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Ocean-Going Plastic Powered Bussard Ram-Ship

Power a large vessel with waste plastic.
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Large, ocean-going transport vessels are numerous and useful devices that represent a fairly mature technology. In general, they are powered by enormous diesel engines specifically optimized for efficiency. Nevertheless, such engines can happily consume 50-150 tonnes/day at 20 knots. This fuel occupies space, costs money and represents a limit to the ship's range.

The ocean is apparently full of plastic, particularly in several oceanic "Gyres". These Gyres are conveniently located in nice spots between europe and N.America, N.America and Asia and other regions that are essentially on the way for much of the world's shipping. Ship fuel is pretty low grade stuff, some of it not too far away in properties from tar. Big, slow ship engines manage to cope.

The Bussard ram jet <link> is a design for space propulsion that scoops up gasses as it travels, compresses them and uses the result as propellant. The main criticism of this system is the lack of gas. Space is, spacious, not full of gasses. However, if we apply the same principle to an ocean going ship things look a bit brighter. Firstly, plastic is reasonably energy-dense. It's essentially the same as ship fuel. Secondly, it is much more concentrated than space gasses. That plastic floats is particularly helpful, it concentrates all the plastic to a few mm at the air- water interface. Sort of like a gravity-powered density gradient centrifugation system.

So, the ship moves along through plastic laden seas. On the front, a huge scoop funnels/filters the surface plastics toward the ship. Here a large conveyor belt lifts the particles out of the water and processing begins. This will consist of slowly drying and pulverizing the material. Then, it's fed into the engines. Hooray for free fuel.

One slight drawback is speed. By extrapolating this graph <link> The expected 3-5kg of plastic per square kilometer will mean the ship has to travel at around 2 to 5 micro knots if we consider the fuel cost of processing the plastic to be negligible. Unfortunately this means the ship will be unsuitable for the transport of perishable goods, with the shorter transatlantic voyages taking 170,000 years or so. One upside of this speed is the extraordinarily low damage sustained should the ship run into another ship.

bs0u0155, May 05 2017

Bussard Ram Jet https://en.wikipedi...wiki/Bussard_ramjet
[bs0u0155, May 05 2017]

Speed fuel curves for ships https://people.hofs...containerships.html
[bs0u0155, May 05 2017]

Solid lead model boat, floating https://youtu.be/XrGUiz9Tnwk?t=1
[not_morrison_rm, May 06 2017]

[link]






       Hmm. The basic problem is the extremely low density of plastic in the ocean. 5kg per square kilometer equates to 5mg (maybe a tenth of a small shirt button) per square metre.   

       The obvious solution is to have a conventional diesel ship travelling ahead of the Bussard ship, laying a trail of plastic.   

       Even better, potentially, would be to have a scoop beneath the surface, harvesting everything from plankton to dolphins. These could then be dried and burned as fuel.
MaxwellBuchanan, May 05 2017
  

       Hmm, so I should go throw lots of plastic into the ocean, seems like a good idea to me [+].
not_morrison_rm, May 05 2017
  

       //Space is, spacious//   

       [marked-for-tagline]   

       It'd be useful to have an engine that could molecularly take apart the small parts, the nuclei or microbes or whatever stuff is made of, and use those directly as fuel, by extracting the energy as the engine goes along. In such a case, maybe sea water mixed with the occasional lump of plastic would be an ideal fuel.
Ian Tindale, May 06 2017
  

       Like the space version, this would work well as a brake.
nineteenthly, May 06 2017
  

       //The obvious solution is to have a conventional diesel ship travelling ahead of the Bussard ship, laying a trail of plastic.   

       Even better, potentially, would be to have a scoop beneath the surface, harvesting everything from plankton to dolphins. These could then be dried and burned as fuel.//   

       That would be a pretty big scoop. I'd think you could reduce the scoop size by coating the plastic your lead ship lays down with poison so the marine life would die, float to the surface and be easier to collect, dry out and burn as fuel.   

       What about some kind of depth charge that you could lay down that would explode and release the plastic fuel AND process the marine life for fuel utilization?   

       Kickstarter campaign?   

       [+]
doctorremulac3, May 06 2017
  

       //coating the plastic your lead ship lays down//   

       That's a very, very bad idea. Lead ships are not only very expensive to make, but have much less bouyancy than conventional steel hulls.
MaxwellBuchanan, May 06 2017
  

       ^ Ground-breaking research.   

       Actually there is some video of a floating solid lead model boat. Linky.
not_morrison_rm, May 06 2017
  

       //lead ship lays down with poison//   

       Careful use of widely available and ever cheaper "crude oil" would get both marine life AND any birds that come looking to snack on the dead fish.
bs0u0155, May 08 2017
  

       // have an engine that could molecularly take apart the small parts //   

       So, a humonguloidous (sp?) solar-powered electrolysis plant which dines on sea water and the occasional plastic gyre and pelagic to produce hydrogen for motive fuel. Brilliant!
whatrock, May 08 2017
  

       I can't help but feel we're headed toward a whale-towed barge. That constitutes a reasonable efficient sun> algae> krill> whale> propulsion system. Just send out one of those lead ships to seed the ocean with minerals that promote algal blooms.
bs0u0155, May 08 2017
  

       That's all well and good until the whale decides it fancies a few giant squid for lunch, and dives.
MaxwellBuchanan, May 08 2017
  

       That's what those retractable leashes on reels are for.
normzone, May 08 2017
  

       Yes, I've tried those. The important thing, really, is never to use on a chihuahua a retractable reel designed for a bassett hound. It doesn't end well.
MaxwellBuchanan, May 08 2017
  

       Chihuahua Trebuchet
Ian Tindale, May 09 2017
  

       No, more of an "Arf! Whoosh! Thwocka-thwocka-thwocka."
MaxwellBuchanan, May 09 2017
  

       //Lead ships are not only very expensive to make, but have much less bouyancy than conventional steel hulls//

I think the problem with lead-based vessel design would be hull strength, rather than buoyancy. This is also why boats are rarely made out of copper.
hippo, May 09 2017
  

       // I think the problem with lead-based vessel design would be hull strength, rather than buoyancy. //   

       Should be alright if it's _solid_ lead, right?   

       If you do as the youtube link suggests and keep your solid lead boat afloat by replacing ocean water with mercury then you can avoid poisoning the plastic that it drops. All the dolphins will float even if they're still alive.   

       This solution is more environmentally friendly because it avoids the use of poisoned plastics.
b153b, May 09 2017
  

       Disappointingly less battery than the sort of ram- ship I'd envisioned upon reading the title.
21 Quest, May 09 2017
  

       I think it would be important to paint the boat's hull, otherwise the mercury would dissolve the lead and over the course of a long trans-oceanic voyage there would be a danger of too much corrosion. Also it might pollute the ocean with lead, which would be unhealthy for marine life and the environment.
pocmloc, May 09 2017
  

       I would like to modify this idea into a beach going art project. It would be like the Strandbeests that dutch dude makes, except this would be the size of a Tonka truck with an onboard steam engine and would go along scooping up anything loose or different in color from the background.   

       This creation could also be released in the park at festivals and other similar venues. The black smoke belched out would not violate any regulations because it is art. When the boiler ran dry a subroutine could have it approach person-appearing shapes and beg for beer or urine.   

       I considered this as a separate idea but it is so derivative I will just leave it here. Plus I feel like I may have encountered a trash-burning urine begging steamboat somewhere else.
bungston, May 09 2017
  

       With 170,000 years to play with it may be more efficient to just put the ship into the right currents in relatively short bursts of relative speed.
Voice, May 10 2017
  
      
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