mogami
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Joined: 8/23/2000
From: You can't get here from there
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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 ]
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Japaense Fuel question - help wanted - 
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