Fuel shortage & saved games

[MajorArtNZ]

Hi everyone,

I am currently on my second patrol hunting around convoy college. I have been following my orders and have been sent to half a dozen different patrol areas. Despite my best efforts at conserving fuel, by the time I was released to go home, and headed for Midway which was the closest base in early '42, I ran out of fuel 400 miles from base.
I cruise at 2/3 speed, stay submerged on batteries for most of the day, use the fastest routes, only speed up when absolutely essential. There's even have a crew member whose special ability is extended fuel range.

Suffice to say from where I last saved my game, there's no way we'll make the nearest base so looks like a new game will need to be started.

Are there any other tips or techniques to conserve fuel?

Also, when loading saved games, sometimes instead of loading the saved game, it will crash the game. As a result, I normally save 3 times, but sometimes even this doesn't work. It's been doing this for years. Stock version, V1.4, and now TMO. I even brought a new game not that long ago, and it still does it. Presumably there is no way around this problem??

Many thanks :)

[fireftr18]

Fuel problem:
You really need to watch your fuel when sailing out of Pearl. Refuel at Midway, then proceed to your patrol area. 9 to 10 knots is usually best with TMO. Patrol around, then when you get about half on fuel, head home. Running underwater if you don't need to works against you. When you surface, your engines will run full speed until the batteries are charged.

Save problem:
If you save in the same file each time, then the files will eventually become corrupted. There is no fix to it, but there is a work around. Save in a different file each time. I will make a save while in port and call it "fireftr" for instance. Then add a number for each subsequent save. For instance, "fireftr1, fireftr2, etc. There are some old rules that I don't think apply anymore. Best to save in calm seas, during the day, on the surface, with nothing in sensor range. Most people lately, including myself, haven't had any problems with saving in rough seas, at night, submerged, in middle of a convoy attack.

[Crannogman]

Command doesn't seem particularly good at telling you when to stay out vs come home. So don't be surprised if they order you around regardless of your fuel and ammunition. At some point, feel free to head back to top-off; you can always just refit and return to your objective area, rather than ending the patrol

[CaptBones]

It's called the "Silent Service" for a reason. Although it was a different strategic situation and a different tactical environment, one of the lessons the USN learned from the Battle of the Atlantic was to maintain radio silence except for really urgent matters...cut the chit-chat and don't perform remote control of submarine commanders from HQ. Even USN "Wolf Packs" were controlled by the on-scene Commander and not by HQ Staff.

Unless you are ordered to conduct a 'special operation' like photo recon or agent insertion, or are ordered to go to a location and then report your arrival there, just proceed at most economical speed to your assigned patrol area and remain there for the required 96 hours.

If you're not having any luck then, you have three choices: (1) stick with it and hope for better luck; (2) proceed to a more promising area on your own; (3) send a status report and take whatever reassignment COMSUBPAC sends to you. I never exercise option 3; HQ doesn't care if you move on your own after completing the 96 hours in the area they sent you to (unlike the real-world, you're the only US sub out there and you will never be mistaken for an enemy unit by your own forces).

What fireftr18 said is absolutely correct...both subjects.

A). You can race from Pearl to Midway to save time and then top-off and proceed at a more leisurely pace to your patrol area (assuming your homeport is Pearl and your patrol area is in WestPac). Monitor your fuel consumption closely (how much fuel did it take to get from Midway to your patrol area?) and leave for the return trip, again via Midway, with some margin of safety (5% should be more than enough).

B). Unique file name for every save is a must. It also makes it easy to 'clean house' every now and then...you can delete any/every saved game file for each patrol without destroying any of the others or the career as a whole.

[Armistead]

Fairly sure now with TMO he adjusted standard speed ,about 15kts to give you the old milage you got at 10kts, but 10kts should give u way more than realistic fuel range.

TMO also has a few mileage tabs, use them to know your range vs. fuel.

[MajorArtNZ]

Thanks for all the help everyone, its greatly appreciated. In future I will save in a new file each time rather than just overwriting the same 2 or 3. ..Really hope that one works. Having the game crash after putting so much time and effort in has killed my interest on more than one occasion..

In regards to the fuel issue, if I were starting from Pearl Harbour, then the tanks would be topped up at Midway. But this particular patrol I started from Java and shortly after, the closest base to that point was Perth. Working out distances from the top of Formosa, it was significantly shorter to head to Midway. But trying to get back with 25% fuel is not possible. A shame really, I had finally found a couple of merchants that went to the bottom. Lesson learned.

[merc4ulfate]

Set your speed no faster than 10 knots unless your duration will be less than three hours. Once your fuel is below 50% plot a course home at 10 knots and not distance and time. If it is within 500 miles of running out then head back right then and there. Weather can slow you down on the way and use up fuel so give yourself some breathing room.

The worst I had it was 0% diesel and only 20% battery left when I made it into port.

you can use Travellers mod for sending an SOS at a renown cost in the future.

Generic Mod Enabler - v2.6.0.157
[Z:\SHOM\MODS]

1_TriggerMaru_Overhaul_2-5
1_TMO_25_small_patch
RSRDC_TMO_V502
RSRDC_V5xx_Patch1
Improved Ship Physics 2.6_TMO_RSRDC
TMO_Visuals_for_RSRDC
FJB_Navigation_Maps
FJB Color Navigation Map
Gyoraitei
11 New Ships + Yamato AA Fix by Miner1436
Ship pack 1
More_DDs_for_AITorpedoLauncher
SMALLER SEA PLANTS SMALL
SMALLER SEABED ROCKS
#5 Depthcharge Sound
#2 Other Clouds
Webster's Eliminate Floating Plankton for v1.4 and v1.5
Aircraft_reflections
Hull_Numbers
TMO Smoke Mod
AITorpedolauncher

[Lokisaga]

Hi MajorArtNZ,
What class of boat are you driving? If it's an S Class, then you're going to be hard pressed to get to the Luzon Strait from Perth and back no matter how efficiently you burn your fuel. Even under optimal conditions they only had a range of 5000 nautical miles. Otherwise, cruise at 10-12 knots (possibly 8 knots if you're driving an S Class), and remember that charging the batteries means 1 diesel is running at flank speed to turn the generator. I play with the TMO mod, and I've found that submerging during the day is basically unnecessary. Your watch crew can usually spot planes in enough time to crash dive as long as you keep the time compression in the 64-128x range. Once you get the SD radar planes aren't a threat at all, IMHO. Did you sustain any damage to the batteries? If your batteries were damaged there's a bug that causes them to "stick" in recharge mode without actually recharging. That can waste a lot of fuel. If that happens you need to manually switch to normal propulsion to stop recharging the batteries.

[SSI01]

That's interesting re: what speed the diesels were run at to recharge batteries. I always thought it was "standard," and the one or two charging the batteries were uncoupled from propulsion for that purpose. But you are correct, you spend a lot of time on patrol just "idling," maybe at 5 or 6 knots, waiting on known or suspected convoy routes for some prey to come trucking along.

I got sent from Pearl via Johnston Island to Carolines. Did OK there with ships coming along at rate of 1 or 2 every three days or so. Got down to about 11 torpedoes. Was then sent on the grand tour of the Marshalls where I saw NOTHING for about a week.:down: After that, COMSUBPAC rerouted me to Solomons where I could make a pit stop before being sent up The Slot for lifeguarding at the northern end.

Time: October/November 1942; class: Gato. You are right also re: the sometimes nonsensical routing. I send a status report every night as soon after midnight as possible. As I recall in real life that's what the boats did, but I'm probably wrong. At any rate, I keep hoping those status reports are somehow used by the sim to eventually recall my boat, or reassign a patrol area or task. From what you're saying in this thread, like the song says, "It ain't necessarily so"?

[Lokisaga]

That's interesting re: what speed the diesels were run at to recharge batteries. I always thought it was "standard," and the one or two charging the batteries were uncoupled from propulsion for that purpose.
You're right; the one or two diesels charging the batteries are uncoupled from propulsion, but they run at flank speed to recharge the batteries as quickly as possible to limit the time you're sitting, vulnerable on the surface with depleted batteries. It makes sense when you consider that the pre-war USN thinking was that submarines would spend most of their time submerged, but that turned out not to be the case.

[TorpX]

That's interesting re: what speed the diesels were run at to recharge batteries. I always thought it was "standard," and the one or two charging the batteries were uncoupled from propulsion for that purpose.


Half the engines run at flank speed (according to the tachometers). When I was doing development of ISP, I found the actual fuel consumption wasn't consistent, though. If the batteries are greatly depleted, more fuel is used at the start of the cycle, than when topping off the charge. Overall, the fuel consumed is at least roughly proportional to the level of depletion.

About fuel consumption in transit: I found fleet boats got the best mileage at ~9 knots, the S-class at ~6 or 6½. Remember, it is the engine speed, not the telegraph setting, that is important. This was with ISP, mods with different engine values may be different. Economical speed is ~3 kn. submerged.

Fleetboats use fuel while sitting still on the surface idling. I found the fuel burned was equivalent to going 9 kn. or so. This seemed outrageous to me, so I put a workaround for this in ISP. Then, you could lay to, and save fuel while you waited for a contact to show up. S-class boats don't burn fuel, at all stop.


I send a status report every night as soon after midnight as possible. As I recall in real life that's what the boats did, but I'm probably wrong. At any rate, I keep hoping those status reports are somehow used by the sim to eventually recall my boat, or reassign a patrol area or task. From what you're saying in this thread, like the song says, "It ain't necessarily so"?
YIKES!!!

USN boats weren't that chatty. They would listen for FOX messages directed to them giving contact reports, but unless they had something important to report, there was no valid reason to break radio silence. Enemy bases could DF these transmissions.

I would not expect very much from the command AI. You can expect to get foolish/suicidal/impossible orders at times. The devs didn't put too much effort into this part of the game. If you want to have a realistic game, I would encourage you to read some of the better books on the subject, and use your own 'house rules', for this purpose.

[aanker]

It is up to you as Captain to make the decision to return to base to refit & refuel.

SH4 cares most about completing Objectives. If you are based at Pacflt - Pearl assigned to the Carolines and you complete that Objective plus sink the required tonnage, ask yourself if you would have enough fuel to sail to the West side of the Philippines or some other distant location, complete another objective there, and safely return to Midway, before radioing in to base for that 2nd, 3rd, or 4th Objective, because the AI could send you anywhere without regard for how much fuel you have remaining. It does keep track of how many torpedoes are remaining and will usually suggest that you may return to base at your discretion when you are down to just a few or empty.

I've read that the Germans & Japanese reported their positions in to base almost on a daily basis and fortunately the Allies cracked their codes - which is how we have our ULTRA map contact updates on the chart.

We were the 'Silent Service' as mentioned above.

I believe that Ducimus set Ahead Standard as the most economical speed in TMO 2.5 with the concern that people would find out that it was even more 'economical' to set their knotmeter at 9-10 knots, Ahead 2/3, or Ahead 1/3, and would be a 'fuel cheat' with the resulting unrealistic extended range. I don't know what he did about preventing that, if anything.

In earlier versions of TMO, 9-10 knots was the correct setting for best fuel economy... as it still is in Stock 1.5 or v1.4.

Happy Hunting!

[Sailor Steve]

I believe that Ducimus set Ahead Standard as the most economical speed in TMO 2.5 with the concern that people would find out that it was even more 'economical' to set their knotmeter at 9-10 knots, Ahead 2/3, or Ahead 1/3, and would be a 'fuel cheat' with the resulting unrealistic extended range. I don't know what he did about preventing that, if anything.
I don't think there's anything that can be done about that. I'm pretty sure his thinking was the opposite - fuel economy at lower speeds doesn't matter if you can get the expected mileage at 15 knots. He considered 'Standard' speed to be the actual cruising speed. I argued at the time that 15 knots was the standard cruising speed for surface ships of the era, and that the surface ships could refuel at sea whereas the submarine couldn't. He didn't see it that way, and of course since it's his mod he could set it any way he wanted.

[TorpX]

Sailor, my memory of his logic is pretty close to yours.

He thought 'standard' should be the customary cruising speed, and left it to the players, as to whether they would milk their fuel by going at 1/3, or transit at standard.



A couple of points that may not be apparent:
A S-class sub has two main engines. The German U-boats had the same number. On their transits to the US east coast, they made their transits running on one engine, clutched to both propeller shafts, to save fuel. This gave them about 6½ knots. This was slow, but allowed them to operate at great distances. The most economical speed of the S-class is also 6½ kn.

The US fleetboats had four main engines. It is axiomatic that the most economical speed will be one-engine speed. This amounts to ~ 9 knots. Even without considerations related to mechanical failures, it is highly advantageous to have 4 smaller engines instead of 1 large one. If you wanted to save fuel, you could reduce the speed of the one engine, but below a certain level, a big engine running at low rpm's would waste a lot of fuel. With multiple engines, you can shut down any that aren't needed, so there is no such waste. Below this 'one-engine' speed, you start to lose ground. That is, you are operating the one engine at a sub-optimum level, so you waste fuel again.

I tried to adhere to the idea of 1/3 = one-engine speed, 2/3 = two-engine speed, etc. when putting together ISP. As far as I could tell, the exact speeds of maximum fuel economy are hard-coded (I never tried to manipulate engine hp values for this purpose). We can set the game ranges in any terms we like, but this doesn't change the actual fuel consumption of the boats. Specifying the range in terms of X mi. @ 10 kn. or Y mi. @ 8 kn. doesn't change the 'ideal' speed, nor does the telegraph settings. Editing the range values say, from 10,000 @ 10 kn. to 10,000 @ 15 kn. gives you extra fuel, it doesn't really change the way the engines operate. I'm not sure everybody realizes this.

One the whole, I think this part of the game works pretty good.

[MajorArtNZ]

Yeah it was an obvious miscalculation on my part. It has been mentioned in this thread that the game keeps an eye on the amount of torpedoes you have as opposed to your fuel level. I thought it was more the other way around- hence following orders until told to go home. It's pleasing to hear that flexibility with orders is encouraged.

I find in TMO that targets are harder to come by than the stock version. One of the patrols I once completed had run down to 25% of fuel and there were still 10 torpedoes on board.

[merc4ulfate]

Sending a radio signal every night at the same time is a great way to have your position triangulated so that you and all your men are dead in a matter of days.

Only a foolish skipper would do that.

Then again ... it might make for a great ambush.

[MajorArtNZ]

Does the game factor that in? There have been periods where I have sent out signals each night, though nothing has ever come of it.

[merc4ulfate]

Maybe ... maybe not ... who knows?

[fireftr18]

I don't think the game factors in status reports for the enemy to hear.

[TorpX]

Some have said that it does, but I have never put the matter to the test.



***
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Something interesting about fuel shortages with subs.
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I am reading about Gudgeon. This boat made the first war patrol to Imperial home waters. They left Pearl Dec. 11, '41 and returned to Pearl Jan. 31, '42, 52 days.
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This was something of a feat of endurance, as they had just sailed into Pearl, and had been due for leave. Nor was there any precedent for a patrol of this length/distance. Though their route went by Midway, they did not refuel or stop there; there were, as yet, no facilities for this, and to conserve fuel, they were ordered to proceed at one-engine speed, and spent many days submerged. Out of the 52 days at sea, only 12 were 'on station'.
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Additionally, the author said the boat did not have a vapor compression still, and this had limited the men to 1.8 gallons of water per day, per man.
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They sank one merchant ship, in their patrol area, and the IJN submarine, I-73, on the way home.
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:salute:

[MajorArtNZ]

Yes, it has been a bit hit and miss with the whole fuel thing, but from all the advice and information you guys have given me, I am definitely now enjoying the gaming experience more. I got down to 50% fuel so I headed back to Midway to refuel before heading back out to complete the objectives...

(Playing TMO on all the hardest settings- save for map contact updates and the external camera)

After a few days patrolling B11, I found an ocean liner, old transport and a small transport with 4 destroyers as escort. Found myself almost directly in front of them so it was easy to get in between the destroyers. Fired 4 torpedoes at the Ocean liner and she went down after 2 hits. Managed to escape without being picked up, and am currently doing an end round to get in position to have another go. :)

And, there's been no more issues with the saved games either! That was the biggest enjoyment killer for me. Thanks for all your help everyone! :)

[TorpX]

Find 'em, Chase 'em, Sink 'em.

:salute: