Submarines
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You are currently reading a thread in /k/ - Weapons
What passive technologies do subs have for detecting ships besides visually acquiring them with a periscope?
There's a shitload of information about ships detecting subs but not much about the opposite
Sonar works both ways anon, and surface ships are usually far noisier than submarines.
>>30039380
I'll take passive sonar for $500, Alex....
>>30039404
Sonar would give away the loca-
>>30039409
>passive sonar
How the fuck does that work?
>>30039445
Passive sonar works like your ears. It picks up vibrations that are translated through the water.
Water is a much better sound medium than air, so you can hear shit A LOT farther out than on land. Using passive sonar you can hear a propeller moving in the water from several miles away depending on speed and shit
>>30039445
Step one: Take microphone
Step two: Hold underwater
Step three: Listen carefully
That's the basics of passive sonar. It's used infinitely more often than active pinging sonar.
http://www.govsupport.us/navynepahawaii/whatisSonar.aspx
>>30039445
>How the fuck does that work?
https://en.wikipedia.org/wiki/Hydrophone
Stop what you're doing right now and go watch Das Boot.
Hydrophone
Radar
>>30039380
Loose lips.
>>30039504
Sinks ships
>>30039380
>What passive technologies do subs have for detecting ships besides visually acquiring them with a periscope?
Uh
Sonar
>>30039380
Towed sonar arrays, hull mounted sonar arrays, conning tower sonar arrays
All carry hydrophones for listening
It's how you can tell which direction a reflection comes from
They're sensitive enough now to be able to visually show you how many blades and how many screws a ship has for identification while underwater
It's called waterfall or something like that
Go pirate 688I and learn some things
It's incredibly boring and tedious but that's submarines for you
Do subs fundamentally have the upper hand locating ships or can the gap be closed with technology?
Do they bother trying to locate ships visually from above or below the water at all?
>>30039530
>Do subs fundamentally have the upper hand
The layer's a pretty big upper-hand to start out with.
>can the gap be closed with technology?
Towed sonar and heli-based dipping sonar or sonobuoys can be used to listen below the layer.
>>30039530
Yeah they have the upper hand, but not by much.
No not usually unless there is a specific need to look at the ship in question
Engage caterpillar drive
So what if a ship is stationary or they develop a quieter method of propulsion? Does a sub have no way of knowing it's there without giving themselves away?
>>30039380
Am I seriously the only person who gets spooked at the underside of ships, subs underwater, and deep, dark water? It's just an incredible feeling of vulnerability.
>>30039602
Yup
>>30039570
this goy here is referring to the thermal layer that makes sound bounce off of it
Its the depth at which the temperature of hte water starts to decline with depth instead of staying relatively the same
>>30039583
I was always curious about this
Was it basically just a water pump?
>>30039602
>So what if a ship is stationary or they develop a quieter method of propulsion?
Everything has to be running to keep the lights on, m8
You can hear the engine
>>30039615
I love submarines but being in them scares the hell out of me because of exactly that
>>30039615
You're probably not alone considering how hard it was to just find a picture of the underside of a boat in the water.
>>30039617
I would have thought they'd at least have cameras pointing up or something. How hard can it be to see a boat on the surface of the water during the day? Like how some fighter aircraft can acquire targets visually.
>>30039615
Submechanophia
>>30039648
The book wrote the caterpillar drive as a quiet pump jet.
In the movie it's using electromagnets to shoot water out the back of the sub like a railgun.
>>30039658
>I would have thought they'd at least have cameras pointing up or something.
I heard somewhere that they have new sensor packages with small cameras scattered around the ship, but you probably wouldn't be able to go very deep with them or they'd crush
>How hard can it be to see a boat on the surface of the water during the day?
Depends entirely on depth
![tvOxSaG[1].jpg](https://i.imgur.com/oSMZmxy.jpg "tvOxSaG[1].jpg")
>>30039661
Not the guy you're responding to but it's not really that
It's the darkness hiding the rest of whatever is underwater that gets me
This pic here is pretty cool
>>30039668
I read the book and never quite understood it and the movie glazed right over it
And it would be gauss gun
>>30039669
>you probably wouldn't be able to go very deep with them or they'd crush
We've sent cameras to the deepest point on earth why would it be a problem on a manned sub that only goes a few hundred meters?
>>30039658
>>30039669
This. You can put up the periscope underwater and look around but it's fairly limited in visibility. You'd have to get close enough that getting detected becomes a danger and typically you don't need to get that close, that's how good sonar is
>>30039684
Fucking 3 AM, I knew there was a different word but I couldn't think of gauss gun/coil gun.
is there any way for subs to tell if they get detected other than catching a torpedo?
>>30039648
>>30039684
There is a boat that actually runs on this method of propulsion. They built it to prove the technology worked.
I hear it's not very efficient.
Some Googling should do justice.
>>30039702
They'd hear the torpedo in the water. And they'd hear if they got hit with active sonar. Otherwise, no
>>30039707
they can hear the ping of the sonar?
from underwater microphones I assume?
>>30039686
>measuring in meters
>We've sent cameras to the deepest point on earth why would it be a problem on a manned sub that only goes a few hundred meters?
What you need in a quiet combat sub are a big difference than what you need on an exploration craft
And most of those cameras are on the inside of the pressure vessel
>>30039718
An active sonar ping is basically a giant blast of sound. It would highlight the submarine and you'd know exactly where it was, but on the flip side, that sub would know exactly where you were too
>>30039702
Hear the doors opening, flooding of the tubes, torpedo launch, torpedo incoming, evasive maneuvers, line up maneuvers, etc
>>30039718
they can hear the screws
>>30039704
Japs did, yes. It sucked.
https://en.wikipedia.org/wiki/Magnetohydrodynamic_drive
>>30039668
>electromagnets
>shooting water
choose one
>>30039677
I have the exact thing man, Finding Nemo almost milled me with this fucking scene,
>>30040165
http://pqasb.pqarchiver.com/washingtonpost/doc/307500788.html?FMT=ABS&FMTS=ABS:FT&type=current&date=Jun%2017,%201992&author=T.%20R.%20Reid&pub=&edition=&startpage=&desc=Ship%20Sails%20on%20High-Tech,%20%60Silent%27%20Drive;%20Japan%20Tests%20New%20Propulsion%20System%20Reminiscent%20of%20%60Red%20October%27
>>30039615
There's a reddit (inb4) or two that constantly posts shit related to that, or underwater structures/creatures/geological formations.
I cry everytime.
>>30039668
didn't read the book did you?
>>30039704
You mean that Kilo class submarine? Isn't it being upgraded?
>>30040326
Russian submarine B-871 Alrosa is an diesel-electric Kilo-class submarine that joined the Soviet Fleet in 1990 and is active with the Russian Black Sea Fleet as of 2011.
In June 2011 she took part in a NATO submarine rescue exercise, 'Bold Monarch 2011,' the first Russian submarine to do so.[1]
Instead of a conventional propeller Alrosa uses a pump jet propulsion system.[2]
>>30040330
>>>30040326
magneto-electrodynamic propulsion is not a pump jet or a cort nozzle or a secluth duct. it is a magnetic motor with the water as the pole piece. Very inefficient very loud. one build and in Tokyo bay.
>>30040330
It's still kinda shitty, but the kilo class sub in general is scary as fuck. When it's running on the battery you literally can't hear it. ITS A GOD DAMN FUCKING GHOST and if you see it you're in a very bad place. Fuck those boats. The us needs to bring back diesel boats
>>30039572
>they have the upper hand, but not by much.
Bullshit not by much. Wargames and exercises were always stupid as shit against surface fleet, because not only did we have to give them a predetermined navigation plan, we had to have extra mats and antennas up at pd, radiating unnecessarilly just so theyed have a chance at finding us. They still hardly ever did. There are also tons of stories about shitty Chinese subs surfacing in the middle of our carrier groups just to fuck with us. Submarines are one of those things thare are impossible to armchair quarterback about because the actual level of capability of modern submarines just isnt public knowledge.
>>30039658
>>30039669
Periscopes have built in cameras, and within a few meters of the surface theres plenty of light. Submarines do a thing called "underhulling" iirc, which is basically drive under and around ships taking pics underwater of the hull, even doing it to other subs. Some good stories out there about US subs catching cutting edge Russian stuff on their maiden voyage and getting great photos of screws and shit before the boats were even combat ready.
>>30040326
Kilos are Russian 50's/60's era diesel garbage that they've sold off to places like Best Korea and Iran. There might be experimental shit out there, but afaik everything actually deployi g and running missions still uses good old propellers. Theyre all shrouded up and shit though, super quiet still.
>>30040406
You a submariner?
>>30040377
Kilos dont even have narrow band sonar. Everything real countries have been using has narrowband, ie we havecreports of X-class sub in the area, we know it radiates a frequency at 233.7htz, we can tune in sonar to listen specifically for that frequency.
Broadband is literally stick a microphone underwater and try to hear shit level tech. Good luck hearing a Virginia over the sound of whales fucking.
>>30040420
Was
>>30040424
I know man I'm an sts lol I'm just saying kilos are fucking ridiculously quite and yeah Virginias are dope. I'm on an I boat. Have you seen the new Russian subs?
>>30040426
What was your rate?
>>30040431
Ive been out for 6 years, and havent kept up with anything. Ive been pretty disgusted with the PCification of sub service and stopped paying attention. Even while in we never fucked with Russians, just bullied countries with shitty navies.
>>30040437
Navet
>>30040406
submarines are fucking cool, man.
can subs take on supplies while underway, like a normal surface ship can?
or are you fucked once you run out of cans of spaghettios?
>>30040406
>50's/60's era.
You know the more I learn about military hardware the less relevant this is. Everything is so damn old. The f-15 eagle was designed in the 60's, the blackbird in the 50's. Even rocketry is still using models from the 60s iirc.
Mechanical engineering just hasn't progressed as much as one would think it's mostly electronic.
>>30040455
Yeah man if I could do it again I defiantly would have been a surface fag or maybe even a grunt idk but I know I'd never recommend subs to anyone haha fuck this shit
>>30040460
No we don't take any supplies underway. We actually have an electromagnetic teleporter that beams food onto the boat every for hours for the crew to eat
>>30040460
Sort of. We never did, not food at least. Since modern nuke subs dont need fuel, and make their own air and fresh water, food is the only real limiter for operation length, aside from shit breaking. We would load the fuck out of the boat before deployments, like even lining every bit of deck space with #10 cans snd then putting rubber mats over them to creat a new deck. Sucked to be tall.
We were taling Iranian Kilos one deployment and our relief fucked up and smashed into a tanker coming into the gulf, and it took a few weeks to spin up another boat and get them out there. We ran out of everything but coffee, canned chiki, rice, and pancake mix. That was every meal, 4 meals a day, for almost a month. To this day i still refuse to eat pancakes.
>>30040495
Wrong, this is pure fiction.
We actually quantum entangle sailors stomachs with a computer and simulate full stomach remotely.
Don't forget ESM, the only watch stood on the boat that most people on the boat don't even understand but is the most underrated passive sensor at pd
>>30040486
Daily life sucked, but i know if i didnt do it i would have regretted it thevrest of my life. My uncle took me to see Das Boot in theaters when i was like 10, and i just couldnt figure out how they fit that many massive pairs of brass testicles in a tube underwater. I knew i had to give it a go after that.
If youre a normal person without some sort of autistic compulsion i wouldnt reccomend it though.
>>30040485
Kilos arentvfront line though, theyre literally to the point where theyre worthless against a modern navy. Theyre like F-4 phantoms or something, sure they used to be hot shit, but what is a Phantom going to do against an F-22? Its not just electronics.
>>30040525
>what is a Phantom going to do against an F-22? Its not just electronics.
If the weather was bad the f-22 wouldn't even be in the air would it? I'm not even being snarky.
A phantom is perfectly capable of intercepting and shooting down an f-22 that is retreating and showing it's engines.
You know what, i lied. Reading wikipedia Kilos actually started deploying in like 1980. Its been a while.
So the age gap is not as vad as i was making it out ti be. Theyre still second line subs though, tine range, short operational limit, and 2nd rate tech.
>>30039380
Just like radar anon, except your speed calculations are slower because you are using sound and not radio(speed of light).
Just as there are PESA (passive) and AESA (active) radars, there are passive and active sonar systems. All modern sumbarines have the ability to choose when and where they want to ping. In a highly populated combat environment they generally will choose just to listen for their enemy. When there is no-one around and are looking for someone, they will start pinging things looking for good reflections. This is dangerous though because it can reveal your presence, and if your not careful, your position, which for a submarine means death.
>>30040497
>our relief fucked up and smashed into a tanker coming into the gulf
lol was that the hartford with that bent-ass sail. I remember hearing about that shit and seeing the damage. So much oil spilled inna med from that tanker gettin can-opener'ed
>>30040555
In 5 years on a boat literally the only time we ever went active was to test the system. Boomers dont even have active sonar installed afaik. No one goes active unless MAYBE you got several torpedos in the water and you know youre already gonna die, and you want to get one good shot off to at least 1 for 1 the bad guys.
Going active is literally like a sniper shining a searchlight around asking if anyones there. It doesnt happen. Its all passive sonar, all the time.
>>30039504
Suck dicks
>>30040566
I can neither confirm nor deny the involvement of any US ships or sailors in that masterful display of target management and situational awareness.
Also i dont remember. We had pretty much the same shit happen 2 deployments in a row, and i forget which boat fucked us when.
>>30040555
god damn it can you tards define this. A passive matrix pulse Doppler radar works from one gun diode that uses software to create a virtual beam. Active matrix uses multiple gun diodes with phase shifting to create a virtual beam for the sensors to receive.
>>30040539
>If the weather was bad the f-22 wouldn't even be in the air would it?
You have to be kidding me right.
>A phantom is perfectly capable of intercepting and shooting down an f-22 that is retreating and showing it's engines.
I don't think you understand anything about radar or the F-22 in general. Fuck me how can you just say shit like that? Have you ever looked at the back of an F-22? There are no visible blades. The exhaust tips are reflective in nature and have a thermal coating as well as RAM. Do you seriously think that 60's tier technology can take down the most advanced 5th gen fighter to date because it was facing the other way around?
>>30040567
that and the sonadrome was made in 47 right?
>>30040567
But you at least have the capability correct? That's all I meant.
>>30040585
What are you yelling about? Gun diodes and single beams are old tech. AESA uses an array of antenna elements (see pic related). The computer will change the strength of certain elements to create a beam-forming effect and essentially pointing the beam at a given target. That's how they do a scan.
>>30040585
Are you asking about sonar? Passive is just listening. You hear a noise, measure its bearing rate of change, turn and do it again, etc. Eventually you can math out the direction the noise is going, and combined with sonar being sensitive enough to hear propeller rpm and number of blades (therefore approximate speed), you can math out range, the blow the fucker up if required. Sub on sub combat is a very very slow affair.
Active is send out a massive sound pulse, and listen for a return from that pulse bouncing off shit. The bearing is obviously the same as the return, and distance is mathed out from the exact speed of sound in those specific salinity and temp conditions. One pulse doesnt give direction of travel or speed of target though, yoy need to keep pinging it and compare movement from previous.
>>30040600
so active matrix which has been around since the end of the 70s?
If a ship were just chilling with all systems off, floating or anchored, how would a sub detect it?
>>30040606
Im >>30040555
In the radar world, we can shoot a small cone of energy directionally, so that the return is more focused directly at us and harder to backtrace. Is there anything like that for sonar? It's all the same math, just different mediums, so I am assuming it's possible in some way, but I don't know if it's been implemented.
>>30040606
dude radar. I can do maxwells equations and don't need you explanation about sonar. Just these stupid AESA PISA arguments. Either you synthetic aperture is created by a single source emitter or by multiple source.
>>30040616
Can you please lengthen your sentences a bit? It's hard to read. I'm not being snarky, I just am having a hard time understanding what it is your try to ask or comment on.
As for what I think your trying to say, here is my response.
Yes, AESA is not a new idea and early techniques related to it were tried on ground based units in the 70's im sure. It was all highly advanced back then and in the real world didn't see action on aircraft until later.
Now I am not sure what the purpose of arguing about radar in a sonar thread is. If you have questions about radar, make a different thread. Let's keep this strictly sonar related.
>>30040620
Honestly i dont know. Wasnt a sonar tech, and again active isnt used in combat. I dont see why not, in fact I belive our torpedoes do something along those lines. Surface guys would know better, their shit is so loud they cant hear anything passivly and they constantly spam active sonar.
But generally if we knew the bearing of a target well enough to know where to throw a narrow beam, we wouldnt need to, if that makes sense. Submarines dont need to "lock on" to something to fire, so an intermittant return is good enough. Plus target id is actually done passively via transient frequency and screw blade count. Active does nothing for id. And most contested areas are places like shipping lanes, ports, and straits, which are crowded af. The middle of the ocean is not worth fighting over. Therefore target id is paramount.
>>30040632
why did it go from passive matrix and active matrix to pisa a aesa? and why do people say spy1 was pisa when it had over 20 emitters per receiving array and phase aligned focusing of the emitters? And yes the active sonar emitter in everthing up to Virginia went out of production in 1947
>>30040555
What? PESA/AESA and Passive/active sonar are completely different.
Both PESA and AESA are emitting to find shit, while passive is only receiving and only active emits
>>30040709
is there an engineer in here that speaks 21st century miltard speak who can explain this?
>>30040740
PESA and AESA both send out radio waves in order to locate things by the reflected waves, its just the way they generate/shape the radio waves is different.
Passive sonar emits nothing, just listens for sounds in the ocean. Active is the only time sonar emits sound waves to listen for reflections.
Basically comparing passive/active sonar to PESA/AESA is retarded
>>30040330
Which was stolen/bought by swedes in Estonia after the wall fell.
>>30040751
I did not compare them. nobody smart uses active sonar except from remote platforms, helicopters, sonabouyes torpedo's.
>>30040647
Thanks for clarifying. It would make more sense for the torpedo to have it as it's less of a liability to the ship.
>>30040709
You are right. PESA's do emit. I had them confused with passive radar, the ones that just strictly listen.
>>30040763
>Just as there are PESA (passive) and AESA (active) radars, there are passive and active sonar systems.
Sounds like a comparison to me my man
>>30040763
I'm aware.
>>30040769
You got the wrong guy. I am >>30040765 and I posted the comparsion you are referring to.
>>30040769
I am an old scada geek. I have worked on many things. including pulse Doppler radar systems of both the active and passive matrix variety. and yes the sonadromes on a 688 were all built before 1947.
>>30040786
Yeah I saw that after I posted, no idea why this guy is getting defensive about a response to someone elses post lel
>>30040796
Thats neither here nor there. I responded to a post comparing PESA to passive sonar to tell them the word "passive" is used completely differently in both of them.
>>30039615
Since no one else posted it, I've got a present for you.
http://www.uboataces.com/sounds/submarine-sinking-2.wmv
>>30039445
>How the fuck does that work?
Play Fast Attack.
This makes me want to watch Down Periscope again.
>that scene where they trick another sub by making theirs look like a fishing boat, and they all start singing.
>>30040759
My bad, it was a nuclear powered propulsion system. Probably akula/equivalent.
>>30040807
>>>30040796 (You)
no shit the receivers are spread out in the same manner and in receive only mode would all based off software. sonar is actually more complex as radar has relativistic constrains rather than gas law.
>>30040874
I cut up a dixie and used electrical tape and markers to do it up like a pirate hat, like in the plank walking scene, and wore it the whole time inderway on my second deployment
>>30040377
LA class boats didn't have problems with Kilos bud
>>30039615
>>30041284
>Catalog
dude I thought I was talking out of school.
>>30041296
At least he has vis, when I went diving onna sub site it was pitch black with a 15 knot current
>>30041299
What?
>>30039615
I hate the sea, and water, and oceans. All the weird shit living in it, and that sense of vulnerability it overwhelming. Also, for some weird ass reason, seeing sunken ships covered in sea life and all dilapidated freaks me out for some reason. I don't feel the same when looking at collapsed, overgrown houses or bunkers on land. I cant even look at a pic of the Bismarck or Titanic without getting an uncomfortable shiver. Fuck the ocean, and sea food too, and fish.
>>30041535
I have no problem with fish because I grew up fishing in lakes, but I feel the same with dark water
I don't know what's there and I don't like it
Also that GIF made me kek heartily
>>30039677
mar sem fim is top spookster
