The World's Shortcut: How the Panama Canal Works

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The purpose of the Panama Canal is pretty easy to understand.

It turns a journey of this into this.

It brings the US west coast closer to Europe, and it brings the US east coast closer to


These rather short 180 foot or 55 meter wide trenches are, combined, perhaps the single

most important and most influential waterway on earth.

That’s because the entire shipping industry worldwide is shaped by the Panama Canal.

Hundreds of years ago, the opportunity of a canal across the narrow country of Panama

was identified.

After a few earlier false starts, the Americans went down to Panama in 1903, signed a fairly

dubious treaty granting them land, dammed up a river to make an artificial lake, dug

a trench from that lake to the Pacific, dug a trench from that lake to the Atlantic, and

$13 billion and 5,600 worker fatalities later, the canal was done.

It officially opened the Pacific to the Atlantic on August 15, 1914 as the first commercial

ship, the SS Ancon, sailed through.

Now, the Panama Canal is not just one straight shot from ocean to ocean.

That’s because the artificial lake they created, Gatun Lake, is 85 feet or 26 meters

above sea level.

So, cargo ships, which can weigh more than a billion pounds, need to get up those 85

feet or 26 meters and then back down again to transit from ocean to ocean.

Like most canals, to do this, the Panama Canal uses locks.

From the Atlantic side, for example, a ship will be pulled into the first lock by the

tug trains on each side of the canal, the downstream gate will close, water from upstream

will be fed in to fill the lock, the boat will float up, then once the water level rises

to match that of the next lock, the gate will open, and the ship will be pulled into the

next lock.

Then, the gates will close, the water level will rise again, the gates will open, then

this will all happen one more time until the third lock raises the ship to the water level

of Gatun Lake—those 85 feet or 26 meters above sea level.

Believe it or not, it is these three locks exclusively that limit what size a large portion

of the world’s container ship fleet can be.

A ship has to be under 1,200 feet or 366 meters long and 168 feet or 51 meters wide to be

accepted in the Panama Canal and so a huge proportion of the world’s ships are built

to be exactly this size.

This class of ship is called NeoPanamax or New Panamax or Post Panamax depending on who

you ask.

Of course, there are certainly ships larger than the NeoPanamax size.

The Panama Canal has a size limit of about 15,000 TEU or twenty-foot equivalent units.

That’s a measure of a ship’s capacity based off how many of these twenty-foot containers

they could carry.

Now, the largest container ship in existence, the OOCL Hong Kong, has a capacity of over

21,000 TEU.

This ship, like many of those larger than 15,000 TEU, exclusively keeps to the east

Asia to Europe route as it can’t efficiently make trips that require transit between the

Pacific and Atlantic since it would have to circumnavigate South America.

But it was really not long ago that the largest ships that could go through the Panama canal

were far smaller than the current 15,000 TEU size.

You see, up until 2016, the Panama canal could only fit ships smaller than 5,000 TEU.

That’s because up until 2016, these didn’t exist—the Panama canal’s new locks.

The old locks can only only fit a ship 106 feet or 32 meters wide but still, given the

enormous importance of this waterway, ships were still then built specifically to fit


In fact, 50% of the old lock’s users were exactly as wide as this width limit suggested

they were likely built for exactly that purpose.

This was a problem for the Panama canal, though, because, believe it or not, the canal has


It all has to do with geography.

When traveling from east Asia to the US east coast, which is one of the busiest shipping

routes in the world, it really is not all that much further to go west than east.

Going from Hong Kong to Newark, for example, the distance heading west through the Indian

ocean, Suez Canal, Mediterranean, and Atlantic is only a few hundred miles or kilometers

longer than going east across the Pacific and through the Panama Canal.

Meanwhile, the Panama canal is not cheap.

They charge a $90 toll per twenty foot container meaning that most ships, carrying thousands

of loaded containers, pay hundreds of thousands of dollars for just a single transit.

With the new locks and their higher capacity, single ships can possibly be assessed more

than $1 million per transit if they’re the largest size, fully loaded.

The Suez canal, meanwhile, typically charges lower tolls.

A ship sailing that Hong Kong to Newark route therefore might choose to take the slightly

longer route via the Suez canal versus the Panama canal as, in the end, when you consider

the tolls, it might end up being less expensive.

Now, both canals are constantly changing their fees in order to compete with the other but

still, throughout the past decade, the Suez Canal seems to maintain a slight edge in cost.

The Panama Canal’s other competitor, though, is trains.

For the crucial east Asia to US east coast route, going through the Panama canal, while

much faster than circumnavigating the continent, is still not a direct route.

On the Hong Kong to Newark route, the Panama canal represents an almost 3,000 mile or 5,000

kilometer diversion from the alternative—crossing the US by land.

It is pretty standard practice to ship cargo from east Asia to Los Angeles and then load

it up on trains to get to the US east coast.

While overall this usually ends up a little more expensive than going through the Panama

Canal, it saves about a week in transit time and, for many shippers, this is worth it.

Trains, with their relatively low cost, represent a considerable competitor to the canal, and

it is the competition with both these and the Suez canal that pushed the Panama Canal

to make an expansion.

That’s why they spent $5.4 billion to build these bigger locks that could fit larger,

15,000 TEU ships.

This would let more of the world’s shipping fleet through and these bigger ships, thanks

to economies of scale, have lower cost per container which helps make the canal more

attractive in comparison the its trains or Suez competition.

Now, this expansion is a great example of the butterfly effect.

In one instance, because the Panama Canal widened its size limit by a few dozen feet,

the state of New Jersey had to spend $1.7 billion to raise a bridge by a few dozen feet.

You see, in order to get to much of the port of Newark, which is one of the largest and

busiest in the US, ships have to pass under the Bayonne bridge.

As a huge proportion of the shipping traffic to the US east coast goes through the Panama

Canal, before the new set of locks many of the ships that wanted to use the port of Newark

were the smaller, 5,000 TEU size which could all fit under the Bayonne Bridge, sitting

at 151 feet or 46 meters above the water.

With the canal expansion project, though, more ships would start making their way to

Newark that would be too large to fit under the Bayonne bridge.

Therefore, in order for the port of Newark to stay competitive, they just had to raise

that bridge.

Beyond that, all up and down the US east coast, from Miami to Savannah to Charleston to Baltimore

and to New York, ports quickly spent millions and billions of dollars to build facilities

that would fit the bigger ships in time for the opening of the new canal locks.

Still today, though, many ports on the east coast do not have the depth and facilities

needed to handle these NeoPanamax ships.

This, though, presents an opportunity for the Caribbean.

Deep-water ports in the Caribbean are developing themselves into major transshipment hubs.

What these are are ports where larger ships, like the largest 15,000 TEU container ships

that can now go through the canal, will unload their cargo which will then be loaded again

onto smaller ships bound for smaller ports closer to the cargo’s destination up and

down the east coast.

Huge amounts of foreign money are flowing into the Caribbean to develop these transshipment


CMA CGM, a shipping company from France that ranks as the world’s third largest, operates

the port of Kingston, Jamaica.

DP World, from the UAE, operates the port of Caucedo in the Dominican Republic.

Meanwhile, the port of Freeport, in the Bahamas, is operated by Hutchison Port Holdings from

Hong Kong.

All of these companies and more have and continue to focus on expanding these Caribbean ports

to suit the increased traffic making its way through the Panama Canal, into the Caribbean,

and eventually to its destination on the east coast.

Sometime soon, though, something could happen that would be simultaneously great for the

Caribbean ports but terrible for the Panama Canal.

You see, two countries to the north of Panama is Nicaragua.

By linking both the Atlantic and the Pacific to the large Lake Nicaragua, one could have

another connection between the oceans.

There has been a long history of attempts to build this canal, most recently in the

past decade with a failed scheme by a Chinese billionaire.

Given that this failure was rather recent there are no current construction plans, but

at least somewhere, the world is going to need more canal capacity between the Pacific

and the Atlantic.

The shipping industry is growing at a solid rate of about 5% annually and the Panama canal

can only expand so much.

One issue is that the Panama Canal could literally run out of water.

You see, each time the canal’s locks open, millions of gallons of water flow out and


Usually this is not a problem because the lake upstream has enough water, but sometimes,

during periods of reduced rainfall, there just won’t be enough water to both release

the amount needed to operate the locks and keep the lake at a deep enough level for the

largest ships to transit.

At these times, which included much of Spring 2019, the canal will have to place restrictions

on how much weight cargo ships can carry as this will affect how deep they sit in the


They’ve attempted to limit the effects of this by installing systems to recapture some

of the water used to operate the locks and there are also potential plans to build an

additional upstream dam to create an additional reservoir, but these problems are only expected

to worsen as climate change exacerbates the severity of droughts in the region.

All told, what happens in Panama affects the world.

If a drought in Panama restricts the throughput of the canal, the world economy will feel


That’s because shipping is what connects the world’s economy and the Panama canal

is one of the most important connectors in shipping.

The canal effectively brings the economies on one side closer to those on the other and

so, no matter what happens, it will continue to serve as the world’s shortcut.

Now, one of the things that those working at the Panama Canal need to understand is

how water works.

As in, how weather works, how the water cycle works, how tides work—all of these things

are also, though, concepts that you can learn about in Brilliant’s Physics of the Everyday


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