3 ms·

Both will be lost at the same time. We don't really know such signal. Submarines cannot communicate more hundred meters in the bottom of sea. Sea water absorbs

by nicce 3y ago

Both will be lost at the same time. We don't really know such signal. Submarines cannot communicate more hundred meters in the bottom of sea. Sea water absorbs the signal quite well. When the signal is lost, the expectation is that the submarine is under the water. https://en.wikipedia.org/wiki/Communication_with_submarines https://en.wikipedia.org/wiki/Communication_with_submarines

bilekas 3y ago
> When the signal is lost, the expectation is that the submarine is under the water. Yes! This is true, I would just like to clarify that there is a difference between 'coms' and 'transponder' here. Some friends of mine conflate the two and think they are almost on the same 'circuit'. In most cases of the Sub (specifically military because there are not many tourist subs), you don't WANT to be located unless in an emergency, whereas here in this situation you most certainly do and in that case you can be located by way of the transponder. Th
krisoft 3y ago
> Submarines cannot communicate more hundred meters in the bottom of sea. Sorry if I am misunderstanding you. It sounds like you are saying that it is impossible to design a system which would be able to keep in contact with the submarine/submersible all the way down to the bottom? Because if that is what you are saying that is simply false. We have the technology to keep in contact with a submarine all the way to the bottom of even the deepest oceans. This is not even speculative. We know it is possible because James Cameron had full communication during his dive all the way to the deepest point on earth. Here is a really cool article about the technical challenges with that system: https://www.hydro-international.com/content/article/communications-to-the-deepest-point-on-earth https://www.hydro-international.com/content/article/communic...
- nicce 3y ago
  If you read the article, you know that the context was extremely specific and not suitable for general use. The noise is too big problem. In ”normal” context such signal is not currently known to be really possible. You know that submarines are not equipped with these. The ship on the surface had to drop cable 100 meters below the ship to combat noise. Which means that for communication to be possible, ship cannot really move. And the ship is supposed to be almost directly above the submarine, to reduce the noise again. For signal to be practical, it should go either over the surface or go long distances horizontally and be usable even with some noise.
  - krisoft 3y ago
    > If you read the article Rest assure that I have read the article i have linked. > the context was extremely specific and not suitable for general use What does general use mean? The context is the same. We are talking about an expeditionary submersible having constant and reliable communication with its support ship all the way to the bottom. This was the setup of Cameron’s dive and this was the setup of the ill-faited Titan mission. Are you claiming that this is not possible?
    - 111111IIIIIII 3y ago
      This is HN. People here will defend "lean startups" to the grave, as long as it's not their own grave.
    - nicce 3y ago
      > We are talking about an expeditionary submersible having constant and reliable communication with its support ship all the way to the bottom. The lost submarine in this context had no similar support ship. It made connection to base on being on the surface from long distance. ”General” would mean that either submarine is capable for keeping long distance communications regardless if is is diving or on the surface. Either to any closeby ships or even the ground station. And for that there is no reliable technology yet.
      - krisoft 3y ago
        > The lost submarine in this context had no similar support ship. Sorry. Are we talking about the same case? I'm talking about the Titan submersible which were lost on 18 June 2023, five days ago as of this writing. It absolutely had a support ship. The MV Polar Prince. Here is a picture of it towing the submersible out from port a few days before its disappearance: https://i.cbc.ca/1.6885535.1687464250!/fileImage/httpImage/image.jpg_gen/derivatives/original_1180/titan-submersible-and-polar-prince.jpg https://i.cbc.ca/1.6885535.1687464250!/fileImage/httpImage/i... The people lost lived on the support ship, and only boarded the submersible when they arrived right above the Titanic. There the crew from the support ship bolted the crew of the submersible in, and the support ship remained in position and in communication with them until they lost that link. Then they waited for a long time, and only when the submersible was overdue that is when they raised the alarm. The only reason why we did know that the submersible went missing is because those on the support ship raised the alarm. > And for that there is no reliable technology yet. You can say that, but you are wrong. Sound waves propagate very well. I think what you might be confused about is that military submarines do not communicate with the shore during operations. They remain silent because if they start to transmit everyone will know where they are. But that is not because there is no reliable technology for it. In fact they can just blast a loud sound wave out with their active sonar and everyone all around the ocean will hear them who cares to listen. I'm not saying that it is easy. All I'm saying that it is perfectly within our capabilities if we want to.
- bilekas 3y ago
  > Sorry if I am misunderstanding you. It sounds like you are saying that it is impossible to design a system which would be able to keep in contact with the submarine/submersible all the way down to the bottom? You can always throw a cable down, if you have a handy 2kM long one. Personally I'm not sure most people can actually grasp the scale of the ocean on it's own. We have the best we have already - transponders. Assumptions are very dangerous, you've made a few here and that's unfortunately the mentality that can result in disaster. Dramatic ending : Never assume. Always confirm.
  - krisoft 3y ago
    > you've made a few here and that's unfortunately the mentality that can result in disaster What assumptions have I made and how would they lead to disaster? Please be specific.
    - bilekas 3y ago
      The assumption being that its easy and should just be a 'given'. The problem is with that and not proper testing/validation you can have false confidence in the systems. The article is actually really interesting, but it's exception, it's certainly not impossible.
      - krisoft 3y ago
        I have made no such assumption. The person who I was responding to said it is not possible. I said it is possible to do. That is all the claim I'm making. Of course it is very hard. It is kinda implied by the fact that I linked an article about the technical challenges! If you order some custom built equipment and the company then later writes an article about all the challenges with it, you can bet that it was a super expensive and specialist device.
somat 3y ago
To clarify EM waves which are used for most(all?) tracking in the atmosphere, are attenuated very quickly in water. Underwater sound waves work better. I don't know what this submarine used but I would expect at minimum an acoustic transponder to aid in underwater tracking. with a acoustic telephone as a comm channel. However reading about some of their other engineering decisions this is probably too optimistic of me. Data recorders(airplane black boxes) have a sound pinging unit for this exact case. being lost under water.

by nicce 3y ago

bilekas 3y ago

> When the signal is lost, the expectation is that the submarine is under the water. Yes! This is true, I would just like to clarify that there is a difference between 'coms' and 'transponder' here. Some friends of mine conflate the two and think they are almost on the same 'circuit'. In most cases of the Sub (specifically military because there are not many tourist subs), you don't WANT to be located unless in an emergency, whereas here in this situation you most certainly do and in that case you can be located by way of the transponder. Th

krisoft 3y ago

> Submarines cannot communicate more hundred meters in the bottom of sea. Sorry if I am misunderstanding you. It sounds like you are saying that it is impossible to design a system which would be able to keep in contact with the submarine/submersible all the way down to the bottom? Because if that is what you are saying that is simply false. We have the technology to keep in contact with a submarine all the way to the bottom of even the deepest oceans. This is not even speculative. We know it is possible because James Cameron had full communication during his dive all the way to the deepest point on earth. Here is a really cool article about the technical challenges with that system: https://www.hydro-international.com/content/article/communications-to-the-deepest-point-on-earth https://www.hydro-international.com/content/article/communic...

nicce 3y ago
If you read the article, you know that the context was extremely specific and not suitable for general use. The noise is too big problem. In ”normal” context such signal is not currently known to be really possible. You know that submarines are not equipped with these. The ship on the surface had to drop cable 100 meters below the ship to combat noise. Which means that for communication to be possible, ship cannot really move. And the ship is supposed to be almost directly above the submarine, to reduce the noise again. For signal to be practical, it should go either over the surface or go long distances horizontally and be usable even with some noise.
- krisoft 3y ago
  > If you read the article Rest assure that I have read the article i have linked. > the context was extremely specific and not suitable for general use What does general use mean? The context is the same. We are talking about an expeditionary submersible having constant and reliable communication with its support ship all the way to the bottom. This was the setup of Cameron’s dive and this was the setup of the ill-faited Titan mission. Are you claiming that this is not possible?
  - 111111IIIIIII 3y ago
    This is HN. People here will defend "lean startups" to the grave, as long as it's not their own grave.
  - nicce 3y ago
    > We are talking about an expeditionary submersible having constant and reliable communication with its support ship all the way to the bottom. The lost submarine in this context had no similar support ship. It made connection to base on being on the surface from long distance. ”General” would mean that either submarine is capable for keeping long distance communications regardless if is is diving or on the surface. Either to any closeby ships or even the ground station. And for that there is no reliable technology yet.
    - krisoft 3y ago
      > The lost submarine in this context had no similar support ship. Sorry. Are we talking about the same case? I'm talking about the Titan submersible which were lost on 18 June 2023, five days ago as of this writing. It absolutely had a support ship. The MV Polar Prince. Here is a picture of it towing the submersible out from port a few days before its disappearance: https://i.cbc.ca/1.6885535.1687464250!/fileImage/httpImage/image.jpg_gen/derivatives/original_1180/titan-submersible-and-polar-prince.jpg https://i.cbc.ca/1.6885535.1687464250!/fileImage/httpImage/i... The people lost lived on the support ship, and only boarded the submersible when they arrived right above the Titanic. There the crew from the support ship bolted the crew of the submersible in, and the support ship remained in position and in communication with them until they lost that link. Then they waited for a long time, and only when the submersible was overdue that is when they raised the alarm. The only reason why we did know that the submersible went missing is because those on the support ship raised the alarm. > And for that there is no reliable technology yet. You can say that, but you are wrong. Sound waves propagate very well. I think what you might be confused about is that military submarines do not communicate with the shore during operations. They remain silent because if they start to transmit everyone will know where they are. But that is not because there is no reliable technology for it. In fact they can just blast a loud sound wave out with their active sonar and everyone all around the ocean will hear them who cares to listen. I'm not saying that it is easy. All I'm saying that it is perfectly within our capabilities if we want to.
bilekas 3y ago
> Sorry if I am misunderstanding you. It sounds like you are saying that it is impossible to design a system which would be able to keep in contact with the submarine/submersible all the way down to the bottom? You can always throw a cable down, if you have a handy 2kM long one. Personally I'm not sure most people can actually grasp the scale of the ocean on it's own. We have the best we have already - transponders. Assumptions are very dangerous, you've made a few here and that's unfortunately the mentality that can result in disaster. Dramatic ending : Never assume. Always confirm.
- krisoft 3y ago
  > you've made a few here and that's unfortunately the mentality that can result in disaster What assumptions have I made and how would they lead to disaster? Please be specific.
  - bilekas 3y ago
    The assumption being that its easy and should just be a 'given'. The problem is with that and not proper testing/validation you can have false confidence in the systems. The article is actually really interesting, but it's exception, it's certainly not impossible.
    - krisoft 3y ago
      I have made no such assumption. The person who I was responding to said it is not possible. I said it is possible to do. That is all the claim I'm making. Of course it is very hard. It is kinda implied by the fact that I linked an article about the technical challenges! If you order some custom built equipment and the company then later writes an article about all the challenges with it, you can bet that it was a super expensive and specialist device.

somat 3y ago

To clarify EM waves which are used for most(all?) tracking in the atmosphere, are attenuated very quickly in water. Underwater sound waves work better. I don't know what this submarine used but I would expect at minimum an acoustic transponder to aid in underwater tracking. with a acoustic telephone as a comm channel. However reading about some of their other engineering decisions this is probably too optimistic of me. Data recorders(airplane black boxes) have a sound pinging unit for this exact case. being lost under water.