5 ms·

A container ship can carry up to 24,000 containers. Even if they don't build to the max size, it still takes 1-3 days to unload an average container ship on the

A container ship can carry up to 24,000 containers. Even if they don't build to the max size, it still takes 1-3 days to unload an average container ship on the shore using the giant container cranes. I can't imagine how long it would take to unload at sea onto smaller vessels but there's pretty much no way it's going to be economical with technology available in the next 20 years.

krasin 5y ago
I agree that the old way of doing things won't work. How about hundreds of cargo drones capable of lifting containers to transfer them from one ship to another? Something like this: https://www.cognitiveseeds.com/395-2/ https://www.cognitiveseeds.com/395-2/ Don't forget - a nuclear-powered ship that's not moving has a lot of free electricity: enough to charge all the drones (likely, bearing supercapacitors, as their flight from one ship to another will be very short)
- cycomanic 5y ago
  It's interesting how further up someone accused people of opposing nuclear energy for ideological reasons and then read proposals like this, which are completely removed from reality. Building drones that can lift containers from cargoships requires electricity/energy storage densities that are so far beyond anything realistic. A container can weigh up to 28 tonnes, there was exactly one helicopter that could carry this kind of load the Mil Mi-12 and that looked really more like a plane. Moreover if we would have those kind of densities why would we even use nuclear ships?
  - fennecfoxen 5y ago
    > Building drones that can lift containers from cargoships requires electricity/energy storage densities that are so far beyond anything realistic. Nuclear drones!!1one! Problem SOLVED. Gee I'm smart. ;)
  - krasin 5y ago
    >It's interesting how further up someone accused people of opposing nuclear energy for ideological reasons and then read proposals like this, which are completely removed from reality. Let's see. There are two variables here in regards to power subsystem: power and energy capacity. Let's start with the power: >A container can weigh up to 28 tonnes, there was exactly one helicopter that could carry this kind of load the Mil Mi-12 and that looked really more like a plane. According to ([1]), we need around 0.28 kW/kg of thrust. Assuming that the drone weights twice more than a container, we need to have a lift of around 84 tonnes-force minimum, and ~100 tonnes-force in reality. That translates to 0.28 * 10^5 kW = 28 MW. This is close to what Mi-12 had (19.2 MW). LTO batteries from Toshiba ([2]) advertise 3.5 kW/kg of energy density, which gives us 28 MW/3.5 kW/kg = 800 kg of batteries. Reasonable, given that our budget for drone dry weight is 56 tonnes. Let's consider the energy capacity. To transfer a container from one ship to another standing 200 meters apart moving at 10 km/h, we would need 144 seconds for roundtrip. Let's make it 300 seconds for redundancy. 28 MW * 300 seconds = 2333 kWh. At 84 Wh/kg ([2]), we get 27.8 tonnes of batteries. Not great, but within out weight budget of 56 tonnes. The gotcha here that I see is the longevity of these batteries (they are rated for 8000 cycles). Do you see any other issues? I mean, basic physics seems to allow for such drones (not saying it's trivial to make). 1. https://store.tmotor.com/goods.php?id=974 https://store.tmotor.com/goods.php?id=974 2. https://www.electrive.com/2022/01/12/toshiba-presents-new-20-ah-lto-cell/ https://www.electrive.com/2022/01/12/toshiba-presents-new-20...
    - adgjlsfhk1 5y ago
      Issue number 1 is cost. At $100 per kwh, each of these drones will cost a quarter million dollars (just for the batteries). Also, since each trip will require recharge, if we assume that the batteries can charge at 500kw (which is really high), it will take about 5 hours to transfer 1 container. That seems pretty much untenable.
      - krasin 5y ago
        Cost on its own is rarely an issue. The thing that matters is payback time. If one container move generates $10, and the drone moves 12 containers per hour, 12 hours a day, it will only take 6 months to earn the quarter of million mentioned. Also, it might actually sound like a very cheap option compared to the ship-to-shore container cranes, which cost $20M-$40M each: https://www.freightcourse.com/port-cranes/ https://www.freightcourse.com/port-cranes/ As for recharging: if our power train is 28 MW, why not charging it at the same speed as we discharge it? Why settle on 500 kW, which is really low? For comparison, Tesla supercharger is up to 300 kW, and a car is a much smaller EV.
- kristjansson 5y ago
  That site users an image from the movie Airplane to illustrate their autonomous pilot.
- Balero 5y ago
  How much is that going to cost to develop, manufacture, deploy, train, maintain etc? Shipping is a VERY price conscious industry.
  - krasin 5y ago
    I assume that the majority of the cost would be to design and build nuclear ships. And it's still worth it, as fuel is 50%-60% of operational costs. As for drones to handle cases of ports which don't allow nuclear ships to dock: this is just a potential workaround. I kind of guess, that they will just focus on other ports first, and then eventually (like, in 5-10 years timeframe) everyone calms down and just allows such ships to dock in LA / NY / other US ports.
- imtringued 5y ago
  It's one thing to do something completely counter productive like using gasoline powered drones to unload/load your electric ship. It's another to assume that the same capability can even be offered by electric drones. There is absolutely nothing wrong with port cranes.
  - krasin 5y ago
    Yes, port cranes are much better, if they can be used. The drones are suggested as a potential alternative to handle "LA does not allow nuclear ships to dock", so that a transfer from a nuclear- to battery-powered container ship happens in the international waters. As for can be offered: we're talking about moving a container from ship to ship which stand just hundreds meters away. The physics / math works, see my other comment.
catherd 5y ago
In most forms of bulk goods transport the power unit can be decoupled from the part the goods ride in. Seems possible that might also work for ships.
- krasin 5y ago
  Oh, good point!

krasin 5y ago

I agree that the old way of doing things won't work. How about hundreds of cargo drones capable of lifting containers to transfer them from one ship to another? Something like this: https://www.cognitiveseeds.com/395-2/ https://www.cognitiveseeds.com/395-2/ Don't forget - a nuclear-powered ship that's not moving has a lot of free electricity: enough to charge all the drones (likely, bearing supercapacitors, as their flight from one ship to another will be very short)

cycomanic 5y ago
It's interesting how further up someone accused people of opposing nuclear energy for ideological reasons and then read proposals like this, which are completely removed from reality. Building drones that can lift containers from cargoships requires electricity/energy storage densities that are so far beyond anything realistic. A container can weigh up to 28 tonnes, there was exactly one helicopter that could carry this kind of load the Mil Mi-12 and that looked really more like a plane. Moreover if we would have those kind of densities why would we even use nuclear ships?
- fennecfoxen 5y ago
  > Building drones that can lift containers from cargoships requires electricity/energy storage densities that are so far beyond anything realistic. Nuclear drones!!1one! Problem SOLVED. Gee I'm smart. ;)
- krasin 5y ago
  >It's interesting how further up someone accused people of opposing nuclear energy for ideological reasons and then read proposals like this, which are completely removed from reality. Let's see. There are two variables here in regards to power subsystem: power and energy capacity. Let's start with the power: >A container can weigh up to 28 tonnes, there was exactly one helicopter that could carry this kind of load the Mil Mi-12 and that looked really more like a plane. According to ([1]), we need around 0.28 kW/kg of thrust. Assuming that the drone weights twice more than a container, we need to have a lift of around 84 tonnes-force minimum, and ~100 tonnes-force in reality. That translates to 0.28 * 10^5 kW = 28 MW. This is close to what Mi-12 had (19.2 MW). LTO batteries from Toshiba ([2]) advertise 3.5 kW/kg of energy density, which gives us 28 MW/3.5 kW/kg = 800 kg of batteries. Reasonable, given that our budget for drone dry weight is 56 tonnes. Let's consider the energy capacity. To transfer a container from one ship to another standing 200 meters apart moving at 10 km/h, we would need 144 seconds for roundtrip. Let's make it 300 seconds for redundancy. 28 MW * 300 seconds = 2333 kWh. At 84 Wh/kg ([2]), we get 27.8 tonnes of batteries. Not great, but within out weight budget of 56 tonnes. The gotcha here that I see is the longevity of these batteries (they are rated for 8000 cycles). Do you see any other issues? I mean, basic physics seems to allow for such drones (not saying it's trivial to make). 1. https://store.tmotor.com/goods.php?id=974 https://store.tmotor.com/goods.php?id=974 2. https://www.electrive.com/2022/01/12/toshiba-presents-new-20-ah-lto-cell/ https://www.electrive.com/2022/01/12/toshiba-presents-new-20...
  - adgjlsfhk1 5y ago
    Issue number 1 is cost. At $100 per kwh, each of these drones will cost a quarter million dollars (just for the batteries). Also, since each trip will require recharge, if we assume that the batteries can charge at 500kw (which is really high), it will take about 5 hours to transfer 1 container. That seems pretty much untenable.
    - krasin 5y ago
      Cost on its own is rarely an issue. The thing that matters is payback time. If one container move generates $10, and the drone moves 12 containers per hour, 12 hours a day, it will only take 6 months to earn the quarter of million mentioned. Also, it might actually sound like a very cheap option compared to the ship-to-shore container cranes, which cost $20M-$40M each: https://www.freightcourse.com/port-cranes/ https://www.freightcourse.com/port-cranes/ As for recharging: if our power train is 28 MW, why not charging it at the same speed as we discharge it? Why settle on 500 kW, which is really low? For comparison, Tesla supercharger is up to 300 kW, and a car is a much smaller EV.
kristjansson 5y ago
That site users an image from the movie Airplane to illustrate their autonomous pilot.
Balero 5y ago
How much is that going to cost to develop, manufacture, deploy, train, maintain etc? Shipping is a VERY price conscious industry.
- krasin 5y ago
  I assume that the majority of the cost would be to design and build nuclear ships. And it's still worth it, as fuel is 50%-60% of operational costs. As for drones to handle cases of ports which don't allow nuclear ships to dock: this is just a potential workaround. I kind of guess, that they will just focus on other ports first, and then eventually (like, in 5-10 years timeframe) everyone calms down and just allows such ships to dock in LA / NY / other US ports.
imtringued 5y ago
It's one thing to do something completely counter productive like using gasoline powered drones to unload/load your electric ship. It's another to assume that the same capability can even be offered by electric drones. There is absolutely nothing wrong with port cranes.
- krasin 5y ago
  Yes, port cranes are much better, if they can be used. The drones are suggested as a potential alternative to handle "LA does not allow nuclear ships to dock", so that a transfer from a nuclear- to battery-powered container ship happens in the international waters. As for can be offered: we're talking about moving a container from ship to ship which stand just hundreds meters away. The physics / math works, see my other comment.

catherd 5y ago

In most forms of bulk goods transport the power unit can be decoupled from the part the goods ride in. Seems possible that might also work for ships.

krasin 5y ago
Oh, good point!