Fuel and range issues!

[drakkhen20]

ok fellow shipmates. this is a problem ive always wondered about and it really is i huge 100% reason why i never play the Fleet side of SH4. i find very hard to believe in reality that American submarines set out to sea knowing they couldnt make it across the pacific to there patrol zones because a lack of fuel. because this is what i experience everytime i start my first patrol on the Fleet side. From Pearl Harbor to 130 E/ 26 N at STD speed i ran out of fuel and had to exit to desktop. am i missing something here? did we really have that short of ranges? do you just stop at every dock and resupply to make across the Pacific? there has to be a mod to fix this? all im running as mods are these:

RFB_2.0
RSRDC_RFB_V575
RSRDC_V5xx_Patch1


regards,
drakkhen20:salute:

[messageboy101]

are you running at a head flank because that eats away fuel

[drakkhen20]

no as stated above im running at STD = Standard speed. ive had the same problem with all the major mods also. i dont know if im doing something wrong or this is just an issue thats been addressed and i dont have the mod for it being that there is a mod for it.

[messageboy101]

what mods do you use, so i can try it out myself
in what year do you start in?
which boat class?
and which mods do you use?

cheers

[drakkhen20]

RFB_2.0
RSRDC_RFB_V575
RSRDC_V5xx_Patch1

thats it. start off in 12/7/41 and the sub was a Gar Class.

[Hylander_1314]

I think in RFB, 8 to knots is the cruise speed you have to use.

If you go into the individual boat sim files, you adjust the range and speed to whatever you like.

As an example, one of the mega mods has the Gato surface range in sim file as:

miles=14138
speed=15.19 knots.

That way you can run across the Pacific at better than harbor speed, but you can adjust your speed on patrol while in the combat zone to get better fuel economy.

Just watch how much diesel is used travelling, and if you are out from Pearl, and it looks like you may run short, you can always stop in at Midway and top up the tanks before the trip home.

You can do the same if you prefer leaving out of Pearl too. Stop at Midway (like the boats did) before heading to the swimming hole.

[HW3]

9-10kts is the best speed in TMO. Also the standing order at the start of the war was to run submerged during the daytime when within 500nm of any enemy base.

[drakkhen20]

ok so theres a strategy to it then. i guess ill have to learn then. thanks for your replies.





regards,
drakkhen20:salute:

[TorpX]

ok fellow shipmates. this is a problem ive always wondered about and it really is i huge 100% reason why i never play the Fleet side of SH4. i find very hard to believe in reality that American submarines set out to sea knowing they couldnt make it across the pacific to there patrol zones because a lack of fuel.
Since this matter comes up now and then, I did a little math to check my opinion. Usually, people have trouble when they try to circumnavigate the Pacific, or use fuel needlessly cruising 24 hours a day.



First, some quick math. (Your figures may vary.)
route....................real life distance..............game distance

Pearl to 29N, 130E....... 3,890 nm................ 4,344 nm

Midway to same.......... 2,896 nm................ 3,302 nm

Note that the game distances are somewhat higher than the actual distances, but the difference is not that large. This is due to the "flat earth" model of the game, and not to the mod.

Most of the fleetboats should give you an endurance of about 10,000 nm @ 10 kts. If you go straight from Pearl you will need 8,700 nm endurance and this does not leave much for contigencies, but if you stop at Midway to top off your tanks, you would have 10,000 - 6,600 = 3,400 , and this would allow much more for patrol/persuit.

I would also point out that you do not have to cruise 24-7 once you reach your patrol area. Excessive zig-zagging, speed boating, unnecessary battery charging all waste fuel and should be avoided if fuel is a consideration. You should periodically check your fuel situation by having your navigator give you your range at current speed. Do this when you start to make sure you can get the 10,000 or 11,000 nm you should have.

Really, if you are reasonably prudent, you should be able to make these long distance patrols ok. This does not mean it is easy or that fuel is not a consideration, though.

[Sailor Steve]

Yep. In real life all ranges are given at 10 knots. Once in your patrol zone it's best to cruise at the lowest setting.

[drakkhen20]

thanks guys, defintly helping out. im still on my first patrol, had 4 patrol areas already and still have alittle over 50% of my deisel. :up:

[messageboy101]

i tested it and the guys above are right, 10 knots are lower is best
are you could still use the gar and dont sail from pearl but from an other port

[drakkhen20]

did some research and found these numbers. as stated before these are all at 10 knots surface speed:
nm / knots
S-Class: 5000/ 10
Salmon:10000/ 10
Sargo:10000/ 10
Tambor:12000/ 10
Gar:12000/ 10
Gato:11800/ 10
Balao:11800/ 10
Tench:12000/ 10
P-Class( Porpoise):12000/ 10
Narwhal:18000/ 10

im going to try to impliment these numbers into TMO to best reflect the actual Range and authinticity. the only other thing i probably need help with is compinsating for the flat world range.

[drakkhen20]

ok so in S3D the knots is what the miles are based off of? so i would put 10000 miles at 10 knots to be correct minus the flat world stuff? just an example. so it would look like this:

miles = 10000
knots = 10.00

???:06:

[Ducimus]

You combine:
- Several mentions in patrol reports of traveling at "3 engine speed". (fleet boats had 4 engines)
- Flat map projection making distances about 20% longer then in real life
- Ballast fuel tank modifications during the war

and you may find, pin pointing the range in actual practice, hard to imitate in game.

[drakkhen20]

ok so how long did you spend tracking all that? and did you base the ranges off the stock SH4 ranges or off of historical values? and as you stated i take it this is not as easy as just changing numbers?

[Ducimus]

Your asking me specifics for something I haven't put any thought into for a couple of years i'm guessing. off the top of my head, (cause its been too long to remember specifics):

- Actual cruising speed of fleet boats. This was an exrtrapolation based upon reading patrol reports, first hand accounts, and looking at specifics such as how many gallons of fuel oil was actually carried, and doing the math of that against listed statistical range, and how much fuel captains reported as having left over after a patrol. Lots of extrapolation here based on what data I was able to find. One key issue is this: Fleet boats were expected to arrive at their patrol stations by such and such time. They were expected to leave their assigned areas at such and such time. They often traveled to their patrol areas at such a speed as to arrive at their assigned station at their appointed time. At which point, they would cruise at 10 knots or whatever to conserve fuel.

Side note: one problem with online sources is they all plagiarize each other.

- Flat map projection is easy to identify. Go download the google earth application. Then go into SH4, and draw a straight ruler line between two known points. Say, from San Franciso to Tokyo for example. Write the number you get in game down. Then go to google earth app, and do the same again. You'll notice the ingame range is longer. Take the google earth (more like actual) range, multiply it by 0.25 or somewhere there abouts, and add the result to the original range given by google earth. It will come close to the listed range in game.

- Fuel ballast is a bitch. Read around and you'll find two boats of the same class listed at different fuel capacities. Some will be like 94,600 gallons or something like that. Another will be listed at 104,000 gallons or more.

[drakkhen20]

ah, so youve done this already and thats the results is whats in the sim files then?

[Ducimus]

ah, so youve done this already and thats the results is whats in the sim files then?

Pretty much. It was the best compromise i could find. For example, in TMO sim file for the gato i think, the @15.19 knots is adjusted to be the exact speed of ahead standard. The way I have the engine throttle set up, ahead standard is 3 engine speed. Look in the submarine cfg file, i think its obvious when you look at the percentages. The 15.19 knots is so exact because i multipied the top speed of the boat by (I think) 75%. (75% being 3/4 or 3 out of 4 engines on the line)


Side note:

The faster you go on the surface, the slower your battery recharge. The slower you go on the surface, the faster your battery recharge. If your going ahead standard you have 3 engines on the line and 1 on the charge.

[drakkhen20]

hhmmm, ok so this is something i dont even need to be messing with then, im sorry didnt mean to seem like i was stepping on your toes there. i think ill just learn how to conserve my fuel better. heres a question though. how many orders do you get before ordered to return to port? is it when all your torps are gone or youve sunk a certain amount of tonnage?

[Ducimus]

The way i intended the fuel, is to travel to your patrol area at standard speed, then kick it down to 2/3rds to conserve fuel. However, this also involves budgeting/managing your fuel. Everyone likes to kick to 2/3ds (9-10 knots or there abouts) and not worry about it. I've always felt like this is the antithesis to a simulation. It's also what people are used to in SH3 and uboats.

Easiest way i find to manage fuel is:
- at the start of a patrol, go to standard, and ask for max range at current speed.
- plot a 1 way route to your patrol area. Take that range, multiply it by 2. Thats your round trip fuel consumption.
- Take that round trip number, and subtract it to your first number of max range at current speed. The remainder will be how much fuel you have to patrol with at standard. It will be a small number, however this number will be stretched greatly by crusing at 2/3rds while in the patrol area. Seriously.

I did just that when i tested this concept. I took that remainder patrol number after doing exactly what i just described, and in a test modlet, imputed that range at 15.19 knots. Then cruised at 2/3rds. to see if the range was adequate, which it was.

Try it.


As for patrol orders. How many missions you can get depends on what missions are nearby, how much fuel and torpedos you have. Reallsitically, you can do as many as you want thats available, or none at all. All that really counts in the end is how much renown you earn.

[drakkhen20]

alright ducimus, will do. thanks for the replies. ill try my best.



regards,
drakkhen20:salute:

[drakkhen20]

ok so even if you have standing orders you can sail to your home port and still end the mission and dock ? because i know in stock SH4 you cant.

[Bilge_Rat]

Ducimus is correct.

I had also looked into changing the fuel usage since I thought TMO 2.5 was too generous, but you can't really use the RL range since:

-fuel usage of subs in game is off, it uses too little fuel at ahead 2/3rds and too much at ahead standard;

-the SH4 flat world distorts the real world and distances in SH4 can be up to 25% longer than in RL.

I did change my TMO instal, basically took the RFB 2.0 figures and increased them by about 25%, so you still have to worry about fuel usage more than in TMO 2.5.

If you use RFB 2.0, there is a mistake in the files for many of the subs. the read me to RFB 2.0 states the range that each sub class should have, but if you check the files, you will see that the actual range is less than that, by a factor of 10-20%, which when coupled with the flat world issue means you are really shortchanged in fuel.

[drakkhen20]

yes, excellent resposes. thats why i asked ducimus before i dug into it. seems theres more to it then just going in and editing a few numbers here and there. but i've gotten better at saving my fuel and measuring it constantly which i suppose is what they did back then also; so it adds more to the "imersion effect" for me. since this is a reaccuring issue in the game there should be a more indepth strategy for using and consuming fuel during a patrol written up and sticked or in a readme. thanks again guys i can finally fully play SH4 Fleetboat style now and not be so frustrated with running out of fuel all the time. :yeah:



regards,
drakkhen20:salute:

[Beardmoresam]

Hi, this thread caught my interest and seeing that some very knowledgeable people are answering, I have a question that has caught my interest a while back. I'm hoping some of you might know the answer.

If Standard speed is running the three main diesels or generators, and full is the 3 main diesels and the Auxiliary Diesel, is flank just squeezing more turns out of the engine? or is it drawing on the batteries (as they would have done in RL) to assist the diesels in getting those emergency extra turns?

Running TMO 2.5 btw.

Thanks, Sam.

[TorpX]

Standard is using 3 main diesels, full is using 4 diesels, flank is using 4 diesels and current from the battery. This is not accurately modeled in the game, though.

[drakkhen20]

well you know theres alot of other things as far as propulsion that are lacking. like the fact that you cant individually adjust the speed of the port or starbaord! you just have to se each at the same speed. so this makes it harder to manouver the sub everywhere.

[Gilead Abyss]

Hello all,

I've been reading the TMO thread, most recently the posts by Ducimus about reworking the cruise speed/range/battery recharge in 2.0. It prompted an idea, and I just ran a search to see if this is discussed elsewhere.

I need to test this again, but I think with some experimentation it is possible to approximate a great circle route (for example from Midway to Luzon/Tokyo/anywhere by laying several waypoints. 4? 10? Have to try it out.

The reported range to course end comes back as fewer nm even though on the flat map projection in game on screen it looks longer.

Is anyone already doing this routinely? Does it save enough fuel to be worthwhile? I like the idea of it for simulation value, but I can imagine getting tired of plotting a dozen waypoints every time I want to sail from A to B.

Obviously this only really makes sense for long transits, not cruising the Celebes.

Any thoughts from SH4 veterans?

Thanks all

[TorpX]

If you can get a great circle route in the game to work, please post the particulars so we can confirm this.

I rather doubt this will work out the way you suggested, but if I happen to be wrong, this would make for a more interesting game.

AFAIK, none travel in this game using a great circle route. I certainly would if there was any advantage in it, though. I wouldn't say it is too tiring. I don't use high TC, and one only needs to make very long transits twice per patrol. Anyway, this was done in real life, so why should we consider it too difficult for us?

The "flat-earth" SH4 world has always bothered me.

[Gilead Abyss]

I'll try it this afternoon and post the results. I'm betting it only matters for E-W crossings, but not N-S.

It also occurred to me to test what happens as you approach the pole. Does the game have a "wall" at the top? Or maybe just ice pack and these diesel boats don't have the submerged range to traverse.

I'll post back from home when I can.
Thx

[Armistead]

Both poles have ice walls that go to the bottom or past crush depth

[Gilead Abyss]

Sorry all for the brief distraction. My fault for posting before testing, and for thinking I've found something new that hadn't already been thoroughly covered by all the more experienced captains here.

I was very clearly wrong - a simple set of waypoint plots shows a straight line on the map is the shortest distance, and the curved route that would (and maybe should) represent a great circle on this simulated flat projection is nothing but an unnecessary detour.

I have screenshots, but I won't waste the space. It's clear this is already either common knowledge. Otherwise, it would show up in Captain's Bag of Tricks sticky or somewhere obvious.

Back to straight-line sailing, and good hunting everyone.

D'oh! Hubris and enthusiasm = :oops:


Also, thanks Armistead for saving me a trip to the Arctic.
:salute:

[troopie]

I don't know much about navigation but out of interest I had a bit of a play with it and this is what I found:

I tried the following: I set a straight course between the longitudes 160east and 130west on the equator and then again at 40north.

Each course showed the same length (plot and ruler) and I also got the Nav oficer to give estimated time to end of course. Using my speed (x time) I determined I'd be covering the same distance on both courses.

I think this means no great circle route? Maybe someone more informed could confirm this.:06:

Edit: No worries Gilead you beat me with your post. Never mind mate was fun to find out, best way to learn eh!

[RedMenace]

ok so theres a strategy to it then. i guess ill have to learn then. thanks for your replies.


There is most definitely a strategy to fuel consumption in this game. I often come back to port with less than 1% fuel. Once I even ran completely out of fuel a few hundred miles from Midway, went submerged, and then used up the last of my battery power to just barely get close enough to port to refuel, and then finally speeded off at flank to Pearl Harbor.:smug:

Make sure to use the "range to end" and "maximum range at current speed" buttons often, as they'll be your best, if not your main tools in conserving fuel. Stopping by ports on your way out to patrol or coming back is a good idea too, I refuel at Midway pretty much every time I leave from/come back to Pearl Harbor.

[BigWalleye]

I don't think there's really a strategy. That makes it sound too elaborate. Best operating range is realized at about 10-12 kts. This can vary by class, by sea state, and by what mods you are using. While under way to my patrol area, I use the knotmeter and "Range at Present Speed" function to determine my boat's most fuel-efficient speed. Except for the old Sugar boats, maximum range is NOT achieved at, or even near, Standard speed. Most references will quote the maximum operating range for all WW2 submarine classes "at 10 kts." (if they qualify it at all) and that's about where you will find the most fuel-efficient performance.

[TorpX]

Sorry all for the brief distraction. My fault for posting before testing, and for thinking I've found something new that hadn't already been thoroughly covered by all the more experienced captains here.


Don't sweat it. You gave us something interesting to talk about.


I hope someday we'll have a subsim with a properly modeled earth to play with.


There is most definitely a strategy to fuel consumption in this game. I often come back to port with less than 1% fuel. Once I even ran completely out of fuel a few hundred miles from Midway, went submerged, and then used up the last of my battery power to just barely get close enough to port to refuel, and then finally speeded off at flank to Pearl Harbor.:smug:


There is a definitely a certain amount of strategy to patrolling. Many have fuel problems because they think they must cruise continually, and thus use excessive amounts of fuel.

[BigWalleye]

There is certainly a strategy to patrolling. But the techniques for fuel managment don't rise to the level of strategy. They are tactical doctrine, at most.