Endurance voyages - Battery vs Diesel

[IRONxMortlock]

Originally Posted by Letum

Claiming you go further running on batteries is saying that you get more out of your batteries than you put in. This is obviously impossible!

I think this real life concept is understood by all, otherwise we'd all be cruising around on perpetual motion machines wouldn't we.

The question is, has this been modelled into the game? According to Ducimus's information it appears that we can in fact create energy in game.
________
karinASS

[Letum]

Originally Posted by IRONxMortlock

I think this real life concept is understood by all

Apperantly not....

Originally Posted by IRONxMortlock

The question is, has this been modelled into the game? According to Ducimus's information it appears that we can in fact create energy in game.

Ducimus neither proves or disproves it.
I'm going to run the test* so I can find out. I will post the results soon.

*see above

[Letum]

OK, first test results are in from this test:
http://www.subsim.com/radioroom/show...48&postcount=3


Boat:IXC with IX/2 conning tower, deck gun and MAN Turbocharger

For the periscope depth run and the battery charge after:
Weather: 5
Test Distance:155.9km
Max distance1: 14120km
Max distance2: 10936km

For the surface only run:
Weather: 6
Test Distance: Test distance (115.9km)
Max distance3: 14488km
Max distance4: 13901km

Conclusion

Indecisive; further tests needed.
The submerged run used 3184kms worth of fuel in 155.9km. It is using almost 20.5kms worth of fuel to go 1km.
The surface run used 587kms worth of fuel to go 155.9km. It is using 3.7 kms worth of fuel to go 1km.

On the surface these number suggest that surface running is far more efficient, This is made even more dramatic when you account for the worse weather on the surface run. However, if the numbers where totally accurate then the surface run should have used 155.9kms worth of fuel to go 155.9km. i.e. 1kms worth of fuel to go 1km!

This difference could have been caused by:
1) Innacurate testing
2) Inaccurate NO maximum range prediction
3) The weather.

I will conduct the test twice more to get better results and reach a proper conclusion.

[Corsair]

If I were you, I'd rather spend my time playing...

[Hakahura]

Corsairs right!

What are we doing here, when theres tonnage to rack up!

[Letum]

Originally Posted by Hakahura

Corsairs right!

What are we doing here, when theres tonnage to rack up!

The more you know your self and your boat; the more you will sink.

Anyway, Ive just finished another 2 runs. I took a average of 4 max range predictions this time.

Something went seriously wrong with the 3rd test as my results made no sense. the 2nd test however got results similar to the first test.

It looks like SH3 models batteries correctly.

According to my test results
It is less efficient to run submerged (in GWx at least)
know thine self

[Ducimus]

As i wake up this morning with the coffee stilll brewing, i knew Letum would be hard at work trying to prove his ideas before i even clicked on this thread. Knock yourself out mate, i know what works and what doesn't.

If you really want to stretch endurance, grab a snorkel and stay submerged the entire patrol. Raise the snorkel only long enough to recharge the batts and then lower it again. I'll bet you'll go a bit farther then you normally could

[Letum]

Originally Posted by Ducimus

As i wake up this morning with the coffee stilll brewing, i knew Letum would be hard at work trying to prove his ideas before i even clicked on this thread. Knock yourself out mate, i know what works and what doesn't.

If you really want to stretch endurance, grab a snorkel and stay submerged the entire patrol. Raise the snorkel only long enough to recharge the batts and then lower it again. I'll bet you'll go a bit farther then you normally could

Get some numbers, get some credability.

[Ducimus]

I honestly have better things to do then arguing over things that have worked for the past year. I really don't feel the need to prove anything. I don't have to be "right" in an argument. You don't have to beleive me. You've been all over this subject in the past and im not surpised your all over it now- it's oddly entertaining ::rotfl:

Two parting thoughts:

- If its so important to you, Try running to GR89 entirely on electric power, using the diesals long enough to recharge the batts, and for nothing else. Then try the same trip on the surface.

- Like most things in life, Theres how a book says things should be done, and then theres how things are really done.

Have fun, topics all yours now.

[FongFongFong]

Now this has probably already been covered in this thread, but


Tried something similar in GWX just a couple of days ago
but I noticed that I actually used fuel while standing still
charging batteries.

So GWX is using extra fuel to charge.
Pointing out a small flaw in the original post in this thread.

Fuel to travel on the surface +
fuel to charge batteries

vs total distance

[Ducimus]

Originally Posted by FongFongFong

I noticed that I actually used fuel while standing still
charging batteries.

Yup, one engine is taken "off the line" as the saying goes and put into charging the batteries. Runs at about 500 RPMs (flank speed) for however long it takes to recharge the batteries. Next time your recharging your battries, look at the RPM gauges in the control room.

[Sailor Steve]

Originally Posted by Ducimus

Like most things in life, Theres how a book says things should be done, and then theres how things are really done.

Have fun, topics all yours now.

I was actually going to say something completely different, but I have to answer this. And the answer is, there are how things are done in real life, and there are how things are done in a game; and in this case the game has little to do with real life. The answer about surface ships was closest: if running batteries was more efficient then everybody would do it that way, only using diesel or steam to recharge the batteries.

Working on a game for over a year doesn't make it anything more than a game.

[Sailor Steve]

What I was originally going to suggest was this: I'm wondering whether cruising on diesels at two knots wouldn't increase the range in the game just as well.

The problem with Stix's calculations is that yes, the range increases but so does the time. Yes, in-game you can travel 84 miles using the same amount of fuel as you do travelling 21 miles on diesels, but you travel that 84 miles in 24 hours versus 168 miles in 24 hours on diesels. You save fuel, but it takes forever to get anywhere. As I suggested above, try cruising at 3 or 4 knots for 24 hours (84nm should be 3.5 knots average); you should go about the same distance. Check to see how much fuel you've used. Try it again at 2 or even 1 knot. Make sure the weather is perfectly clear and calm every time.

[Ducimus]

Originally Posted by Sailor Steve

Yes, in-game you can travel 84 miles using the same amount of fuel as you do travelling 21 miles on diesels, but you travel that 84 miles in 24 hours versus 168 miles in 24 hours on diesels. You save fuel, but it takes forever to get anywhere.

Thats what time compression is for



Honestly i always wondered if it was true that running submerged most of the time saved on fuel until i proved it to myself with a patrol to GR89. I plotted out the course after leaving lorient harbor, to the grid, and back to port. The range to course end, exceeded my maximum range at current speed. In short, i did not have enough fuel to make the trip. If i remember correctly with the calculations i had at the time, i would have run out of fuel somewhere in the vacinity of, or just north of gibralter on the return trip.

It was 1944, aircraft in abundance, i submerged after just leaving port, and did not surface again until i reached GR89. I had no fuel to chase targets at all. I went down there, did my alloted 24 hours and headed home, with no diviations, and no surfacing. If a sound contact appeared and wasnt in an approachable position i HAD to let it pass.

The entire patrol i raised the snorkel only long enough to charge batteries. At 100% charge i immediatly brought the snorkel back down. Long story short, i made the trip back to port, i had a few drops of fuel to spare (quite literally im sure), and had a 130 day patrol. It was an agonizling long patrol, but i was determined to do it, and i did. I didnt sink a single ship the entire patrol, but i made it back, which turned into my goal at the time just to see if i could do it.

edit: btw, if you submerge at 0500, and surface at 0 hour, you have like 20% batteries left, and it takes 2 and a half hours to recharge to 100%

[Letum]

Originally Posted by Sailor Steve

I'm wondering whether cruising on diesels at two knots wouldn't increase the range in the game just as well.

No it wouldn't.
I understand what you are saying, but its not a case of the slower you go; the further you go.


Think of riding a bike. You could take all day to go one mile, you could go one mile in a few minutes or you could find a comfortable steady pace.
Even if you have all day, you will chose the steady speed. This is because at the slow speed you use more energy. The extra energy is lost because most motors (and bodies) have numerically constant economy penalties at any speed.
With the bike analogy, one such constant is the energy required to power your brain or keep your body temperature at a minimum. These are unavoidable inefficiencies that will be there at 1mph or at 100mph. A diesel motor has these inefficiencies also and so does a water screw.
The slower you go; the more time constant inefficiencies waste energy; the less efficient you are.
Going fast is also going to use more energy. This is because some inefficiencies are greater the higher the speed is. A dubbeling of the speed will require something like a squaring of the energy expended. This is mainly because the forces of friction are greater at high speed.
In-between extreme slow speed and extreme fast speed there is a speed that is most economical.
There are a few other factors that involve gearing and external forces on the vehicle that feed back into the motor, but we don't need to go into that. (thank god)

The most economical speed for your car is about 55mph. Your car will go further at 55mph than it will at 10mph.
For a VIIC U-boat the most economical speed is somewhere around 7knts.

It is easy to prove that UBI soft have modeled this. Just run your VIIC at 1knt and ask your navigator for your maximum range (do it twice and take a average)
Now repeat this at 16knts and at 7 knts. The range he reports at 7knts will be the highest.