Loss of fuel efficiancy!?!

[Fade Anadarkus]

After departing from Pearl, steaming to Midway, refueling, departing for some missions over at Honshu, killing everything in site I have 60% fuel left and im 200 nm east of tokyo. I try to sail back to midway with 60% fuel and I run out of fuel before I get there! I used the same cruising speed of 9.5 kts that i used to get to japan but i cant make it back and I had more than half my fuel left! I have no hull damage and nothing is broken (or was broken for that matter) Please help!

Fade

[Lexandro]

Do the dials still register fuel in the tanks or are the tanks dry? If there dry you may need to lower to crusing speed a touch to try and get some extra range.

[Fade Anadarkus]

Do the dials still register fuel in the tanks or are the tanks dry? If there dry you may need to lower to crusing speed a touch to try and get some extra range.

The tanks are dry. I have tried making the cruise at 9.5kts and 9 kts and both times I am still 1000nm away when i run out of fuel. I am attempting a third try and am going to see if i can turn off battery recharging

[Lexandro]

Do the dials still register fuel in the tanks or are the tanks dry? If there dry you may need to lower to crusing speed a touch to try and get some extra range.

The tanks are dry. I have tried making the cruise at 9.5kts and 9 kts and both times I am still 1000nm away when i run out of fuel. I am attempting a third try and am going to see if i can turn off battery recharging

Never dive when trying for fuel economy. Diving means your wasting fuel to recharge the batteries, and if auto recharge is on your not getting fuel efficiency. Thats what your problem is.

[Fade Anadarkus]

Do the dials still register fuel in the tanks or are the tanks dry? If there dry you may need to lower to crusing speed a touch to try and get some extra range.

The tanks are dry. I have tried making the cruise at 9.5kts and 9 kts and both times I am still 1000nm away when i run out of fuel. I am attempting a third try and am going to see if i can turn off battery recharging

Never dive when trying for fuel economy. Diving means your wasting fuel to recharge the batteries, and if auto recharge is on your not getting fuel efficiency. Thats what your problem is.
Well it looks like the third time is the charm. For some unknown reason for the second half of this cruise I have to turn the "recharge batteries" button off every time I surface dispite never being damaged this cruise and having 100% battery charge.

My biggest regret is an entire night (I dont get nearly enough) wasted trying to sail accross the pacific... real life is a bitch, i want to play computer games :(

[Lexandro]

Uh use time compression. Press the + or - keys on the number pad to increase/decrease the time compression amount. And as I said when your charging your batteries you use fuel, so you need to take that in to account on fuel economy. If you dont like the fuel/battery limits simply untick them in gameplay options.

[Fade Anadarkus]

Uh use time compression. Press the + or - keys on the number pad to increase/decrease the time compression amount. And as I said when your charging your batteries you use fuel, so you need to take that in to account on fuel economy. If you dont like the fuel/battery limits simply untick them in gameplay options.

I will try to make this clear while trying to not be a jerk. I understand how to play this game, I play at or near 100% realism. I understand all the finer points of fuel management and battery reacharge. I also understand how to use TC but with the constant planes flying over and framerate limitations due to my computer (8000x is not any faster than 1500x for me) coupled with the fact that I cruise at 9.5 kts, three full trips accross the pacific takes up a very large chunk of my night.

In this particular case I believe a glitch is causing extra engines to be run to charge my batteries at surface even though i already have 100% charge and I NEVER incured damage to my sub, let alone batteries. This has cropped up only once for me in all my in game time.

I believe my problem was outside of the normal scope of fuel consumption/ battery recharge

Thank you for your time and help

[Seminole]

Do you also understand that when you dive you can go to all stop...not drain your batteries...and therefore not waste fuel recharging when you surface and resume course ? Do you understand that battery recharge needs to be turned off eveytime you surface? Do you understand that repaired damaged batteries will not always recharge 100% and continue to recharge,thus waste fuel, until you turn off recharge?

If you have trouble making it from Japan to Midway with a 60% fuel range remaining then there is something definitely wrong with your ship handling. I do it rountinely at Ahead Full...even Flank at times ...forget 9 knots...:nope:..I save that for patrols when I'm down to 20-30% and need to get back to Midway. Sometimes I have to head south to refuel before I RTB via Midway or Johnson's Atoll.

Also this....three full trips accross the pacific takes up a very large chunk of my night.


LOL...3 trips across takes up a huge chunk of my week...if you are trying to play a full patrol in a single session then...no wonder....

[doulos05]

LOL...3 trips across takes up a huge chunk of my week...if you are trying to play a full patrol in a single session then...no wonder....

That, in fact, is why my latest career is Asiatic fleet. I got tired of spending 1 of my 2-3 play sessions per week in transit. Now, I still spend 1 play session in transit, but that's because I'm transiting through a target-rich environment. Not 2000+ nm of empty ocean.

[Quillan]

I posted a reply after reading only the first post, so I thought you'd suffered some battery damage somewhere along the way. It's acting as if you did. So, you're going to have to manually turn it off every time for the duration of the patrol. It'll be fixed when you get back to your home port.

[SteamWake]

As Quillan said

Did you recieve any damage and then repaired it?

There is a 'bug' where if you recieve damage to the batterys and later they appear to be repaired to 100% yet will only take on some percentage of full charge. Lets say 90%.

This causes your battery charging system to run continusually wreaking havic with your 'milage'. To stop this you have to manually select 'normal propulsion' after every time you dive. You can check the battery charge state by hovering the cursor over the 'gauge'.

This is the most likely scenario as fuel leaks are not modeled in the game.


Also when going submerged for whatever reason cut your speed to ahead slow. That way you can run for several hours without totally draining the batterys and therefore taking less time to re-charge.

[Diopos]

I had the same problem.
And yes it was a battery thing (recharching up to 99%) and yes manually canceling auto-battery-charge really helped BUT...
it was not always the case. There were some cases were I felt that the problem was weather conditions. Making 10 kts with an opposing storm that lasts days isn't the same as making 10 kts in swimming pool conditions fuelwise, at least in Real Life! :yep: Maybe this is also somehow included in the game engine (which would be a great :up: for the devs, by the way!).
Anyway, I got transfered to Fremantle and as the war progresses (now I'm in Spring '44) you also get some forward refueling posts, much closer to the action!
Life is so much easier when you're winning the war! :lol:

[SteamWake]

Currents are not modeled in the game.

Im not sure if sea state influences fuel consumption, but Ive sailed in all kinds of sea states and never really noticed a loss in fuel effency.

Perhaps the 'battery bug' can also be applied to the diesels. In as much if one of the diesels is damaged at some point, then repaired, it still will not reach 100% efficency.

Im pretty sure that neither sea state, wind, or currents do not effect fuel consumption in the game.

[Diopos]

...
Im pretty sure that neither sea state, wind, or currents do not effect fuel consumption in the game.

Well another one of my SH4 theories going out of the window! :rotfl:

[doulos05]

...
Im pretty sure that neither sea state, wind, or currents do not effect fuel consumption in the game.

Well another one of my SH4 theories going out of the window! :rotfl:

I think I'd have to disagree on a technicality. While sea state, wind, and currents may not directly affect fuel consumption, how deep you are in the water does. To set the technical portion of the discussion: Using the bell (Ahead 1/3, 2/3, etc) basically tells your engine crew to maintain a fixed number of RPMs (actually it's run 1, 2, 3, or 4 engines at cruising rpms except for flank which is run all engines flat out). Using the knots annunciator tells your crew to maintain a speed regardless of how many rpms you turn.

Now, if your decks are awash, that takes more work than if they aren't. And this must be modeled because when your decks are awash, ahead 2/3rds isn't as fast as if they aren't. So if the waves are setting your decks awash (generally indicated by your depth to keel indicator bouncing up and down) then it stands to reason that would affect RPMs (and therefore fuel consumption) if set to maintain speed, since it affects speed if set to maintain RPMs.

[Diopos]

Decks awash means that you're running on batteries hence the lower speed with the same general engine setting (1/3, 2/3 etc).

Sometimes when sea is really high and you're on the bridge you might instantly find yourself in the control room. High waves have caused you to involuntarily submerge!:yep:

[doulos05]

From what I've seen (1.4, no significant boat mods), it sounds like (based on ambient engine noise) that the electrics don't kick in until your Depth to Keel is around 30. So if you're fluctuating between 15 and 25, the electrics never kick in, yet I've noticed my speed reduced.

[Diopos]

Decks awash = ~10m =~30ft
Stock 1.4, no mods here as well

[Quillan]

While currents may not be modeled in the game, speed reductions due to rough seas are modeled. Getting swamped is not required. Try it once and see: set Ahead Standard when setting out from your port at the beginning of the patrol and see what speed you get with calm seas, then do the same at some point when you have 15 m/s winds; you'll find you're going a knot or two slower.

[Nisgeis]

<SNIP>then do the same at some point when you have 15 m/s winds; you'll find you're going a knot or two slower.

That implies a fault in the game. Surely having a tail wind should increase your speed, whilst a head wind would reduce it? You imply there is no differentiation in the wind direction's effect on your submarine's speed, thus that is a fault.

I have similar concerns over the 'decks awash' theory. There's a very real chance that only the keel depth is taken into account when calulating surface speed and wave height (also known as wind speed) has nothing to do with it. Unless observations have been taken to the contrary. The only test to confirm that would be to run at x depth with y wind speed for all cases of y and x.

[Lexandro]

There is a simple reason why in rough weather you get a lower rate of knots than clear weather. If you take note, in rough weather the boat is tossed arouond quiet a bit. Watch the propellers, in rough weather on stock they can lift out of the water and the screws will race. This means you loose forward momentum, and will increase full consumption. It can be noted if you also watch the telegraph speed, it will bounce between your set speed, and a few knots less for each time the screws lift clear of the water.

[Quillan]

It's not the headwind/tailwind that affects your speed, it's the sea state. Rough seas mean you are effectively sailing uphill and downhill, but the game measurement of "knots" is in nautical miles per hour as the crow flies. Thus, you're slower in rough seas.

[SteamWake]

I have yet to see the sea state effect my speed.

Maybe I just never noticed, but typically Ill set for a speed (9.5 knots) in lieu of ahead foward etc.

I do see the uhhh 'spedometer' bounce back and forth alot so I guess the net foward speed is reduced a bit. But again Ive never really noticed it increasing fuel consumption.

[Nisgeis]

Watch the propellers, in rough weather on stock they can lift out of the water and the screws will race. This means you loose forward momentum, and will increase full consumption.

Hmmm, that's odd... I've watched the screws for sure, but they just rotate really quickly no matter what.. perhaps you have to have a special viewing apparatus to enable you to see that they are 'racing' ? How much faster do they rotate if they are out of the water compared to when they are in the water? What RPM are they turning at in the water during a normal sea and a rough sea?

Unless you have results regarding the performance of the boat in various sea states, you don't have a theory at all.

[Lexandro]

Sorry its not theory its fact. Simply by observation can you see the forward speed of the boat getting reduced in heavy sees as the screws lift clear of the water. If the screws are not in the water, they are not providing forward motion. Reduced forward motion @ a set RPM speed compared to flat sea automatically means increased fuel consumption. This is because the distance traveled is higher in rough seas than calm, its basic physics and is included in the game (as per the speed change noted above). If the sea state played no part in speed change there would be no change in range or fuel consumption. This is the main reason I use the diverate mod, as it tends to keep the screws in the water allowing for better forward speed in rough conditions.

And racing screws describes ANY prop that is out of the water, not its particular rational speed.

I do realise I am a new member here but I do have a background in shipping and sailing. I have also physically used ship mounted Radar in RL and sailed on a number of vessels since childhood. Plus there is a rather large Nuclear Submarine base not 30 miles away from me I can see from my living room window across the river and we also have a shipyard in the middle of town. To not know of sailing here is practically unheard of.

Example;
I travel 11.5 miles in an hour @ 10 Knots in calm seas
I travel 11.5 miles in an hour, 15 minutes @ 10 knots in rough seas
Therefor Rough seas = longer travelling time which = more fuel consumption.

To show this, the game has your forward speed change in a heavy sea. If your not maintaining the same forward speed 100% of the time and are loosing speed at intervals you are going to take longer to travel the same distance.

Do you understand now?

[Diopos]

I don't know how it "happens" in the game engine but "lower then set" speeds in high seas are there alright. If you use TC you can easily see that you're actual speed is lower a significant fracture of your traveling time. So I just assumed that your fuel consumption was based on your "set speed" (equivalent to setting the engines to a certain RPM level) with your actual speed dropping due to high seas.

I also tried setting a lower speed (the equivalent to shifting to lower gear) but I can't say if it made a great difference or not. This requires a experimentation/verification procedure (small test scenarios) via the scenario builder (with wich I'm not familiar with,yet...). Would be a nice and useful project though.

[Nisgeis]

Lexandro, I'm sorry if my earlier post sounded a little harsh. That wasn't my intention. If 'racing' means purely lifted from the water, then in real life that would explain things, but not in game, where things are often set up strangely.

You get slightly reduced speeds in rough weather even if the screws don't come out of the water. I believe what you are seeing is not the speed dropping when your screws coming out of the water, but when another point gets deeper. When the screws are out, ie when they are in a trough, there is also another part of the boat that is under a peak of water. I think it's the increased depth on that particular part (possibly conning tower) that affects the speed.

I also did some testing on the RPM of the engines, to see if that was modelled - e.g. increased RPM for the same speed in different weather. Rather bizarrely, the RPM of the engines is HIGHER in calm seas than it is for rough seas, at any given speed or telegraph setting. So, RPM is not a factor in fuel consumption. I believe that speed is modified by the depth of one point (conning tower?) and the fuel consumption, as Diopos says, is simply throttle setting multiplied by time.

Using stock, I got hardly any noticable difference in speed in rough weather, probably about half a knot as it flipped between target speed and one knot below. Mods that change wave height will probably cause more noticable speed drops. The speed reduction is linked linearly to the depth.