[HN Gopher] NEEMO ___________________________________________________________________ NEEMO Author : throwoutway Score : 36 points Date : 2022-12-10 04:02 UTC (18 hours ago) (HTM) web link (en.wikipedia.org) (TXT) w3m dump (en.wikipedia.org) | travisporter wrote: | "It is deployed on the ocean floor next to deep coral reefs 62 | feet (19 m) below the surface." | | Divers - would a breach be fatal at this depth? | rich_sasha wrote: | Sort of, yes and no. | | Divers dive with no pressure protection far, far deeper, | certainly as deep as 100m and beyond. If the station floods but | they have air to breathe, then that's fine. | | However, they are doing saturation diving. This means their | bodies are full of dissolved nitrogen, which, if they were to | ascend to the surface over any shortish frame of time, would | regassify and kill them - that's "the bends". When ascending | grona saturation dive, it takes hours to days, depending on | depth, to surface. | | So if the station floods and they each have a scuba kit, they | still can't surface and are potentially in trouble. | marcinzm wrote: | I'm wondering if due to the station being at the same | pressure as outside a catastrophic breach is less likely. | Slow flooding versus implosion. | rich_sasha wrote: | I was wondering that. I'm not sure. | | If there is a hole, the things that matter are the outside | pressure and resistance to water flow. The latter is mostly | viscosity I'd think and very little to do with air pressure | on the inside. Whereas water pressure is 3x surface. | | That said 19m is really not that deep, I don't think it | would be _dramatically_ different to a leak closer to the | surface. Some ships have draft of like 15m and, while | generally holes in hull are bad, I 'm not sure that this is | some kind of special design precaution. But I wouldn't | really know. | Gordonjcp wrote: | Not a diver, but recreational divers often go down to that sort | of depth on compressed air without any ill effects. You'd need | to ascend slowly and hang about at ten metres and five metres | for about ten minutes to let nitrogen out of your system, to | get back to the surface. | | It's about three times normal atmospheric pressure so it's not | going to be ideal if there's an accident, but it's not like | going to smash you flat with pressure, it's not going to Byford | Dolphin you. | bonzini wrote: | As the other commenter explained, you absolutely need to do | decompression for long-enough dives. The limit at 19m might | be a few hours so it doesn't affect recreational diving, but | in this case they exceed it. So if they had scuba gear they | would have to stay at 19m and wait for help. ___________________________________________________________________ (page generated 2022-12-10 23:00 UTC)