4 ms·

What I don't understand is, if it imploded, why didn't the boat hear the implosion? Surely that would be really loud. Louder than the 15 min audio ping that t

What I don't understand is, if it imploded, why didn't the boat hear the implosion? Surely that would be really loud. Louder than the 15 min audio ping that the boat is normally listening for.

j-a-a-p 3y ago
I would be surprised if the supporting vessel would have heard (were they listening?) or recognised that. Probably from the data from other hydrophones somebody will write an article on this sooner or later. I can't imagine it was loud: vessel was tiny, and the energy will reduce at the order of 3 quite a bit at 4 km distance. I can imagine it would be detectable with the right equipment and that this equipment is installed in the Atlantic.
whytai 3y ago
The boat may not have heard it, but the navy certainly did: https://news.ycombinator.com/item?id=36439661 https://news.ycombinator.com/item?id=36439661
Arn_Thor 3y ago
Turns out the Navy heard it, based on a WSJ article. They started actively listening when notified that contact was lost, and shortly after they picked up what sounded like an implosion or explosion.
- archagon 3y ago
  Weren’t they notified 8+ hours after contact was lost?
  - Arn_Thor 3y ago
    "The Navy began listening for the Titan almost as soon as the sub lost communications, according to a U.S. defense official. Shortly after the submersible’s disappearance Sunday, the U.S. system detected what it suspected was the sound of an implosion near the debris site discovered Thursday and reported its findings to the Coast Guard commander on site, U.S. defense officials said. [...] The Navy said it shared its findings Sunday with the Coast Guard, which led the search, U.S. defense officials said. " https://www.wsj.com/articles/u-s-navy-detected-titan-sub-implosion-days-ago-6844cb12 https://www.wsj.com/articles/u-s-navy-detected-titan-sub-imp...
rich_sasha 3y ago
I don't know. But sea water isn't a homogeneous medium as far as sound propagation is concerned. There are layers of changing salinity, temperature etc and these can effectively cut off sound propagation. Submarines (used to?) depend on such effects to avoid detection. Also, would the implosion necessarily be that loud? It would be like crushing a large tin really. Maybe blends in with background noise.
- m2fkxy 3y ago
  > Submarines (used to?) exploitation of heterogenous and anisotropic ocean conditions definitely remains the crux of submarine warfare.
- Rapzid 3y ago
  Like crushing a tin can with tactical nuke. 400 atmosphere of seawater pressure suddenly slamming together creates massive pressure wave.
- deleted 3y ago
  [deleted]
flir 3y ago
Or half the east coast. The implosion[?] of the ARA San Juan was supposedly heard 6000km away by hydrophones at Ascension Island. (https://www.ctbto.org/news-and-events/news/ctbto-hydroacoustic-data-used-aid-search-missing-submarine-ara-san-juan https://www.ctbto.org/news-and-events/news/ctbto-hydroacoust...) Or maybe they did and the data hasn't been processed/made public yet.
- joe5150 3y ago
  San Juan appears to have been about ten times the size of Titan, and that article says it took them over ten days to report the finding.
- saberdancer 3y ago
  San Juan was 2300 tons and is made of metal. Titan was 10 tons and mostly made of carbon fibre.
  - methodical 3y ago
    The size is irrelevant, the energy released is significant either way and definitely beyond the thresholds of hydrophones. During the USCG press conference today it was stated that the implosion made a significant soundwave as a result of the implosion, and I think in the coming weeks we'll hear reports of findings in regards to hydrophones which picked up the noise.
  - robotnikman 3y ago
    It also probably was armed with torpedoes when it was sunk, which probably detonated due to the explosive decompression.
    - checkyoursudo 3y ago
      > It also probably was armed with torpedoes when it was sunk, which probably detonated due to the explosive decompression. I don't think that submarines explosively decompress under the ocean.
- 3y ago
sigstoat 3y ago
oceangate seems like a clown show, were there hydrophones on site, in the first ~24 hours, that were not operated by them? at this point i expect it had imploded before the coast guard or anyone who knew what they were doing was on-site.
whimsicalism 3y ago
have we ever identified an implosion from carbon fiber? does it matter?
FinnG 3y ago
My guess would be that the Oceangate ship ignores everything that it's not 'expecting' to hear. I don't really know anything about deep sea exploration, but having general purpose microphones in the water seems like a bit of an oversight to me, given the marginal cost of having them.
- beowulfey 3y ago
  So many things about this venture were not really considered. I am terrified that this guy was an aerospace engineer. It feels like he threw the book about engineering safety out the window. The big one is designing the sub to travel to 95% of the expected maximum depth, leaving a 5% margin of safety. I was taught to aim for a margin of safety of (I think it was) 50% back in the day. Operating so close to the safe limit for the sub is appalling. That doesn't even include all the other warning signs about the design that were brought up. The missing beacon on the sub, in case of loss of radio contact, is another standout. No consideration given for loss of power or anything. Consideration of contingency plans is so important. A minor one that is really indicative of the overall attitude is drilling screws into the carbon fiber hull, possibly exposing the hull to stress fractures from both the screws and the constant weight of holding a monitor. It's... just a silly thing that could have been avoided. I'm not saying those screws are why it failed, but if you can use an adhesive to hold your monitor in place, wouldn't you rather do that then by drilling directly into the hull keeping ~100 atm of ocean out of your face? It just makes me so sad for so many reasons. It definitely could have been avoided...
  - kristjansson 3y ago
    There ... there were screws into the structual carbon fiber??
    - Spastche 3y ago
      this is the first I've heard of that but it would not surprise me one bit
    - amatecha 3y ago

What I don't understand is, if it imploded, why didn't the boat hear the implosion? Surely that would be really loud. Louder than the 15 min audio ping that the boat is normally listening for.

j-a-a-p 3y ago

I would be surprised if the supporting vessel would have heard (were they listening?) or recognised that. Probably from the data from other hydrophones somebody will write an article on this sooner or later. I can't imagine it was loud: vessel was tiny, and the energy will reduce at the order of 3 quite a bit at 4 km distance. I can imagine it would be detectable with the right equipment and that this equipment is installed in the Atlantic.

whytai 3y ago

The boat may not have heard it, but the navy certainly did: https://news.ycombinator.com/item?id=36439661 https://news.ycombinator.com/item?id=36439661

Arn_Thor 3y ago

Turns out the Navy heard it, based on a WSJ article. They started actively listening when notified that contact was lost, and shortly after they picked up what sounded like an implosion or explosion.

archagon 3y ago
Weren’t they notified 8+ hours after contact was lost?
- Arn_Thor 3y ago
  "The Navy began listening for the Titan almost as soon as the sub lost communications, according to a U.S. defense official. Shortly after the submersible’s disappearance Sunday, the U.S. system detected what it suspected was the sound of an implosion near the debris site discovered Thursday and reported its findings to the Coast Guard commander on site, U.S. defense officials said. [...] The Navy said it shared its findings Sunday with the Coast Guard, which led the search, U.S. defense officials said. " https://www.wsj.com/articles/u-s-navy-detected-titan-sub-implosion-days-ago-6844cb12 https://www.wsj.com/articles/u-s-navy-detected-titan-sub-imp...

rich_sasha 3y ago

I don't know. But sea water isn't a homogeneous medium as far as sound propagation is concerned. There are layers of changing salinity, temperature etc and these can effectively cut off sound propagation. Submarines (used to?) depend on such effects to avoid detection. Also, would the implosion necessarily be that loud? It would be like crushing a large tin really. Maybe blends in with background noise.

m2fkxy 3y ago
> Submarines (used to?) exploitation of heterogenous and anisotropic ocean conditions definitely remains the crux of submarine warfare.
Rapzid 3y ago
Like crushing a tin can with tactical nuke. 400 atmosphere of seawater pressure suddenly slamming together creates massive pressure wave.
deleted 3y ago
[deleted]

flir 3y ago

Or half the east coast. The implosion[?] of the ARA San Juan was supposedly heard 6000km away by hydrophones at Ascension Island. (https://www.ctbto.org/news-and-events/news/ctbto-hydroacoustic-data-used-aid-search-missing-submarine-ara-san-juan https://www.ctbto.org/news-and-events/news/ctbto-hydroacoust...) Or maybe they did and the data hasn't been processed/made public yet.

joe5150 3y ago
San Juan appears to have been about ten times the size of Titan, and that article says it took them over ten days to report the finding.
saberdancer 3y ago
San Juan was 2300 tons and is made of metal. Titan was 10 tons and mostly made of carbon fibre.
- methodical 3y ago
  The size is irrelevant, the energy released is significant either way and definitely beyond the thresholds of hydrophones. During the USCG press conference today it was stated that the implosion made a significant soundwave as a result of the implosion, and I think in the coming weeks we'll hear reports of findings in regards to hydrophones which picked up the noise.
- robotnikman 3y ago
  It also probably was armed with torpedoes when it was sunk, which probably detonated due to the explosive decompression.
  - checkyoursudo 3y ago
    > It also probably was armed with torpedoes when it was sunk, which probably detonated due to the explosive decompression. I don't think that submarines explosively decompress under the ocean.
3y ago

sigstoat 3y ago

oceangate seems like a clown show, were there hydrophones on site, in the first ~24 hours, that were not operated by them? at this point i expect it had imploded before the coast guard or anyone who knew what they were doing was on-site.

whimsicalism 3y ago

have we ever identified an implosion from carbon fiber? does it matter?

FinnG 3y ago

My guess would be that the Oceangate ship ignores everything that it's not 'expecting' to hear. I don't really know anything about deep sea exploration, but having general purpose microphones in the water seems like a bit of an oversight to me, given the marginal cost of having them.

beowulfey 3y ago
So many things about this venture were not really considered. I am terrified that this guy was an aerospace engineer. It feels like he threw the book about engineering safety out the window. The big one is designing the sub to travel to 95% of the expected maximum depth, leaving a 5% margin of safety. I was taught to aim for a margin of safety of (I think it was) 50% back in the day. Operating so close to the safe limit for the sub is appalling. That doesn't even include all the other warning signs about the design that were brought up. The missing beacon on the sub, in case of loss of radio contact, is another standout. No consideration given for loss of power or anything. Consideration of contingency plans is so important. A minor one that is really indicative of the overall attitude is drilling screws into the carbon fiber hull, possibly exposing the hull to stress fractures from both the screws and the constant weight of holding a monitor. It's... just a silly thing that could have been avoided. I'm not saying those screws are why it failed, but if you can use an adhesive to hold your monitor in place, wouldn't you rather do that then by drilling directly into the hull keeping ~100 atm of ocean out of your face? It just makes me so sad for so many reasons. It definitely could have been avoided...
- kristjansson 3y ago
  There ... there were screws into the structual carbon fiber??
  - Spastche 3y ago
    this is the first I've heard of that but it would not surprise me one bit
  - amatecha 3y ago