Very good explanation: A few more factors I would add to this discussion are 1) Effective Target size (aspect) 2) bottom type (hardness) 3) sea state all play a factor in active effectiveness as well. My opinion is that this new design will significantly reduce Active Target visibility in all environments when compared to similar conventional submarine examples.
I presume this is the same idea you referred to recently when discussing the Astute's bow? If that was the goal I wonder why Astute and Trafalgar didn't continue the bow chine all the way down their sides. Difficulty mounting the flank array maybe?
@@SonB288 Couple of things strike me on this question, the chine does end exactly where the flank arrays begin, that may have been a compromise where they focused on frontal aspect stealth for approaching a target. Second the torpedo tubes in the Astute are right at the side edge, there isnt any internal space given over to outer hull shaping beyond the pressure hull. Finally the Chine is exactly the same location as the floor of the upper deck, it might be a reinforcement strut to redistribute some of the squeezing away from that particular location (and the same location the forward superstructure) and add increased structural strength.
One thing I'd like to point out and what i don't know if you deliberately omitted or missed: the HMS Astute appears to exhibit this very same feature, by about 20yrs. In addition, like astute, subs with this angled feature have a tendency as Astute, to have a slower design speed; because of the hydrodynamics of a angled hull over a teardrop design. Just speculation btw, not a professional.
Another thing to add: the German 212 submarines use Hydrogen fuel cells and batteries. So they basically don't have any moving parts except for the propeller itself. They have reached a point where you can't do much to reduce engine noise anymore for passive sonar stealth. So active sonar was the only remaining weakness, the only thing you could tackle and get better at. Also interesting, the German submarines are usually small because they must be fully operational in just 17m deep Baltic waters.
As far as I know: anechoic tiles were first (to my knowledge) used in Germany during WW 2. Called "Alberich" after a dwarven king in german mythology, it was developed in 1931 and applied to multiple submarines in 1941 🙂
@@labschi No, they had problem with the glue, the tiles started to fall off. I believe that they finally fixed that in late -44 but then it was too late and the Anglo menace triumphed;)
I mean everything from 1920 to 1970 can be summarized by "we had the best German scientists and engineers". Nuclear weapons were developed by a lot of German scientists in exile in the US. The space race? The German V2 rocket engineers picked up by the US vs. the German V2 rocket engineers picked up by the USSR.
I believe that is something that can actually be done through the use of active pings from torpedoes. Calculations might be a bit more tricky, but the pings won’t be coming directly from your ship.
actually I came here to raise the same question, some sonars have a remote emitter. And for airspace some systems use the reflections from telecom emitters to spy without emitting themselve.
I think it's a lot more common to have nuclear powered listening station which can permanently listen to an area rather than a drone which has a temporary lifespan. But on the attack into enemy waters remote sonar station drones make a lot of sense.
You can use existing biological noise as the source for a semi-active sonar in which you look for shadows using passive sonar and the more angles you can use to look at the target you will be able to better develop your target location depth and speed..
It's not actually artificial intelligence that has enabled these designs, it is computers with more computing power to handle the millions and billions of calculations necessary in a reasonable amount of time to simulate the behavior of sound waves in various densities of water reflecting off of of very complex shapes.
Great video, just one detail: Norway isn't just a customer, it's a joint development and meant to be the beginning of a strategic cooperation in Research & Development of AIP submarines, a German-Norwegian Research facility has been established at TKMS, and both German and Norwegian units will receive maintenance at a Norwegian central facility. The Netherlands have been offered to become somewhat of a third participant in this strategic cooperation if they should decide on the slightly modified Type 212 C/D-E for their new submarines.
That’s really important to know, I wouldn’t have learned that if you didn’t take the time to post that so thank you very much. Idk why we don’t have news that tells us these things in the USA . No real news , just nonsense on the news here 😂
@@MattttG3 I watched a lot of American news when Trump became president, daily for 1-2 years and as far as cable news is concerned, I'd have to agree. It's 95% domestic, rather petty, and depending on whether you watch Fox or MSNBC, you get everything served with a lot of spin. 🇩🇪 news is more like CBS. News at eight have no commentary at all. News at ten have become more opinionated in the last ten years. Btw, since this seems to interested you: 🇩🇪 and 🇳🇴 signed a general treaty for strategic cooperation in Defense Matters. May seem silly since Norway's rather small, but the whole German Defense Sector ain't that big either. Rheinmetall builds the Lynx, Panther, Boxer. TKMS builds frigates and corvettes, usually with two much recon equipment, good motors and not nearly enough armaments, KMW was grandfathered in as important because they build the Leopard 2. And Diehl build Air Defense, like recently the Iris-T SLM for Ukraine. And that's about it. Maybe 75,000 employees altogether.
The algorithms used for the shape design are typically evolutionary algorithms or genetic algorithms, which are not AI in how the wod is tday used but rather a well-established soft computing practice. They are useful for optimising any computational impossible problem whose outcome can be measured for fitness and who accepts a finite set of input variables.
I think the sharp angles in the early stealth plain have more to do with the difficulty to calculate the radar reflection rather than that they are particular good for that. Newer stealth air crafts are more curved.
@@MusikCassette i guess he meant 8:38 there is the thing with the thermocline layer (the layer between the warm surface water and the cold deep water) and different layers of seawater too, as sound waves can be diffracted between the surface and the thermocline, or be reflected from the thermocline back to the depth
Few people realise that weapons designers have “fashion fads”, this is related to sales, I.e. what they can sell and “demand” what the higher ups (superior officers and politicians) want. THEN, there is the corruption factor, both overt corruption I.e. some one gets money to make a decision or covert I.e. some one or some group gets a benefit (free holidays, women, political donations, relatives jobs etc).
The Navies around the world are finally waking up. In the book "Skunkworks" by Ben Rich it said they did make a quick model and gave it a try. It had a sonar reflection (IIRC) 1/100th that of a normal sub. The USN response was "Submarines are round".
@@hint0122 real question from a plane nerd: why would that matter? If the ship is sufficiently hard to detect, then it can simply sit at shallower depths without caring, right?
@@IntrusiveThot420 There may have been issues when it comes to the body creating hydrodynamic noise. basically the fear was likely that the body would induce turbulent flow in the surrounding air, making noise that can be picked up on passive arrays.
Very good Hutton, previous works by the germans paved the way for today . The example are the models XXI and XXIII and my favorite the Horten 229 jet the first with the available materials of that time.
Great video, as always! Really interesting how technological developments can force a continuous cycle of one technology over the other, being replaced by each other in a loop. That is ongoing until a major breakthrough happens, or a major technological leap is achieved.
Couldn't agree more. I like sub brief but he's added America on his American, Americanism when it comes to his view points. It colours the information a bit.
Nice video. Question: these shaped hulls reduce the capacity of going deeper? Also, what's the sonar range? Can a submarine avoid detection by doing deeper? Thank you in advance!!
I like the unscripted style of video. Most of my favorite sites are definitely of the unscripted type. I think that the unscripted style videos, aside from the "organic" aspects, are that they show more technical knowledge on the part of the video creator.
Just a note to say that the classic angular shape of the F-117 was almost entirely down to 1970/80 computing power. The next stealth aircraft, the B-2, was far less angular and the modern F-35 not angular at all. My point is simply that blocky angles does not necessarily equal stealth.
2:45 "active sonar lets you be heard farther away, typically twice as far." I don't think so--not a naval engineer, but still an engineer. If the target reflected the signal perfectly back as a flat mirror, you would hear it at twice the distance but in fact no target does that. Typical targets will reflect less than 100% of the sound, and reflect it with more dispersal than it came in with, causing reflections to be far weaker. I'm just reasoning from first principles here, but I know aircraft radar can be spotted at 250km despite only seeing targets within 50km. Another thought experiment: at night on a moor, how far away could you see someone with a flashlight? several km if the ground is flat enough, no? Would he be able to see you at half that range? Yes... if you were a mirror. But even if you were dressed in white, so little of his light would reach you over a km that he probably wouldn't see the return light since a white object would scatter light in all directions not just back to the man with the flashlight.
I think H I Stutton meant the ship sending out the blip can be heard twice as far away than what they themselves can hear an eco back. Ie, the silent sub can hear the approaching ship long before the ship can hear the eco from the sub.
@@Br1cht > You´re arguing with known axioms that been researched and understood for a very long time I´m afraid. If so then please cite a source I can refer to that the range to detect an active sonar emitter is only twice its detection range. To be clear I'm not arguing the general shape of the premise, only that the 2x here is likely to be more more like 5x (as it is in aircraft radar as I explained) or higher.
You should do one on the rubber coating. First developed by the Germans in WWII. Two layers, one with a specific pattern of holes with the signal absorbed by the 2d layer.
I figured out a "Stealth" design over twenty years ago, but the problem is the extra turbulence created by the angular hull. You can still detect it with passive sonar.
Yes, agreed! Hydrodynamics would definitely play a big part insofar as operating envelope/efficiency, too. Clearly, screws would be OUT in favor of specially shrouded propulsors (or even magneto hydrodynamic propulsion...the "caterpillar"). Also, I would imagine a stealth boat would have to be exceptionally well-trimmed to avoid deployment and use of control plane surfaces (e.g. retractable bow planes). I am not convinced this will be viable with large boats (modern nukes, etc.).
You might also add the British Astute class to the list, at least because of the bow section, aft to around where the foreplanes are located, which is noticeably more angular than the hull continuing aft of the foreplanes. Something else that occurs to me is that the future use of UUVs, deployed from larger boats, will permit a "stand-off" active sonar capability, where a relatively expendable asset, at a distance from the mother craft, "goes loud", paints the target, and transmits the data to the attack boat, which can then put in an attack, hopefully leaving it much less vulnerable. At least until torpedo launches are detected.
An angular outer casing would be easier to fabricate and the tiles would likely stay on better. When you see a boat return to dry dock for maintenance there are always numerous tiles missing.
Some other factors that make stealth on submerged vehicles quite different from the challenge of stealth with aircraft. For example, longer wave lengths, spherical spreading, cylindrical spreading, SVP and convergence zones, etc.
Even if a reflected signal from the water surface and off the bottom comes back to the sender. What good is a reflected signal that took unknown detours and coming from a random position? No distance info, hardly any usable bearing info...
Autonomous underwater vehicles and underwater drones could bring new age of active heavy environment to naval battlefield, painting targets to silent killers that lurk elsewhere. These sonar cross section reducing designs might suit very well there.
Just had an interesting thought: If the stealth sheath over the hull had an embedded material in it angled to reflect sonar, you could go back to having a smoother, less turbulent exterior shape by relying on the angles of the embedded material to reflect sonar rather than the physical shape of a homogeneous material.
As I understand it, stealth jets already do this. They have angled ‘echo chambers’ inside the jet to increase radar deflection. This is one reason why the F35 is much more aerodynamic than the old F111. No doubt, weapons designers will have thought of things long before you and I will.
That's the principle of metamaterials. But the challenge is always matching the acoustic impedance of the metamaterial to the impedance of the water, because it is at impedance changes that reflections form. If you can get the wave into your metamaterial then you could acoustically "cloak" your submarine by guiding the sound around it. But that is a LOT easier said than done.
@@jeffcauhape6880 No idea, I do EM. The physics of wave propagation are very similar between acoustics and EM but I don't know much about acoustic material properties. I think it is mostly a property of temperature but dont take my word for it.
One of the big problems with this, and the angled hull, is hydrodynamics. They are similar to aerodynamics, but by no means the same. friction and vortices created by "rough" surfaces or edges might cause sound that is even MORE telling than the sub itself. Kind of why the F-35 is not invisible in rain. The "splatter" can be seen by sensors and infer where the plane is, even when the plane itself does not show. Some thing if a sub is too angled. The edges will cause the water to stir in different ways, that might be picked up easier than from a drop-formed sub.
that was interesting-- what about textured hulls, because if you had uneven or cobbled surface it might scramble the pursuant sonar. When an angled hull bounces the incoming sonar, it deflects the sonar to a different position like a billiard ball hitting two or three points, so misdirects the sonar reading. That could be very useful ploy, something akin to the idea behind Dazzle paint schemes.
One issue would be increased drag, another would be with scattering, you don't actually have 0 bounces back, instead you'll reduce the chance of a single return. You'd probably see increased echoes from all the bounces striking the sea bed and waves. Whilst reduced it's still sending out a large signal.
What is also true about having more complex "AI" and real-time algorithmic computational capabilities is that these hull shapes will give you a set of possible boat locations back, and by tracking the progress of the signal over time, eventually the "true" boat location should be able to be computed. An implication of this, however, is that there is the possibility for a new kind of "morphic" hull (made from titanium?) that would change shape to send a false progression of signals and lead the tracking boat on a wild goose chase. This should be obvious to the folks working on the problem, but the question is whether any such technology is in development.
Thank you! I was thinking about 'shape shifting' hull too but 'morphic' hull is probably a more accurate description. Could be made of titanium or some new age material being researched.
However. In regards to dispersing the incoming sound in "other directions", will have a big issue of its own. One isn't particularly hidden when wearing all black in a gray room. Nor all white for that matter. Sonar can hear the eco of the sea bed itself, it there is a spot where it clearly is missing, and said spot shows clear signs of parallax error as one moves, then there is clearly something there at a now known depth and position that disperses the expected eco from the sea bed itself. (to actually know the depth and location of the anomaly, we have to have more than 1 sonar, as to get some stereoscopic view of the scene. But on a 100+ meter ship, that shouldn't be all that hard.) So it is a fine balance. Perhaps subs could use phased array piezoelectric transducers covering their exterior, as to both notice the incoming signal (and "perfectly" cancel it out), and mimic a returned eco with appropriate delay for where the sea bed is known to be. But this would be fairly complex system to say the least...
In theory, you could simulate this with an RTX. Just simulate the parts of the sonar pulse that should reach it in 2 bounces, and then simulate the pulse as a bunch of rays eminating from one source. Set the water, the thermal layer, and the surface to be reflective layers to the degree that they are, and you get a good approximation (at least from my understanding of this topic)
bro that's super clever. might not be the most accurate way. but would be a very affordable way to rough and sketch things out. And probably still reach functional designs.
@@ALegitimateUA-camr Yeah, though you'd need to run a more detailed analysis to make sure probably, but rapid prototyping is kind of a big deal nowadays, so getting a rough idea of wether it works is a good start. And besides, i dont see why an RTX wouldnt be able to do the detailed version too. You'd need to trace more rays, sure, but in theory, sonar behaves enough like light to make it work anyway with a few adjustments, at least as far as i know.
@@Chrischi3TutorialLPs regardless that is a genius idea for a lot of independent or small company's to explore ideas with. Since a real pain in the ass is simulations. because it's either always insanely expensive, not for sale, or requires a huge amount of set up.
@@ALegitimateUA-camr Start a company thats all about running the simulations thats too exhausting for everyone else to run... interesting idea, i must say.
@@Chrischi3TutorialLPs honestly i'm kinda working on that but for a shop space. Because i'm formally from the independent side of things. And you have zero restrictions there. And i would like to bring a similar to the public. Just sucks how expensive such things are. But baby steps. unless i get super lucky and can form another IRG (independent research group). Though if you as smart as you have lead me to think you are. you start that idea. Because offering that kinda of simulation service without restrictions or monitoring. Oh man, you'll get easy attention.
Curious to know what is between the outer stealth hull and the inner pressure hull. Whatever is in that space is going to dramatically affect performance either adding ballast or buoyancy and of course test depth and crush depth would also be affected. I'm fairly sure the depth performance will be "classified" but an educated guess perhaps?
I would think with this design you'd get a lot of extra dead space outside of the pressure vessel. I would think that you could slide your launch tubes and torpedo tubes outward and into this dead space, leaving a lot less if the tubes in the pressure vessel, which would open up interior space. I would look into mounting as much hardware as you can between the outer skin and the inner hull that you can get away with.
Seems to be the perfect spot for lithium batteries: they can widstand high pressures and putting them inside the actual living space is a fire hazard. Seems to be a win-win to me.
Boy howdy am I glad y'all aren't building subs! I'm sure it's full of the real magic sauce in this "stealth". What kind is anyone's guess... I'll go with some kind of very special foam, but it could be the prayers of schoolkids and we would not know.
Perhaps just use the space as extra emergency ballast tanks. Divide the space into sections and force water out of all of the undamaged ones in case of emergency.
That is the goal but currently crew is still needed to maintain batteries and torpedoes often enough they need access during cruise. As technology continues in improve in reliability I am positive that external batteries and torpedoes will come about. But for now we are still needing human beings to be able to put their hands on these things
Seeing this video (maybe because it is somehow related to sonar), I was wondering if you could make a presentation, from an analyst perspective, on multistatic sonar techniques (e.g. which are employed by the different navies...). ... Also read a comment stating, that natural sonar sources from marine life could be used in that case, is that a thing?
Do you think that there may also be a need to specialize depending on the projected target environment. Types of sonar used, water makeup, sea floor makeup and depth of water and layers. Your target shore or harbor may not have the same physical makeup of the testing range.
At 8:29, you say that "each of those bounces reduces the noise" -- does not each bounce increase the noise and reduce the _signal_ in what reaches back to the sending sonar?
Dolphins use active sonar to locate prey. Thus being more stealthy (having facets) would be an evolutionary advantage to a prey species fish. I wonder if this has happened to any extent.
Active sonar was self-defeating to use back when the main place for the sonar was the sub. Nowadays sub drones and stationary sentries are powerful and cheap. I imagine a sub may have "loyal wingmen" doing the pinging.
2nd that. I am Australian. Keen to see if they go for US based platform or UK based platform. The pros and cons for both would make an interesting video.
@@telinoz1975 No expert here, but I expect it is going to depend on how fast the subs are to be aquired and who can/and will supply them with a possible loan/rental of boats not currently being operated by the supplier.
The French subs we rejected were nuclear, we asked for diesel, why didn't we just say "change of plans" we'll go back to nuclear. I suspect or AUKUS allies were passed off that the French would get the money. As I understand the French was a more recent design than UK, or USA.
Interesting, Le like consistent comment on both range and crew endurabiity. For example, does the 212cd have different handling problems, is it a rougher ride for the crew, does it cause more crew fatigue, does it affect range (I think it would dramatically affect range, but I don’t know).
That kind of information probably won't be available until stealth submarines have been in service for decades and we get books written by crew or whatever
I suspect that an angular outer hull would have horrific hydrodynamics, meaning that turbulence would cause significant noise at anything above dead slow.
Interesting but the B2 showed that the complex calculations needed for smoothly curved shapes are possible hence there's no longer a need for the flat faceted surfaced of Have Blue and the F-117 Nighthawk. Also, these "stealth" shapes simply deflect the signal away from the emitter so this kind of stealth is ineffective if there is an unpredictable distance between the signal source and the hydrophones (receivers). With radar and planes, it has been suggested that the background radio emissions from cell phone towers be used to illuminate stealth aircraft as the geometry between the towers and the radar receivers would be variable and hence could not be accounted for by the shape alone. Likewise, with a tradition of wireless connected hydrophone buoys and the seismic acquisition techniques of towed hydrophone arrays, such stealth shapes should be easily countered. I would be more interested in meta materials directing the sound around the submarine though what we publicly know of are only effective at specific frequencies and low frequencies at that. Calculations for a selection of frequencies may be computationally difficult perhaps even impossible and the scale of the construction may be very fine for higher frequencies and hence difficult to manufacture.
Would a signal from a vessel using active sonar, during its journey reduce to half when travelling to a target then back again, or one quarter (inverse square law)?
have to say it; F-117 is not a fighter, but an attacker, despite the misnomer "F" in its type number. It was designed to not manoeuvre much and is easily beaten in a turnfight by nearly any other aircraft. It needs to fly in low radar coverage areas, and get out before scrambled fighters can get up to catch it.
Anechoic tiles was used on a few U boats during WW2 but the coating had holes/pits of differant diameters , A kriegsmarine survivor said we never was detected by enemy sonar .........
Is it a known fact there is a conventional inner round steel construction or merely speculation? Given that is correct, when will the angular oyter construction brake down as it cannot withstand the pressure? Is there any scenario where one will rely on the inner construction in a fully functional mode or do we speak of safety to the crew only?
Not sure how good rubber paneling is at absorbing sonar when it gets harder as it compresses at depth! 2ndly whales are something sonar picks up as active, but non metalic contracts! You can also tell if they are closing or opening range! ;p Cold layers are the best way to hide from sonar as the beam digs in or bounces off the layer pressure difference! Dimpling the rubber would be the best way to diffuse an echo return! Turning a round profile into many flat surfaces doesn't sound like a great strategy!
The German stealth aircraft was probably the MBB Lampyridae which apparently was twice as stealthy as the F-117 and was allegedly cancelled in 1987. As this was during the cold war and before German reunification, it might be possible that there was some backroom pressure applied by the US but so far this is just a rumour. MBB and its sucessor company DASA (now part of Airbus) never disclosed why they ended the project. Germany at that time had another fighter jet program ("Jäger 90") also in development, also by DASA that they might have just settled for a more conventional design. The Jäger 90 program was essentially a blueprint and became part of the EF 2000 Typhoon (aka "Eurofighter") program. To me that sounds more plausible, but maybe Airbus will at some point release the information.
Probably just to save money, as usual. Germany is smaller country with less GDP so U.S. has natural advantage in developing super expensive projects. Germany spent money on reunification. Politically wise U.S. is happier when EU spends more money on defence, not less.
@@denysivanov3364this was the reason. The reunification was a multi billion dollar project, and the threat was gone all of a sudden. Why build a jet you don’t need, with money you don’t have?
From my armchair expert opinion, seems like this could be defeated by networking multiple active sonar transmitters and receivers to triangulate signals. You can deflect a signal away from the sender, but you can't make it disappear completely, especially if your opponent can observe you from 360º.
Stealth isnt about boncing all signals anyhow since that is imposible no matter how you design your stealth no matter if subs or aircrafts. The goal is to make the return siginal as weak as posible and thus drasistically decreasing the range were the return signial gives the sender any informations. Sonar is a LOTS more complex than radar thogh. besides the metioned surface/seabed bouncing Temperature diference and curents can effect how Sonar behaves. BTW the brits use the same method as the germans in their newer subs......gues they forgot to metioned it to their US allies that this is a thing now. Bit sidenote on arcustic tliles (rubbercoating) For deepdiving subs thease can be quite a problem since the presureddiferences between operational and deepdiving wear them out realtively quickly. Its not like the interatcion beween pasive and active changes thogh. The main factor today are naval drones can be used by any naval ship to deploy sonar boyies in numbers if nessesary were before deployment were limited to a small number of helicopters and dedicated long range aircrafts..
Great topic. Thank you for taking the time and making the stab at addressing this. Curious about any trade-offs between designing a submarine for operating depth (ability to go deeper), stealth and speed. Figure materials (titanium or Hastelloy-100 steel), design (double hull) all come into play. But wonder about the implication of undertaking certain shaping, of the outer hull for subs designed to go down to pretty deep test depths, the kind that it seems the have Russians aspired to (e.g. Akula, Typhoon, Borei, etc.?)?
The pressure hull is still cylindrical or spherical, the outer hull is a free flood space, so it does not experience the pressure difference that the pressure hull has to withstand.
I imagine that this will be more relevant to the relatively slow SSKs since they cannot get out of the way of active sonar nearly as effectively, whereas SSNs with their high continuous speed can out maneuver an actively searching contact/torp much better. I mention this, but then watch the USN with it's SSN only fleet decide to stealth everything, but of course we Americans have to make everything stealth.
It's more relevant for subs working close inshore and esp in smaller waters. Much easier to hide from active sonar in the depths of the Pacific than in the 50m deep Baltic sea.
@@positroll7870 I would have thought the opposite, since the shallow water means that any potential long range contacts may have quite a few bounces off the bottom/surface to get to where they're going, losing a little energy each time.
@@jermainerace4156 In that sense, yes, and there is also more covering noise. But in restricted waters you can drop a lot of sonar buoys from aircraft to saturate an area, and also use a lot of uuvs launched from the coast to try and flush out any subs. Out in the open ocean nobody has enough such buoys or uuvs available to really go after a silent sub.
The problem of how to make stealth aircraft visible to radar is nowadays solved , and in a very elegant way. The stealth aircraft design uses the assumption that a radar transmitter and reciever are located in the same object. Thats the way radar has been designed from its start until now. So you try to reduce your radar reflection to a minimum in the direction of the source of the beam. And try to reflect it in another direction away. But what happens when radar transmitter and reciever are not in the same place? Or when you use the "radar background noise " created by a variety of sources like mobilphone transmitter stations ? Then you can percieve a moving aerial object as a local perturbation or disturbance of this background noise. If you connect two recieving stations and their signal , than you can analize for the correct location of the moving aerial object. As your own station is only a reciever you are invisible to anti radar measures which lock on the radar signal of a foe to locate and destroy ist.
Very good explanation: A few more factors I would add to this discussion are 1) Effective Target size (aspect) 2) bottom type (hardness) 3) sea state all play a factor in active effectiveness as well. My opinion is that this new design will significantly reduce Active Target visibility in all environments when compared to similar conventional submarine examples.
I presume this is the same idea you referred to recently when discussing the Astute's bow? If that was the goal I wonder why Astute and Trafalgar didn't continue the bow chine all the way down their sides. Difficulty mounting the flank array maybe?
Hi mate can you do a video on Scorpene submarines please
@@SonB288 Couple of things strike me on this question, the chine does end exactly where the flank arrays begin, that may have been a compromise where they focused on frontal aspect stealth for approaching a target. Second the torpedo tubes in the Astute are right at the side edge, there isnt any internal space given over to outer hull shaping beyond the pressure hull. Finally the Chine is exactly the same location as the floor of the upper deck, it might be a reinforcement strut to redistribute some of the squeezing away from that particular location (and the same location the forward superstructure) and add increased structural strength.
I like your channel keep it up what is your opinon on the F 126 is it any good ?
One thing I'd like to point out and what i don't know if you deliberately omitted or missed: the HMS Astute appears to exhibit this very same feature, by about 20yrs. In addition, like astute, subs with this angled feature have a tendency as Astute, to have a slower design speed; because of the hydrodynamics of a angled hull over a teardrop design.
Just speculation btw, not a professional.
5:14 I genuinely did not know Germany had a concurrent stealth program. Learn something new everyday.
Thanks for another great video!
indeed. best info in the video
Same here. This really is informative.
en.wikipedia.org/wiki/MBB_Lampyridae
Never underestimate the uber German Empire
@@goodputin4324 ah pretty sure this research was done post 1918. It was probably a republic at the time.
Another thing to add: the German 212 submarines use Hydrogen fuel cells and batteries. So they basically don't have any moving parts except for the propeller itself. They have reached a point where you can't do much to reduce engine noise anymore for passive sonar stealth. So active sonar was the only remaining weakness, the only thing you could tackle and get better at.
Also interesting, the German submarines are usually small because they must be fully operational in just 17m deep Baltic waters.
Well, can the propeller be eliminated? I've been able to get good forward speed only using dive planes and buoyancy changes.
@@lqr82417 meters.
Unscripted shows your knowledge and confidence. Thanks for the info.
Glad it was helpful!
@@HISuttonCovertShores would love to hear your thoughts on the UK decommissioned nuclear subs still waiting to be disposed til now.
@@goodputin4324 It´s the Russian model, save for a rainy day;)
Glad you started a channel. Been checking out your website for a long time.
Not scripting your videos actually gives them a more relaxed and conversational feel which I really like.
As far as I know: anechoic tiles were first (to my knowledge) used in Germany during WW 2. Called "Alberich" after a dwarven king in german mythology, it was developed in 1931 and applied to multiple submarines in 1941 🙂
Exactly but they were removed because it caused some kind of problems with the sub
@@ramal5708 the coating wasn't removed, Germany just hadn't enough resources. Only few subs were equipped with Alberich.
Alberich was super cool.
@@labschi No, they had problem with the glue, the tiles started to fall off. I believe that they finally fixed that in late -44 but then it was too late and the Anglo menace triumphed;)
I mean everything from 1920 to 1970 can be summarized by "we had the best German scientists and engineers".
Nuclear weapons were developed by a lot of German scientists in exile in the US. The space race? The German V2 rocket engineers picked up by the US vs. the German V2 rocket engineers picked up by the USSR.
Wonderful Presentation Mr. Sutton. Thank You and Godspeed.
I'm sure I'm not the only person to imagine active sonar emitting drones so that the mother ship can receive the reflections passively.
I believe that is something that can actually be done through the use of active pings from torpedoes. Calculations might be a bit more tricky, but the pings won’t be coming directly from your ship.
actually I came here to raise the same question, some sonars have a remote emitter. And for airspace some systems use the reflections from telecom emitters to spy without emitting themselve.
Checkout SOSUS
I think it's a lot more common to have nuclear powered listening station which can permanently listen to an area rather than a drone which has a temporary lifespan.
But on the attack into enemy waters remote sonar station drones make a lot of sense.
Buoys are placed and moved by helicopter.
It’s a shame there aren’t more naval nerds in the world.
This channel should be huge.
I always feel like I’m in a Royal Navy briefing
You can use existing biological noise as the source for a semi-active sonar in which you look for shadows using passive sonar and the more angles you can use to look at the target you will be able to better develop your target location depth and speed..
It's not actually artificial intelligence that has enabled these designs, it is computers with more computing power to handle the millions and billions of calculations necessary in a reasonable amount of time to simulate the behavior of sound waves in various densities of water reflecting off of of very complex shapes.
VERY well done!
Excellent graphics!
Well narrated!
Nicely organized!
Great video, just one detail: Norway isn't just a customer, it's a joint development and meant to be the beginning of a strategic cooperation in Research & Development of AIP submarines, a German-Norwegian Research facility has been established at TKMS, and both German and Norwegian units will receive maintenance at a Norwegian central facility. The Netherlands have been offered to become somewhat of a third participant in this strategic cooperation if they should decide on the slightly modified Type 212 C/D-E for their new submarines.
That’s really important to know, I wouldn’t have learned that if you didn’t take the time to post that so thank you very much. Idk why we don’t have news that tells us these things in the USA . No real news , just nonsense on the news here 😂
@@MattttG3 I watched a lot of American news when Trump became president, daily for 1-2 years and as far as cable news is concerned, I'd have to agree. It's 95% domestic, rather petty, and depending on whether you watch Fox or MSNBC, you get everything served with a lot of spin. 🇩🇪 news is more like CBS. News at eight have no commentary at all. News at ten have become more opinionated in the last ten years.
Btw, since this seems to interested you: 🇩🇪 and 🇳🇴 signed a general treaty for strategic cooperation in Defense Matters. May seem silly since Norway's rather small, but the whole German Defense Sector ain't that big either. Rheinmetall builds the Lynx, Panther, Boxer. TKMS builds frigates and corvettes, usually with two much recon equipment, good motors and not nearly enough armaments, KMW was grandfathered in as important because they build the Leopard 2. And Diehl build Air Defense, like recently the Iris-T SLM for Ukraine. And that's about it. Maybe 75,000 employees altogether.
The algorithms used for the shape design are typically evolutionary algorithms or genetic algorithms, which are not AI in how the wod is tday used but rather a well-established soft computing practice. They are useful for optimising any computational impossible problem whose outcome can be measured for fitness and who accepts a finite set of input variables.
Eh, the machine learning people like to pretend that they're the only kind of AI. They're not.
Oo Lampyridae is interesting. Another fine vid, thank you Sir.
I think the sharp angles in the early stealth plain have more to do with the difficulty to calculate the radar reflection rather than that they are particular good for that. Newer stealth air crafts are more curved.
Water is more complicated than air.
@@Br1cht What are you trying to say?
To an extend.
There is also the advancement in ram that allow the uses of less stealthy geometry.
@@MusikCassette i guess he meant 8:38
there is the thing with the thermocline layer (the layer between the warm surface water and the cold deep water) and different layers of seawater too,
as sound waves can be diffracted between the surface and the thermocline, or be reflected from the thermocline back to the depth
Few people realise that weapons designers have “fashion fads”, this is related to sales, I.e. what they can sell and “demand” what the higher ups (superior officers and politicians) want. THEN, there is the corruption factor, both overt corruption I.e. some one gets money to make a decision or covert I.e. some one or some group gets a benefit (free holidays, women, political donations, relatives jobs etc).
The Navies around the world are finally waking up. In the book "Skunkworks" by Ben Rich it said they did make a quick model and gave it a try. It had a sonar reflection (IIRC) 1/100th that of a normal sub. The USN response was "Submarines are round".
My question is if it would work as far as a pressure hull
@@hint0122 real question from a plane nerd: why would that matter? If the ship is sufficiently hard to detect, then it can simply sit at shallower depths without caring, right?
@@IntrusiveThot420 There may have been issues when it comes to the body creating hydrodynamic noise. basically the fear was likely that the body would induce turbulent flow in the surrounding air, making noise that can be picked up on passive arrays.
Very good Hutton, previous works by the germans paved the way for today . The example are the models XXI and XXIII and my favorite the Horten 229 jet the first with the available materials of that time.
The drawings Sutton makes are in MS paint. This man has such an intimate understanding of his subject
Excellent explanation for non-experts, thank you Mr. Sutton (according to the voice).
Keep them coming please!!! There's a lack of good, detailed vids on sub tech on UA-cam.
Mostly classified
,,, and lets not forget, that the angular hullshape is beeing combined with the sound absorbing coating. One does not exclude the other.
Great video, as always! Really interesting how technological developments can force a continuous cycle of one technology over the other, being replaced by each other in a loop. That is ongoing until a major breakthrough happens, or a major technological leap is achieved.
very Kool channel.. more techie than sub brief and none of the 'hoorah' BS
Couldn't agree more. I like sub brief but he's added America on his American, Americanism when it comes to his view points. It colours the information a bit.
Same here
Nice video. Question: these shaped hulls reduce the capacity of going deeper? Also, what's the sonar range? Can a submarine avoid detection by doing deeper? Thank you in advance!!
Not if unpressurised, although weight could be a factor
@@Daimo83 thank you!
Astute Class also uses active deflection with angled hull plates. Especially noticeable on the front and upper hull.
Excellent and clear explanation as usual , thank you for posting !
Wicked break down thank you.
Would you class the Astute as having stealth characteristics?
I like the unscripted style of video. Most of my favorite sites are definitely of the unscripted type. I think that the unscripted style videos, aside from the "organic" aspects, are that they show more technical knowledge on the part of the video creator.
Just a note to say that the classic angular shape of the F-117 was almost entirely down to 1970/80 computing power. The next stealth aircraft, the B-2, was far less angular and the modern F-35 not angular at all. My point is simply that blocky angles does not necessarily equal stealth.
2:45 "active sonar lets you be heard farther away, typically twice as far." I don't think so--not a naval engineer, but still an engineer. If the target reflected the signal perfectly back as a flat mirror, you would hear it at twice the distance but in fact no target does that. Typical targets will reflect less than 100% of the sound, and reflect it with more dispersal than it came in with, causing reflections to be far weaker. I'm just reasoning from first principles here, but I know aircraft radar can be spotted at 250km despite only seeing targets within 50km. Another thought experiment: at night on a moor, how far away could you see someone with a flashlight? several km if the ground is flat enough, no? Would he be able to see you at half that range? Yes... if you were a mirror. But even if you were dressed in white, so little of his light would reach you over a km that he probably wouldn't see the return light since a white object would scatter light in all directions not just back to the man with the flashlight.
You´re arguing with known axioms that been researched and understood for a very long time I´m afraid.
I think H I Stutton meant the ship sending out the blip can be heard twice as far away than what they themselves can hear an eco back.
Ie, the silent sub can hear the approaching ship long before the ship can hear the eco from the sub.
@@todayonthebench yes, that's what he meant, and no, he's wrong on this very narrow point, as right as he is about most other things
@@Br1cht > You´re arguing with known axioms that been researched and understood for a very long time I´m afraid.
If so then please cite a source I can refer to that the range to detect an active sonar emitter is only twice its detection range.
To be clear I'm not arguing the general shape of the premise, only that the 2x here is likely to be more more like 5x (as it is in aircraft radar as I explained) or higher.
The Astute's seem to have some angles in their design.
sure u boat did 😂😆😂😆😂😉😂
Thank BAE
You should do one on the rubber coating. First developed by the Germans in WWII. Two layers, one with a specific pattern of holes with the signal absorbed by the 2d layer.
Shoutout to whoever designed the Type-XXIX-H submarine.
Bad timing, but apparently a neat idea.
I figured out a "Stealth" design over twenty years ago, but the problem is the extra turbulence created by the angular hull. You can still detect it with passive sonar.
Yes, agreed! Hydrodynamics would definitely play a big part insofar as operating envelope/efficiency, too. Clearly, screws would be OUT in favor of specially shrouded propulsors (or even magneto hydrodynamic propulsion...the "caterpillar"). Also, I would imagine a stealth boat would have to be exceptionally well-trimmed to avoid deployment and use of control plane surfaces (e.g. retractable bow planes). I am not convinced this will be viable with large boats (modern nukes, etc.).
You might also add the British Astute class to the list, at least because of the bow section, aft to around where the foreplanes are located, which is noticeably more angular than the hull continuing aft of the foreplanes. Something else that occurs to me is that the future use of UUVs, deployed from larger boats, will permit a "stand-off" active sonar capability, where a relatively expendable asset, at a distance from the mother craft, "goes loud", paints the target, and transmits the data to the attack boat, which can then put in an attack, hopefully leaving it much less vulnerable. At least until torpedo launches are detected.
Thank BAE
An angular outer casing would be easier to fabricate and the tiles would likely stay on better. When you see a boat return to dry dock for maintenance there are always numerous tiles missing.
Some other factors that make stealth on submerged vehicles quite different from the challenge of stealth with aircraft. For example, longer wave lengths, spherical spreading, cylindrical spreading, SVP and convergence zones, etc.
Is the astute class one of these submarines that are foing for this stealthy pressure hull
Even if a reflected signal from the water surface and off the bottom comes back to the sender. What good is a reflected signal that took unknown detours and coming from a random position? No distance info, hardly any usable bearing info...
Autonomous underwater vehicles and underwater drones could bring new age of active heavy environment to naval battlefield, painting targets to silent killers that lurk elsewhere. These sonar cross section reducing designs might suit very well there.
Better than scripted. Always excellent
Just had an interesting thought: If the stealth sheath over the hull had an embedded material in it angled to reflect sonar, you could go back to having a smoother, less turbulent exterior shape by relying on the angles of the embedded material to reflect sonar rather than the physical shape of a homogeneous material.
As I understand it, stealth jets already do this. They have angled ‘echo chambers’ inside the jet to increase radar deflection. This is one reason why the F35 is much more aerodynamic than the old F111. No doubt, weapons designers will have thought of things long before you and I will.
That's the principle of metamaterials. But the challenge is always matching the acoustic impedance of the metamaterial to the impedance of the water, because it is at impedance changes that reflections form. If you can get the wave into your metamaterial then you could acoustically "cloak" your submarine by guiding the sound around it. But that is a LOT easier said than done.
@@jamesperry1358 This is probably a dumb question: Does the acoustic impedance change with pressure, or tep, or salinity?
@@jeffcauhape6880 No idea, I do EM. The physics of wave propagation are very similar between acoustics and EM but I don't know much about acoustic material properties. I think it is mostly a property of temperature but dont take my word for it.
One of the big problems with this, and the angled hull, is hydrodynamics. They are similar to aerodynamics, but by no means the same. friction and vortices created by "rough" surfaces or edges might cause sound that is even MORE telling than the sub itself. Kind of why the F-35 is not invisible in rain. The "splatter" can be seen by sensors and infer where the plane is, even when the plane itself does not show. Some thing if a sub is too angled. The edges will cause the water to stir in different ways, that might be picked up easier than from a drop-formed sub.
that 1980 design looks insanely advanced
Aircraft have ECM. So modifining incoming waves to their advantage. Do subs have something similar?
Another great episode! Thank you Mr Sutton!
Don't worry about too much being unscripted ur videos r brilliant and informative 😁
Please make more videos these are great
Good video...Very informative...Technology changing so fast....amazing...
brilliant content mate, would you consider doing a wee video on anechoic tiles/SHT?
Really like that your videos are unscripted!
It makes them more genuine, and much more enjoyable compared to over-scripted/-narrated videos :)
Thanks!
P.S. The planes on the boat have to retract/fold or otherwise be taken out of the geometry or it will be the Achilles Heel of such a boat.
that was interesting-- what about textured hulls, because if you had uneven or cobbled surface it might scramble the pursuant sonar. When an angled hull bounces the incoming sonar, it deflects the sonar to a different position like a billiard ball hitting two or three points, so misdirects the sonar reading. That could be very useful ploy, something akin to the idea behind Dazzle paint schemes.
One issue would be increased drag, another would be with scattering, you don't actually have 0 bounces back, instead you'll reduce the chance of a single return. You'd probably see increased echoes from all the bounces striking the sea bed and waves. Whilst reduced it's still sending out a large signal.
An excellent overview. Where are the additional hints showing up?
Thanks for sharing this information with us. It’ll be interesting to see what the future holds !
How do the hard chines affect water flow? Doesnt it make the passive signature larger/louder.
correction needed: they type 212 is already a double hull design. the echo would bounce of of the outer hull and not the pressure hull.
What is also true about having more complex "AI" and real-time algorithmic computational capabilities is that these hull shapes will give you a set of possible boat locations back, and by tracking the progress of the signal over time, eventually the "true" boat location should be able to be computed. An implication of this, however, is that there is the possibility for a new kind of "morphic" hull (made from titanium?) that would change shape to send a false progression of signals and lead the tracking boat on a wild goose chase. This should be obvious to the folks working on the problem, but the question is whether any such technology is in development.
Thank you! I was thinking about 'shape shifting' hull too but 'morphic' hull is probably a more accurate description. Could be made of titanium or some new age material being researched.
@@Mork2001 Why would the outer hull be made of titanium? Regardless of whether it changes shape.
However. In regards to dispersing the incoming sound in "other directions", will have a big issue of its own.
One isn't particularly hidden when wearing all black in a gray room. Nor all white for that matter.
Sonar can hear the eco of the sea bed itself, it there is a spot where it clearly is missing, and said spot shows clear signs of parallax error as one moves, then there is clearly something there at a now known depth and position that disperses the expected eco from the sea bed itself. (to actually know the depth and location of the anomaly, we have to have more than 1 sonar, as to get some stereoscopic view of the scene. But on a 100+ meter ship, that shouldn't be all that hard.)
So it is a fine balance.
Perhaps subs could use phased array piezoelectric transducers covering their exterior, as to both notice the incoming signal (and "perfectly" cancel it out), and mimic a returned eco with appropriate delay for where the sea bed is known to be. But this would be fairly complex system to say the least...
3rd video in a row. Very nice even unscripted. I wish I had know about this channel long ago
QUESTION!- does sonar have a different efficacy at different depths??
In theory, you could simulate this with an RTX. Just simulate the parts of the sonar pulse that should reach it in 2 bounces, and then simulate the pulse as a bunch of rays eminating from one source. Set the water, the thermal layer, and the surface to be reflective layers to the degree that they are, and you get a good approximation (at least from my understanding of this topic)
bro that's super clever. might not be the most accurate way. but would be a very affordable way to rough and sketch things out. And probably still reach functional designs.
@@ALegitimateUA-camr Yeah, though you'd need to run a more detailed analysis to make sure probably, but rapid prototyping is kind of a big deal nowadays, so getting a rough idea of wether it works is a good start. And besides, i dont see why an RTX wouldnt be able to do the detailed version too. You'd need to trace more rays, sure, but in theory, sonar behaves enough like light to make it work anyway with a few adjustments, at least as far as i know.
@@Chrischi3TutorialLPs regardless that is a genius idea for a lot of independent or small company's to explore ideas with. Since a real pain in the ass is simulations. because it's either always insanely expensive, not for sale, or requires a huge amount of set up.
@@ALegitimateUA-camr Start a company thats all about running the simulations thats too exhausting for everyone else to run... interesting idea, i must say.
@@Chrischi3TutorialLPs honestly i'm kinda working on that but for a shop space. Because i'm formally from the independent side of things. And you have zero restrictions there. And i would like to bring a similar to the public. Just sucks how expensive such things are. But baby steps. unless i get super lucky and can form another IRG (independent research group).
Though if you as smart as you have lead me to think you are. you start that idea. Because offering that kinda of simulation service without restrictions or monitoring. Oh man, you'll get easy attention.
Curious to know what is between the outer stealth hull and the inner pressure hull. Whatever is in that space is going to dramatically affect performance either adding ballast or buoyancy and of course test depth and crush depth would also be affected. I'm fairly sure the depth performance will be "classified" but an educated guess perhaps?
In case of the regular Type 212A submarine there are oxygen and hydrogen tanks for the fuel-cell propulsion between the two hulls.
I would think with this design you'd get a lot of extra dead space outside of the pressure vessel. I would think that you could slide your launch tubes and torpedo tubes outward and into this dead space, leaving a lot less if the tubes in the pressure vessel, which would open up interior space. I would look into mounting as much hardware as you can between the outer skin and the inner hull that you can get away with.
gee- the USN should hire you!
Seems to be the perfect spot for lithium batteries: they can widstand high pressures and putting them inside the actual living space is a fire hazard. Seems to be a win-win to me.
Boy howdy am I glad y'all aren't building subs! I'm sure it's full of the real magic sauce in this "stealth".
What kind is anyone's guess... I'll go with some kind of very special foam, but it could be the prayers of schoolkids and we would not know.
Perhaps just use the space as extra emergency ballast tanks. Divide the space into sections and force water out of all of the undamaged ones in case of emergency.
That is the goal but currently crew is still needed to maintain batteries and torpedoes often enough they need access during cruise.
As technology continues in improve in reliability I am positive that external batteries and torpedoes will come about.
But for now we are still needing human beings to be able to put their hands on these things
I really like your unscripted-but-prepared style *thumbs up
Seeing this video (maybe because it is somehow related to sonar), I was wondering if you could make a presentation, from an analyst perspective, on multistatic sonar techniques (e.g. which are employed by the different navies...).
... Also read a comment stating, that natural sonar sources from marine life could be used in that case, is that a thing?
Do you think that there may also be a need to specialize depending on the projected target environment. Types of sonar used, water makeup, sea floor makeup and depth of water and layers. Your target shore or harbor may not have the same physical makeup of the testing range.
I really enjoy the channel and explanations, thank you!
At 8:29, you say that "each of those bounces reduces the noise" -- does not each bounce increase the noise and reduce the _signal_ in what reaches back to the sending sonar?
Dolphins use active sonar to locate prey. Thus being more stealthy (having facets) would be an evolutionary advantage to a prey species fish. I wonder if this has happened to any extent.
Once again a very interesting and highly educational video. Thanks!
The Norhtrop 'Tacit Blue' stealth testbed actually looks like a flying stealth submarine hull🤣
the best solution to ASDIC is penciling..
Thank you, I'm here all night
Active sonar was self-defeating to use back when the main place for the sonar was the sub. Nowadays sub drones and stationary sentries are powerful and cheap. I imagine a sub may have "loyal wingmen" doing the pinging.
Can you give any more info about that German stealth aircraft ? Who worked on it ? Designation ? - thx
en.wikipedia.org/wiki/MBB_Lampyridae Looks like origami...
really enjoying your vids
glad to see some open voices upon these things
reminds me that we are still in the free world....just ;)
F 35 of subs Astute being a good ref
As the details come to surface could you do a video of Australian submarines and the future nuclear attack subs please? Thank you 🙏
2nd that.
I am Australian.
Keen to see if they go for US based platform or UK based platform.
The pros and cons for both would make an interesting video.
@@telinoz1975 No expert here, but I expect it is going to depend on how fast the subs are to be aquired and who can/and will supply them with a possible loan/rental of boats not currently being operated by the supplier.
@@telinoz1975 gentleseas.blogspot.com/ In more detail. Perhaps the aerospace forces are more promising?
The French subs we rejected were nuclear, we asked for diesel, why didn't we just say "change of plans" we'll go back to nuclear. I suspect or AUKUS allies were passed off that the French would get the money. As I understand the French was a more recent design than UK, or USA.
@@robertwilliamson4456 but smaller, so less weapon options
Interesting, Le like consistent comment on both range and crew endurabiity. For example, does the 212cd have different handling problems, is it a rougher ride for the crew, does it cause more crew fatigue, does it affect range (I think it would dramatically affect range, but I don’t know).
That kind of information probably won't be available until stealth submarines have been in service for decades and we get books written by crew or whatever
I suspect that an angular outer hull would have horrific hydrodynamics, meaning that turbulence would cause significant noise at anything above dead slow.
This is all explained in summary in the 1991 book, Skunk Works, by Ben Rich. Still one of the best books on the subject.
Interesting but the B2 showed that the complex calculations needed for smoothly curved shapes are possible hence there's no longer a need for the flat faceted surfaced of Have Blue and the F-117 Nighthawk. Also, these "stealth" shapes simply deflect the signal away from the emitter so this kind of stealth is ineffective if there is an unpredictable distance between the signal source and the hydrophones (receivers). With radar and planes, it has been suggested that the background radio emissions from cell phone towers be used to illuminate stealth aircraft as the geometry between the towers and the radar receivers would be variable and hence could not be accounted for by the shape alone. Likewise, with a tradition of wireless connected hydrophone buoys and the seismic acquisition techniques of towed hydrophone arrays, such stealth shapes should be easily countered. I would be more interested in meta materials directing the sound around the submarine though what we publicly know of are only effective at specific frequencies and low frequencies at that. Calculations for a selection of frequencies may be computationally difficult perhaps even impossible and the scale of the construction may be very fine for higher frequencies and hence difficult to manufacture.
Would a signal from a vessel using active sonar, during its journey reduce to half when travelling to a target then back again, or one quarter (inverse square law)?
Essentially it's about wave reflection, no? Radio (electromagnetic) wave and sound wave.
have to say it; F-117 is not a fighter, but an attacker, despite the misnomer "F" in its type number. It was designed to not manoeuvre much and is easily beaten in a turnfight by nearly any other aircraft. It needs to fly in low radar coverage areas, and get out before scrambled fighters can get up to catch it.
Would rubber shields give noise propulsion a cover for not being heard.
Noise reduction no signature for sonar
Anechoic tiles was used on a few U boats during WW2 but the coating had holes/pits of differant diameters , A kriegsmarine survivor said we never was detected by enemy sonar .........
The sonar source is far away, reflections from shorter panels would miss the sender, so why are they so long?
Is it a known fact there is a conventional inner round steel construction or merely speculation? Given that is correct, when will the angular oyter construction brake down as it cannot withstand the pressure? Is there any scenario where one will rely on the inner construction in a fully functional mode or do we speak of safety to the crew only?
Yes the inner hull is round, just a regular submarine construction.
The outer hull is flooded so not under pressure
Great video as usual. An here is Aaron as well commenting !!!!!!!!!! oO !!! How cool is that?
Not sure how good rubber paneling is at absorbing sonar when it gets harder as it compresses at depth! 2ndly whales are something sonar picks up as active, but non metalic contracts! You can also tell if they are closing or opening range! ;p Cold layers are the best way to hide from sonar as the beam digs in or bounces off the layer pressure difference! Dimpling the rubber would be the best way to diffuse an echo return! Turning a round profile into many flat surfaces doesn't sound like a great strategy!
The German stealth aircraft was probably the MBB Lampyridae which apparently was twice as stealthy as the F-117 and was allegedly cancelled in 1987. As this was during the cold war and before German reunification, it might be possible that there was some backroom pressure applied by the US but so far this is just a rumour. MBB and its sucessor company DASA (now part of Airbus) never disclosed why they ended the project. Germany at that time had another fighter jet program ("Jäger 90") also in development, also by DASA that they might have just settled for a more conventional design. The Jäger 90 program was essentially a blueprint and became part of the EF 2000 Typhoon (aka "Eurofighter") program. To me that sounds more plausible, but maybe Airbus will at some point release the information.
Probably just to save money, as usual. Germany is smaller country with less GDP so U.S. has natural advantage in developing super expensive projects. Germany spent money on reunification. Politically wise U.S. is happier when EU spends more money on defence, not less.
@@denysivanov3364this was the reason. The reunification was a multi billion dollar project, and the threat was gone all of a sudden. Why build a jet you don’t need, with money you don’t have?
@@foximacentauri7891 also Soviet Union started to roll back expansionist policies with Perestroyka ("rebuilding" by Gorbachov)
Lampyridaes outdated stealth shaping was most likely reason for cancellation.
Did you hear about the Lockheed stealth submarine? It never took off.
Sorry, I couldn't resist.
From my armchair expert opinion, seems like this could be defeated by networking multiple active sonar transmitters and receivers to triangulate signals. You can deflect a signal away from the sender, but you can't make it disappear completely, especially if your opponent can observe you from 360º.
Well, that also means bringing a lot of potential targets inside the submarines attack range.
Stealth isnt about boncing all signals anyhow since that is imposible no matter how you design your stealth no matter if subs or aircrafts. The goal is to make the return siginal as weak as posible and thus drasistically decreasing the range were the return signial gives the sender any informations.
Sonar is a LOTS more complex than radar thogh. besides the metioned surface/seabed bouncing Temperature diference and curents can effect how Sonar behaves.
BTW the brits use the same method as the germans in their newer subs......gues they forgot to metioned it to their US allies that this is a thing now. Bit sidenote on arcustic tliles (rubbercoating) For deepdiving subs thease can be quite a problem since the presureddiferences between operational and deepdiving wear them out realtively quickly.
Its not like the interatcion beween pasive and active changes thogh. The main factor today are naval drones can be used by any naval ship to deploy sonar boyies in numbers if nessesary were before deployment were limited to a small number of helicopters and dedicated long range aircrafts..
boncing?
Great topic. Thank you for taking the time and making the stab at addressing this. Curious about any trade-offs between designing a submarine for operating depth (ability to go deeper), stealth and speed.
Figure materials (titanium or Hastelloy-100 steel), design (double hull) all come into play. But wonder about the implication of undertaking certain shaping, of the outer hull for subs designed to go down to pretty deep test depths, the kind that it seems the have Russians aspired to (e.g. Akula, Typhoon, Borei, etc.?)?
The pressure hull is still cylindrical or spherical, the outer hull is a free flood space, so it does not experience the pressure difference that the pressure hull has to withstand.
I imagine that this will be more relevant to the relatively slow SSKs since they cannot get out of the way of active sonar nearly as effectively, whereas SSNs with their high continuous speed can out maneuver an actively searching contact/torp much better. I mention this, but then watch the USN with it's SSN only fleet decide to stealth everything, but of course we Americans have to make everything stealth.
Who says SSK are slow?
@@goodputin4324 SSNs and surface combatants.
It's more relevant for subs working close inshore and esp in smaller waters. Much easier to hide from active sonar in the depths of the Pacific than in the 50m deep Baltic sea.
@@positroll7870 I would have thought the opposite, since the shallow water means that any potential long range contacts may have quite a few bounces off the bottom/surface to get to where they're going, losing a little energy each time.
@@jermainerace4156 In that sense, yes, and there is also more covering noise.
But in restricted waters you can drop a lot of sonar buoys from aircraft to saturate an area, and also use a lot of uuvs launched from the coast to try and flush out any subs.
Out in the open ocean nobody has enough such buoys or uuvs available to really go after a silent sub.
The problem of how to make stealth aircraft visible to radar is nowadays solved , and in a very elegant way.
The stealth aircraft design uses the assumption that a radar transmitter and reciever are located in the same object. Thats the way radar has been designed from its start until now. So you try to reduce your radar reflection to a minimum in the direction of the source of the beam. And try to reflect it in another direction away. But what happens when radar transmitter and reciever are not in the same place? Or when you use the "radar background noise " created by a variety of sources like mobilphone transmitter stations ? Then you can percieve a moving aerial object as a local perturbation or disturbance of this background noise. If you connect two recieving stations and their signal , than you can analize for the correct location of the moving aerial object. As your own station is only a reciever you are invisible to anti radar measures which lock on the radar signal of a foe to locate and destroy ist.
Add to that: bistatic sonar arrays are not uncommon for military aplications, these days.