theCarthaginian

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.

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. :-)

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 🧐.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.