tl;dr version as I recall: keep holds either mostly full or mostly empty, make assymetric holds and tanks, and use baffles if you have no other options.
True but most of the research is around how to safely handle liquid cargoes.
What the article talks about is 2-phase cargoes, cargoes which are expected to behave as solids but could turn to liquid under certain unpredictable conditions.
Accounting for these scenarios might involve upsetting the economics of said cargo.
I'd think that towing anything in violent weather would be dangerous. If self propelled rather than towed your idea becomes a merchant submarine. That would have to greatly complicate things and be slower and/or use much more fuel.
It doesn't have to be underwater to be either towable or self propelled. See the other comment about barges on the Mississippi for towing and SpaceX's "of course I still love you" (and friends) for self propelled.
Autonomous and underwater would be hard, radio doesn't travel well through water.
They're not only common on the Mississippi, but also the Rhine area in the Netherlands and Germany as hinterland operations for the port of Rotterdam, as well as the Danube area in eastern Europe.
Both self-propelled barges and push barges have been used for ages already in inland shipping in Europe, but have not been used a lot in the rest of the world. They also seem to only be suitable for river transport. With small scale transport over sea you have so-called feeder ships, which have an entirely different build, and never push extra barges/ships.
No, I mean autonomous too. Autonomous vehicles still want access to GPS, you still want to know where your stuff is, you still want to be able to give new orders if something changes, etc.
"The International Maritime Organisation has codes governing how much moisture is allowed in solid bulk cargo in order to prevent liquefaction. So why does it still happen?
The technical answer is that the existing guidance on stowing and shipping solid bulk cargoes is too simplistic."
Is bauxite really new cargo? Or do they mean ship-operators need to be careful when switching to bauxite cargo?
My read on it was that bauxite was new as a solid bulk cargo, not that bauxite itself was a new cargo in general. I know nothing of the industry however, so I'm not sure whether this is a legitimate interpretation or not.
At a guess, they have to do the loading, hauling, and dumping outside in all weather and also probably barge it out to the hauler in some cases. All of these things can add a significant amount of water to an otherwise "dry" solid.
Seafarer here. This is basically correct, but the problem is mainly storage before loading.
Ideally, is mined, then either stored somewhere dry, out of the weather, or delivered directly to the ship in a covered train/conveyor belt.
In reality, it's usually mined, then stored in a big pile outside in the weather for weeks/months until it's loaded. It won't pass the pre-loading transportable moisture limit (TML) tests, so they falsify the results.
A cargo with a slightly high TML can appear dry on loading, but the vibration causes the moisture to migrate down to the bottom of the hold and cause the cargo at the bottom to liquify. When the ship rolls, this layer shifts, and the rest with it.
Obviously, if the TML is way too high, the whole thing turns to slurry.
To pump out, we need it to settle out of the cargo so that we can get it to the pumps. That works for certain types of cargo (iron ore and most types of coal are easy), but if it forms slurry instead, we can't get it out unless we can somehow pump the slurry out.
Why not pump the 'water' out of the bulk into a separate containment vessel. This way the ship's crew could neutralise the risk without reducing the weight of their cargo. When unloading they can give back the 'water' component of the cargo separately. So the weight of the cargo is basically unchanged.
Because the water would need to be separated from the sand grains. The "water" in the sand is very little: it's more akin to damp sand we're talking about, or in the "wettest" case mud.
Drying that would require a lot of area, effort, and sun, or some type of oven. Any method of making sand drier costs orders of magnitutde more than the sand itself.
Compartmentalisation is fine for liquid cargoes, but make it a lot harder to load and unload particulate solids like these because the walls and baffles get in the way.
The amount of energy to vibrate 25-25000 tonnes for any extended duration of time would be staggering. Then you have to manage forces this subjects the ship to... maintence would be a fright
Based on a spot check of some of the bolded words, bolding seems to be used here to highlight links.
The old way of indicating "this is a link" was underlining. That seems to have largely fallen out of favor and most websites seem to use color coding these days.
Is this just a joke? If not, do you have a better source to back up the suggestion?
I'm asking because it's a fictional story and the sink ships because of the wet rice expanding. It doesn't actually save the ship, though it does likely delay its demise.
That's what I'm guessing, but I know basically nothing about cargo ships. I'm googling around to see if there are any potential prevention methods along the lines of "just add a bit of rice to your ore..." 0_o
https://en.wikipedia.org/wiki/Free_surface_effect
https://en.wikipedia.org/wiki/Metacentric_height
tl;dr version as I recall: keep holds either mostly full or mostly empty, make assymetric holds and tanks, and use baffles if you have no other options.