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So who just lost a submarine?

China unveils ultra-deepwater drillship
The 42,000-tonne Dayang, which will be able to reach almost all of the world’s seabeds, is part of China’s quest to become a major sea power


20 thoughts on “So who just lost a submarine?”

  1. Manganese nodules, eh?

    Actually it’s lucky for Howard Hughes and the CIA you didn’t have a blog in 1972, Tim.

    But I reckon this one is probably what it says on the tin. The Chinese are never going to Net Zero, they’re laughing at the stupid gwailos in the West who keep enriching China.

    The West isn’t unaware of this, but impoverishing and Third Worlding their own citizens is an important step towards… something.

  2. There’s a company trying to do it right now. Once you’ve got them up then it’s wildly economic. Trivially easy to process, just jam-packed with metallic goodness. It’s the energy cost of bringing them up from 5,000 metres down that’s the killer. As it always has been and as they – Hah! – claim they’ve solved.

  3. “The Dayang has nine major laboratories” … good to know they’re “major”. At least it didn’t claim they’re “significant”.

  4. from 5,000 metres down
    That was the problem, wasn’t it? The flow rate wouldn’t support the infrastructure cost required.

  5. You need to find a way of bringing them to the surface as a by-product of doing something else. “We happen to be on the ocean bottom, grab some nodules before we go back to the surface”.

  6. @JitA

    I wouldn’t quarrel with China’s ability to build ships, but design them? No worries, they’ll just nick the plans from someone else.

  7. I’ve been trying to puzzle out how this company’s supposed to have solved the problem. Because I don’t think it’s particularly scalable. It would be if there was a convenient heap of nodules on the ocean floor. You just build a bigger winch & haul them up. Increases the flow rate. But I gather they’re randomly but evenly distributed. If you were doing this on the surface you’d have some sort of vehicle collecting them & dumping them at a rail head. And a train running backwards & forwards shifting them to where you want them. That’s scalable. More collectors. Bigger train With the seabed & bigger winch, you’re just going to spend a lot longer with it on the bottom collecting a larger load.

  8. Surely all you need is a pulley, a 5km and a bit cable and something slightly more massive but much less valuable than the nodules to drop into the ocean…

  9. A 5km cable…. That’s going to need a mega winch
    That’s one of the things I was thinking about. I believe the Hughes tub used the sort string they use for drilling. Lengths of pipe screwed together. So a lengthy process of both dropping the string then retrieving it. 5km of cable? With both the grab on the end plus the payload. It’s a similar problem as an orbital tether. You’re not only suspending the grab & the payload. You’re also suspending 5km of steel cable capable of taking the load. That’s heavy cable. All on the one drum for a continuous lift? How big’s that?
    One thinks of an inflatable balloon as an option. Float the payload up. It doesn’t work. Gasses are compressible. Liquids aren’t. You open the valve of your compressed gas cylinder at 5km & nothing comes out. At those pressures what’s the difference between the density of water & the density of gas? Watch film of bubbles escaping from undersea vents at those sort of depths. They just gently bobble up. The temperature of the gasses in those bubbles are at hundreds of degrees. At near surface pressures they’d be virtually a vacuum. They’d float up like a rocket. You can do this sort of thing diving. Take a plastic football down. On the surface it floats with virtually none of it penetrating the surface. You don’t have to descend very far down & it starts collapsing.

  10. There are cranes already working that can go to at least 3,000m They are heave compensated as well so the load stays where it is in relation to the vessel. The payload is quite a few tonnes. Should be scalable for deeper if it hasn’t been done already for the new generation of ultra deep water drilling rigs.

  11. I’ve sailed on some Chinese built ships. Most of the equipment is European and Japanese with very little of it Chinese tech. One exception was the electric sockets, lights and switches for the accommodation block. The shipowner wanted UK standard gear but the shipyard couldn’t get any in China, so they bought all they needed in the UK and shipped it out to China. All this stuff was, of course, made in China. World trade, doncha just love it?

  12. Em,
    Drillships are for drilling holes below the seabed cos we’re interested in what lies below the seabed, lots n lots of luvverly oil & gas, but we have to drill a hole to get to it- hence drillship.
    There are at least 100 round the world capable of drilling holes in various deeper water depths.
    Discussion so far has been about methods of recovering what’s lying about on the seabed, which isn’t really a drillships job despite the Hughes cover story.
    At least the oil & gas ventures seem commercially viable at some Oil price level, unlike nodule recovery which seems much more speculative, mainly as BIS has pointed out due to difficulty of getting solids to the surface unlike fluids & gases which can flow.

  13. Regarding the lifting to the surface it is done in water which makes it easier due to Archimedes. A cable of spectra/vectran (ie basically polyethylene) would weigh very little, steel 12% lighter and MnO2 20% lighter.

  14. @jc
    It’s an interesting idea. But you’d need to know how plastics perform at the pressures of hundreds of pounds per square inch. Their properties may be entirely different. Likely to be entirely different.

  15. @bloke in spain
    Off the top of my head better in tensile
    In the books they show polyethylene as a string which is at an atomic level. The molecules are crumpled up and held together by Van der Waals forces (ie chewing gum). Think of steel wool.

    By similar analogy Spectra etc are long lengths of straight steel wire held together by Van der Waals forces. External pressure will increase the forces holding them together.

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