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Veteran submariner on how sonar crews tirelessly hunt enemies they can't see

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Re: Veteran submariner on how sonar crews tirelessly hunt enemies they can't see

#51

Post by Goronmon »

wcarey wrote: post #30
jonplackett wrote: post #7

Earlier quoted context omitted.

I was just going to say exactly this. It’s amazing to see them doing this with such incredibly basic technology. - Having to draw their ship and the submarine and constantly update its movement. - sonar guy is just looking at a screen that blips every now and then. - all communication by morse code - must be horrendously slow in the heat of battle - even communication within the ship is passed between multiple people…

The book by C.S. Forester that the movie is based on is even more realistic, though the movie is pretty good. To really dig into it, Samuel Eliot Morison's magisterial History of Naval Operations in World War II does a good job talking through the development of both the technology and organization of naval operations. Not all communication was by morse code. We did use ship to ship voice radio, but it was a tradeoff…

To really dig into it, Samuel Eliot Morison's magisterial History of Naval Operations in World War II does a good job talking through the development of both the technology and organization of naval operations.

Man, that looks like a hard series of books to actually get a hold of. Either spending multiple hundreds of dollars for a used set, or struggle to find individual copies for $15+ each (a quick google search seems to show Vol 2 unavailable anywhere I looked).

Re: Veteran submariner on how sonar crews tirelessly hunt enemies they can't see

#52

Post by wcarey »

briandear wrote: post #25
adriancooney wrote: post #4

I'm not normally one to promote Hollywood but the film Greyhound (2020) with Tom Hanks does an _excellent_ portrayal of this technology (albeit slightly more primitive) in fighting German U-Boats in WW2. Well worth a watch if this interests you.

Tom Hanks wrote the film as well. He has done a lot of good in terms of WWII history. Greyhound was one of those movies that really brought to life just what combat looks like on the water. To an outsider, naval combat seems rather benign and “far away” compared to Infantry, but the reality is that naval combat is terrifying and up close. It was an incredible film in capturing the horrors of naval warfare. Just seein…

And Greyhound depicts a relatively calm series of engagements, compared to what actually happened. Consider the U.S.S. Borie:

https://en.wikipedia.org/wiki/USS_Borie_(DD-215)

which rammed (!) a U-Boat in high seas, was repeatedly picked up by waves and dropped on top of the surfaced U-boat, whereupon a small arms engagement broke out (!) until the U-boat attempted to disengage and was damaged by the Borie's main guns. Both ships sinking, the Borie attempted to rescue the German submariners until a torpedo from another nearby submarine caused them to reconsider. The Borie then promptly sank from seams opened by being repeatedly bounced off the top of a submarine and most of the crew were rescued.

Re: Veteran submariner on how sonar crews tirelessly hunt enemies they can't see

#53

Post by wcarey »

Goronmon wrote: post #51
wcarey wrote: post #30

Earlier quoted context omitted.

The book by C.S. Forester that the movie is based on is even more realistic, though the movie is pretty good. To really dig into it, Samuel Eliot Morison's magisterial History of Naval Operations in World War II does a good job talking through the development of both the technology and organization of naval operations. Not all communication was by morse code. We did use ship to ship voice radio, but it was a tradeoff…

To really dig into it, Samuel Eliot Morison's magisterial History of Naval Operations in World War II does a good job talking through the development of both the technology and organization of naval operations. Man, that looks like a hard series of books to actually get a hold of. Either spending multiple hundreds of dollars for a used set, or struggle to find individual copies for $15+ each (a quick google search se…

I think there's a new paperback printing under way. Happily, it's not the end of the world acquiring them piecemeal, as each volume tells a coherent story and takes some time to read through!

Re: Veteran submariner on how sonar crews tirelessly hunt enemies they can't see

#54

Post by pjc50 »

adriancooney wrote: post #4

I'm not normally one to promote Hollywood but the film Greyhound (2020) with Tom Hanks does an _excellent_ portrayal of this technology (albeit slightly more primitive) in fighting German U-Boats in WW2. Well worth a watch if this interests you.

For a detailed and in places dramatic book on the primitive technology of WW2 surface naval warfare, I can recommend "Neptune's Inferno": https://erenow.net/ww/neptunes-inferno-the-u-s-navy-at-guada...

While radar existed, it had similar problems of manual plot, was only on a few ships, and the commanders had not updated their training and doctrine to match.

Several of the key engagements around Guadalcanal were fought at night. Without radar, and without any reliable means of telling friend from foe other than eyeballing the shape. Total chaos.

Re: Veteran submariner on how sonar crews tirelessly hunt enemies they can't see

#55

Post by rotten »

bmitc wrote: post #50

Articles like this leave a bad taste in my mouth. They venerate the subject and participants involved and leave out the vast amount of detrimental effects they cause. Whales, other marine mammals, and other wildlife are affected by these systems, and they are never considered. The Navy is currently still trying to increase its weapons testing off the coast of the Pacific Northwest, bringing further harm to the alread…

The systems described in this article are "passive". They are simply listening to the sounds around them. This is much more common for submarines than "active" sonar - which ensonifies the water around you and then you listen for echos. It is those loud pings which can threaten or frighten wildlife. However they are also like holding up a big lit sign that says "there is a submarine here!" - and the whole point of submarines is stealth. They say that if you hear a ping from a submarine, it is too late - there is already a torpedo heading your way.

source - used to be a sonar tech

Re: Veteran submariner on how sonar crews tirelessly hunt enemies they can't see

#56

Post by rotten »

ThinkingGuy wrote: post #11

Obviously, being a skilled sonarman would seem require a good physical sense of hearing (frequency range, etc.), but as as the article mentions, the ability to recognize patterns is also important. Have there been any studies or analyses to see if there's also a correlation between skill at, say, music (relative pitch, etc.) or language (detecting subtle differences in accents, etc.) and sonar skill?

The best sonar operators have perfect pitch, except instead of saying "that is an A-flat but there is a ghost harmonic because the slot in the bridge for that string is too wide" they would say "that is a 415 Hz sound with up doppler. sounds like a 3 bladed prop with a notch on the second blade". It was pretty amazing to watch the really good ones in action.

Re: Veteran submariner on how sonar crews tirelessly hunt enemies they can't see

#57

Post by rotten »

rotten wrote: post #56
ThinkingGuy wrote: post #11

Obviously, being a skilled sonarman would seem require a good physical sense of hearing (frequency range, etc.), but as as the article mentions, the ability to recognize patterns is also important. Have there been any studies or analyses to see if there's also a correlation between skill at, say, music (relative pitch, etc.) or language (detecting subtle differences in accents, etc.) and sonar skill?

The best sonar operators have perfect pitch, except instead of saying "that is an A-flat but there is a ghost harmonic because the slot in the bridge for that string is too wide" they would say "that is a 415 Hz sound with up doppler. sounds like a 3 bladed prop with a notch on the second blade". It was pretty amazing to watch the really good ones in action.

They would go to a bar and comment that the ceiling fan was spinning at 23 rpm, and the compressor motor on the cooler had a bad bearing.

Re: Veteran submariner on how sonar crews tirelessly hunt enemies they can't see

#58

Post by munificent »

Somewhat related. I went to the Oregon Museum of Science and Industry (OMSI) in Portland last fall and did a tour of their submarine, the USS Blueback. Our tour guide was a retired Cold War-era submariner and he was fantastic. He gave us tons and tons of details about what life and working on an active sub was actually like. It felt like being there, and you could tell he delighted in being able to share his past with people.

Re: Veteran submariner on how sonar crews tirelessly hunt enemies they can't see

#59

Post by zkms »

mhh__ wrote: post #18
canada_dry wrote: post #2

> The second step in classification requires analysis. It takes 30 to 45 seconds to get a look at a new detection and discover what kind of engine she’s running, what kind of hydraulic pumps are online, and what screw blade configuration she is using. One can imagine ML making this job somewhat obsolete in the not-too-distant future.

That's if they aren't already. Without having the data I can't try but I'd guess that Fourier analysis (or something a bit more clever to deal with noise e.g. Welch) would get you a lot of the way there even without invoking AI

This is not based on any classified information and sonar signal processing is not something i know much about, but cyclostationarity (and other higher-order statistical signal processing) does tend to be useful when processing signals that are generated by processes where there's multiple periodicities at work: https://en.wikipedia.org/wiki/Cyclostationary_process#Angle-...

Re: Veteran submariner on how sonar crews tirelessly hunt enemies they can't see

#60

Post by x86_64Ubuntu »

rotten wrote: post #56
ThinkingGuy wrote: post #11

Obviously, being a skilled sonarman would seem require a good physical sense of hearing (frequency range, etc.), but as as the article mentions, the ability to recognize patterns is also important. Have there been any studies or analyses to see if there's also a correlation between skill at, say, music (relative pitch, etc.) or language (detecting subtle differences in accents, etc.) and sonar skill?

The best sonar operators have perfect pitch, except instead of saying "that is an A-flat but there is a ghost harmonic because the slot in the bridge for that string is too wide" they would say "that is a 415 Hz sound with up doppler. sounds like a 3 bladed prop with a notch on the second blade". It was pretty amazing to watch the really good ones in action.

Blades are numbered? I would think each blade would be indistinguishable from the next, so any of them could be the 2nd one depending on where you started counting.
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