4 ms·

That BBC documentary shows or exposes very shallow thinking skills at this timestamp 6m42s: https://youtu.be/_xZCh8eDZFc?si=AHyDPgoDucsCRllS&t=402 https://yout

That BBC documentary shows or exposes very shallow thinking skills at this timestamp 6m42s: https://youtu.be/_xZCh8eDZFc?si=AHyDPgoDucsCRllS&t=402 https://youtu.be/_xZCh8eDZFc?si=AHyDPgoDucsCRllS&t=402 They claim the panama canal is continuously fed by freshwater for the canal locks (which segment the canal into sections with different water levels, and which enable ships to be raised or lowered to the next water level during travel along the canal). It's 2026, why are humans dumping freshwater into the oceans? This can perfectly be done without wasting freshwater. Archimedes screws can essentially be operated quasistatically at extremely high efficiencies. The energy released when lowering can be stored either in gravitational energy of a mass, or be used to power a second parallel lock operated in counter phase (so while one lock is lowering ships say eastwards, the energy is used to raise ships traveling westwards, and afterwards their roles reverse). To speed up a second gravitational potential energy store (and optional flywheel) can be used to accelerate and decelerate the pumping. Apart from some frictional losses (minimal compared to the potential energies involved) this doesn't cost energy, and is easily covered by a small number of solar panels. Is this misreporting by the BBC, or is it mismanagement by the Panama Canal operators? Keep the freshwater, use it for irrigation etc, make Central America more attractive to South American refugees and the migration burden on Mexico and US lowers. The operation as currently described is so inefficient, even for the 1960's!

markdown 2mo ago
Wow, guy on internet solves problem within seconds. And you didn't even have to visit the site. Incredible.
- DoctorOetker 2mo ago
  If you have studied physics, its easy to see water locks can be operated with near zero energy consumption. What site? I was commenting on a youtube video. If you misattribute my comment as replying to something else, thats your superficial attitude not mine...
MSM 2mo ago
> Keep the freshwater, use it for irrigation etc. In this scenario, haven't you poured a bunch of ocean water into the lake? I don't see how to can fill the locks with ocean water and not have it pour into the lake.
- DoctorOetker 2mo ago
  no connection to a lake is necessary.
  - lhopki01 2mo ago
    A trivial look at the Panama canal will show that it is a not a connection to a lake but rather it goes through a lake. Bypassing the lake would require digging a length of canal longer than the existing canal. So you would be dumping salt water into a freshwater lake.
anon84873628 2mo ago
So putting the technical critique aside, are you blaming the BBC for accurately reporting how the canal functions?
- zamadatix 2mo ago
  I think they were saying "That BBC documentary shows or exposes very shallow thinking skills <of those involved with designing the canal> at this timestamp". not "<of those making the documentary for not correcting the design of the canal>" That said, I can't quite understand the complaint. It's either take the freshwater out of the lake and into the ocean or take the ocean water into the lake (or invest build the entire length without using natural bodies). The former seems to make a lot more sense and is effectively what's supposed to happen with water eventually anyways.
  - DoctorOetker 2mo ago
    No connection to a lake is necessary, imagine 2 locks in parallel both connected to the same low water level canal section "on the left" and both connected to the same high water level canal to the right (its not necessary to have 2 locks in parallel, its just easier to demonstrate the scheme doesn't require significant energy consumption): Imagine one lock is currently filled to the high level, while the other is currently filled to the low level. The locks have been closed. As you let water from the high lock flow into the low lock through Archimedes screws, those screws can lift a weight, until they have equilibrated at the midpoint of the high and low water levels. But you have raised the weight and can now use that to power the draining of the lock that has only halfway sunk in level, by pumping its water to the lock that has only halfway risen. Apart from friction there is no energy consumption. Slow quasistatic transfer drives the friction energy consumption to 0. In practice you want to use an "extra" weight to attain higher pump speeds, and then recover the kinetic energy. That will consume more friction energy, but a small number of solar panels suffice, the energy is not used to lift water, but to overcome friction (haste makes waste).
    - zamadatix 2mo ago
evil-olive 2mo ago
> The operation as currently described is so inefficient, even for the 1960's! https://en.wikipedia.org/wiki/Panama_Canal https://en.wikipedia.org/wiki/Panama_Canal Construction began: 1 January 1881 Date completed: 15 August 1914 > The energy released when lowering can be stored either in gravitational energy of a mass, or be used to power a second parallel lock operated in counter phase (so while one lock is lowering ships say eastwards, the energy is used to raise ships traveling westwards, and afterwards their roles reverse). To speed up a second gravitational potential energy store (and optional flywheel) can be used to accelerate and decelerate the pumping. if the canal didn't exist, and we were designing it as a greenfield project in 2026, that would definitely be a design worth considering. could it be retrofitted onto the existing canal? sure, in theory. in practice, they currently handle 36 ships per day, and lowering that limit by just 2-4 per day is significant enough that it makes international news [0] so whatever retrofitting you have in mind, the construction would need to be done completely non-invasively, without disrupting the daily operation of the locks. it's nowhere near as simple as you're making it out to be. 0: https://www.lemonde.fr/en/economy/article/2026/08/21/panama-canal-to-cut-ship-traffic-over-el-nino-fueled-drought_6756722_19.html https://www.lemonde.fr/en/economy/article/2026/08/21/panama-...
- DoctorOetker 2mo ago
  Its not that difficult to do it while in use, you just construct a parallel lock next to the existing ones that can remain in use. It's even possible to upgrade a lock while in use, you just add new inlets and outlets for the new archimedes screw system, an unused archimedes screw or inlet/outlet is just a differently shaped boundary wall... Even in 1881 all the necessary physics was already known, but I'm less surprised less informed people could rise to the top that easily back then. I'm more surprised by the post-war 60's when physics and engineering became a lot more democratized, less elite...
  - evil-olive 2mo ago
    > you just construct a parallel lock next to the existing ones that can remain in use. are you aware that they did that already? https://en.wikipedia.org/wiki/Panama_Canal_expansion_project https://en.wikipedia.org/wiki/Panama_Canal_expansion_project and that it took almost 10 years to complete? if they had put you in charge instead, do you think you could have gotten it done faster?
teekert 2mo ago
Well, the Panama canal could have been at sea level, easy to traverse without the shenanigans, and with some of the wealth it generates flowing to the Panamanians. But then the CIA killed Omar Torrijos.
- DoctorOetker 2mo ago
  > Well, the Panama canal could have been at sea level From a technical perspective, PNE's have been proposed to excavate a sea level canal, it would take much less than 10 years. Personally I consider a few Archimedes screws and minimal works to the locks much less invasive than PNE's,... but if your argument is that taste can not be argued I can only agree at a fundamental level... > The collection of data was substantially completed on Route 17 in Panama one of the routes considered for nuclear excavations... The Atomic Energy Commission has recently conducted the first two of the planned series of nuclear excavation experiments designed to determine the feasibility of nuclear excavation of a sea level canal. https://www.congress.gov/90/crecb/1968/09/05/GPO-CRECB-1968-pt20-1-1.pdf https://www.congress.gov/90/crecb/1968/09/05/GPO-CRECB-1968-...
hvb2 2mo ago
You do realize that the problems you raise were not even remotely an issue when this was designed? You're blaming the engineers who designed this with 100 years of hindsight. Every solution can be improved over time as conditions evolve. Yours included.
wat10000 2mo ago
“It's 2026, why are humans dumping freshwater into the oceans?” They’re called rivers and they do that naturally.
- DoctorOetker 2mo ago
  As long as there is no shortage of freshwater locally, it would be fine. They are throttling Panama Canal traffic to conserve water during El Nino drought, as posted by @evil-olive: https://www.lemonde.fr/en/economy/article/2026/08/21/panama-canal-to-cut-ship-traffic-over-el-nino-fueled-drought_6756722_19.html https://www.lemonde.fr/en/economy/article/2026/08/21/panama-...
  - wat10000 2mo ago
    I understand that it’s a problem that sometimes restricts the capacity of the canal. I just take issue with this incredulous “they dump fresh water into the ocean” phrasing. You make it sound like they’re depriving thirsty people of precious water so they can inefficiently float their boats.
    - DoctorOetker 2mo ago
      > You make it sound like they’re depriving thirsty people of precious water so they can inefficiently float their boats. I make it sound like that, or Le Monde? There is so much conflicting information, all I care about is that while it's possible to operate a lock by consuming freshwater, it's only a marginal increase in knowledge to operate a lock without freshwater consumption... But for some reason every country with continent-bypassing canals is modulating traffic for flex...
      - wat10000 2mo ago
        The word "fresh" doesn't occur in the Le Monde article. You're doing it again when you say "consuming freshwater." You make it sound like this is a precious resource that could be used to sustain human life but instead it's being dumped into the ocean because the canal is wasteful. It's not. It would go into the ocean regardless, as it has done since the river formed. The freshness of the water is irrelevant, the problem is only about the consequences to canal capacity.

markdown 2mo ago

Wow, guy on internet solves problem within seconds. And you didn't even have to visit the site. Incredible.

DoctorOetker 2mo ago
If you have studied physics, its easy to see water locks can be operated with near zero energy consumption. What site? I was commenting on a youtube video. If you misattribute my comment as replying to something else, thats your superficial attitude not mine...

MSM 2mo ago

> Keep the freshwater, use it for irrigation etc. In this scenario, haven't you poured a bunch of ocean water into the lake? I don't see how to can fill the locks with ocean water and not have it pour into the lake.

DoctorOetker 2mo ago
no connection to a lake is necessary.
- lhopki01 2mo ago
  A trivial look at the Panama canal will show that it is a not a connection to a lake but rather it goes through a lake. Bypassing the lake would require digging a length of canal longer than the existing canal. So you would be dumping salt water into a freshwater lake.

anon84873628 2mo ago

So putting the technical critique aside, are you blaming the BBC for accurately reporting how the canal functions?

zamadatix 2mo ago
I think they were saying "That BBC documentary shows or exposes very shallow thinking skills <of those involved with designing the canal> at this timestamp". not "<of those making the documentary for not correcting the design of the canal>" That said, I can't quite understand the complaint. It's either take the freshwater out of the lake and into the ocean or take the ocean water into the lake (or invest build the entire length without using natural bodies). The former seems to make a lot more sense and is effectively what's supposed to happen with water eventually anyways.
- DoctorOetker 2mo ago
  No connection to a lake is necessary, imagine 2 locks in parallel both connected to the same low water level canal section "on the left" and both connected to the same high water level canal to the right (its not necessary to have 2 locks in parallel, its just easier to demonstrate the scheme doesn't require significant energy consumption): Imagine one lock is currently filled to the high level, while the other is currently filled to the low level. The locks have been closed. As you let water from the high lock flow into the low lock through Archimedes screws, those screws can lift a weight, until they have equilibrated at the midpoint of the high and low water levels. But you have raised the weight and can now use that to power the draining of the lock that has only halfway sunk in level, by pumping its water to the lock that has only halfway risen. Apart from friction there is no energy consumption. Slow quasistatic transfer drives the friction energy consumption to 0. In practice you want to use an "extra" weight to attain higher pump speeds, and then recover the kinetic energy. That will consume more friction energy, but a small number of solar panels suffice, the energy is not used to lift water, but to overcome friction (haste makes waste).
  - zamadatix 2mo ago

evil-olive 2mo ago

> The operation as currently described is so inefficient, even for the 1960's! https://en.wikipedia.org/wiki/Panama_Canal https://en.wikipedia.org/wiki/Panama_Canal Construction began: 1 January 1881 Date completed: 15 August 1914 > The energy released when lowering can be stored either in gravitational energy of a mass, or be used to power a second parallel lock operated in counter phase (so while one lock is lowering ships say eastwards, the energy is used to raise ships traveling westwards, and afterwards their roles reverse). To speed up a second gravitational potential energy store (and optional flywheel) can be used to accelerate and decelerate the pumping. if the canal didn't exist, and we were designing it as a greenfield project in 2026, that would definitely be a design worth considering. could it be retrofitted onto the existing canal? sure, in theory. in practice, they currently handle 36 ships per day, and lowering that limit by just 2-4 per day is significant enough that it makes international news [0] so whatever retrofitting you have in mind, the construction would need to be done completely non-invasively, without disrupting the daily operation of the locks. it's nowhere near as simple as you're making it out to be. 0: https://www.lemonde.fr/en/economy/article/2026/08/21/panama-canal-to-cut-ship-traffic-over-el-nino-fueled-drought_6756722_19.html https://www.lemonde.fr/en/economy/article/2026/08/21/panama-...

DoctorOetker 2mo ago
Its not that difficult to do it while in use, you just construct a parallel lock next to the existing ones that can remain in use. It's even possible to upgrade a lock while in use, you just add new inlets and outlets for the new archimedes screw system, an unused archimedes screw or inlet/outlet is just a differently shaped boundary wall... Even in 1881 all the necessary physics was already known, but I'm less surprised less informed people could rise to the top that easily back then. I'm more surprised by the post-war 60's when physics and engineering became a lot more democratized, less elite...
- evil-olive 2mo ago
  > you just construct a parallel lock next to the existing ones that can remain in use. are you aware that they did that already? https://en.wikipedia.org/wiki/Panama_Canal_expansion_project https://en.wikipedia.org/wiki/Panama_Canal_expansion_project and that it took almost 10 years to complete? if they had put you in charge instead, do you think you could have gotten it done faster?

teekert 2mo ago

Well, the Panama canal could have been at sea level, easy to traverse without the shenanigans, and with some of the wealth it generates flowing to the Panamanians. But then the CIA killed Omar Torrijos.

DoctorOetker 2mo ago
> Well, the Panama canal could have been at sea level From a technical perspective, PNE's have been proposed to excavate a sea level canal, it would take much less than 10 years. Personally I consider a few Archimedes screws and minimal works to the locks much less invasive than PNE's,... but if your argument is that taste can not be argued I can only agree at a fundamental level... > The collection of data was substantially completed on Route 17 in Panama one of the routes considered for nuclear excavations... The Atomic Energy Commission has recently conducted the first two of the planned series of nuclear excavation experiments designed to determine the feasibility of nuclear excavation of a sea level canal. https://www.congress.gov/90/crecb/1968/09/05/GPO-CRECB-1968-pt20-1-1.pdf https://www.congress.gov/90/crecb/1968/09/05/GPO-CRECB-1968-...

hvb2 2mo ago

You do realize that the problems you raise were not even remotely an issue when this was designed? You're blaming the engineers who designed this with 100 years of hindsight. Every solution can be improved over time as conditions evolve. Yours included.

wat10000 2mo ago

“It's 2026, why are humans dumping freshwater into the oceans?” They’re called rivers and they do that naturally.

DoctorOetker 2mo ago
As long as there is no shortage of freshwater locally, it would be fine. They are throttling Panama Canal traffic to conserve water during El Nino drought, as posted by @evil-olive: https://www.lemonde.fr/en/economy/article/2026/08/21/panama-canal-to-cut-ship-traffic-over-el-nino-fueled-drought_6756722_19.html https://www.lemonde.fr/en/economy/article/2026/08/21/panama-...
- wat10000 2mo ago
  I understand that it’s a problem that sometimes restricts the capacity of the canal. I just take issue with this incredulous “they dump fresh water into the ocean” phrasing. You make it sound like they’re depriving thirsty people of precious water so they can inefficiently float their boats.
  - DoctorOetker 2mo ago
    > You make it sound like they’re depriving thirsty people of precious water so they can inefficiently float their boats. I make it sound like that, or Le Monde? There is so much conflicting information, all I care about is that while it's possible to operate a lock by consuming freshwater, it's only a marginal increase in knowledge to operate a lock without freshwater consumption... But for some reason every country with continent-bypassing canals is modulating traffic for flex...
    - wat10000 2mo ago
      The word "fresh" doesn't occur in the Le Monde article. You're doing it again when you say "consuming freshwater." You make it sound like this is a precious resource that could be used to sustain human life but instead it's being dumped into the ocean because the canal is wasteful. It's not. It would go into the ocean regardless, as it has done since the river formed. The freshness of the water is irrelevant, the problem is only about the consequences to canal capacity.