[Unreal Torpedo Spotting]

Ok... Nice charts. You don't give any context though. You can plunk down charts all day long without context and it means little. Cavitation, for instance, isn't an absolute limit. It's a function of multiple things: RPM, pressure, blade geometry, etc. Two otherwise identical plants can have different geometry screws and cavitate at different points.
Speed being a function of noise is correct, but it is not THE BIGGEST FACTOR, as a turbine powered ship is MUCH QUIETER at a given speed than a ship powered by expansion engines at an equal speed. Indeed, even on a modern submarine, the lower frequencys are heard first and farthest away. The higher-frequency noises, again, do not propagate as for for a given energy. It's why you hear whale songs documented as being heard literally oceans away... frequency, frequency, frequency.

 

You apparently misunderstand about me asking for Bismark and sonar info. I genuinely did not know (or indeed, care) if she mounted one. We see all the good it actually did her, too... so your whole 'statistics show' argument fails the test of logic. Having a good or bad sonar operator didn't save Bismark, Tirpitz, or any other German 'major surface combatant.' Putting 'the best' on them sinply takes those men and removes them to vessels that spent majority of their operational lifespans accomplishing very little effect. German surface raiders had a single major hurrah, and the Twins did that relatively early on - 08JUN40 to be precise. By the end of 1941, though, the German surface raider was a useless concept and the German surface fleet had largely taken up hiding in port as an occupation and sorties became a mere hobby.

The U-boats, by contrast, made meaningful contributions right up till the end of the war. Indeed, U-2511 could have sank a British cruiser (per her logbook, since you like to cite those as inviolate) on the day of the surrender.

 

If you want me to dig up exactly which boats heard what when you'll have to let me dig up copies of books I haven't read in a fair bit. my U-boat fanboy period ended quite early and most of the books on German naval hardware got shelved a couple of decades ago in favor of books on PACT hardware out of relevant professional interest. I'll give a dive for them though, to be fair.

[Unreal Torpedo Spotting]

16 minutes ago, madham82 said:

Food for thought, I don't think I heard of this before:

Torpedowarn (TAG)

Designed as an early warning system for incoming torpedoes, the TAG was installed on the Type XXI and intended for future generation U-boats. It was connected to a loudspeaker inside the pressure hull which would give audible warnings on an approaching torpedo. It functioned by listening in to certain pre-programmed sounds, which would trigger the alert status.

http://www.uboataces.com/hydrophones.shtml

Now if they could make an automated system in '44/'45, you bet an at least competent sonar operator could detect an incoming torpedo.  

False assumption, again.

Machines do not 'hear.' They do not get distracted, they do not miss things; contrariwise, they cannot interpret info on the fly if the incoming data doesn't trip their preset parameters. They are, as my old high school math teacher loved to say 'high speed idiots.' They merely multiply the mistakes of others at incredible rates.

A particular pattern recognition in those early automated systems was not very reliable, was easily spoofed, and was very limited in range. Think about the difficulties that early homing torpedoes had... the system you mentioned would echo those problems... and came something on the order of a DECADE after P.E. was put into service. :-)

[Unreal Torpedo Spotting]

31 minutes ago, DougToss said:

Just generally speaking, the U-Boat arm got the pick of the Kriegsmarine. By the time the major surface units were expected to do no more than be bombed at anchor, I’m not sure why they would prioritize sending the top of the sonarman class there. I’m sure I can poke around for something on how the Kriegsmarine was kitted out for ASW and how their acoustics were.

From O’Hara’s On Seas Contested: The Seven Great Navies of the Second World War:

Antisubmarine Doctrine

ASW Equipment

 

At the service level, having undeveloped doctrine, insufficient sets for operations, let alone training, and having tremendous difficulty detecting and engaging submarines does not bode well for their major surface combatants masterfully using sonar in battle, but there are surprises there too. 

 

@theCarthaginian, the author does note the advanced set installed on Prinz Eugen, but mentions it tracking Hood. I don't see any reference to torpedos. The easiest thing to do would be to look for that  GHG (Gruppenhorchgerät) set:

Which "consisted of two rows with sixty Rochelle salt hydrophones at each side, arranged in an elliptical array on her bows."

And to find out more about the capabilities from there. A 120 hydrophone array is significant, but it still doesn't tell us much about the kind of information it provided. I would guess based on the example, and Germany's surface raider doctrine mentioned above, that it was intendant to track merchants (to attack) and warships (to evade). To use the radar example, that seems like an Early Warning Radar. I don't know enough about sonar to say if the implications for frequency, wavelength and resolution. 

Yeah... the actual performance info on GHG transducers in general and the great socking linier array on P.E. in specific is quite limited. I've been looking between games of HOI4 since I got off work on Wednesday morning and have found precisely diddly-squat beyond what you mentioned.

All of which make the cited case look more like an outlying case rather than the mean performance of the set... more reason for me to doubt 🧐.

[Unreal Torpedo Spotting]

PS - I find no records of Bismark or Scharnhorst having any sonar systems installed.
Could you point me toward your source for that?
If they did not, in fact, have them... well, you ARE dealing with a single instance - especially if those ships didn't exhibit exactly the same performance.

[Unreal Torpedo Spotting]

8 hours ago, arkhangelsk said:

First, we are already using combat logs, so at least we are not dealing with "theoretical" or even "highly optimistic and unrealistic test" results. In fact, we are dealing with pretty unfavorable conditions - the seas far from being a flat and the ships themselves moving at over 20 knots. And between Bismarck, Schanhorst and Prinz Eugen, we are at least not talking about one source.

Re German U-boats, the first thoughts that come to mind are as follows. Other than them just not listening in the right direction at the right time, there is a huge gap in operator quality. There are about 1000 U-boats versus ten battleships + heavy cruisers. Do you really think the average U-boat sonarman would be of the same cut? Third is the target - with the U-boats mostly trying to hear merchies and tiny escorts that are moving at low speeds (low noise).

Third, I don't want to deny the possibility of assistance that did not make it into the log, but there's still a huge gap between this and what DougToss is doing.

1.) You are kidding, right?
The creme de la creme of sonar operators in the Kreigsmarine were put on a heavy cruiser? 🤣 I'm sorry, no... that's a MASSIVELY counterintuitive comment with neither grounding in rationality nor the ability to cite proof. Occam's Razor would lead one ot believe that the better sonarmen were on U-boats, simply by virtue of their ships' entire existence depending on how well that system is operated. Pulling a guy that can hear, differentiate, and triangulate targets at 40km from a sub to a surface ship is like taking the best door gunners in the Ia Drang valley out of their Hueys and making them Apollo Program Door Gunners. You lose any real utility that cannot be gained by other systems. We know this, because, no major Kreigsarine vessel was lost to surface-launched torpedoes in spite of several facing them. AGAIN, you are citing a single instance and applying the Mediocrity Principle in the face of convincing evidence across multiple nations that other circumstances point to this being an outlying case. Your argument is not based on logic, or it is rather based on bad logic.
2.) Again, you're making a false assumption. Lower frequencies carry farther in water than higher ones. This means that higher-frequencies - like what a torpedo gives off as opposed to, say, a churning Liberty ship propeller - attenuate FASTER and you won't hear them as far away. :-) Also, the Expansion engines that most merchant ships of the inter-war and WWII period used were orders of magnitude louder than a turbine-driven warship due to the fact that they caused far more vibration and impact forces that propagated through the structure and into the water. Turbines simply spin... the multiple expansion engines of a merchant ship and some escorts ware just like a car engine - a piston on a connecting rod that turned a crankshaft. If you own a car, fire it up and open the hood. Watch your engine sit and vibrate. Ever wonder why it isn't precisely hard-mounted to the frame, but instead has dampening mounts?
*ding, ding, ding*
We have a winner. :-D
So, your entire basis for the second part of your argument is utterly and irredeemably flawed.

[Unreal Torpedo Spotting]

51 minutes ago, arkhangelsk said:

I don't know what is this resistance to the idea of it being possible to have a somewhat competent hydrophone system.

You can eventually derive range, course and speed using only bearings, but if you don't even have somewhat decent bearings, you aren't plotting.

Never mind:

 

It's not a resistance to a 'competent hydrophone system' - it's a resistance to some people confusing 'theoretical maximums' with 'consistent performance under combat capabilities.' Those two things are a fair piece away from each other, realistically... yet armchair quarterbacking on third-hand sources sometimes leads to their confusion.
For instance, the 'maximum effective range' on my beloved M249 was (theoretically) 1000m for an area target.
Even in Iraq, that was a most generous assumption:
- It first assumes that I'm engaging on open terrain that lets me have that kind of option, and I was in town rather often without that kind of LOS.
- It doesn't take into consideration weather on any given day... if there was a sandstorm, every weapon had a MER of "the end of my nose."
- Even the sunlight could play hell with that 1000m figure - if it was a particularly blistering day, the haze and glare could make you lose economy cars at a kilometer.
- Iraq wasn't all flat scrublands or gentle dunes... and it's hard to get 1000m worth of LOS in a wadi.

Likewise, the performance that is exhibited in one engagement isn't indicative of the average performance of a sonar system.
Yet, it is seized upon by some as a mean performance... because it's the only well-known documentation.
That's called 'the mediocrity principle' - an assumption that all other things being equal, you got your single result because it was the most likely outcome. While that is a recognized principle, it is not something that you should engage in capriciously or regularly. And we have other information on the basic hydrophone design from multiple German sources, because it was used on U-boats. Reading the accounts of the boats gives us everything between 'we head it before we saw it' and 'we could have drove into a ship before hearing it' (largely attributable to weather near the surface).

So, I don't doubt the man heard something.
I don't doubt that he said it was possibly a torpedo when he got a good listen to it.
I DO DOUBT that he was tracking the torpedo from the instant of launch up to whenever he consciously decided to stop, constantly and consistently, and that no other information was used to verify what he saw or assist in identification of the torpedoes. THAT is just, bluntly, a dumb line of reasoning. When a sonarman reports a contact, it is SOP for it to be verified by multiple other methods - as many as possible under the circumstances. Lookouts WILL be told to check that bearing line. If it is likely a ship, it WILL be verified by RADAR if they aren't trying to avoid detection. Likewise, a radar contact would be verified by visual and sonar as soon as possible, if possible.
That's just how it works.
And what gets written in the ship's logbook is the sum of ALL those things.

 

[Torpedoes are supper underpowered]

1 hour ago, DougToss said:

Modelling Longitudinal bulkheads and subdivided machinery spaces seems like the best way to model this weakness. 

And would, coincidentally, assist massively with the whole "clown car" situation... with more accurate modeling of INTERNAL components and bulkhead placement comes the unavoidable, but highly pleasant, side effect of getting better placement of EXTERNAL components that connect to those. No more will we see insane turret placement where half-a-dozen different gun calibers are packed into every available square inch of deckspace. The computer will have more accurately modeled the magazines, and will resultantly have better gun mount arrangement.

[Unreal Torpedo Spotting]

59 minutes ago, DougToss said:

Given the German’s handling of radar… lol I wouldn’t place a lot of confidence in that. Information management as a whole in German surface ships seems to have been subpar. Even during the Channel Dash, which was doubtlessly operationally successful, on the tactical level I’m not convinced anyone on the bridge of a given Kriegsmarine ship knew what was going on. 

Nor do I... not while it was happening - in fact, I'm quite skeptical that the sonar crew figured out what they heard was a torpedo. I'm of the opinion that the 'information integration' we see in the log happened on the bridge, and that the recording of 'torpedo detection' was the result of sonar relaying a "probable intermittent contact" report, lookouts reporting suspicious enemy asset behavior, and then the actual spotting of a wake or group of wakes. Then you have that eureka moment, and realize what the sonarman heard in that direction for the last 5 minutes (probably defined as "out there, that-a-way" for most of it) was the torpedoes fading in and out of detectability as conditions changed. Subs actually have a bit of an advantage here, as a crew of 70 - 100 men is a LOT easier to disseminate information amongst than a cruiser with a crew nearing a fifteen hundred. In one situation, you simply call someone's name/title out and he takes a few steps or even just turns his head... in another, you're dealing with a chain of a dozen or so guys that are spread over what could generously be called "Hell's half acre", and none of whom can actually see or hear what the other guy is doing or looking at - and will, in battle, be contending with another dozen or so groups just like that vying for the attentions of the one person that's supposed to be coming up with all the answers.

I've never felt that the information management of any navy in WWII was particularly bad, in that it roughly corresponded to what had been considered acceptable for centuries. What I have felt is amaxement that some navies and, more specifically, particular fleets within some navies evolved the astounding levels of information management that they accomplished. The Germans were at a terrible disadvantage in that regard, not really conducting any large scale fleet actions like some fleets... like, say, the Italians. 😉 German availability meant that they never had more than a handful of large ships out of the relatively few that they possessed in coordinated action at once, and that's how you get good at information management on large ships.

[Unreal Torpedo Spotting]

4 hours ago, DougToss said:

I know this discussion is about Torpedos, but @Nick Thomadis - the higher hit rate is what is causing issues for every step of the line down! Ships have to be armoured and gunned entirely differently than they would be in reality because engagements are so different!

I digress, but you can very easily test this by using approximately the same ship in UA:D, Jutland Pro and RTW 2. During the battlecruiser exchange at Jutland the British scored 11 hits iirc. They would easily get 100+ in the same conditions in UA:D right now. That means any sensible person would have to put 16 inch guns and vastly more armour on the German battlecruisers.

To return to the problem at hand, is it possible that in this instance sonar acted more like a primitive RWR, or IRWR - only indicating that there was a launch, but not range or bearing? From what I know of German sonar arrays, that seems more feasible than  plotting the torpedo. It would also still be useful in game and prime players to look for visible tracks.

I was reading about Tactics in 1912, I’ll look for the passage later, and it said that evasive drills were taken if torpedos were suspected to have been launched. Of course at the ranges torpedos could reach by 1910, you couldn’t see the shot leave the tube, and I think trails were weak until more advanced torpedos came along, but the idea was to turn towards the bearing of the launch, so that you would pass through the “rake”.

It could be as easy as telling players “if you think a torpedo has been launched, turn directly towards or away from it”, having sonar alert players to launch would just help them know to take evasive action, not tell them exactly when and how to evade by accurately plotting the torpedo in the water.

We can understand why the Devs 'compressed' things a bit as far as hits - very few players want to spend hours in a game with 50 ships plowing around the ocean, fight a 24 hour (realtime) long battle in half-a-dozen 2 hour long main phases and a dozen short-duration skirmishes... and sink maybe 7 or 8 ships (and few of them be large ones). It, sadly, goes back to the 'Realism vs Entertainment' issue - and that people could by and large want to see more substantial results for their efforts.

As far as the torpedoes:
Yeah, the launch sequence for a torpedo is the dead giveaway... a ship GENERALLY makes a highly-recognizable, easily detectable, and simple-to-counter (at anything other than stupidly close ranges) set of course changes when firing a torpedo. They have to close to a specific range bracket, turn to within a certain angle of approach, hold that course for a predictable period of time, and then (presumably, if they are acting rationally) change course again to escape the wrath of their enemies. Anyone looking for a torpedo attack would notice a ship that was engaging in this pattern, and would act accordingly. Of course, that DOES assume that the opponents can ACTUALLY SEE YOU - say, they aren't making smoke while you are making smoke (like in my original post) - and know that you are doing this.

Given favorable acoustic conditions, a warning 'cone' like the RDF 'finger' pointing out a suspicious contact (in, say, red - to differentiate) in a given arc would be appropriate. The debate is over the timeframe of the warning: exactly how far out would you be able to detect that the threat is actually a specific threat rather than something they thought they heard. That's where the 'vigorous discussion' part comes in; what would the sonar tell them, how fast they are going to be able to interpret that, and how it would integrate with the other information you get from other sensors to give a whole picture.

[Unreal Torpedo Spotting]

25 minutes ago, madham82 said:

Was pretty sure observation is the foundation of science.

The Germans on two separate ships (probably more if we dig through more records) and the US Navy both validated it's ability to detect torpedoes. Scharnhorst was not in calm perfect seas, it was in the North Sea during winter. Not at all ideal weather/seas. I believe I also heard Yamato had passive sonar for this purpose as well. 

Originally the game did not feature sonar on BBs/BCs until people posted evidence.  

But you are free to disagree. I'm not going to argue the effectiveness/testing done on the units. 

You are focusing on a single documented instance to fit your desired outcome.
While I acknowledge this exists I am able to point to a plethora of other documented instances by ships of multiple nations that had a much broader range of results. Convoy escorts saw torpedoes strike without ever hearing them (or the launching sub) on their sonars. Sub skippers saw ships before they heard them, and vice versa.
Observation that depends on a single instance and the mediocrity principle isn't the best policy.

[Unreal Torpedo Spotting]

On 9/29/2021 at 8:45 PM, HistoricalAccuracyMan said:

I brought up a similar issue with rangefinders a while back and how coincidence/stereoscopic rangefinders were used and what their strengths and weaknesses were...and the best answer I got was (I'm summarizing here): the choice between coincidence and stereoscopic rangefinders in this game is just a design choice you make to decide whether your guns aim faster or if they are more "accurate" at long range.

Yeah... they used two items grossly similar in actual performance to separate focuses on 'Field of View' (obtaining sight picture) versus 'Precision Optics' (point-target accuracy).
I'd like them to change those names, personally, as coincidence and stereoscopic rangefinders are pretty much 'six of one, half dozen of the other' in end result.

[Unreal Torpedo Spotting]

3 hours ago, madham82 said:

Rather that arguing over semantics, are you saying you do not believe the logs from Scharnhorst or the US Navy's test of Prinz Eugen’s (which is the same passive sonar system) that they were able to detect torpedoes? I mean the US Navy liked the unit so much they mounted it one of their submarines. 

Or are you just arguing the game handles detection unrealistically? 

The concept clearly has merit, it's implementation in UA:D may not so much IMO. 

For reference, this is from the wiki on the GHG sonar used by the German ships. 

"The group listening device (‘’Gruppenhorchgerät’’), abbreviated "GHG", consisted of two groups of 24 sensors (one group on each side of the ship). Each sensor had a tube preamplifier. These 48 low frequency signals were then routed to a switching matrix in the main unit. The sonar operator could determine the ship's side and the exact direction of the sound source. To improve the resolution, there were three switchable crossover with 1, 3 and 6 kHz center frequency. A disadvantage of the side mounting, was a dead zone of 40 ° to fore and aft. Range: 20 km to individual drivers, 100 km against Convoy" 

Yes, I doubt everything - skepticism is the foundation of Science.
Your pointing to the wiki article tells me nothing.
It regards a submarine, which you yourself admit has different characteristics than a surface ship. It doesn't talk about the number of hydrophones in the array, whether it was fixed or mechanically steered, what conditions were during the test, whether the sub was surfaced or submerged, the speed bands across which the testing was conducted, the depth of the submarine if it was submerged, the presence of a thermocline, salinity of the water, time of the year or any of 10,000 germane variables that could have yielded a skewed result. It also only cites a single data point, whereas there are multiple hundreds of submarines exhibiting lower performance from the same set... indicating a possible statistical anomaly in this case.

The US Navy did indeed test the set on Flying Fish... much to the detriment of her appearance, and used the system in the development on the sonar system that they installed on the Tang class - and it bears noting that the installation was not repeated in their nuclear-powered cousins the Skates, nor in any following vessel class (only Tullibee, which was more of an open-ocean operational test platform than a fleet submarine). One of the things this hints at is that the performance wasn't worth the trouble after all, and that more conventional arrays were effective enough when it mattered.

So, yeah... I have doubts.
Many, many doubts.
And that wiki just makes for a lot more questions.
If I get a chance I might look for the actual British tests - though the odds of finding them are slim. Until then, I have the data that is gathered from reading accounts of dozens of commanders of vessels both surfaced and submerged that talk about sonars losing contacts at remarkably short ranges (some using that EXACT hydrophone) and acquiring them at excessively unbelievable ones under differing conditions. This tells me factually that operator skill, external conditions and pure dumb luck was at least as important as equipment in acquisition and retention of a sonar contact during the 1940's and well into the Cold War... possibly even more important than the equipment.

[Unreal Torpedo Spotting]

10 minutes ago, madham82 said:

1. Submarines are a hell of a lot quieter than a torpedo, which is the primary threat sonar is used against today.

2.The depths they can operate are much different than a torpedo on the surface.

3. Related to the depths they have to take into account thermal layers and there impact on sound.

4. Today's sonar can hear ships at great distances, even in the 1940's subs would submerge to listen for ships because they could hear them farther away than they could see them in many cases. Ships are actually quieter than torpedoes at the distances we are discussing. 

5. Most importantly, you don't need precise information to dodge an incoming torpedo. It doesn't take much analysis to determine the bearing and whether you are closing/opening the range. That's all that is needed to take evasive action. The key with torpedo avoidance is detecting them as early as possible. 

Now here's what is too "gamey" about UA:D. We should only get a bearing and direction from sonar detection. The game should not render an actual wake until visually detected. This would make evasion more realistic and make for more calculated decisions on when to take evasion action. 

1.) Submarines lost contact with surface ships up to and including fast-moving escorts... negating the 'subs are quiet' argument.
2.) Indeed, it's quieter and more stable for a sub... and, barring something like a sound channel or a thermocline, more conducive to them getting BETTER overall performance in the general area under any given variable.
3.) But for a surface ship, this is moot... and both the extra performance and the interference that go with it.
4.) EXACTLY - part of the reason was the degradation of sonar performance on the surface versus that of sonar submerged. And the whole 'hear them before you can see them' was a very common thing at night and in bad weather - when sonar performance on the surface was trashed by the very conditions I mention. 😉
5.) Yeah... but then you run into the actual distance at which you'd be able to make that out over ownship noise - and whether or not that warning might be more than you'd get visually under any given circumstance, and that would vary by torpedo type. It would be a really big reason to love that crew experience variable, that's for sure.

[Torpedoes are supper underpowered]

On 9/27/2021 at 5:19 AM, Lucas_Slavik said:

Still. I think this (Musashi) is en extreme example. She was at least a state-of-art-super-battleship.

Since the last patch, I had situation like this:

1x 18 inch torp vs Heavy Cruiser, 1930. 25 Dmg.

+-10x 24 inch torp vs (normal) Battleship, 1930. 800 Dmg.

 

I dont say, every torp have to do 5000 dmg. But at least 100+ would be fair...

 

 

And, yet, even older or less protected battleships and cruisers have taken some pretty astounding torpedo damage and either sank slowly or even not sank.
North Carolina, for instance, continued to blaze along at what was roughly her maximum sustainable speed (remember her peculiar issues with her top speed) of 25 knots and maintain formation with Saratoga. Even Wasp not only took the single Type 95, but three more much weaker Mk 15 torps... and even then took hours to sink in the face of the combined damage (without anyone trying to stop her from sinking, BTW). Heck, in that battle, a close-aboard detonation damaged O'Brien - which then took over a month for the cumulative explosion + stresses to cause her to cease to be watertight on such a scale that she eventually couldn't float.

[Unreal Torpedo Spotting]

On 9/28/2021 at 4:32 AM, arkhangelsk said:

Koop, Gerhard. Heavy Cruisers of the Admiral Hipper Class: Warships of the Kriegsmarine (p. 47). Pen & Sword Books. Kindle Edition. 

During the battle with HMS Glorious, Scharnhorst started at 1700 at 19knots. 7 minutes later, she's at 24 knots. It then took her until 1726 to reach 26 knots (but only two more minutes to work to 29), finally reaching 30 knots at 1738.

At 1745, she heard and avoided a torpedo. She continued to hear more torpedoes throughout the battle.

I'm yet to hear any example of 'perfect sonar' like Prinz Eugen managed in this account.
In fact, every other accessible account of sonar (including the one sonarman I know) use seems to contradict it... indeed, if sonar was so incredibly and amazingly clear as this alleged account states, then why does modern sonar require computer assistance for noise-canceling or target tracking or a host of other  duties? Until shown other documented episodes of similar instances with similar results (which I haven't found), then such an aberration can only be put down to the fact that someone is stretching the truth.

If you can corroborate the capabilities of ANY OTHER SITUATION where this feat is repeated in the face of the thousands of times that contact loss due to flow noise...
well, I await your convenience.

EDIT: also, IIRC, the same basic hydrophones fitted to P.E. were fitted to U-boats... which suffered from flow noise interference at speed.

[Torpedoes are supper underpowered]

28 minutes ago, TBRSIM said:

AFAIK there is no historic example for any warship taking more than three heavyweight (i.e. full size, for the time, surface ship or submarine torpedoes) torpedo hits and not sink...

Musashi was likely sinking well before the number of torpedo hits went double digits, even with the smaller warheads of aerial toroedoes and contact fusing. The sinking of a hardened warship however can take a dozen hours or more (and be sped up by pile-on attacks).

She was certainly sinking...
she was also still intact as a fighting unit.
A ship can, paradoxically, be both at the same time.

Musashi was settling in the water rather evenly.This presents a situation where the mechanisms of the ship are still working more-or-less as intended. Turrets can traverse, shell hoists can still feed, water inlets are still in the water and drawing flow, etc.
A ship that is settling slowly can take an amazing amount of punishment before it sinks, reference SMS Seydlitz after Jutland. She pulled into port hit more than 20 times by battleship-caliber shells, once by a torpedo, and several times by smaller caliber guns. The substantial damage, however, was mitigated by the manner in which the flooding occurred and the ability of the ship to successfully counterflood while taking it. Even though she was actively sinking able to make it far enough to be rescued by ships with pumps sent out specifically to help stabilize her.

And, again, the Mk13 torpedo was a full-size torpedo.
I don't understand where the myth that they were not came from.

[Unreal Torpedo Spotting]

13 hours ago, Drenzul said:

There are sonar/hydrophones as well. Torpedeo 'spotting' via mk1 eyeball was generally a last resort 'oh its too late' kinda thing

Sonar/hydrophones in WWII didn't work at the kinds of speeds that destroyers in a fleet action would be moving... flow noise will blind modern sonars at moderate speeds on submarines - which exist in a much more stable environment that a surface ship's hull-mounted sonar. Remember, not only is it being plowed through the ocean at speeds in excess of 30 knots; it's also being slapped and slammed by wave impacts, picking up the flexing of the hull by conduction, ect. Sonars in WWII were not very advanced at all in the grand scheme of things. I mean, think about a voice recording of the era. Those were made under as near to perfect conditions as could be contrived under the circumstances of the time's technology. Now, translate that into State 4 or State 5 seas. It's amazing that sips could hear anything AT ALL. Indeed, sometimes, they couldn't - and that just from the environment, while they were doing everything they could to control ownship noise generation!

[Torpedoes are supper underpowered]

13 hours ago, Drenzul said:

Yeah but weren't they all air-dropped torps which had a significantly smaller payload.

Uhm... no sir, they weren't.
The Mk 14 (21" torp) warhead used by subs came in two flavors... 500-ish pounds in early marks and 650-ish pounds in later ones.
The Mk 13 (22.4" torp) warhead used by planes came in two as well... 400-ish pounds in earlier ones and 600-ish pounds in later ones.
While the air-dropped torpedo was 'smaller' (13.3' vs 20.5') in length, the greater diameter gave the option to cram in a pretty acceptable warhead in comparison. So, we're talking about a <10% difference in the strength of the torpedoes that a sub would fire and an aircraft would drop by the time that the Yamato and Musashi faced their ends. While that's nothing to sneeze at, it's not really THAT big a difference, and basically amounts to how much overkill that you want to inflict - that's ESPECIALLY true in the marks where they switched to Torpex, because you're talking a 50% increase in potential energy over TNT on a pound-for-pound basis and something of a different profile for the explosion itself and resultant pressure wave.
 

[Unreal Torpedo Spotting]

I'm a bit confused as to how an OPFOR destroyer - which is making smoke - can notice that I am - while also making smoke - am launching torpedoes several kilometers away and immediately react by going hard over to let a spread of five torpedoes whizz by totally ineffectually. It seems that the AI is as acutely aware of our actions during combat as it is in how our ships are designed in order to counter our tactics.

Exactly what penalties in spotting is the AI suffering due to two smokes and at what range are the torpedoes of each type visible both in and out of smoke?

[Torpedoes are supper underpowered]

Well, do remember, Musashi took an INSANE amount of torpedoes - at least ten and possibly as many as nineteen, and this does not include the fact that she was also hit by many bombs as well, which well could have caused internal damage that could exacerbate the torpedo flooding - before she went down. A battleship focused on underwater protection taking a dozen torpedo hits and remaining afloat as a fighting unit isn't outside the realms of possibility... as long as those hits are 1.) in areas that the torpedo defense system covered and 2.) distributed more-or-less equally on both sides of the ship which allows for effective counterflooding and lowers the risk of capsizing. That was the difference between the two sisters; in light of the extreme suitability of Musashi strikes on Yamato were more-or-less intentionally concentrated on one side of the ship to make counterflooding exceptionally difficult.

Also, as an aside, Yahagi  (which was escorting Yamato) - a light crusier not particularly built with underwater protection in mind - soaked up an impressive seven torpedoes herself before she sank. Multiple destroyers and escort vessels survived being hit by a torpedo as well, though location of the hit played a major part in this.

So, depending on how/where/when you hit the ship (a ship traveling at high speed floods more and takes more damage), it isn't impossible for them to survive like that.