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Why isn't the solution to put empty containers back on unloaded ships to be sent away? BTW for fun reading on operations logistics and identifying and attackin

Why isn't the solution to put empty containers back on unloaded ships to be sent away? BTW for fun reading on operations logistics and identifying and attacking bottlenecks see "The Goal" by Eli Goldratt. https://en.wikipedia.org/wiki/The_Goal_%28novel%29 https://en.wikipedia.org/wiki/The_Goal_%28novel%29

AngryData 5y ago
Can cargo ships with empty containers actually sail back? In the past we shipped tons of alfalfa to China, partially because meat (and thus cow feed) is worth more in China, but I was under the impression that the main purpose was ballast for the ships because they can't sail without enough weight in them and alfalfa was the cheapest bulk weight they could source.
- hammock 5y ago
  There is unlimited ballast all around a ship (water)
  - ceejayoz 5y ago
    You can't just pump a bunch of salt water into the cargo hold of a container ship, I suspect.
    - Danieru 5y ago
      You can into the ballast tanks.
      - ceejayoz 5y ago
        Sure, but the tanks will be sized on the assumption the ship will be under a normal load, not completely empty.
  - ryukafalz 5y ago
    I'm no expert, but I believe many of these ships aren't designed to transport liquid cargo. In fact when their solid cargo starts to act too much like a liquid, things go south real fast: https://www.theshipyardblog.com/liquefaction-of-bulk-cargo-explained/ https://www.theshipyardblog.com/liquefaction-of-bulk-cargo-e...
    - hammock 5y ago
      Well for sure liquid ballast needs to be in many compartments (not one big one) to mitigate the effects you link to
- digikata 5y ago
  I know little about ship operations - but what is ballasting them when they’re sailing away now without empty containers?
  - HeyLaughingBoy 5y ago
    Completely empty with no cargo? The ship itself is designed to be stable under nominal conditions. Also, remember that fuel is heavy and part of the load & balance equation. Carrying empty containers or with minimal cargo, or depending on cargo distribution, ballast tanks can be filled to get the center of gravity in the right place.
raverbashing 5y ago
Agree. The real bottleneck (or better, root cause) is not that the ports are full of containers. But where should those containers be in the first place. The issue is not, fundamentally, "container parking space is temporarily constrained", it is: they should be elsewhere (read: China or wherever) and they aren't
dragonwriter 5y ago
> Why isn’t the solution to put empty containers back on unloaded ships to be sent away? IIRC, stacks of empty containers (large surface area and low mass) act as, in effect, giant crosswise sails, which is a dangerous thing on a ship, so you can’t safely stack as many empty containers as optimally weighted containers on a ship (too full, and you end up with issues with strength of ship deck and containers at the bottom of the stack, so maximally loaded containers aren’t optimal either.)
Sparkle-san 5y ago
They've been doing more of that recently actually and it's causing some other effects. American soybean farmers would rely on those empty containers coming by rail for their exporting chain, but that's no longer happening. https://www.npr.org/2021/07/23/1019496567/farmers-have-a-big-problem-on-their-hands-they-cant-find-a-way-to-ship-their-stu https://www.npr.org/2021/07/23/1019496567/farmers-have-a-big...
- OldHand2018 5y ago
  That’s a really interesting article, but it also points to a different answer. Instead of shipping low-value raw specialty soybeans to Asia where they will be transformed into a high-value product, they should be creating the high-value product in North Dakota and exporting that. If it is valuable enough, you could even ship it by air and skip the cargo ships altogether.
  - seoaeu 5y ago
    Sure, it is better for North Dakota to make high-value products there, but why would it benefit manufactures to be there (except during rare global logistics disruptions)? Transporting cargo by ship is super cheap during normal times
andrekandre 5y ago
was just going to say the same... if i understand the situation correctly, it seems caused by "over optimization" of the whole chain, so when a surge in demand occurred a "pipeline bubble" resulted that started the whole pileup?? in my understanding, this is why he stressed that being too optimized and efficient (demming says something similar) is actually dangerous... right?

AngryData 5y ago

Can cargo ships with empty containers actually sail back? In the past we shipped tons of alfalfa to China, partially because meat (and thus cow feed) is worth more in China, but I was under the impression that the main purpose was ballast for the ships because they can't sail without enough weight in them and alfalfa was the cheapest bulk weight they could source.

hammock 5y ago
There is unlimited ballast all around a ship (water)
- ceejayoz 5y ago
  You can't just pump a bunch of salt water into the cargo hold of a container ship, I suspect.
  - Danieru 5y ago
    You can into the ballast tanks.
    - ceejayoz 5y ago
      Sure, but the tanks will be sized on the assumption the ship will be under a normal load, not completely empty.
- ryukafalz 5y ago
  I'm no expert, but I believe many of these ships aren't designed to transport liquid cargo. In fact when their solid cargo starts to act too much like a liquid, things go south real fast: https://www.theshipyardblog.com/liquefaction-of-bulk-cargo-explained/ https://www.theshipyardblog.com/liquefaction-of-bulk-cargo-e...
  - hammock 5y ago
    Well for sure liquid ballast needs to be in many compartments (not one big one) to mitigate the effects you link to
digikata 5y ago
I know little about ship operations - but what is ballasting them when they’re sailing away now without empty containers?
- HeyLaughingBoy 5y ago
  Completely empty with no cargo? The ship itself is designed to be stable under nominal conditions. Also, remember that fuel is heavy and part of the load & balance equation. Carrying empty containers or with minimal cargo, or depending on cargo distribution, ballast tanks can be filled to get the center of gravity in the right place.

raverbashing 5y ago

Agree. The real bottleneck (or better, root cause) is not that the ports are full of containers. But where should those containers be in the first place. The issue is not, fundamentally, "container parking space is temporarily constrained", it is: they should be elsewhere (read: China or wherever) and they aren't

dragonwriter 5y ago

> Why isn’t the solution to put empty containers back on unloaded ships to be sent away? IIRC, stacks of empty containers (large surface area and low mass) act as, in effect, giant crosswise sails, which is a dangerous thing on a ship, so you can’t safely stack as many empty containers as optimally weighted containers on a ship (too full, and you end up with issues with strength of ship deck and containers at the bottom of the stack, so maximally loaded containers aren’t optimal either.)

Sparkle-san 5y ago

They've been doing more of that recently actually and it's causing some other effects. American soybean farmers would rely on those empty containers coming by rail for their exporting chain, but that's no longer happening. https://www.npr.org/2021/07/23/1019496567/farmers-have-a-big-problem-on-their-hands-they-cant-find-a-way-to-ship-their-stu https://www.npr.org/2021/07/23/1019496567/farmers-have-a-big...

OldHand2018 5y ago
That’s a really interesting article, but it also points to a different answer. Instead of shipping low-value raw specialty soybeans to Asia where they will be transformed into a high-value product, they should be creating the high-value product in North Dakota and exporting that. If it is valuable enough, you could even ship it by air and skip the cargo ships altogether.
- seoaeu 5y ago
  Sure, it is better for North Dakota to make high-value products there, but why would it benefit manufactures to be there (except during rare global logistics disruptions)? Transporting cargo by ship is super cheap during normal times

andrekandre 5y ago

was just going to say the same... if i understand the situation correctly, it seems caused by "over optimization" of the whole chain, so when a surge in demand occurred a "pipeline bubble" resulted that started the whole pileup?? in my understanding, this is why he stressed that being too optimized and efficient (demming says something similar) is actually dangerous... right?