<i>> It is unwise, in the course of a search and rescue operation, to report that you think the vessel was irrecoverably lost.</i><p>I made this point several times on social media during the Titan incident but it fell on deaf ears; it seemed crazy to me that people were accusing the US Navy of some nefarious cover-up regarding possible acoustic detection of implosion.<p>Anyone who’s ever worked with any type of signal analysis would be aware of the huge uncertainty involved; the idea that we could positively identify the specific destruction of the Titan remotely was ludicrous on its face.<p>That aside, even if the Navy was 100% certain, would you want the search for your loved ones called off because someone heard a noise? Of course not. You search for people missing at sea until you find them or until the point where any reasonable hope of finding them is gone. That applies to billionaires as well as anyone else.
Reminded me of this story: <a href="https://en.wikipedia.org/wiki/Toshiba%E2%80%93Kongsberg_scandal" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Toshiba%E2%80%93Kongsberg_scan...</a><p>Toshiba wasn't allowed to export a 9-axis (C)NC-machine to the Soviet union, because it could (and would) be used to create ultra-silent submarine props, in the 80s.<p>Asianometry video about it: <a href="https://www.youtube.com/watch?v=uaRyqAVIkwI">https://www.youtube.com/watch?v=uaRyqAVIkwI</a>
An almost mandatory entertaining article, whenever topics about cables, ocean floor, submarines come up:<p><a href="https://www.wired.com/1996/12/ffglass/" rel="nofollow noreferrer">https://www.wired.com/1996/12/ffglass/</a><p>"Mother Earth, Mother Board" (stories about laying undersea cable and the history of wiring the Earth up"<p>(or unpaywalled: <a href="https://archive.is/ICkHe" rel="nofollow noreferrer">https://archive.is/ICkHe</a>)
Related but off topic (so I could understand being flagged, etc.), but in all likelihood, these capabilities could say a lot about what happened surrounding the Nord Stream pipeline explosions. I think it's a reasonable assumption that the US has these detectors beyond the borders of the US -- I've seen others claim as much: <a href="https://www.thenation.com/article/world/nord-stream-pipeline-explosions/" rel="nofollow noreferrer">https://www.thenation.com/article/world/nord-stream-pipeline...</a>
On this:<p>> <i>Instead, the battle of submarine silence has mostly revolved around obscure technical problems of fluid dynamics, since one of the loudest noises made by submarines is the cavitation around the screw. I don't know if this is true today, but at least years ago the low-noise design of the screw on modern US submarines was classified, and so the screw was covered by a sheath whenever a submarine was out of the water.</i><p>I wander if they are Toroidal or "tipless" propellers? They create less turbulence and cavitation.<p><a href="https://en.m.wikipedia.org/wiki/Toroidal_propeller" rel="nofollow noreferrer">https://en.m.wikipedia.org/wiki/Toroidal_propeller</a><p>Previous posts on HN:<p>> Toroidal propellers turn your drones and boats into noiseless machines<p><a href="https://news.ycombinator.com/item?id=34571282">https://news.ycombinator.com/item?id=34571282</a><p>> Sharrow MX-1: Tipless propeller<p><a href="https://news.ycombinator.com/item?id=33949895">https://news.ycombinator.com/item?id=33949895</a>
Active sonar has been back in use for searching for submarines for a few decades now, the article is out of date. Low frequency active sonar towed sonars are fitted to modern submarine hunting ships; the low frequency is necessary to get a long range as higher frequencies are heavily attenuated. If you've seen news stories about the danger to marine mammals from military sonar it was these systems that were involved, as they put large amounts of energy into the frequency bands that propagate well - these bands being the most useful for whales to communicate with as well.<p>eg: <a href="https://en.wikipedia.org/wiki/Sonar_2087" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Sonar_2087</a>
> Instead, the battle of submarine silence has mostly revolved around obscure technical problems of fluid dynamics, since one of the loudest noises made by submarines is the cavitation around the screw.<p>Cavitation is loud, but usually only happens if they're running full out. What they're really listening for now are reactor plant noises.<p>> I don't know if this is true today, but at least years ago the low-noise design of the screw on modern US submarines was classified, and so the screw was covered by a sheath whenever a submarine was out of the water.<p>Many US fast attack (Virginia, Seawolf) and the upcoming Columbia SSBN use some sort of external pump jet. I'm not sure if they cover those up out of water like they did with more 'traditional' screws.
I guess I'm feeling a little dumb and outlying on my immediate theory to the delay between USN officially reporting hearing the implosion, but here it is anyway: It would make sense to me that in the vast world of US Intelligence, especially when combined with signals-intelligence (like listening on what channels in Russia or China are communicating internally to each other), that when you have an event like Titan imploding, relatively close to US waters, you would want to not show those cards, and listen to hear <i>if anyone else reports hearing anything</i> ..
Kind of like a sophisticated game of counterespionage .. That way you can get an idea of whoever else might have equipment in the water very near your own.
But idk .. just the first thing that came to mind.
Love this read btw
Ever since that MH370 plane disappeared, I've been wondering. Would it going into the water make a splash that is audibly significant (compared to other surface noise i.e. waves) and would there be hydrophones in that area of the ocean, and would enough signal processing perhaps be able to locate the splash? And has all this perhaps already been done, but the people who have, can't talk about it?
This writing is so clear and good. I can't tell you how many NYT articles I read where the paragraphs feel out of order, chopped up and there is no consistent flow. This reads very enjoyably.
An excellent read but one thing caught my attention:<p>> The Navy did not withhold information on the detection for four days out of some concern for secrecy.<p>I think it's more likely than not that the statement is correct, but what gives the author the authority to make the claim so definitively? The author's bio indicates he's a consultant and there is no indication of direct involvement in this or any other SAR effort.<p>While the workings of the SOSUS and IUSS systems may be declassified, the deployments and capabilities (mostly range and computation related) of such systems most likely are not. And there is always the possibility that there is yet another system the author simply isn't aware of.<p>IMO, it isn't negligence to value the secrecy of systems used for defense above some number of lives, in some situations.
Somewhat tangentially, I've been wondering why the Soviets weren't able to locate K-129. From what I've read, they searched in a location hundreds of miles away from where SOSUS detected an implosion - why didn't the Soviets pick it up? Surely they had a hydrophone array?
There's an interesting link between K-129 and the current 'boom' around deep sea mining: <a href="https://en.wikipedia.org/wiki/Project_Azorian" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Project_Azorian</a><p>The cover-story to build the Glomar Explorer to recover K-129 was that Howard Hughes thought that it was economically feasible to mine manganese nodules from the deep sea. A lot of engineering research started that year (1974) that now, 2023, bears fruit in several large companies trying to mine the ocean floor with approvals to start probably happening this year: <a href="https://www.nature.com/articles/d41586-023-02290-5" rel="nofollow noreferrer">https://www.nature.com/articles/d41586-023-02290-5</a><p>Without the cover-story and Howard Hughes I wonder how many researchers would have ever looked at deep sea mining.
I really think SAR should be realistic about what's going on and quickly publish what they are trying. Otherwise you can get people who could help showing up with the wrong equipment, or not showing up at all, or people showing up who think they can help but can't and don't know it due to the lack of information.
>Much more appealing is passive sonar, which works by listening for the sounds naturally created by underwater vehicles.<p>Experts in marine biology. Reminds me of the night vision camera the british military were showing off on BBC Countryfile program. Who would have thought the military are experts in biology, but probably explains why the brits took off sunglasses in Iraq when talking to people, but the US didnt. You should see the british scarecrows as well!<p>> Instead, the battle of submarine silence has mostly revolved around obscure technical problems of fluid dynamics, since one of the loudest noises made by submarines is the cavitation around the screw.<p><a href="https://en.wikipedia.org/wiki/Toroidal_propeller" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Toroidal_propeller</a>
Difference in cavitation.
<a href="https://youtu.be/k0yzBTTqfzs?t=436" rel="nofollow noreferrer">https://youtu.be/k0yzBTTqfzs?t=436</a><p>Dont know if these toroidal propellers scale up to submarine sizes, they keep them hidden under an large oily rag along with the front of the subs.<p>> did the Navy withhold information on the detection from searchers out of concern for secrecy<p>Location of sensors maybe, after all something like the titanic will attract treasure hunters, why wouldnt interested govt's deploy remote sensors to detect who is in the area? Submarines make it easy for crew to be kept in the dark on missions as not many can use the periscope or other sensors.<p>I read somewhere once that a sensor, sonar or hydrophone, in UK waters could detect the sounds come from a New York harbour, which gives an insight into the distance sounds can travel underwater, but considering all the noises that can be detected, having sound processing abilities, a little bit better than something like Dolby Noise Reduction, is the key part of the underwater arms race.<p><a href="https://www.theguardian.com/environment/2023/may/15/listen-to-a-toadfishs-grunt-ai-helps-decode-a-symphony-of-ocean-sounds" rel="nofollow noreferrer">https://www.theguardian.com/environment/2023/may/15/listen-t...</a><p><a href="https://news.sky.com/story/titanic-sub-search-what-are-the-sonobuoys-that-picked-up-underwater-noises-12906691" rel="nofollow noreferrer">https://news.sky.com/story/titanic-sub-search-what-are-the-s...</a>
Amazing read, convincingly explains a lot of confusion around the aftermath of the search operation. And kind of mind blowing that IUSS exists primarily to detect submarine movements around the world.<p>I would love to learn more about the technology — are these wireless transmitters? Undersea cables all around the oceans of the world?
A question about ELF and VLF for whoever knows:<p>I just finished reading <i>Thunderstruck</i> (Erik Larson, author of <i>Devil in the White City</i>), which I don't recommend. It ineffectively juxtaposes the story of Marconi with Hawley Crippen, a murderer in London whose case became famous around 1910. (I say "ineffectively" because their stories really don't intersect, IMHO) The book goes on and on about all the demos and tests he ran for years and years, to the point of being eye-glazingly boring. All that aside...<p>Anyhow: at the very end, the author tells us that Marconi discovered near the end of his life that higher frequencies obviate the need for the gigantic transmitters and receivers he'd been using. Yet he never tells us what frequencies Marconi <i>was</i> using! Does anyone know?
> This website is begrudgingly generated by the use of software. Letters to the
editor are welcome via facsimile<p>What does this mean? Is it a reference I'm missing, a vague disclaimer for generated text, or am I reading too much into the footer?
In World-War-One J.H. Rogers demonstrated and patented a method for communication with submarines via special antennas. Anyone have anymore information on these types of systems?:<p>"James H. ROGERS
Underground & Underwater Radio
( Static-free Reception & Transmission Underwater & Underground )"
<a href="http://rexresearch.com/rogers/1rogers.htm" rel="nofollow noreferrer">http://rexresearch.com/rogers/1rogers.htm</a>
> This system, called SOSUS for Sound Surveillance System, remained secret until 1991. The secrecy of SOSUS is no great surprise, as it was one of the most important military intelligence systems of the Cold War.<p>I grew up in West Wales in the 80s, ‘everyone’ knew that the US Navy staff at RAF Brawdy were monitoring the cables that listened for submarines in the Atlantic
A very interesting web page but my main reason for posting is to inform everyone that it's well worth checking the archive link. There, those of a technical bent will find many more intesting artices, in fact I lost sight of time I was so engrossed in reading these articles.<p>I've bookmarked the page and will definitely return.
There was a SOSUS based on the Oregon coast near where I grew up. For years it was, "That naval base" but there were rumors of cables going off shore for a long time.<p>It would be interesting to know what the compute power was there back when, let alone what kind of people worked there.
I wonder if an active sonar array would be desirable. It would of course be easy to locate the beacons but they would probably be relatively cheap. Also, that much sonar noise would probably be bad for marine life. Would it give us capabilities we currently do not have?
I think the question on everyone's mind is probably how to produce a signal from inside the hull of a single-hulled cargo vessel in the North Atlantic that will allow one to relay messages in morse code to the US Navy.
There's a declassified short film about SOSUS from the 60s. It's a fun watch<p><a href="https://youtu.be/qsADWTHlmKI" rel="nofollow noreferrer">https://youtu.be/qsADWTHlmKI</a>