Submarine Specs

[Akotalaya]

well i read that boats that were made even in the early 1900's before the s-boat could get a range of around 100 nm, even the worst could get up to around 60 nm! but the s-boat as cool as it is...25 nm...

[TorpX]

Originally Posted by Akotalaya

well i read that boats that were made even in the early 1900's before the s-boat could get a range of around 100 nm, even the worst could get up to around 60 nm! but the s-boat as cool as it is...25 nm...

The range means little without knowing the specified speed. I'm not sure where you get the 25 nm figure. 20 hr. @ 5 kt. is 100 nm. This is actually a very high level of submerged performance.

[It occurs to me you might be referring to actual game performance. In any case, battery capacity/charging is really messed up in the game. Fortunately, Ducimus thought of a fix for this. Otherwise, one must just accept a poor level of performance. Sad that the game was released with these sorts of bugs.]

Designers were forced to accept that they had to compromise submerged performance to achieve surface performance, or vice-versa. The S-class were designed for high underwater speed, and almost all successive classes in WWII were designed for surface performance.

***

I test every new sub on 1st patrol and determine these numbers. Then I know for sure where I stand when the battle starts heating up.

I used to do that in SHCE.

[Akotalaya]

TorpX i run at ahead slow, ive even tried 1 kt..ive tried it all...but from what research ive done the s-boat should atleast have a range of 100nm underwater and sadly it doesent, and older boats they apparently had better performance than that..5 kts just drains the battery too fast, ive never had much luck with that boat under water

[ETR3(SS)]

The underwater performance of all the boats is hosed. The S Class is the worst as it was included at the last minute. Anything below 5 or 6 kts will actually use MORE battery power than running at a higher speed. Try running the S Class out of power and time how long it takes to recharge them to 100% at All Stop. Oh you might wanna try that somewhere safe, like in the middle of your home base or something.

[Akotalaya]

so then what speed would you recommend going to get the most out of my battery?

[TorpX]

Originally Posted by ETR3(SS)

The underwater performance of all the boats is hosed. The S Class is the worst as it was included at the last minute. Anything below 5 or 6 kts will actually use MORE battery power than running at a higher speed. Try running the S Class out of power and time how long it takes to recharge them to 100% at All Stop. Oh you might wanna try that somewhere safe, like in the middle of your home base or something.

I've been thinking about this a lot because I've never noticed this in my play or testing. Maybe it is different with other mods or stock.


To make sure, I tabulated a few tests with a S-boat and a Gato, using RFB 2.0 (patched):

S-18 class

50% battery @ 5 kt. _________ 20.4 nm.
50% battery @ 4 kt. _________ 27.0 nm.
50% battery @ 3 kt. _________ 33.4 nm.
50% battery @ 2.5 kt. ________ 40.0 nm.
50% battery @ 2 kt. _________ 32.9 nm.

I performed the tests in the order of 5, 4, 3, 2, and then suspecting there was a peak between 2 and 3, tried 2.5 kt.

The recharge took about 19 1/4 hrs., a ridiculous time that, practically speaking, prohibits heavy use of the battery in anything less than life and death circumstances.



Gato class

50% battery @ 5 kt. _________ 19.2 nm.
50% battery @ 4 kt. _________ 26.0 nm.
50% battery @ 3 kt. _________ 31.8 nm.
50% battery @ 2.5 kt.________ 38.9 nm.
50% battery @ 2 kt. _________ 32.6 nm.

Note that there is not really a significant difference here.

The recharge took only 3 3/4 hrs.

Also, the telegraph setting are not what determine fuel consumption; it is the speed. People can use different settings without changing the underlying physics. It's a matter of convenience, really.



The conventional wisdom is to stay on the surface, and avoid using the battery, as much as possible. However, there are a number of things to consider.

All the diesel-electric boats burn fuel at idle. I tested this and found that the fuel consumption to be alarmingly high. Submerging means you use fuel to recharge batteries, but at least you don't burn fuel in pointless idling. So the difference in fuel consumption isn't as great as it might seem.

The S-class is different though, and doesn't idle.

If you are going to conduct submerged patrols, you should not use excessive speed. I would consider anything above 3 kt. excessive. If you have trouble with batteries/recharging, drop it to 2 kt. The speed itself doesn't matter, as you are really just waiting for your next contact to come along. You want to reduce the drain as much as possible.

The fuel used to recharge is roughly proportional to the percentage of battery recharge. If you start with the batteries fully discharged, the rate of recharge is higher, but so is the rate of fuel consumption, so it evens out. I found the rate of fuel consumption in recharging was about 4 times the idle rate.

Another thing about the practice of sitting on the surface; one of the reasons this was done was that they could see farther being higher up. This isn't modeled in the game, though. We can see nothing farther than ~ 10 nm.



I put in a fix for the IDLE FUEL issue in my ISP mod, because I considered it to be important.

[TorpX]

Originally Posted by Akotalaya

TorpX i run at ahead slow, ive even tried 1 kt..ive tried it all...but from what research ive done the s-boat should atleast have a range of 100nm underwater and sadly it doesent, and older boats they apparently had better performance than that..5 kts just drains the battery too fast, ive never had much luck with that boat under water

Yes, I've had to struggle with the S-class battery issue. When I did submerged patrols, I would generally run at 1.5 kt., or thereabouts. That was the only way I could recharge the battery in one night.

Thankfully, those days are over. A major goal of ISP was to fix the horrendous battery issues.

Try using this mod loadout (with SH4 v1.5):

RFB_2.0 (Real Fleet Boat)
RFB_2.0_Patch_23April2010
RSRDC_RFB_V575 (Run Silent Run Deep Campaign)
RSRDC_RFBV5xx_Patch1
Improved Ship Physics 1.1

[You can forget RSRDC if you want, but most people like it.]

This will get you much better battery performance. It won't be quite up to the specs I listed, but pretty close. Follow the directions in the mod, as regards recharging. Other classes of US subs are fixed, as well.

[Snarf]

I've noticed that ahead 2/3 seems to get the best performance for the trade off of speed vs. battery life.

[Fizwalker]

I've been running a Gar for my boat out of Pearl... and 1/3 allows me to stay submerged during daylight hours with about 40% of my battery remaining. I'm guessing that the 48 hour endurance is real world as opposed to game?

I started playing with the S-Boats out of Cavite.... They're rough.

Akotalaya, with the Gudgeon (A Gar class boat) I've found that she cannot go from Pearl to the home islands and back on one tank.... My first trip out, I tried handling her like I had been with my S-32 and, having kept an eye on my fuel state, I headed back at standard on the surface. At about the halfway point, I realized I wasn't going to make it unless I changed things... So, I reduced speed to 1/3 and adopted running submerged during the day and on the surface at night. I managed to limp into Midway, refuel and head back to Pearl at standard, on the surface. Since then, I refuel at Midway after a surface run, and then proceed to my patrol area at 1/3, with daylight hours submerged and night time surfaced. Even still you really have to keep a close eye on your fuel state. Once you hit the 50% mark you really have to think about heading back to the barn (probably sooner if you're farther out than Kyushu). Hope this helps!


Torpx, I'll have to pick up those mods... (currently only running the radio ones...if they can be considered mods!)

[Akotalaya]

Fizwalker dont run submerged unless you have to, because recharging batteries does burn more fuel, and as far as running 1/3, dont do that on the surface or you will only fo a few thousand miles at that speed, ive found that fleet boats normally get the best range at around 9 kts, on a full tank ive gotten up to 23,000 nm..allowing me to stay in enemy waters longer and come back with an empty torpedo load because im not having to head home for refuel, i will have to take the gar class out for a patrol or two and see what she can do! i love trying new things

[Akotalaya]

Originally Posted by Fizwalker

I've been running a Gar for my boat out of Pearl... and 1/3 allows me to stay submerged during daylight hours with about 40% of my battery remaining. I'm guessing that the 48 hour endurance is real world as opposed to game?

I started playing with the S-Boats out of Cavite.... They're rough.

Akotalaya, with the Gudgeon (A Gar class boat) I've found that she cannot go from Pearl to the home islands and back on one tank.... My first trip out, I tried handling her like I had been with my S-32 and, having kept an eye on my fuel state, I headed back at standard on the surface. At about the halfway point, I realized I wasn't going to make it unless I changed things... So, I reduced speed to 1/3 and adopted running submerged during the day and on the surface at night. I managed to limp into Midway, refuel and head back to Pearl at standard, on the surface. Since then, I refuel at Midway after a surface run, and then proceed to my patrol area at 1/3, with daylight hours submerged and night time surfaced. Even still you really have to keep a close eye on your fuel state. Once you hit the 50% mark you really have to think about heading back to the barn (probably sooner if you're farther out than Kyushu). Hope this helps!


Torpx, I'll have to pick up those mods... (currently only running the radio ones...if they can be considered mods!)

so far on full realism runnign at around 9 kts i have gotten the gar to reach a maximum range of 21,000 nm..she has been a decent boat to me so far, ill see what the performance under water is when i run into a ship!

[merc4ulfate]

It has all been hashed and rehashed in the forum ifd you look around enough.

It is all semantics anyway because all of this changes depending on what mods you use. Some mod appropriate speeds and some do not. Some mods adjust the jack rabbit starts and stops and some do not.

The key is finding the mods that make it realistic.

If you want to read what the real skippers thought and did during WWII all you have to do is read the reports.

http://www.hnsa.org/doc/subreports.htm

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Generic Mod Enabler - v2.6.0.157
[Z:\Silent Hunter\MODS]
RFB_2.0
RFB_2.0_Patch_23April2010
RSRDC_RFB_V575
RSRDC_V5xx_Patch1
Improved Ship Physics_1.1
EAXsoundsim_without_WebstersManeuver_STOCK_GFO_OM
Classe_Balao_CamoTri