Japaense Fuel question - help wanted

[Joel Billings]

Would anyone like to make a guess at the amount of fuel that would be available to the IJN in the South Pacific during 1942 and 1943? We would like any info on fuel tonnage that was historically available, and what might have been available had the South Pacific been made the priority area for the entire IJN fleet. Any help would be appreciated. Currently in UV the only fuel restriction is getting the fuel shipped from Truk to the advance bases. Once the IJN fleet is committed to the campaign in 42, fuel becomes a key element for Japanese succes, but should it be limited?

Joel

[Jason629]

Now thats a tough question! Assuming historical conquest of the DEI and surronding areas and historical appropriations between the Army and Navy....the Japanese were importing about 1.75 million barrels per month (Aug '43). General consensus at the time said the IJN required 1.6 million barrels a month to operate. To the extent that american sub activity affected the import number I have no idea. To the extent that any of this information is relevant to your issues...I am equally unsure. I would note that I personally think that Japanese fuel considerations have to be manifested in this game in some capacity. They most certainly did not have a "blank check" when it came to fuel consumption! Source data - Mark Parillo, "The Imperial Japanese Navy in World War II," in Reevaluating Major Naval Combatants of World War II (New York, Greenwood Press, 1990), p. 64.)

[madflava13]

Subs hadn't really started pinching off the oil supply until later on in '44 sometime. It was then that TKs were put at the top of the priority list. I don't have my source book (US Sub Operations in WW2) with me, but I will try to get some better data when I get home.

[Jason629]

True enough, they werent yet loading BB's with barrels of crude for the trip home or trying to make gasoline out of potatoes!

[Snigbert]

I think fuel for Japan should be unlimited.

I also think we should get more carriers perhaps some atomic bombs.

Ok, maybe I'm biased because I enjoy playing the Japanese. <img src="smile.gif" border="0">

[Zakhal()]

"American fleet submarines did to Japan what Germany's U-boats failed to do to Britain: impose a near total blockade of the island nation. By the Fall of 1944, US subs had thrown a ring of steel around Japan's main ports. This blockade cut off all of Japan's imports of oil, rubber, iron ore, copper and other strategic metals, as well as virtually everything else Japan's import-dependant industries required.

In a few months, Japan, one of the world's leading industrial nations, ground to a halt. Her factories shut down, her air force was grounded; her navy immobilized in port. Tanks and army transport vehicles had no fuel. Japan's military was reduced to pre-World War I capability."

In fall -44 japans fuel importing had halted totally, meaning there was no oil at all coming to the home islands. So fuel must hav allready bin in reduced levels months before that. Maybe even early as fall-1943.

[James Taylor]

according to John Ellis, WW2 facts and figures, Jap. oil production in millions of barrels was 1941/11.5, 1942/13.7, 1943/17.3 of which imports were 8.4/10.5/14.5 respectively. Understand that naval assets can use raw crude oil to run their boilers in most cases, where as aircraft need a complex refined fuel (gasoline). So proximity of crude supplies will enhance naval mobility in the local environment. KISS principles dictate "no IJN restriction" other than interdiction to forward bases without local raw crude. The Japanese sustained decent strategic reserves 1941/48.9, 1942/37.8, 1943/25.8, 1944/15.3 to the end of each of these years, only 1945/3.7 did fuel resources become critical.

[Joel Billings]

Thanks for the info. Seems like IJN should not be fuel restricted in UV in 1942 or even in 1943.

Joel

[Warpup]

Surely there is something in books on the Solomons campaign to indicate whether or not fuel shortages in that theatre restricted Japanese operations.

I guess UV can just treat the rest of the Japanese navy and airforces and army as being in port or grounded or stationary in order to make sure that the southern operations got plenty of fuel. That's how it would look from a PacWar perspective.

[mogami]

Hello I would check storage cap in places like Truk and Rabual then limit supply to Truk to whatever it could store (but unlimited access to more) then I would require Japan to move it to Rabual in game to limit of what it can store. I will return after I have procured some figures.


After some searching I am suprised to find Truk was not that good of a base. (excellent anchorage poor facilities. It seems the fuel storage was simply anchoring a tanker?)

OK here is some data from a guy who believes oil avaibilty did have a impact on the South Pac operations.
Ship Fuel Usage at Cruising Speed (tons/hour)
Battleship 8 - 16
Fleet Aircraft Carrier 6.5 - 13
Light Carrier 3.5 - 6
Heavy Cruiser 3.5 - 5.5
Light Cruiser 1 - 2
Destroyer 1.5 - 2
...And Oil

Next, let's examine Japan's situation with respect to petroleum production at this stage in the war. In the fourth quarter of 1942, Japanese oil production (which was almost entirely concentrated in her conquered territories, such as the Indies) was 1,194,000 tons. Of that, only 643,000 tons made it to Japan (which is where practically all the refineries were), the rest being either lost to attack, or consumed in the conquered territories. So roughly 214,000 tons of oil per month was making it to Japan. However, the Imperial Navy alone was consuming about 305,000 tons of heavy oil (in the form of fuel oil) per month by this stage in the war (Parillo, p. 237). Keep that figure in mind: 305,000 tons.

Furthermore, by this time (October-November 1942) it must have been begining to become clear to the Japanese that the oilfields in Java and Sumatra were not going to be brought back into production at nearly the rate that pre-war estimates had counted on. The Dutch and their Allies had done a much more thorough job of demolition in the oilfields than the Japanese had hoped. This, coupled with the sinking of a transport filled with equipment and valuable refinery personnel, meant that Japanese efforts to get the production field back into production were doomed to be much slower than hoped by the Japanese military. The fact that the Imperial Navy had built up large stocks of petroleum before the was could not compensate for this sobering knowledge, especially given the high rate of fuel consumption thus far in the war. The week-long Battle of Midway alone had consumed more fuel than the Japanese Navy had ever used before in an entire year of peacetime operations (Willmott, "The Barrier and the Javelin"). With this in mind, let us examine what it took to fight effectively around Guadalcanal.

Scenarios

At this point, it's appropriate to construct some scenarios illustrating Japanese petroleum consumption during the Solomons campaign.

Scenario One: 'The Bombardment' Redux

On the night of October 13-14, the battleships Haruna and Kongo subjected Henderson Field to one of the most intense naval bombardments of the entire war. Without question, this was one of the more succesful naval forays the Japanese made into the waters of IronBottom Sound. When the Americans emerged the next morning, Henderson Field was wrecked, most of its aircraft destroyed, and much of the stock of aviation fuel gone up in smoke. Many Americans remember this as the most desperate phase of the entire battle. With Henderson temporarily out of action, the Marines could do little except watch helplessly as the Japanese landed troops further up the coast during the morning. Frantic searching managed to turn up enough fuel to get a few aircraft flying, but it seemed likely that the days were gone when Henderson Field could dominate the seas around Guadalcanal. The sense of American isolation at this time was quite acute, and had an immediate negative effect on American morale.

But what was the cost to the Japanese in terms of their petroleum reserves? Let's examine this operation from a logistical standpoint. To perform the mission, the Japanese brought the two battleships (Haruna and Kongo), a light cruiser (Isuzu), and nine destroyers down from Rabaul. From Rabaul to Guadalcanal is approximately 650 miles as the crow flies. For our purposes, we'll call it 800 miles each way (to allow for geography, zig-zagging to avoid submarines, and so on). Japanese practice was to cruise down the Slot at normal cruising speed (call it 16 knots), and then dash in under cover of darkness. Thus, one might have a 'mission profile' looking something like this: 650 miles at 16 knots, and then a 150 mile dash in the late afternoon into the combat area at a speed of 25 knots. This would be followed by an hour-long bombardment, or naval combat, and then a similar dash back out so as to be well away from Henderson Field by morning. In addition, we will add in the fuel needed to maneuver at high speed for an additional hour, which will replicate a submarine scare, air attack, or similar combat event as the force cruises down The Slot. Base fuel consumption for these vessels is as follows:


Ship Tons of Oil Burned / Hour (16 kts.)
Kongo-class BB 9.25 (est.)
Isuzu-class CL 3 (est.)
DD 1.35 (est.)
For the purposes of our model (and throughout this essay) we will assume that fuel consumption will triple at 25 knots. In combat operations, fuel consumption will increase by a factor of five for the larger ships (cruisers and above), and by a factor of ten for destroyers. These are rough figures, but they serve to illustrate the point. When matched against the 'mission profile', fuel consumption looks as follows:


Event Speed Total Miles Traveled (nm) Total Hours Traveled Tons of Oil Burned/ Hour Total Tons of Oil Burned
Cruising Operations 16 knots 1300 81.25 34 2734
Run In/Out of IronBottom 25 knots 300 12 101 1211
Combat 30 knots 60 168 2 336
Totals - 1660 95 - 4,282

Thus, one 4-day mission consumes over 4,000 tons of oil. That equates to roughly 1.4% of Japan's total monthly consumption of 305,000 tons. 1.4% may not seem like a lot, but remember, that 305,000 tons has to power the entire Japanese Navy. That includes Combined Fleet, all of its combat units, all of it's submarines, all the training exercises, all the patrol boats out on routine operations, escorts for convoys: everything. And just wait, it gets worse...


Scenario Two: 'The Bombardment' Deluxe

Next, let's take a look at another favorite scenario: Yamamoto gets serious and brings Yamato et. al. down from Truk to put Henderson Field out of business. In fact, Yamamoto purposed to do this at at least one point in the campaign, but was overruled by Imperial Headquarters (Agawa, "The Reluctant Admiral", pp. 328-329). The reason? Apparently, the fuel reserves at Kure, one of Japan's most important naval bases (and therefore presumably a bellwether for the supply situation of the Navy as a whole) had slipped to 65,000 tons. Navy consumption of fuel had recently topped 10,000 tons a day (which jibes nicely with the 305,000 tons/month figure I arrived at independently from other sources). This explicitly points to the importance of fuel in the Solomons campaign, and indicates that in this one instance at least the IJN could not afford to commit its heavy units because of fuel constraints.

It should be noted, too, that

In any case, had Yamamoto proceeded with such an operation, his task force would probably also have included Musashi, as well as the usual contingent of cruisers and DDs. I'm going to postulate a task force composed of Yamato, Musashi, four Myoko-class heavy cruisers, a Nagara-class light cruiser, and her attendant flotilla of, say, nine destroyers -- a powerful shore bombardment force with plenty of anti-surface power. Their individual fuel consumptions at 16 knots look like this

Ship Tons of Oil Burned/ Hour
Yamato 14
Myoko-class CA 5
Nagara-class CL 3 (est.)
DD 1.35 (est.)


Of course, Truk is a lot further away from Guadalcanal than Rabaul: 1,400 miles one way. Again, I will tack on an additional 25% (for a total of 1,750 miles) to account for zig-zagging and all that. So, our mission profile will be: cruise at 16 knots for 1,600 miles, followed by a 150-mile run in at 25 knots, followed by the bombardment and the run back out, and then the cruise home. Again, we'll also assume an air attack on the task force, and some high-speed running around in IronBottom as well, for a total of 2 hours worth of high-speed maneuvering. The fuel consumption rates for this mission look like this:


Event Speed Miles Traveled (nm) Hours Traveled Tons of Oil Burned/ Hour Total Tons of Oil Burned
Totals - 3560 214 - 15,535
Again, knowing what we know about Japanese petroleum usage rates, we have just consumed 5.1% of the IJN's monthly allowance. Was it worth it? You'd better hope so, and you'd better be prepared to repeat the exercise, because airfields have a tendency to repair themselves. This points to one of the frustrating aspects of the Guadalcanal campaign from the Japanese perspective -- decisive results didn't seem to be achievable. Rather, the campaign was one of prolonged attrition. As Admiral Ugaki noted in his diary, "It's infuriating -- we shoot them down and we shoot them down, but they only send in more." (Agawa, p. 326). From a naval perspective this meant that a one-shot attack against Henderson was probably not going to get the job done. Rather, if the Japanese were truly committed to bombarding the island airfield out of business, they needed to be able to mount such operations on a sustained basis. It might take weeks of such activity before the airfield was either eliminated or captured by ground forces. Imperial Naval HQ's refusal to send Yamato and consorts on such a mission to IronBottom Sound may have been an admission of this fact. One such bombardment mission in isolation, while possible, wasn't going to be sufficient in and of itself to secure victory. And the fuel for committing heavy units to Guadalcanal, night after night, doesn't seem to have been available

Scenario Three: The Tokyo Express

By the mid-point of the Guadalcanal campaign, the only way the Japanese could get any troops or supplies into Guadalcanal was via destroyer -- the 'Tokyo Express.' Let's take a look at what it took to keep the Express running. Typically, the Express would consist of four to six destroyers acting as transports, and another pair acting as escorts, for a total of six to eight DDs. A typical 'transport' destroyer would be able to carry either 150-200 troops or 200 55-gallon drums worth of supplies. According to our standard 'mission profile', total fuel usage for an individual destroyer under such conditions would be 172 tons round trip. Thus, a 'typical' Tokyo Express run could be expected to consume roughly 1,374 tons of oil fuel. That's nearly 1.5 tons of oil per man or barrel (counting the amortized fuel for the 2 escort DDs) delivered to Tassafaronga Point! A ton and a half of oil, for a couple hundred pounds of rice, or one half-starved infantryman without heavy equipment, is a lamentable exchange by any standard.

Such runs occurred as often as every three or four days. Postulate a month in which six large (6 'transports' + 2 escorts = 8 DDs) Express runs occurred, bringing in roughly 7,000 men or supply barrels. It takes about 8,250 tons of oil to get that done. Congratulations! You have just consumed roughly 2.7% of the Imperial Navy's monthly oil supply to put a scant regiment of troops (4000 guys) and their rice and miso soup (3,000 or so barrels worth) on Guadalcanal! That's a lot of oil, for very little in the way of credible logistical result, because of course destroyers were manifestly incapable of bringing in the sorts of heavy weapons and equipment which were necessary for the Japanese to eject the heavily dug-in Americans around Henderson Field

Scenario Four: The Tokyo Express ad absurdum

But in fact, by November 1942, the needs on Guadalcanal were much greater. The Japanese 17th Army's staff calculated its supply needs as being five destroyer loads per night, or 150 loads per month. Including, say, two escorts for each 5-load run (7 DDs total), that's 1,200 tons of oil per night, or more than 36,000 tons per month! And again, this doesn't begin to bring in the heavy equipment. To do that, 17th Army calculated that they would need 800 destroyer runs, as well as 20 runs from seaplane tenders. The destroyers alone (even if they had been available, which they were not) would have consumed 137,000+ tons of oil to do that job. Throw in the seaplane tenders (which were fuel hogs -- worse than a heavy cruiser), and the total fuel needed tops 150,000 tons, or nearly 50% of the IJN's monthly fuel allotment. When presented with 17th Army's plans, Yamamoto remarked that they were so unrealistic that success might be unattainable with such brains in charge of the Imperial Army's forces on Guadalcanal (Frank, p. 408). Clearly, the Tokyo Express was not getting the job done over the long haul.

Conclusion

The solution to Japan's dilemna, of course, was embodied in neither battleships nor the sleek destroyers of the Tokyo Express, but rather in the chunky hulls of humble cargo ships. 100 tons of fuel oil and a single decent-sized (12,000 ton deadweight) freighter will deliver a battalion of troops, and a good chunk of their supplies, too. Instead of the absurd number of destroyer loads outlined above, 17th Army's needs could have been met with 50 cargo-ship loads of troops and supplies. In fact, in terms of tonnage delivered for a given amount of oil burned, a cargo ship is something like 30 times as efficient as a destroyer. However, in order to use the plodding cargo vessels, the Japanese needed to neutralize American air power. Yet without the supplies and heavy weapons such ships could deliver, the Japanese ground forces were incapable of capturing the airfield. Quite a vicious Catch-22 indeed.

This dilemna, coupled with the perceived need to hold Guadalcanal at all costs, led to an even more ominous strategic situation. Japan had started the war severely disadvantaged in the area of petroleum stocks. If the Japanese were to win, they would have to make a virtue of necessity and fight effectively 'on the cheap' against their larger, more powerful opponent. Japanese doctrine acknowledged this inferiority, and sought to remedy the situation with an emphasis on moral superiority, training, and the usage of powerfully armed light forces to compensate for its disadvantage in numbers of expensive, gas-guzzling capital ships. In the Japanese Army, extreme aggressiveness, forced marching, and bicycles, were seen as replacements for petroleum-powered motorized transport and armored forces.

You will have to decide what percentage of the 214000ton per month supply is allowed for Southern Operations. Then you need to decide how and where and when it becomes available. It seems one lucky US sub sinking the right tanker between Truk and Rabaul could play a large role it deciding what the Japanese player can do. He may need to plan ahead and conserve fuel while he builds up an in theatre reserve before he can do any large scale sustained operations.

[ February 09, 2002: Message edited by: Mogami ]</p>

[Paul Goodman]

Mogami: A fine analysis. I hereby chastize you mightily for being asleep when the call for beta testers went out.

However, without any disagreement on your calculations, I disagree with your conclusion that fuel supplies were a major limit on operations around Rabaul. Your own numbers suggest 50% of the monthly total of IJN requirements. However, well over 50% of the navy must have been in the area, with nearly all the major units.

What I have never really understood is why the Japanese, once they had neutralized Henderson field with night bombardment, simply didn't stay. Heavy units could have shuttled to the Shortlands for ammunition and a few CVE's could have provided protection for the limited attacks the Cactus air force could make.

I note that as late as May 1943, virtually the entire Combined Fleet sortied from Truk, along with the 4 heavy cruisers in the Kuriles to oppose the Attu landing. Clearly, they were not overly concerned with fuel reserves and this is a cruise involving several thousand miles. Granted, this force was recalled by IGH, but I don't see any reference to fuel concerns being the reason.

In my opinion, fuel supply considerations should be tactical, rather than strategic at this stage of the war.

Paul

[Bulldog61]

Good Analysis Mogami!

Found a copy of Dunnigan's Victory at Sea. On Page 176 he list some ships fuel consumption per hour (in tons) at 15 Kts.
Yamato 9.5
Nagato 8.4
Shokaku 6.2
Mogami 3.2
Aoba 3.0
Agano 2.1
Fubuki 0.8
Akitsuki 1.6
He also states that at 30 Kts Vessels consumption would quadruple.

On pages 360-361 there are some tables of Japanesse oil consumption which pretty well jive with your figures. One of the challenges is which definition of ton we're using.
The US Ton 2000 Pounds AKA "Short Ton"
The "Long Ton" or 2240 pounds
The "Metric Ton" or 2204.6 Pounds.

In Richard B. Franks "Guadalcanal" on Page 269 where the IJN and IJA were planning the October Offensive for Guadacanal. IJN offices told IJA officers that once the fleet sortied from Truk it was limited to 14 days availability.

Still researching.

Mike

[swamp fox]

I think Mogami is on the right track. I think the fuel limit should a function of the storage capacity at Truk and realistic resupply rates rather than a total limit on the amount of fuel that can be used in the game. I don't think those limitations would be a major issue for the Japanese player except in the "extra forces" scenarios.

[ratster]

From what I've read the Japanese command claimed to have an 18 month war supply of oil as of June/41. The Oil embargo was one of the reasons they attacked us.

Anyway this would suggest that fuel for naval operations, as a strategic consideration, wasn't a problem well into 43.

Of course it was a problem at the tactical/operational level, even for the allies, but that's represented in the game already.

So I'd have to go with some kind of storage limit at Truk (as Mogami suggests), although for simplicities sake it would be easier to have an unlimited amount available there. I mean the difficult part is moving it from Truk to where it's needed.

Back to 12 o'clock high...

[madflava13]

I disagree completely on limiting the supply based solely on Truk's capacity. I don't know offhand if this historically occurred, but it seems to be to be fairly simple to create a convoy of TKs, load em up, and send them straight to Rabaul. In this manner, Truk has nothing to do with the equation. Hell, you could have a regular shuttle run from Palembang to Rabaul if you wanted...
I agree there should be some kind of limits, but Truk shouldn't be part of the equation.
My two cents...

[madflava13]

Sorry for the double post, but I'd rather see an arbitrary supply per week. You get X tons of oil/avgas per week to use. Sortie the Yamato left and right and you run out real quick...

[mogami]

Hi, Personally I think the fuel issue for UV should be what is moved from Truk to Rabaul (ships fuel free at Truk) Oil reserves however will be a major issue in WITP when the time comes.
In UV fuel at Rabaul does have to be measured,
it has to be a target and the Japanese player should be required to use it wisely (he can not just maintain a constant TF of BB's and CA's running down the slot everynight)

[Joel Billings]

Great info. The way the game works now is unlimited fuel in Truk. However, you need to move it down to Rabaul/Shortlands to be of use, and that's the issue. Sounds like we can leave it alone.

Joel

[mogami]

Hi, In my little notebook of things to do when I finally get to play this game.
1. As Japan increase AA protection of Rabaul
2. Work out various TF compositions based on how much fuel they require. (might need to keep BB's and CV's at Truk and only move lighter units down to Rabaul)
3. As Allies target fuel storage at Rabaul (how long does it take to get PM capable of supporting a B-17 group?) Gives a greater understanding of why Japan would bother trying to capture PM

[EDDUNN115]

I remember a great Gary Grisby game for the Apple II platform, "War in the South Pacific" I believe. The combat attrition of ships seemed to follow the war closely and unlimited fuel at Truk never seemed to be a factor.

The bigger issue to me is the repair rates for aircraft/ships. Perhaps as an optional rule/play balance factor the rates for aircraft repair/damage control can be modified.