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Former Navy submarine officer here. This sucks, but it happens. (It happened to a boat I was on.) It could be hitting the bottom of the ocean (which nearly k
by jedc 5y ago
Former Navy submarine officer here. This sucks, but it happens. (It happened to a boat I was on.)
It could be hitting the bottom of the ocean (which nearly killed 130+ people on the USS San Francisco years ago - https://en.wikipedia.org/wiki/USS_San_Francisco_(SSN-711)#Collision_with_seamount https://en.wikipedia.org/wiki/USS_San_Francisco_(SSN-711)#Co...), it could be hitting another ship above it (coming to and/or operating at periscope depth is dangerous), or potentially another sub.
Invariably people get fired, and whatever happens becomes a lesson learned that the Navy trains on in the future.
- nicoburns 5y ago> coming to and/or operating at periscope depth is dangerous Is there any reason why they can't check what's above them before ascending?
- ethbr0 5y agoHow would they check what's above them? Visual is out. Passive sonar will only detect noise sources. And pinging with active sonar loudly announces to everyone around exactly where you are.
- toomuchtodo 5y agoMagnetic induction tomography. Detection at a distance isn't yet practical, but the physics are known (eddy current effect).
- kfarr 5y agoWhy is visual out? Cameras are cheap
- bayindirh 5y agoBut water is not always transparent or clear enough. Also there's not enough light all the time. Also pressure proofing cameras are not cheap I presume.
- ethbr0 5y agoYup. There's not much light below 100m. Certainly not down to 500m+. Which would also be 50atm+ worth of pressure.
- dylan604 5y agoAlso, nighttime
- paranoidrobot 5y agoThey have upward-looking cameras, at least on some of them. You can see it in the last Smarter Every Day video[1] where they're talking about surfacing a submarine in the arctic ocean. At several points you can see a video monitor showing an upward view of the ice. [1] https://youtu.be/XFJnWp1tAdU?t=1427 https://youtu.be/XFJnWp1tAdU?t=1427 e: to be clear, that upward looking camera isn't going to be enough to detect much beyond your own footprint. If someone is about to cross that area you'd need some other way of detecting them.
- jedc 5y agoThere’s special equipment/procedures for surfacing in the Arctic. That’s another really dangerous place to operate. (Default action in a submarine emergency is to get to the surface. That’s… NOT easy when there’s ice above you that’s potentially too thick to punch through)
- runsonrum 5y agoIsn't everything expensive for the military?
- tshaddox 5y agoIsn't it dark?
- digikata 5y agoA small tethered float with accelerometers that ascends along the path of the surfacing submarine.
- ethbr0 5y agoSubmarines typically conduct powered or semi-powered ascents. No forward motion = no steerage.
- digikata 5y agoAdd some steering and if needed power - if you’re lucky you only need to steer to the path with the energy of the vertical ascent.
- da_chicken 5y agoI think the point was that you have enough forward movement for steerage, your tethered float will always be behind you.
- digikata 5y agoThat's why I mentioned powering the float if needed ... I suppose it's more of a tethered drone at that point.
- speedybird 5y agoSurface ships are very noisy so submarines listen for other ships in the area before surfacing. They have dead zones in their sonar coverage, but can usually deal with that by turning to listen in those dead zones before surfacing. Nevertheless, there are occasional accidents.
- mpyne 5y agoSurface ships are not always noisy. This is especially a problem with supertankers if you they are head-on to you, they can be hard to hear from underwater, especially with the high level of noise from the surface around the supertanker. This was a contributing factor to a collision in the Mediterranean about a decade or so ago.
- jedc 5y agoI personally had what we called an “ass-puckering” moment for exactly this reason once. At periscope depth in fog, huge cargo ship coming at us… it was the only time in 3 years on board I (or anyone else) had to call “emergency deep”.
- dctoedt 5y ago> in fog, huge cargo ship coming at us And Iron Mike probably had the conn aboard the cargo ship .... (Source: A similar experience in the South China Sea.)
- baybal2 5y ago> And pinging with active sonar loudly announces to everyone around exactly where you are. From what I overheard in cafeterias frequented navy navy men while living in Vladivostok is that active sonar is used all the time unless deep blue waters. Navigational active sonars are nowhere near as detectable as long range military ones.
- mpyne 5y agoAny sonar useful enough to navigate at speed is going to give away your position. It's the "flashlight in the dark room" problem. Your sonar ping has to travel to an object and reflect back to the submarine. But an adversary just needs to hear the original ping to know what direction it came from, so you can be detected at a longer distance, and potentially a much longer distance, than you could reliably detect the other submarine at. That's not to say active sonar is never used, but at least with the U.S. it's not going to be continuously used, and it's going to be rare to use it if you're in a mission area. A sonar transducer that can emit a ping with directionality is sometimes useful (e.g. a fathometer to measure depth to the ocean bottom, since the crushing pressure of the depths ensures the area below you is generally clear of enemy subs), and those are used. But even there, that wouldn't be useful for navigating when otherwise blind; you use fathometers to confirm that you're approximately in the area you think you're in based on the chart readings.
- baybal2 5y ago> Any sonar useful enough to navigate at speed is going to give away your position. I mean the difference is possibly hundreds of metres to hundreds of kilometres in between navigational sonars, vs sub detection sonars.
- ChrisMarshallNY 5y agoI'm no expert, but my guess is that the sub runs nearly completely blind, most of the time (charts are very important). This is because they need to stay undetected, and rely completely on passive sensors; which can be dicey.
- jedc 5y agoSubmarines do you passive sonar extensively before going to periscope depth. There are lots of ways to figure out where contacts are, your range to those contacts, and then avoid them all. But there's no sensor that can tell you with 100% accuracy what's above you.
- ethbr0 5y agoWhat's the sensation inside the boat? Noise? Impact? Momentum change? I imagine it'd be like being on a glacier, hitting another glacier.
- jedc 5y agoThat's not far off? Our boat grounded on a rock, and it sounds exactly what you'd think a 6000-ton steel tube going over a rock would sound/feel like.
- ethbr0 5y agoOof, listening to rock-on-hull while underwater has to be "interesting". You folks are made of stern stuff.
- giantrobot 5y agoOnly the ones in the back.
- dctoedt 5y ago> Only the ones in the back. Ding ding! "Knuckledragger, arriving!" (For those mystified: This is an inside joke.)
- jedc 5y agoIn my case we were on the surface. Still a bad day, but we had more signs something potentially bad was about to happen. :(
- ashtonkem 5y agoAhh, the fine differences between “we’re going to get shouted at” and “we’re gonna die”.
- senectus1 5y agoPersonally I imagine it would be utterly terrifying.
- BitAstronaut 5y ago> and whatever happens becomes a lesson learned that the Navy trains on in the future. Former enlisted here. Unfortunately death by power point doesn't solve the problem of overworked sailors.
- galacticaactual 5y agoNo one said the training was PowerPoint.
- Jenk 5y agoI'm pretty sure that GP just did. Their post was a multi-pronged dig at their time serving - the first being that their training was (mostly?) ppt based, and secondly that sailors are overworked.
- imwillofficial 5y agoThe training is not PowerPoint.
- MaximumYComb 5y agoHow do you think they deliver this training to enlisted?
- galacticaactual 5y agoHave you received training as an enlisted person? Because PPTs are but one - of numerous - ways, to include drills, exercises, and other physical doing.
- MaximumYComb 5y agoYes, 12.5 years enlisted. I've sat through more dumb PPT's that are a reaction to an incident than I care to remember. With Covid, the model seems to have moved to doing an online course which is a bunch of slides and some multiple choice questions.
- holler 5y agoSilly question, could it have been an animal? Would hitting a full-grown blue whale or anything less at 30 knots cause such a disturbance? Also is there any way to detect marine life at close proximity? I saw the story about USS San Francisco earlier today and that led me to reading about the USS Thresher... Really sad story but it led to changes that years later resulted in the USS SF surviving intact. https://en.wikipedia.org/wiki/USS_Thresher_(SSN-593) https://en.wikipedia.org/wiki/USS_Thresher_(SSN-593)
- speedybird 5y agoA grown blue whale weights about 1/50th of the submarine (~200 tons vs ~10k tons) and is quite a bit squishier. But maybe that would still be enough to knock some submariners around and cause some injuries? I'm not sure.
- throwaway0a5e 5y agoIf you hit a 60lb object while driving your car you'll know.
- VWWHFSfQ 5y agoIf you're driving a ~3,200lb Honda Accord, sure. But the mass difference at the scale of 10,000 tons is a lot different. Especially under water.
- adwww 5y agoI think the weight difference is more like hitting a badger with a fully loaded semi truck.
- 542354234235 5y agoThis sounds like a job for the Mythbusters.
- Chris2048 5y agoBut the dynamics of large things change, because the bond-strength of metals don't scale up as you build bigger things. Also, this happened underwater, so the harder-to-displace water would give more resistance ("inertia"?) to the whale maybe?
- catskul2 5y agoAm I reading wrong? It seems to say 1 person was killed rather than 130+.
- jedc 5y ago1 person was killed by injuries upon impact. But there was one piece of equipment on board that normally runs for ~20-30minutes at a time. It had to run continuously until the ship came into port or the submarine would have sank and 130+ people would have died. They got VERY lucky everything worked out.
- Sebguer 5y agoYes, you missed 'nearly'.
- mrtksn 5y agoHow much visibility(Visual or sensory) there’s in a submarine? Are there cameras or sensors where you can observe in every direction or is it more like driving really large and old vehicle where you don’t know what’s happening around the vehicle most of the times?
- kiklion 5y agoOne of these videos gives some good information. And all of them are interesting. https://youtube.com/playlist?list=PLjHf9jaFs8XWoGULb2HQRvhzBclS1yimW https://youtube.com/playlist?list=PLjHf9jaFs8XWoGULb2HQRvhzB...
- mLuby 5y agoSub Brief is another good channel: - how submarine systems work: https://www.youtube.com/playlist?list=PLF9K78gj2FP2fDVRu_BkcWxI9tN7-6Rhx https://www.youtube.com/playlist?list=PLF9K78gj2FP2fDVRu_Bkc... - sonar acoustic signal analyses: https://www.youtube.com/playlist?list=PLF9K78gj2FP2D-EIZkYN1sBsVauj_MdXu https://www.youtube.com/playlist?list=PLF9K78gj2FP2D-EIZkYN1... - overview of sub classes: https://www.youtube.com/playlist?list=PLF9K78gj2FP0hID8jeOp_wr5Gntvn3W7R https://www.youtube.com/playlist?list=PLF9K78gj2FP0hID8jeOp_...
- jedc 5y agoUnder the water you've got sonar, which only tells you sound (and sound pressure levels) from a particular bearing. If you're up at periscope depth you can stick a periscope up to see and other antennas. If you're on the surface you typically send people up into the sail and the boat is commanded from there. (Only a couple people fit up there, so the people actually operating the rudder and navigating are belowdecks). Overall you generally get a good indication of what's happening, but... it's definitely possible to be surprised.
- dhx 5y agoThe navigator would be looking at a screen displaying ECPINS Submarine[1] or similar software. The inputs they'd be able to use would include: 1. GNSS location (only if surfaced) 2. Passive sonar data (detecting location of electromagnetic signals through water e.g. acoustic noise of another ships propeller) 3. Active sonar data (only if stealth is unnecessary) 4. Radar data (only if surfaced) 5. Bathymetry models/charts[2] (accuracy depends on location in the world) 6. Tide prediction models[3] (availability is location dependent) 7. Inertial navigation sensors (dead reckoning so accuracy drifts over time) 8. Surface Electronic Support Measures sensors (allows geolocation of signals from other ships, aircraft and ground transmitters) [1] https://osimaritime.com/solutions/software/ecpins-submarine/ https://osimaritime.com/solutions/software/ecpins-submarine/ [2] https://www.admiralty.co.uk/digital-services/digital-charts/admiralty-vector-chart-service https://www.admiralty.co.uk/digital-services/digital-charts/... [3] https://www.admiralty.co.uk/publications/admiralty-digital-publications/admiralty-totaltide https://www.admiralty.co.uk/publications/admiralty-digital-p...
- dockd 5y ago> coming to and/or operating at periscope depth is dangerous Silly question: how do you identify a target? Sound only? It seems like you would want something visual.
- _3u10 5y agoEach sub / surface vessel gives off a unique acoustic signature. My understanding is that US subs don’t travel in packs, so anything they detect is generally the enemy, and especially so if it’s submerged, unless they are escorting a carrier.
- jedc 5y agoYep, just sound. And you don't even know range, you only know how strong sound is on a particular bearing. The Navy trains to do a series of maneuvers that helps you understand the range to the ships you do hear, and positions the sub most safely to come to periscope depth. And then while you're coming to periscope depth you're looking out to see if there are any indications you've screwed up. But yeah, there's nothing visual available when you're under the water.
- HarryHirsch 5y agoSound only. Submarine navies go to great lengths to collect sound samples of potential opponents.
- sas224dbm 5y agoI worked on Target Motion Analysis (TMA) software that was live on S&T class UK submarines in the 90s. There were only a few types of data that were highly classified and which we never saw, Electronic Surveillance Measures (ESM) databases were an example. Emitter characteristics could pretty much allow a good SONOP (Jonesy!) to be able to identify specific instances of a class of boat. Fun stuff.
- dylan604 5y agoSonar identification is incredibly accurate (with computer assitance). We've been dragging "mics" through the ocean for a long time. They can identify the exact ship by noises coming from the engine(s), the propellers, etc. They can count the rpm of the props of that ship and determine it's speed. They can tell if it is approaching, going away, etc. During sea trials of a new boat, they have it do passes specifically for sonar to listen to it. Partly so they can learn its sound signature, but also to see if they can hear annomalies during construction. They've found toolboxes left inside a double hull by the builders. They do have visuals with the waterfall displays and what not. Last I looked into sonar operations was in the early 90s, so not sure what the kids are using now. They can do all of this without making a sound to allow someone else to know they are there.
- wahern 5y ago> Invariably people get fired, and whatever happens becomes a lesson learned that the Navy trains on in the future. In the debates surrounding some of the most recent incidents (see, e.g., https://www.propublica.org/series/navy-accidents-pacific-7th-fleet https://www.propublica.org/series/navy-accidents-pacific-7th...) I remember reading claims to the effect that submarine captains are the last ones in the Navy who actually know how to pilot a boat. I know that claim is hyperbolic rhetoric but those Pro Publica pieces really make me think it's not far from the truth, and that while submariner training may still be exceptionally rigorous and responsive to newly identified risks, that's not necessarily true in the case of surface ships.
- jedc 5y agoPossibly? There are far fewer officers on a submarine, so there's more opportunity for training. But submarines don't spend a heck of a lot of time on the surface where piloting skill matters. They stay submerged through the Straits of Gibraltar, the Straits of Hormuz, a lot of the Red Sea, etc. Submarines are slow on the surface and appear much smaller than they really are, so it's generally best for everyone if they go underneath or around chokepoints.
- QuarterReptile 5y ago> it's generally best for everyone if they go underneath or around chokepoints. Theoretically yeah, but radar is pretty great for resolving ambiguity.
- pyinstallwoes 5y agoThis is going to be a stupid question, and I am going to already guess an answer but I have to ask. Given that there is a collision about to happen, isn't there a sensor that would give some type of warning? And I'm guessing that the answer to my stupid question is that a sensor would give away the position of the submarine because anything emitting a signal would defeat the point of the sub?
- captainoats 5y agoYa, not a dumb question, and you are correct. Submarines can’t use active navigational systems (anything that emits energy) like radar because it would defeat its own core mission of being a stealth weapons platform. They do use passive sensors to detect the environment around the ship and probably some other spooky secret stuff that I don’t know about.
- imwillofficial 5y agoWhat He said ^
- pyinstallwoes 5y agoPerhaps vision based and ML prediction or whatever would be considered passive in the sense that is doesn't pin an energy signature. Got it, thanks!
- arethuza 5y agoA few years back two submarines from France and the UK collided - turns out that although the ocean is pretty big the places that missile subs are likely to hang are smaller than you might think: https://en.wikipedia.org/wiki/HMS_Vanguard_and_Le_Triomphant_submarine_collision https://en.wikipedia.org/wiki/HMS_Vanguard_and_Le_Triomphant...
- david422 5y agoSame with planes. How on earth do two tiny planes manage to enter the exact same point in space and time in that gigantic sky?! It happens.
- addingnumbers 5y agoThe probability of mid-air collisions actually went up in step with the finer granularity of GPS systems. > The navigation paradox states that increased navigational precision may result in increased collision risk. In the case of ships and aircraft, the advent of Global Positioning System (GPS) navigation has enabled craft to follow navigational paths with such greater precision (often of the order of plus or minus 2 meters), that, without better distribution of routes, coordination between neighboring craft and collision avoidance procedures, the likelihood of two craft occupying the same space on the shortest distance line between two navigational points has increased. [1] It got to the point on many routes where regulators had to mandate an offset in opposite directions along common flight paths to effect "lanes" of traffic. [2] [1] https://en.wikipedia.org/wiki/Navigation_paradox https://en.wikipedia.org/wiki/Navigation_paradox [2] https://en.wikipedia.org/wiki/Strategic_lateral_offset_procedure https://en.wikipedia.org/wiki/Strategic_lateral_offset_proce...
- mulmen 5y ago> Invariably people get fired Is this how the Navy deals with accidents? I can understand being fired for failing to do your duty but operating a sub is both hard and dangerous. Things are going to go wrong. If everyone did their job isn’t this just a learning opportunity?
- Chris2048 5y agoThey used to just fire people out of a cannon, but morale didn't improve.
- michaelt 5y agoFor people who aren't the captain, it might indeed merely be a learning opportunity. But if you're the captain of a ship that's at fault in a crash? The inadequacies revealed in the crew's training are kinda your fault. For example, in 2017 when the USS Fitzgerald collided with a container ship [1] and the captain was relieved of his command, despite the fact he'd been in bed during the collision. It's normal, in 95% of jobs, that if you cause $$$$$$$$ of damage by making a mistake, you get fired. [1] https://en.wikipedia.org/wiki/USS_Fitzgerald https://en.wikipedia.org/wiki/USS_Fitzgerald
- belter 5y agoWould this be because Sonar was not being used as they would be under some "stealth" mode?
- Tuna-Fish 5y agoSubmarines don't use active sonar as a matter of course. That is, it's not something you turn off when you want to be sneaky, it's something you only ever use in very limited and specific situations.
- nimbius 5y agoocchams razor here. This increase in recent collisions (including training jets) is probably due to the Navy's "five and dimes" sleep schedule that basically guarantees every squid mustang and sardine is a combat worthless zombie due to sleep depravation. https://www.usni.org/magazines/proceedings/2017/july/let-our-sailors-sleep https://www.usni.org/magazines/proceedings/2017/july/let-our...