turn out for the USN?
Is loosing the Enterprise a bigger lose to the USN than the old BB's where? How would that change the early Pacific Navel battles?

 

[SaparotRob]

The Pennsylvania wasn't docked on Battleship Row, but berthed near the Navy yard - ironically, within walking distance of one of the oil tank farms

I know BB-38 was in drydock. I guess the OP threw me when it said the BBs were gone.

 

[Glider]

You also have to consider how it would have turned out if the USN BB's were caught in the open sea, yes they have a better chance of dodging bombs & Torpedo's, but it is also much harder to salvage a Sunk BB from the bottom of the Pacific, than from the bottom of a shallow Harbor. Also as no mention of the USN Carriers has been made, are they still off delivering planes to Wake & other more forward bases? Enterprise was very close to Peal Harbor at the time, actually close enough to launch F4F's to Pearl. If the Japanese fleet does start looking for the BB's do they stumble on the Enterprise? If so how do you think a 6 to 1 battle would turn out for the USN?
Is loosing the Enterprise a bigger lose to the USN than the old BB's where? How would that change the early Pacific Navel battles?

Had the USN been caught in the open sea then I doubt that the result would have been much different.

a) The AA defences on nearly all the USN vessels were almost non existent often been limited to single mount HMG and a handful (make that a small handful) of 1.1in guns.
b) They wouldn't have anything like their war compliment of crew or weapons and in the case of the carriers, aircraft.
c) Radar was very limited as well.

The only result would have been a very heavy loss of ships and more importantly crews.

 

[EwenS]

Pacific Fleet ships with radars (all CXAM or CXAM-1 air search sets) in Dec 1941 were:-
Carriers - Yorktown, Lexington, Saratoga & Enterprise
Battleships - California, West Virginia, Pennsylvania
Cruisers - Pensacola, Northampton, Chester, Chicago + 2 light cruisers
Seaplane tender - Curtiss

Ships fully alerted and able to manoeuvre at sea are a different kettle of fish from a fleet unprepared and tied up in harbour like sitting ducks.

 

[GrauGeist]

Enterprise was very close to Peal Harbor at the time, actually close enough to launch F4F's to Pearl.

Enterprise's SBDs scouting ahead of the fleet intended to land at NAS Ford Island instead of returning.

 

[Shortround6]

a) The AA defences on nearly all the USN vessels were almost non existent often been limited to single mount HMG and a handful (make that a small handful) of 1.1in guns.

Not quite right.
It leaves out the 5in/25 AA guns. Most of the big ships had 8, some accounts vary. Some of the Cruisers were fitted for 8 but only given 4 for weight savings (fitted for means magazines, ammunition lifts and reinforced deck areas.) the extra 4 guns were to be fitted in war time. This is for cruisers built in late 20s and early 30s. By the late 30s or 1940 many of theses ships were brought up to "war standard" or war standard as planned in the 30s.
The 5in/25 was a pretty good gun as far as these things went. Since the battleships had 5in/51s for anti destroyer work the 5in/25s were optimized for AA work. Even the manual mounts had good (or at least as good as anybody else's) elevation and traverse and they were set up for more convenient loading at high elevations.

Granted this is the USS New Mexico in 1944 but most of the old BB at Pearl Harbor would have been somewhat similar. The guns would have been director controlled (perhaps with an earlier MK of director) but there would have inputs to the fuse setting machines to the left of each gun. Perhaps at Pearl there might not have been the ammunitions carriers in such numbers?
The USS Houston managed to survive several sizable Japanese aircraft attacks. We can argue about how many she shot down but on the other side, the Japanese didn't hit the Houston with much in the way of bombs considering the number of aircraft used against her. One account claims 940 5in AA shells fired in 45 minutes?

 

[Glider]

Pacific Fleet ships with radars (all CXAM or CXAM-1 air search sets) in Dec 1941 were:-
Carriers - Yorktown, Lexington, Saratoga & Enterprise
Battleships - California, West Virginia, Pennsylvania
Cruisers - Pensacola, Northampton, Chester, Chicago + 2 light cruisers
Seaplane tender - Curtiss

Ships fully alerted and able to manoeuvre at sea are a different kettle of fish from a fleet unprepared and tied up in harbour like sitting ducks.

I am afraid that I believe that you are too optimistic. The Radar was installed n a few ships but not all and knowing the enemy are coming is one thing but defending yourself another. The AA defences on board that majority of the ships were minimal to the point of almost being defenceless. The Repulse and POW had far more extensive Radar and AA equipment, were at a full wartime compliment and we know what happened to them.

Carriers
Lex and Saratoga had the most extensive AA weapons 12 x 5in (15 x 1) 20 x 1.1 (5 x 4 ) 28 x 0.5 (28 x 1)
Yorktown and Enterprise 8 x 5in (8 x 1) 16 x 1.1 (4 x 4 ) 24 x 0.5 (24 x 1) Note - some sources say that they didn't have the 1.1 until after war was declared
Battleships
California 8 x 5in (8 x 1) plus 12 x 5in LA guns, 10 x 0.5 (10 x 1)
West Virginia 8 x 5in (8 x 1) plus 10 x 5in LA guns, 10 x 0.5 (10 x 1)
Pennsylvania 12 x 5in (8 x 1) plus 10 x 5in LA guns, 8 x 0.5 (10 x 1)
Cruisers
Pensacola 8 x 5in, (8 x 1) 8 x 0.5 (8 x 1)
Northampton, Chicago and Chester, 8 x 5in (8 x 1) 8 x 0.5 (8 x 1)
Destroyers
Most USN destroyers at the start of the war had 4-6 0.5 (4-6 x 1) but had DP 5in.
Porters and Somers had 8 x 1.1 (2 x 4) but the 5in were not DP.

The warships larger that DD had the 5in/25 gun which was far less effective that the later 5in 38, which without the radar directors made them largely ineffective and all ships relied to a large degree on a handful of unguided HMG's. Some had the 1.1 which was an ineffective weapon and replaced as quickly as it could be.

So in brief, it would have been a major disaster for the USN. Once the air combat was over, most of the USN ships were almost defenceless against air attack.

 

[Thumpalumpacus]

Pacific Fleet ships with radars (all CXAM or CXAM-1 air search sets) in Dec 1941 were:-
Carriers - Yorktown, Lexington, Saratoga & Enterprise
Battleships - California, West Virginia, Pennsylvania
Cruisers - Pensacola, Northampton, Chester, Chicago + 2 light cruisers
Seaplane tender - Curtiss

Ships fully alerted and able to manoeuvre at sea are a different kettle of fish from a fleet unprepared and tied up in harbour like sitting ducks.

But I do think the point about about weak AA is apt. If the battleships and supporting units are off on exercises and pick up incoming bogeys, they're still in for a hard time, and in deep waters, imo.

 

[Shortround6]

The Repulse and POW had far more extensive Radar and AA equipment, were at a full wartime compliment and we know what happened to them

The PoW AA was bit over-rated. The 5.25in guns didn't fire as fast as desired and elevation and train may have been a bit slow (10 degrees).
PoW may have had a very good fire control system for the time.
The Repulse was 3rd rate (at best).
Six 4in guns and then the three octuple 2pdrs.
Then the smaller stuff (which was way ahead of the American small stuff at that moment)
The Repulse had two directors which were older than the ones on the PoW and they were different (?) A MK II forward and MK I aft.
Repulse radar was for surface fire only (?).
The 4in guns were not particularly fast firing (they were not the more common 4in/45 MK XIX).

The 5in/25s could fire almost twice as fast as the 5.25in guns, and they could fire around 50% faster than the Repulse's 4in guns.
American fire control is a bit sketchy. The BBs may have MK 19 or a few may have had MK 33s. There were no MK 37s among these ships at this time.
The American BBs had 2-4 3in AA guns. Most or all had been set up to take the 1.1in quad mounts but production was slow and at least of few of the BBs got a 3in AA gun in the 1.1in gun tubs while they were waiting for the 1.1in. These local control and ammo supply may have been less than ideal (ready lockers ?) A June 10th 1941 status sheet shows 3in guns in all BBs except Arizona and Nevada which had empty gun tubs. Nov 1 1941 shows only the Maryland with 1.1in guns in the Battle Force although 3 of the old Atlantic BBs had them (they also only had 3in AA guns)

The US had better big AA guns and the British had better light AA guns in this match up.

Nice drawings of the PoW and Repulse AA lay out on this website.
https://i.redd.it/ziknvqrszkq61.jpg
click on it and it enlarges.

 

[Admiral Beez]

Also as no mention of the USN Carriers has been made, are they still off delivering planes to Wake & other more forward bases? How would that change the early Pacific Navel battles?

If a fleet exercise is underway i expect USS Enterprise to be with the fleet. This should reduce the odds of being located, if only due to one less place to look. As for navel matters, idk.

 

[Tkdog]

I have been floating around in a US Navy ship around Hawaii. The Pacific is very big. Going to be hard for the Japanese to find them. Do they really want to be on the wrong side of Oahu looking?

 

[GrauGeist]

If a fleet exercise is underway i expect USS Enterprise to be with the fleet. This should reduce the odds of being located, if only due to one less place to look. As for navel matters, idk.

CV-6 Enterprise and TF-8 was returning from a supply mission to Wake Island and was within 215 miles of Oahu Sunday morning.

CV-2 Lexington and TF-12 was enroute to Midway Atoll and was about 500 miles from Oahu on the 7th.

CV-3 Saratoga was just entering San Diego's Harbor at 7 a.m.

And AV-3/CV-1 Langley was anchored near Manila on that morning.

To be honest, unless the fleet sailed east, there's no real chance of a carrier joining the group.

 

[wlewisiii]

I keep reading and rereading this thread and I can't help but wonder if the Japanese having a successful attack on Pearl Harbor wasn't, honestly, the best possible situation for the USN at that time. Without the old Standard BB's holding them back, they had to rely on modern carrier tactics rather than what the BB captains would have done.

Despite the loss of life, we were better off for the losses at Pearl because it forced the USN to fight a modern war rather than try for the ultimate surface conflict between two fleets of battleships that we might well have lost ala Force Z.

I may well be wrong but I am left wondering...

 

[Shortround6]

I keep reading and rereading this thread and I can't help but wonder if the Japanese having a successful attack on Pearl Harbor wasn't, honestly, the best possible situation for the USN at that time. Without the old Standard BB's holding them back, they had to rely on modern carrier tactics rather than what the BB captains would have done.

Despite the loss of life, we were better off for the losses at Pearl because it forced the USN to fight a modern war rather than try for the ultimate surface conflict between two fleets of battleships that we might well have lost ala Force Z.

I may well be wrong but I am left wondering...

It is a real can of worms.
The USN was under no illusions as to both the state of the Battlefleet, many of the old ships needed extensive refits to be considered suitable for modern warfare as it was known in Pre Dec 7th) and the state of "Modern Naval" warfare as they understood it pre- Dec 7th.

The US had been getting reports from the British about the actions off Greece/Crete/Med and had a very good idea how lacking the US ships were in AA, especially light AA.
The King Board had been trying to figure out improved AA. The King Board had wanted the existing 5in guns (both low angle and high angle) replaced with 5in/38s in twin mounts.
The US had a a problem with it's old battleships that they were well aware of. They were overloaded and were floating too deep with too much of their armor below the waterline. This was why the Colorado was under going "refit" on the West Coast, to get bigger bulges to restore floatation and improve torpedo protection. Maryland had already had her refit and West Virginia, Tennessee and California were scheduled in rotation following Colorado.
The New Mexico's were in the Atlantic. Wither they would have been transferred to swap with Nevada, Oklahoma and Arizona (?) is a question but it would have delayed any expedition to the the Philippines. Of course any expedition to the Philippines would have needed tanker support and other logistic support (or turned around part way). The Bases at Manila and Subic Bay were gone by the end of the December.
It didn't really really matter if some of the BB admirals dreamed of a classic fleet action against the Japanese. Without a bases or a crap load of tankers it wasn't going to happen in the Western Pacific. Planning on basing (fueling) at Java? Would planning have been completed and ships sent before the Japanese invaded?

 

[Thumpalumpacus]

I keep reading and rereading this thread and I can't help but wonder if the Japanese having a successful attack on Pearl Harbor wasn't, honestly, the best possible situation for the USN at that time. Without the old Standard BB's holding them back, they had to rely on modern carrier tactics rather than what the BB captains would have done.

Despite the loss of life, we were better off for the losses at Pearl because it forced the USN to fight a modern war rather than try for the ultimate surface conflict between two fleets of battleships that we might well have lost ala Force Z.

I may well be wrong but I am left wondering...

I think CinCPac would have had to pivot to carriers anyway. There weren't enough escorts for both the carriers and the battleships unless you grouped them together and robbed the carriers of their speed asset. Further, iirc USN only had eight fleet oilers (i.e. capable of keeping up with fleet at the latter's cruise speed), so fueling those gashogs is going to be a challenge.

When Nimitz did have the opportunity to use them in battle, at Midway in Jun 42, he instead kept TF 1 on the West Coast.

 

[Peter Gunn]

Interesting "what if", does provoke some thought.

As I understand it, as muskeg13 stated, KdB would have been aware that the Pacific Fleet was NOT at anchor in PH on the morning of December 7. So with that being said, I'd wager there might be no attack as the whole idea was to cripple the US Pacific Fleet.

But my feeble brain figures that since this was a planned all out attack around the Pacific Rim, KdB would go ahead and wreak havoc on the naval base and attending facilities and whatever ships were actually in port. I can see the value of doing rather extensive damage to Pearl Harbor's facilities but I doubt that whatever was done would be so devastating as to close the base. Probably enough damage to set the US timetable back 4-6 months at best.

 

[cammerjeff]

I agree, but from what I have read in the past just destroying the fuel farms alone would have forced the USN to pull back to the west coast for at least 6 months. They actually did not have to do any actual damage to the fleet to force that move. As already stated the USN does not have the Fleet oilers at the time to both supply the fleet and replenish the fuel reserves at Pearl. And that would have to wait for the tank farms to be rebuilt.
I have no idea how long that would have taken, as I am sure most if not all materials would have to come from the Mainland.

 

[Shortround6]

There is also a bit of a disconnect between the state of the US fleet in Dec 1941, the planned for fleet in 1938-40 and the idea of taking the old ships, round up the Hawaiian field workers as extra crewmen and head for the Philippines
In 1940 the US had laid down
4 Atlanta's
4 Cleveland's
1 South Dakota
2 Iowa's
In 1941 the US had laid down
2 Atlanta's
9 Cleveland's
4 Baltimore's
3 Essex
2 Iowa's

Granted even these ships didn't have enough small AA as designed. But they KNEW in 1938-40 that better AA was needed compared to the mid 1930s standards, it was being planned for.
In war you have to do what you have to do at times but the US Navy KNEW the ships they had were well short of the desired AA armament, even by 1940 standards.

However the BBs and Cruisers had been fitted with the extra 5in/25s and newer control systems than they had been built with originally, the 1.1 s were being built too slowly but there was only so much money to go around (build new ships or refit old?). US was in the process of tooling up for the 20mm and 40mm cannon and may have held off ordering more .50 cal MGs while waiting (not that extra .50s would have done much except for morale).

I would note that the Japanese 5in/40 AA gun in common use at the time fired slower than the US 5in/25, only had about 200fps (10%) more muzzle veleocity and the train and elevation rates were not good. Granted the the US and Japanese probably didn't know the capabilities of their opponents weapons but they did know how well they matched up to their own aircraft and could judge from that.

 

[Glider]

The PoW AA was bit over-rated. The 5.25in guns didn't fire as fast as desired and elevation and train may have been a bit slow (10 degrees).
PoW may have had a very good fire control system for the time.
The Repulse was 3rd rate (at best).
Six 4in guns and then the three octuple 2pdrs.
Then the smaller stuff (which was way ahead of the American small stuff at that moment)
The Repulse had two directors which were older than the ones on the PoW and they were different (?) A MK II forward and MK I aft.
Repulse radar was for surface fire only (?).
The 4in guns were not particularly fast firing (they were not the more common 4in/45 MK XIX).

The 5in/25s could fire almost twice as fast as the 5.25in guns, and they could fire around 50% faster than the Repulse's 4in guns.
American fire control is a bit sketchy. The BBs may have MK 19 or a few may have had MK 33s. There were no MK 37s among these ships at this time.
The American BBs had 2-4 3in AA guns. Most or all had been set up to take the 1.1in quad mounts but production was slow and at least of few of the BBs got a 3in AA gun in the 1.1in gun tubs while they were waiting for the 1.1in. These local control and ammo supply may have been less than ideal (ready lockers ?) A June 10th 1941 status sheet shows 3in guns in all BBs except Arizona and Nevada which had empty gun tubs. Nov 1 1941 shows only the Maryland with 1.1in guns in the Battle Force although 3 of the old Atlantic BBs had them (they also only had 3in AA guns)

The US had better big AA guns and the British had better light AA guns in this match up.

Nice drawings of the PoW and Repulse AA lay out on this website.
https://i.redd.it/ziknvqrszkq61.jpg
click on it and it enlarges.

Fair comments as all the heavy AA guns from 3in up to 5.25 were pretty useless against dive bombers as these defeated all early war control systems. Only when more sophisticated directors and proximity fuses did they have much of a chance.

What really counted were the light AA guns and this was seriously lacking in the USN.

 

[muskeg13]

I agree, but from what I have read in the past just destroying the fuel farms alone would have forced the USN to pull back to the west coast for at least 6 months. They actually did not have to do any actual damage to the fleet to force that move. As already stated the USN does not have the Fleet oilers at the time to both supply the fleet and replenish the fuel reserves at Pearl. And that would have to wait for the tank farms to be rebuilt.
I have no idea how long that would have taken, as I am sure most if not all materials would have to come from the Mainland.

This is an impossibility unless the prime mission of the Kido Butai from the very inception of the attack plan, months before 7 Dec, was the destruction of the fuel tank farms, and even then, the fleet wasn't going to be withdrawn to the west coast. All of the training, weapons development and the weapons load out of the Kido Butai was directed towards the destruction of the ships of the Pacific Fleet while anchored in Pearl Harbor. They sought to destroy major warships, mostly armored ships, primarily with torpedoes and heavy naval artillery shells converted to armor piercing bombs. Hitting the naval tank farm "on the fly" would have been completely ineffective.

They lacked the training and armament to create any significant destruction of the naval fuel farms that contained heavy viscous and nearly inflammable bunker fuel. Aircraft 7.7mm and 20mm rounds could not ignite the fuel even if they managed to hit and penetrate the tanks. If a few GP bombs managed to hit, a gooey mess would ensue, not a firestorm. Naval bunker fuel needed to be preheated to get it to burn properly in ship powerplants, and it wasn't going to explode and burn in a chain conflagration, particularly given tank farm spacing and containment walls. The Kido Butai would need special training and specially developed incendiary munitions to attack the fuel farm. Heavy fuel oil - Wikipedia

There were gasoline (including AVGAS) tanks, particularly at Hickam and Ford Island that were vulnerable to attack, but these would need to be effectively targeted. Even then, it would only be the exposed above ground tanks that were vulnerable. There were a number of "secret" below ground tanks, particularly at Hickam, that would survive.