Help for Novel

[Rich Keller]

There is going to be another surface supplied diving event at Dutch Springs on October 19th & 20th if there is going to be a big enough turn out. If you want to attend let them know ASAP. NEDEG - North East Diving Equipment Group Homepage

 

[Rich Keller]

Here is an upcoming event you might find useful.

Beneath the Sea

 

[Grenouille]

Here is an upcoming event you might find useful.

Beneath the Sea

Hey, long time no see Thank you for the link, I think I'm going to go there in March and check it out.

 

[Grenouille]

Hey guys, not sure if you're still around, I'm trying to look into modern lifeboats (like the one you see in Captain Phillips), the ones that have a hard shell and are driven from the inside, like a little cabin, some are even hyperbaric, and I was trying to see if one of those found at the bottom of the ocean more or less intact could be used to send someone back to the surface (if you let it shoot up and add some weights to slow it down). I'm basically wondering how that would resist to the pressure, if it could be adapted to be breathable inside and be a one-atmosphere vehicle etc. Since they're not meant to be underwater at those depths, I wonder how it would react. Anyone knows about that, or knows someone who would?

 

[Rich Keller]

Those type of lifeboats are watertight and were made to be dropped from a significant height so they are well built and can take a hit. They were not made to operate too deep though so enough pressure on the hull would probably crush it. One atmosphere transfer vehicles are all round so the pressure on their hulls is even and self canceling. The pressure would not be even on something like this so the hull would fail at it's weakest point and implode.

 

[Grenouille]

Gotcha. You said once that there was no way to build a one-atmosphere vehicle with plane wreckage but that maybe we could with another material. Do you know what sort of material exactly? We're trying to have the characters look for years and fail at building one, until they eventually reach a cargo plane that had something in its containers that they could finally use. But we have trouble wrapping our minds around the fact that metal from boats or planes couldn't do the trick, since we don't know what exactly could do the trick. Is it just about the round shape? My idea is to use something that the "preppers" (people who believe they have to prepare for the apocalypse) use in the US, they have those shelters made for them, and some are actually pretty small and made to resist a tsunami, or things like that. You can hop in them and be safe from anything, storm, fire etc. If we have one of those, any idea what kind of material would be considered working, if we have a round shape? (I believe a pyramid would break?) I'm trying to put together a list of materials that wouldn't work and a list of those which might.

 

[agesilaus]

If you are thinking about using something like artificial gills to extract oxygen from seawater you should be aware that seawater contains at the most 10 ppm O2 (that's 10 parts per million parts of water). Air on the other hand contains about 210,000 parts per million. That means you would have to pump very large volumes of water thru those gills in order to extract enough oxygen. Anything less that 100% extraction efficiency would increase that volume even more.

The water outlet on the gills would be blasting so much water out that it would be like strapping a jet engine onto your back.

This brings up a question I've wondered about. If Navy divers lock out of a submarine at say 100 feet. What happens when they want to reenter the sub. They would be going from 3 Bars to 1 Bar inside the sub. Do they do decompression inside the escape chamber?

 

[Rich Keller]

Even if water gills could work you would be left with 100% oxygen that could not be breathed at depth. The sub has two separate sections, and the divers would have to decompress in the lockout section or the sub could be connected to a chamber on deck where they could also decompress.

 

[agesilaus]

Even if water gills could work you would be left with 100% oxygen that could not be breathed at depth. The sub has two separate sections, and the divers would have to decompress in the lockout section or the sub could be connected to a chamber on deck where they could also decompress.

Well I spent a lot of time on subs thanks to the USN. Divers enter and leave subs via a chamber, that is a spherical chamber maybe 8 feet in diameter IIRC. The top hatch opens to the outside of the sub, and the bottom hatch opens into the boat. But I don't recall seeing any controls inside the chamber which would control pressure in the chamber and would allow controlled deco. There was a valve that let you fill the chamber with water and would equalize the pressure in the chamber with the surrounding water.

Actually a small sub (DSRV) could be attached to the outside hatch and divers could exit directly into that DSRV. The Seals have more advanced vehicles these days but I think those operated via 'garage' built on the specialized subs intended to supports diver operations.

The boat I was on did carry divers and they were involved in operations the were covered in the book 'Blind Man's Bluff'.

 

[Grenouille]

Huh... I never talked about artificial gills, I'm not sure what gave you guys that idea? I'm talking about using a small pod (shelter) big enough for one person, attached to a pocket of air or something, that will take you back to the surface. Something that is one-atmosphere, so no need for decompression or anything, you go from your one-atmosphere habitat to that pod and to the surface. I'm trying to determine the materials in which this pod can't be built, and the materials that could work (because of pressure etc).