• Cyborganism@lemmy.ca
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    25 days ago

    Can you please explain to me, a simple person with no knowledge in that sort of thing?

    I’m assuming the sonar emits a loud “ping” sound and the divers would probably deafened by it?

    • BaroqueInMind@lemmy.one
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      25 days ago

      Military sonars are so loud that if you happened to be idly floating near one (let’s say 500 meters away) as it does one of its weakest pings, your entire body would cavitate into pink mist; it would rupture every organ in your body instantly, all of your bones would fracture in place and all of your blood would boil from the sonars ping causing rapid pressure changes right in front of whatever is supposed to remain of your face.

      Imagine standing next to a hundred grenades as they all simultaneously explode, but also pretend you are spared from the heat wave of the explosion and not the blast wave.

        • jagungal@lemmy.world
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          25 days ago

          There’s two types of military SONAR: active and passive. Active SONAR is using pings and listening for the echo, but it’s not very commonly used by submarines. Passive sonar is just listening out for engine noise from ships and prop noise from other submarines. Warships use active SONAR more because they’re already noisy and so if they think an enemy submarine is in the area they’ll use it to try and locate, but in peacetime it’s mostly reserved for training exercises. It’s still terrible for wildlife, even if they don’t die it’s very distressing and disorientating but it’s not constantly scanning like a RADAR.

      • saltesc@lemmy.world
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        25 days ago

        Sonar systems[…]generate slow-rolling sound waves topping out at around 235 decibels[…]. These sound waves can travel for hundreds of miles under water, and can retain an intensity of 140 decibels as far as 300 miles from their source.

        140 dB is a gunshot at the source. About 190 in air pressure will cause an explosive shockwave that can kill a person. 235 dB in dense water pressure is…somewhat more violent, as we understand how the decibal curve works and molecular pressure at depth.

        • NoiseColor @lemmy.world
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          25 days ago

          But that means that a person would be killed even if they are miles away? Maybe tens of miles.

          Found it: Based on sonar guidelines and studies on sound propagation, a diver exposed to 235 dB low-frequency sonar would likely need to be more than 1.5–2 kilometers (1–1.2 miles) away to ensure safety.

          However, pings are conical and the strongest sonar is at the bow. So you could literally be safe if you were diving behind it.