Non-Vitriolic Concrete Submarine Thread

Discussion in 'Boat Design' started by Stumble, Jan 20, 2012.

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  1. hoytedow
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    hoytedow Fly on the Wall - Miss ddt yet?

  2. mydauphin
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    mydauphin Senior Member

    Yep, absolutely probably... at least that is one theory, or a torpedo or the garbage disposal.
     
  3. Frosty

    Frosty Previous Member

    I think steel would be better because when it doe'snt come up and you drown every one with claustrophobic asphyxiation in a horrible terrible way your wife will have some scrap value on the steel where as cement would need to be broken up and taken away.
     
  4. mydauphin
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    mydauphin Senior Member


    lol, they both will fail over time and corrosion anyway. It is amazing what seawater does to any materials except perhaps titanium.
     
  5. Submarine Tom

    Submarine Tom Previous Member

    Plastic fairs pretty well to sea-water.

    Ohhhh, here we go, plastic submarines...

    -Tom
     
  6. padilac
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    padilac Junior Member

    Well Tom, acrylic is a plastic i believe? If it worked for the portholes of Trieste, then i suppose...
     
  7. Boston

    Boston Previous Member

    most of the modern research subs are build using an acrylic sphere about 6 to 10 inches thick


    When WHOI was accepting design ideas for its new sub I suggested an onion ring of shells each holding out a lesser amount of pressure than the total. Say each holding ten atmospheres, then a layer of alcohol or somekinda clear fluid. They rejected the idea. I guess it was to complex
     
  8. rwatson
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    rwatson Senior Member

  9. Boston

    Boston Previous Member

    yah that one looks solid, like the WHOI most of the medium depth research subs. I was thinking of a series of layers, each separated by a layer of something as incompressible as sea water. A valve between each layer would allow ten atmospheres difference from one side to the other.

    I guess the hatch would be the tricky part although some of those research subs are two halves bolted together with the crew inside so I guess the same thing could work on my onion design. Or something. I didn't put a ton of time into the idea cause I don't know squat about sub design. I was just throwing a bone and seeing if any of them down there wanted to chase it.
     
  10. ancient kayaker
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    ancient kayaker aka Terry Haines

    Interesting approach.

    The same technique is used in ultra-high pressure pumps, I've seen up to three stages with each one having a separate pump surrounded by pressurized fluid from the previous pump. They are often used for water-jet cutting; most WJCs use an abrasive at lower pressures but the precision ones work without abrasives at 50,000 psi or higher. That is more than 3x the pressure at the bottom of the Marian trench. Water compresses by more than 30% at those pressures as I recall; long time ago.

    However, I can see the advantage doing this for a pump but not for a submersible where the pressure is provided free and the compression strain should distribute itself evenly throughout the thickness of the shell.
     
  11. Boston

    Boston Previous Member

    well the problem with large acrylic production for deep sea submersibles is that the more voluminous the pore the more likely defects are. Bubbles are absolutely unacceptable for obvious reasons. I think the success rate on a truly huge pore like that is something 1 in 10. So I thought if they just pored less total volume into each individual shell and then bolted the two halves together like some of the larger ones do then they'd end up with a cheaper safer unit than if they relied only on one super thick shell.
     
  12. ancient kayaker
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    ancient kayaker aka Terry Haines

    Now I see where you are coming from; makes sense. I assume there would have to be some kind of automatic device to even out the pressures between the shells, which its related failure rate.
     
  13. rwatson
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    rwatson Senior Member

    The documentary I saw on the building of the UK sub took us through all the problems with the acrylic half bubble. It was (at the time ) the largest half sphere ever constructed, and had to be certified by the UK authority, and the manufacturer mentioned all those problems. It wasn't until they started polishing the surfaces that they could check for any faults. It was a very nerve wracking process.

    I haven't been able to locate the info on the web, maybe I am asking the wrong questions.
     
  14. BATAAN
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    BATAAN Senior Member

    As far as hemispherical acrylic shells go, in the movie business we'd take a thick sheet of acrylic, heat it over a circular opening, then apply pressure/vacuum to pull a perfect hemisphere with no mold required beyond the accurate circular template you pull it through. This winds up thinnest at the top of the sphere but by differentially heating the plastic, this can mostly be overcome. For shallow-water use, this could possibly be a cheap alternative.
     

  15. rwatson
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    rwatson Senior Member

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