Veteran submariner on how sonar crews tirelessly hunt enemies they can't see • Hacker News Board

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

#81

Post by MrBuddyCasino » Thu, Aug 13, 2020, 1:34 PM UTC

GCPGCP wrote: post #75

Anechoic wrote: post #34

Earlier quoted context omitted.

Keep in mind that's likely not related to the dB sound pressure level in air that we're all familiar with. dB is a logarithmic ratio to pressure to a reference. In air, that reference is 20µPa, acoustic pressure in water typically uses a different reference (1µPa). There is also an adjustment of 36 dB to account for the higher impedance of water. So 235 dB in water is roughly 173 dB SPL -- still loud, but many orders…

This is what you can expect https://www.youtube.com/watch?v=sCmyZYYR7_s&t=90s This diver was near a sub base for training.

Comments say this was very likely not a sub‘s sonar.

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

#82

Post by mezentius » Thu, Aug 13, 2020, 7:35 PM UTC

GCPGCP wrote: post #80

remarkEon wrote: post #76

Earlier quoted context omitted.

I recently got into realistic combat simulators (Squad, Arma, DCS, Cold Waters ... there are some other sub sims out there too) and I had no idea JiveTurkey and Aaron were the same person. Maybe I just missed it or wasn't paying attention. Anyway, if you're a military geek and want to get into realistic naval combat sims play Cold Waters (Uboat is also good, but way different play style). Like all realistic sims the…

688(I) Hunter/Killer with the Jane's manual is great too. I find it more immersive than Cold Waters as you are in charge of the waterfall and have to move the cursor like a true sonarman to find the good signature.

If you liked 688(I), I strongly recommend giving Dangerous Waters a shot. It’s a sequel made by the company, featuring submarines as well as surface and helicopter platforms, and is currently on sale.

https://store.steampowered.com/app/1600/Dangerous_Waters/

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

#83

Post by rotten » Fri, Aug 14, 2020, 1:03 PM UTC

robotnikman wrote: post #8

I've heard the sonar ping from a submarine is so powerful that it will kill you if your a diver near the sonar dome.

Usually it is surface ships which get that loud. In harbors where sabotage is a concern it is not uncommon to run a regular ping as a deterrent to underwater saboteurs.

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

#84

Post by skmurphy » Sat, Aug 15, 2020, 5:42 AM UTC

pjc50 wrote: post #54

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 foug…

Thanks for this reference to Neptune's Inferno by James Hornfischer, it was a fantastic book. I like two quotes in particular

"The epic of the Pacific war found new chapters for everyone. The endless game of personnel-rotation musical chairs saw the continuous replacement of the experienced by the inexperienced, until, by the end, only the experienced remained."

"Ascending to theater command had never been his ambition, for ambitions, he felt, were meant not for personal gain but to pursue common goals within the established order of a group."

A description of Chester Nimitz

I like this description of ambition as a model for leadership: "pursue common goals within the established order of a group." I think it's a good one for startup CEO's as much as any other leader.

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

#85

Post by Apofis » Tue, Aug 18, 2020, 6:48 PM UTC

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.

From TFA: "Patterns are matched and measured with onscreen tools and cursors. Automatic artificial intelligence algorithms flag potential targets for the sonar operators to verify. "