Matrix Games Forums

So I went to play The Silent Service campaign mission The Enemy Below. (awesome movie)
Tasked to search a large area for a convoy, I surface the sub and run at flank. Of course. You're in a diesel. That's what you do. Flank just cuz I needed to haul ass to get where I needed to be; otherwise I'd run at full, not flank.
The batteries drain. FAST
...... uhhhmmmm ... How? Why? .... Huh? .... No.
I have to slow the sub (Balao class; flank on the surface is 18kts) to 8kts so as to not drain the batteries. At 9 kts the sub drains battery. That's under cruise speed .... Yeahhh ... I don't think so. At 8 kts the battery holds level, at 7 kts it charges, at 9 kts it drains. Running on the surface. This is wrong.
Perhaps my decades of submarine enthusiasm have failed me, but when on the surface diesel subs shouldn't be draining the batteries no matter how fast they're going. They're running both diesel engines to run at flank, which means they can't charge the batteries. Not that they USE battery.
Surely this is amiss. This behavior would have made subs utterly useless in WW1 and WW2.
Any info saying old diesel subs had to run batteries to travel fast when on the surface sure would be interesting to see, to a whole lot of highly studied people.
This can't be right.
Yes, The Silent Service is older. Every mission should still work 100% without fail with CMO as it is updated. Especially at full price. If it's not going to stay up to date it (any campaign/scenario) should be seriously discounted. Every campaign and scenario that is sold should be fully tested to work right with any CMO updates.
I mention this because I've been told before "some scenarios are just old and don't work right." It gets rather old (and frustrating and irritating) to keep encountering such things. Old scenarios just don't seem to get updated with CMO itself. I'm just talking about the included ones here, and campaigns and Live scenarios etc. The stuff we pay for. That should always remain up-to-date and work right.

HOW TO REPLICATE
Open that scenario. Surface the sub. Set speed above 8 kts. Battery will drain, but it shouldn't.

I have not tested this in other scenarios, so no idea if it's just this one or wide spread behavior.

Thanks for the report, logged as 0015393

From everything I looked up the Balao should be able to go 20 kts on the surface. I've already reported that problem.

I have no idea about the Balao class specifically, but a number of WW2 subs could not attain full speed without batteries contributing. And they couldn't attain full speed while charging. I think the original Gato class was limited to 10-12 knots in calm water while charging at a reasonable rate. IIRC subs have been modeled like that since the CMNAO days.

Also, the 20 knots seems to be a generic spec. from Wikipedia. Looking at Navypedia, its a little more nuanced with timing of upgrades.

https://www.navypedia.org/ships/usa/us_ ... _tench.htm

They lump the Gato and Baloa together, but I think you can sort the differences in engines and such.

Here is the thread where the devs point out hybrid usage of battery/diesel at full speed.

https://www.matrixgames.com/forums/view ... g#p4637362

I think that this came down to a modeling choice that assumes "modern" (i.e. post-WWII) diesel-electric configurations where the majority of the power comes from the batteries and the diesels only act as slow snorkeling battery chargers- so that the submarine can stay submerged nearly all the time. I know it's Wikipedia, but to demonstrate, take the Collins class:
https://en.wikipedia.org/wiki/Collins-class_submarine

Notice that it only has 3x 1400 kW diesel motor/electric generator pairs for a 5400 kW propulsive DC electric motor. So yeah, it would make sense that you would need to drain down the battery to make full power, even with the diesels running.

I agree with the OP that this is not the best assumption for WWII era subs. Those would have big beefy diesels relative to what the batteries could produce because they were intended from the start for sustained surface propulsion. So yeah, you might loose a little on top speed during a battery recharge, but I'm sure that the 20 kt (or whatever) surfaced-on-diesels top speed rating was obtained without draining the battery further- because that was not the design intention of the propulsion system at the time. (Before anyone mentions "Hotel Load"- if I recall, in the case of the later WWII US fleet boats- those had a separate auxiliary diesel motor for that kind of thing.)

On the other hand, CMO does not prioritize WWII tech.

Osprey's New Vanguard titled US Submarines, 1941-45, states specifically that a late war addition to the Gato class (they look at the Balao class as an extension of that class) had a "dinky" diesel installed specifically so they can run full speed on the surface while also charging batteries. The implication is that prior to that, running full speed drained the battery. They also didn't get snorkels until post-war.

The interesting part is they had a propulsion "cubicle" designed specifically so they could mix electric and diesel energy to the shafts for greater power. And there is conflicting info on top speed of both the Gato and Balao classes. It seems to depend on what modernization program they were in. Migraine I/II/III or GUPPY I/IA/II, III. It added different engines, snorkels, torpedo tubes, radars, etc. And the engines were not all power upgrades. A couple actually reduced HP available to the shaft.

But I think the comment about WW2 era subs being abstracted a little and lumped in the early post war subs is spot on.

btw, I played Enemy Below last night. I had played it back when Silent Service came out. I see no difference in how it played then and how it plays now. So I'm interested in hearing the OP's reasoning for thinking there was some fundamental change that altered the scenario.

Just a follow up on max speed. The post-war modernization of the Balao class GUPPY mods...

"Instead of a steel fairwater, the two GUPPY I boats came with a streamlined fibreglass-reinforced plastic structure referred to as a ‘sail’. Submerged top speed came out at 17.8 knots, with a maximum surface speed of 18.2 knots. Not wasting any time, the US Navy quickly pushed ahead with the ‘GUPPY II’ programme that encompassed twenty-two additional boats from the Balao and Tench classes."

From Pen & Swords US Navy Submarines 1900-2019.

And later on the same page...

"The Balao-class submarines chosen for the GUPPY II programme had their original propulsion system, including their reduction gears, replaced by heavy-duty low-speed electric motors that had first appeared with the Tench class. Mounted directly on the submarines’ two propeller shafts, the new propulsion system gave the GUPPY II vessels a submerged top speed of 16 knots and a surface speed of 18 knots."

So it sounds like the 18 or so knots is about right. And note that GUPPY mods went to completely electric drives. GUPPY I started in 1946 and II started in 1948.

From the same book a quote from a US Navy source...

"Able to operate at will on the surface at night in the Pacific, the US Navy felt no urgency to develop and adopt the snorkel and took until 1948 to field an operation snorkel for its boats. (US Navy)"

So no US sub had a snorkel until at least 1946, and most wouldn't have one until after 1948.

Here is the Osprey booking showing the new electric drive for the Gato


Sounds like some of these electric drives were done before the end of the war.

So this link:

https://www.usni.org/sites/default/file ... 2028-6.pdf

Shows the original Balao class as capable of 20.25 kts surfaces and 8.75 kts underwater. And the max. depth of in game sub is much greater than 400 ft. Probably because the "collapse depth" was reputed to be 900 ft.

The Segundo (the scenario sub) is specifically mentioned in it's own Wiki as having only the "Fleet snorkel" upgrade during the Korean War time span aka no Guppy. The speeds are still listed as 20.25 kts and 8.75 kts.

https://en.m.wikipedia.org/wiki/USS_Segundo

This article mentions only the "Fleet Snorkel" upgrade as well.

https://www.history.navy.mil/research/h ... 68e1OnpyHs

In game Balao doesn't seem to line up with any version. It's much too fast underwater and too slow on the surface and it uses batteries on the surface for high speeds. Honestly this is confusing.

(SPOILER ALERT:)

Anyway, the reason I'm interested in getting this "fixed" is that in the Enemy Below scenario if you miss the initial intercept it's basically hopeless that you'll ever be able to catch the convoy again. They are running at 14 kts and you'll run out of battery (and therefore flank speed) long before you'll catch up with them again if the current stats and coding stand. There's no possibly of an end around sweep to try and re-acquire them and re-position for attack.

There are some people I simply don't respond to and would simply block if I could because they almost invariably show up in my threads and start blathering. Yay.

Regardless. Draining battery in calm seas on the surface at 9 kts is clearly wrong. I'll go with every single submarine documentary and book I've read and, yes, submarine simulation I've played. Laugh if you want, but I'd wager submarine simulators are in general more accurate than CMO on a unit-specifics level. Anyhow ...
Use common sense. If WW2 fleet submarines had to drain their batteries to run at high speeds they'd barely be able to cover their patrol areas and would end up with partly-drained batteries at the moments when they encounter ships and need fully-charged batteries. They were designed to run on the surface normally, and submerge to attack (or in bad weather). Snorkel at that time was primarily for a) Charging batteries while enemy ships are near and b) Remaining harder to detect when enemy ships are near (Tho the smoke limited that usefulness).
Okay, some later subs needed both to run at max speed. Fair nuf. But not standard for WW2 subs.

The database lists battery consumption at various speeds and diesel consumption at various speeds. Nowhere does it say it ever needs to use both at the same time. If this is true, it should be stated in the DB. It also lists specific max speed for each, with no mention of interdependence. Regardless of what various data being presented says, CMO is in conflict with itself here.

Incidentally, there are varied reports about max speed and max depth because <drum roll> Every sub was individually hand-built, and thus every one had its own characteristics. Which weren't precisely the design specs.

But that hasn't changed. You said it changed. Bring sources to the db team to ask for a change. A generic, "I saw it in a movie", isn't very compelling. I at least brought a valid source.

Again, when did this change?

btw, according to the Osprey book, the specific class in the scenario had a "dinky" diesel installed in one of its upgrades. This was an auxiliary diesel installed specifically to charge batteries on the surface when the mains were engaged for max surface speed. But there were so many upgrades to the Gato/Balbao class from 1944 to 1960, its hard to tell what the scenario unit represents. Auxiliary charging diesels were becoming common towards the end of WW2 it seems for the exact reason being discussed in this thread. As powertrains became focused on electric drives instead of complex diesel direct drives with hybrid battery couplings, diesel spec-ing shifted to focus on maintaining charge of the battery cells. Auxiliary diesels went away.

artao5 wrote: Mon Nov 06, 2023 8:16 am
Yes, The Silent Service is older. Every mission should still work 100% without fail with CMO as it is updated. Especially at full price. If it's not going to stay up to date it (any campaign/scenario) should be seriously discounted. Every campaign and scenario that is sold should be fully tested to work right with any CMO updates.
I mention this because I've been told before "some scenarios are just old and don't work right." It gets rather old (and frustrating and irritating) to keep encountering such things. Old scenarios just don't seem to get updated with CMO itself. I'm just talking about the included ones here, and campaigns and Live scenarios etc. The stuff we pay for. That should always remain up-to-date and work right.

So I'm coming back to this in particular. Thats some pretty strong sentiment. So I'm curious what you see different in latest versions vs older versions?

"Any info saying old diesel subs had to run batteries to travel fast when on the surface sure would be interesting to see, to a whole lot of highly studied people."

So at a minimum, the development of the "power cubicle" and the "dinky" diesel are pretty strong indications that for subs built before 1945, battery drain during max surface speed was a known issue. As to speed on the surface...its a known limitation of WW1 and WW2 era subs. The Germans also began installing auxiliary diesels mid- to late-war. Its why the concept of the fleet sub came about for subs in the UK and the US. They wanted a sub that could keep up with the battle fleet on the surface. These were very large, for the time, subs with very large diesels. It ended up not being a success.

thewood1 wrote: Mon Nov 20, 2023 11:45 am Osprey's New Vanguard titled US Submarines, 1941-45, states specifically that a late war addition to the Gato class (they look at the Balao class as an extension of that class) had a "dinky" diesel installed specifically so they can run full speed on the surface while also charging batteries. The implication is that prior to that, running full speed drained the battery.

Umm...no. Simply not charging a battery is not the same thing as discharging or draining a battery. If it were, then batteries would serve no purpose.

If anything, what is implied there is that "running full speed on the surface" is defined as a speed that can be obtained with the four main diesels running at full power- independent of the battery. That should get you to about 20 knots.

Defining "running full speed on the surface" as a speed that required diesels + batteries makes no sense for that era since that was not the design intent. Design intent was to use the batteries as a means of very temporary underwater propulsion, and not much more.

The issue is as old as CMANO and here's a bug report for CMO from 2021:

https://www.matrixgames.com/forums/view ... 8#p4932928

It seems clear that there's no plan to fix the problem of diesel boats exhausting batteries while surfaced and running at speed. The save was posted but never downloaded which speaks to the developer's priority concerning finding a fix for this matter.

-C

This time Raptorx7 logged a bug number, hopefully it will be fixed.

I think the gray area is late WW2 and early post-war. Sub powertrains were in transition. The Gato/Balao class had the power cubicle installed specifically so it had three modes: battery only for submerged, diesle only on the surface, and hybrid diesel and battery. This was before electric motors were installed post-war in GUPPY mods. I don't know if other subs of that era had anything like that. Because its called out specifically for these subs, I doubt it. The dinky diesel was installed specifically because in hybrid mode at full speed on the surface the batteries were draining.

As to the abstracted modeling of other WW2 subs, I mostly agree that the modern modeling with hybrid propulsion is not generally correct. I have been looking through our research docs for specific mention of battery usage at max speed on surface and have nothing except on the US later war subs.

Also, I have found more sources listing 18+ knots as max surface speed than 20+ by far. I suspect the 20+ speed comes mixing up knots and mph. 18 knots is about 20 mph. There were also so many upgrades and mods to those classes it can get very confusing.

Looking into this more, the confusion specifically on the Balao is WW2 original design and early post-war mods. The GUPPY program was completed on the first Balao (and Tench's) in 1947. The sail was created by fairing over the conning tower and the fleet bow was also faired over to create the rounded bow. And a snorkel was added. From that point on, max surface speed dropped from 20 knots to 18 knots and submerged speed went from 8 to 16/18. The propulsion was also changed from gear boxes and clutches to using electric motors powered at all times by battery. The large diesels were to keep a constant charge on the battery. As was mention by boolagon, this is where the modeling by CMO kicks in. As was already suspected, that modeling carries over to the WW2 era subs.

But the post-war modeling appears to be mostly correct. Its specifically mentioned in a couple articles the difficulty in managing the load on the diesels and that biggest challenges to charging were surface speed, crew air air handling, and newer electronics. If at max speed/power, full internal air handling, and all electronics energized, you could drain the battery on the surface. The new electronics were one of the key drivers for auxiliary diesels to help charge.

Is this an issue that needs a sim core fix, or could it be addressed with a ticket on the DB request page?

Maybe we could just request a big reduction in battery consumption at the highest depth band?

I think its mostly a db issue. My opinion looking at the sources is that IRL, managing battery vs diesel at speed is a big issue in post-war subs as the move to greater focus on submerged speed. One comment I saw was that cruising on the surface any time after 1950 was a death sentence as radar range and accuracy improved massively.

Frankly, I think a lot of the subs and ships from 1946 to 1950 need a big review. For example, US subs for Tench, Balao, Gato and their Migraine/GUPPY updates seem to be all mixed up with sensors and propulsion.