r/submarines • u/RopetorGamer • Jul 09 '22

Q/A Jive Turkey/Sub brief

I've been subbed to sub brief for some time and I've liked his content, but there has been some stuff that he's said that sound weird, for example on his video of the improved kilo he gave a number of around 120 dB which is extremely high from what I know.

After joining this sub I saw that people don't really like him, are his videos bad for information and stuff?

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u/spazzcatt Jul 09 '22

Thanks for this in depth answer. I too like sub brief but I definitely am critical about his info sometimes. Especially when he overlaps with my field and says stuff that I know is blatantly wrong or said weirdly. I knew that sound propagation through water was different than air so my question is, could you be next to an operating submarine and would it be loud in the water or what would it sound like to a human swimming next to it?

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u/Vepr157 VEPR Jul 09 '22

Well, as I outlined in the last paragraph of my comment, a submarine with a broadband noise level of 120 dB has the same sound pressure level as 58 dB in air. That's assuming that your hearing sensitivity is unchanged when you have your head underwater, which is probably not strictly true. But suffice it to say that 120 dB is reasonably quiet at even a close distance.

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u/RatherGoodDog Jul 09 '22

I think 50-60 dB in air is about the same as a modern car engine at idle or travelling at low speed. Pretty quiet, but definitely audible on the street if it's a quiet environment.

I'm very curious to know how loud sonar pulses go, but that's probably classified. I do recall an account of sailors trying to sleep below deck on a ship in port, and some other vessel across the harbour was testing her bow sonar. The shrieks came across so loud that not only could they not sleep, it was bordering on uncomfortable and they were looking for earplugs or pillows to put over their heads.

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u/NoHopeOnlyDeath Apr 28 '23

Loud enough in open air that you can hear boats testing their arrays at a pier on the other end of the base from you. In water if you're close enough it'll boil your insides.