I need better fuel economy here, a 4 cyl would help!!

[CobraDriver]

Ok so I've gotten into the bay, took the pictures of the subs, snuck out and half way home out of gas.

I've gone into the bay, did the recon of merchants, killed a few, haf way home out of gas.

Now it was obvious I wasn't going to make it home because it took more than 50% fuel to get there. I was at 2/3 speed and and standard and making sure that as soon as my batteries were charged I would go to periscope and run off batterythus maximizing my fuel, and it still took a bit over the 50% to get to the objective. Silent running was not an issue cause I don't do that much. I even went as far as coming to a complete stop to recharge my batteries so I wouldn't burn gas and still didn't make it.

Someone have a reason for this?. I keep thinking when you compress time it screws the economy up, and I run alot of compresion to and fro. I keep it around 1000.

Any help would be appreciated.

Oh yea, running 1.5 with no major mods, just green bulbs, the compass rose and clearer torpedo wake.

[claybirdd]

Where is your home port? And also where was the photo recon mission. On a side note I only run submerged when absolutly necessary, and run at standard bell except when recharging batts at 2/3. I have never run out of diesel except when damage was taken.

[Task Force]

surfaced you should run at 1/3 speed, Ive gotten over 9,000 in a S boat and over 10,000 in a fleet boat.;)

[-Pv-]

I agree with Task Force. You should not be using anything higher than 8-9 knots when on long missions and you're not chasing a target. You should be charging batteries at 1/3 speed so they charge at a fast rate, thus when they are charged, you will get maximum speed. Also, mods which try to lower the sub in the water to reduce the visual effect of wave striding, also reduce the sub's range to less than historical.
-Pv-

[Quillan]

Assuming you're in a Gato or a Balao, your most efficient speed on the surface is between 9 and 10 knots. I can go from Midway to the East China Sea, patrol there for two weeks with intercepts along the way and make it back to Midway with plenty of fuel to spare.

[CobraDriver]

I leave from Pearl, go to Midway, refuel, went to the Tokyo bay, saw the 7 subs, took some pics and was already past 1/2 fuel on the way there.

As far as speed, I have it at 2/3 and standard....neither have done it for me.

So in short I figured out how to kill stuff :up: I just suck at driving the thing :damn:

CD

[jamz]

I did the math on this a few weeks ago. If I understand you corectly, you are travelling mostly at PD.

However, unlike SH3, where this method works, in SH4 it actually uses almost twice the fuel. Do not run on battery, run on the surface at best range speed (9-10kts) and you will get much better range. Submerge only when necessary, and you will find the range and fuel economy you are missing.

[Rockin Robbins]

Ditto what jamz said. Keep it on the surface and batteries on full charge most of the time. 9 knots is the sweet spot for fuel economy, and that should be 2/3 throttle in stock, ahead standard (thanks for the correction claybirdd) in RFB and TMO. If in doubt, click the button under the engine annunciator and just click 9 knots.

A World War II submarine is a surface vessel which has the ability to submerge in an emergency for a limited length of time. Working it that way saves fuel, develops more targets and puts more enemy steel on the bottom.

[Task Force]

Couldnt you take the distance you traveled( times that by two) also you might want to add in 600 km to that. Then see what your range at that speed is, and see if you can make it. ( always use ahead standard when on long crusies);)

[claybirdd]

In TMO standard bell is 9 kts. 2/3 is about 6 kts.

[Task Force]

If you go slower than the standard bell you use up more fule cause your motors are useing fule at a higher rate than you are moveing.;)

[SteamWake]

9.5 knots... best range for all but the S boat :know:

[Seminole]

Learn and use Shift G and Ctrl G these keys are key...they are your fuel friends.

[SteamWake]

Learn and use Shift G and Ctrl G these keys are key...they are your fuel friends.

Hrm :hmm: wonder what those do?

Seriously neve used them... range at current speed perhaps? If so I just click the buttons or are those buttons just an RFB thing.

[aanker]

They're in TM too I think. You can edit your own Commands.cfg with a text editor like Notepad. It's in Data\Cfg\Commands.cfg

Find Cmd257 and edit to look like:

[Cmd257]
Name=Report_time_to_turn
Ctxt=1
MnID=0x3F250002
Key0=0x47,s,"Shift+G"

I even edited in a new button on the Nav HUD in OrdersBar.cfg to use instead. Why not? It's in Data\Menu\cfg\OrdersBar.cfg

In [Station2] in that OrdersBar.cfg file if Button7 is your last button add a button 8:

Button8Command=Report_time_to_turn
Button8IconRowColumn=2,3
Button8Tooltip=Maximum range at current speed

If Button8 is already used make the new button - Button9 etc.

I don't use the Ctrl + G function. I think I "borrowed" the above edits from TM. The max range at current speed is very useful. And he's right 9.5 kts - 10 kts is the most economical speed.

Art

[groomsie]

I even went as far as coming to a complete stop to recharge my batteries so I wouldn't burn gas and still didn't make it.

The diesels are still running to charge the batteries, so this too consumes fuel. I think the only way to consume no fuel is to have a full battery charge and not move--I do this some when loitering on station but it is no good for transiting obviously.

Allowing you to recharge at a complete stop without consuming fuel would amount to a free lunch.

[SteamWake]

Comming to a complete stop to recharge?!

What is that supposed to accomplish. Your batteries are going to recharge wether or not you making headway.

[Seminole]

For one thing..you don't burn any fuel while the batteries recharge...and even though it is most unrealisitc to reharge while the diesels are idle .....it is a fact of life in SHIV World...sorta like the stars being closer to earth than the clouds...:yep:


Oh..forgot to add...after you are fully recharged you can then resume steaming with recharge batteries "off" which increases fuel range efficiency...enormously.

You could of course simply turn off recharging but some skippers don't feel at ease traveling with batteries not fully charged.

[Diopos]

OK groomsie, Seminole and SteamWake.
Please put your cards (mods) on the table.
The battery recharging at zero surface speed and an empty diesel tank was a supposed to be an early stock version bug! Am I right? The ability to recharge at zero surface speed with no fuel consumption is still a bug! Groomsie how did you deduce there is no fuel consumption?

@ Seminole & SteamWake,
there are posts which state that during battery recharge all diesel engines work at "maximum". If you're static your batteries charge faster. If you're moving the highre your speed the lower the battery recharge rate!

DID YOU LIE AT ME! :damn: :damn: :damn: :damn: :damn:

I think I must walk the I-must-experiment-plank!:yep:

[groomsie]

Nope, my point was I thought you always burned fuel on a recharge, irrespective of speed. That would be realistic (after all, the battery is simply storing the energy generated by--you guessed it--the generator, which is turned by (surprise) the diesels).

I understood that recharging at all stop with no fuel consumption was a bug in older SH versions (prior to IV), but I thought it was corrected here. If that bug is still present it is certainly unrealistic and would be nice to have corrected.

Bottom line, it should cost you a certain amount of fuel to place a certain amount of energy into the batteries. Period.

[groomsie]

I even went as far as coming to a complete stop to recharge my batteries so I wouldn't burn gas and still didn't make it.

The diesels are still running to charge the batteries, so this too consumes fuel. I think the only way to consume no fuel is to have a full battery charge and not move--I do this some when loitering on station but it is no good for transiting obviously.

Allowing you to recharge at a complete stop without consuming fuel would amount to a free lunch.

Maybe I got too "cute" with my wording and made it confusing. If I have a full battery charge (100%) and don't move, no (very little) energy is needed. Anything else should be consuming fuel. So sometimes when on station and waiting I'll sit in one spot rather than just burn fuel (and if the batteries are topped off that should not be consuming fuel). Sorry for any confusion stemming from my post.

[Quillan]

Even with a fully charged battery set, you still burn fuel sitting still on the surface. It's just not much. Once I'd been sent on a 7 day patrol of the Marshal Islands (where there are no ships, not even friendly). I spent the entire week stationary on the surface, and burned off 2% diesel while doing so.

[SteamWake]

Even with a fully charged battery set, you still burn fuel sitting still on the surface. It's just not much. Once I'd been sent on a 7 day patrol of the Marshal Islands (where there are no ships, not even friendly). I spent the entire week stationary on the surface, and burned off 2% diesel while doing so.

Hey you got to keep that Ice Cream Maker working you know.

[SteamWake]

@ Seminole & SteamWake,
there are posts which state that during battery recharge all diesel engines work at "maximum". If you're static your batteries charge faster. If you're moving the highre your speed the lower the battery recharge rate!

DID YOU LIE AT ME! :damn: :damn: :damn: :damn: :damn:



Never claimed such a thing, in fact I stated that in the game it appears that the batteries recharge at a constant rate regardless of 'throttle' settings. If there is a difference it is not enough for me to notice. So sitting still or all ahead flank the batterys charge.

Just keep it at around 9 knots and you will be okay. The thing is you will consume more fuel while recharging at 9 knots than when your not recharging. But... your still doing 9 knots.

This is contrary to 'real life' where what you state would be true.

[groomsie]

Even with a fully charged battery set, you still burn fuel sitting still on the surface. It's just not much. Once I'd been sent on a 7 day patrol of the Marshal Islands (where there are no ships, not even friendly). I spent the entire week stationary on the surface, and burned off 2% diesel while doing so.

And to me that seems to be as it should be...after all, even sitting stationary you will have an electric demand to satisfy (unless you sit cold and dark...) to run lights, radar, ventillation, etc... Not sure if 2% seems high or low, but I agree it should be something.

[groomsie]

Well, my understanding of "real life" is to charge batteries the engineers placed engines on the generator, and the engines on the generator ran at capacity to recharge the battery. With 4 engines available, I think typical was to place 1 on generator and anywhere from 1 to 3 on propulsion (depending on if they needed to go anywhere and--if so--how fast they needed to get there).

So, if you assume 1 engine on generator at capacity then I'd think that while charging the fuel consumed should be equal to a single diesel running at capactity for the duration of the charge.

I don't think speed was impacted per se unless at the upper ends of the range when that 4th engine would be called into service--since it isn't available for propulsion but instead being used to recharge then the speed would be impacted.

For the game though it seems to model only 2 engines (and we can't control them imdividually) with a speed reduction at all requested engine orders while the batteries are being charged. A simplification that deviates from reality but so be it. It would be cool if all 4 engines were in fact modeled and brought on / taken off line as needed for charging and propulsion needs. Not sure if that could be done in a mod (or if the benefit is worth it if it could). My gut feeling is it is hard-coded.

[SteamWake]

Way I understand it the generators are always inline and provide power to electic motors for standard propulsion. Similar to modern day diesel electic locomotives.

In a charging state some of that current is diverted (and rectified) into a charging system therefore the electric motors recieve less energy and run slower.

On an assumption I would think that only two out of the four engines actually had the charging apparatus connected to them. Somewhere there is a link that describes in detail the whole of the system but I was un-able to find it. If I do Ill edit it in.

Here is the link http://www.maritime.org/fleetsub/diesel/index.htm

Pretty heady reading... enjoy.

[groomsie]

I found the next chapter to be more relevant to this side-topic though:

Generators: http://www.maritime.org/fleetsub/elect/chap2.htm#2A

Diagram: http://www.maritime.org/fleetsub/elect/foldout/fig2-01.htm

It indicates that a single generator (or any combination of all 4) can be used for charging batteries or propulsion. Also apparently an auxiliary diesel generator that could be used for auxiliary load, slow charge of battery, or for even main propulsion (via the main battery) at slow speeds. Interesting.

[CobraDriver]

Learn and use Shift G and Ctrl G these keys are key...they are your fuel friends.

Ok with all the great responses for a question, I feel abliged to post an update from all this great help. :up:

First off 9.5 is the way to go, I am patrolling and cruising for 14 k plus miles when my trips are 2-3 k so no issues there

Second this post regarding Ctrl G / Shift G is a beautiful thing. :rock: It just makes you feel good to see you are very much inside your fuel window, very nice and I thank you for that 1. I use it all the time just because.

CD

[SteamWake]

I found the next chapter to be more relevant to this side-topic though:

Generators: http://www.maritime.org/fleetsub/elect/chap2.htm#2A

Diagram: http://www.maritime.org/fleetsub/elect/foldout/fig2-01.htm

It indicates that a single generator (or any combination of all 4) can be used for charging batteries or propulsion. Also apparently an auxiliary diesel generator that could be used for auxiliary load, slow charge of battery, or for even main propulsion (via the main battery) at slow speeds. Interesting.

Shame it is not modeled in the game.

Lose two engines and your hosed... :hmm:

[wetwarev7]

All this realism and battery stuff aside, is there a mod that will increase the total max fuel by about 25%?

[SteamWake]

All this realism and battery stuff aside, is there a mod that will increase the total max fuel by about 25%?

Dont know prob best to ask the modders. But I think it may be a problem as ... well its done in a percentage. 0 to 100 no actual units of measure liters gallons whatever.

Probably the easiest thing would be to just tick 'unlimited fuel' in the options and move on if you want.

Personally since Ive learned to keep an eye on fuel Ive made it back every time. Although its been very very close a couple of times.

[Quillan]

I'd imagine one of the data files probably stores a "max range at speed X" series of values, where each minute at speed X uses up a certain percentage of fuel, and could be adjusted up that way. You'd certainly need help from the modders to figure it out, and probably would need a hex editor to do the actual changes.

[wetwarev7]

Bummer, I wish it were something I could tweak easily. I like having to watch my fuel, so I always leave 'unlimited fuel' off, but there are times when I've had to forgo chasing that last fat target because of low fuel. :cry:

[SteamWake]

there are times when I've had to forgo chasing that last fat target because of low fuel. :cry:

To me thats how it should be....

Only problem I have is when subpac decides to give you an objective which is obviously outside of your fuel range. They seem to only consider how many munitions (torpedoes) you have left when considering when to call you home.

[Rilder]

The best fuel economy is gained by having Bernard get out and push.

Though if you do that you'll probably end up in Antarctica.

[SteamWake]

The best fuel economy is gained by having Bernard get out and push.

Though if you do that you'll probably end up in Antarctica.

Or the western front... somehow... :rotfl:

[-Pv-]

This charge rate and endurance speculation stuff just doesn't go away even though there is definitive proof various propulsion settings have a significant result:

http://www.subsim.com/radioroom/show...+charge+t ime (http://www.subsim.com/radioroom/showthread.php?t=114474&highlight=battery+charge+time)

-Pv-

[Q3ark]

I can't understand why people are having so much bother with this. I have had this game for over a year now and have never run out of go juice while out on patrol. I always cruise to patrol grid at 9 kts (most fuel efficient speed) and only dive when radar detects inbound aircraft, as charging batteries does reduce fuel efficiency.