The Thiccctionary

Most of the things we catalog are objects you might walk past: an avocado, a Chesterfield sofa, a refrigerator. Their thiccc-ness is observational. You see the silhouette, you make the call.

But there is a separate category of thiccc that is not observational. It is required. At a certain scale, the laws of materials simply do not permit a thin object to exist at all. The thing has to be wide. It has to be heavy. It has to commit to its own bulk to keep from collapsing under it. And so the largest machines and structures on Earth all share a family resemblance, they look the way physics insists on.

This is a tour of four of them.

The square-cube problem

Galileo wrote it down in 1638. As a thing scales up, its volume grows as the cube of its length while its cross-sectional area grows only as the square. Double the linear size of a beam and it weighs eight times as much, but its load-bearing area only quadruples. Triple it and you've got 27× the mass on 9× the cross-section.

This is why a fly can land on a ceiling and an elephant cannot. It's also why an industrial machine cannot be a scaled-up version of a hand tool. To stay rigid at large size, the structure has to disproportionately thicken. The bigger it gets, the chunkier its members must become, not for style, but to keep their own weight from breaking them.

Everything below is what happens when humans build right up against this limit.

Bagger 288

The Bagger 288 is a German bucket-wheel excavator, commissioned in 1978, used for surface mining of lignite coal. It weighs 13,500 metric tons. It is roughly 95 meters tall, taller than the Statue of Liberty including her pedestal, and 220 meters long. Eighteen caterpillar tracks support it. It moves at about 0.6 km/h on its own power, on the rare occasions it moves at all.

It is currently the largest land vehicle ever built.

Look at a photograph of one. The bucket wheel itself is 21.6 meters across, fitted with eighteen buckets, each of which can scoop 6.6 cubic meters of earth at a time. The wheel is held aloft by a counter-weighted boom that itself weighs as much as a small ship. None of this is decorative. The boom has to be that deep because it has to span far enough to keep the wheel away from the body, and it has to weigh enough to balance the wheel without flexing. If you halved the boom's cross-section, it would buckle the first time the wheel met dense ground.

The Bagger 288 is what a shovel looks like when a shovel is required to move 240,000 cubic meters of earth a day.

Saturn V, first stage

The Saturn V rocket carried Apollo astronauts to the Moon. The first stage, the S-IC, was built by Boeing and stood 42 meters tall by itself, 10 meters in diameter. Five Rocketdyne F-1 engines fired beneath it, each producing 1.5 million pounds of thrust, for a combined liftoff thrust of 7.5 million pounds. The whole rocket, fully fueled, weighed about 3,000 metric tons. The first stage held most of that weight in kerosene and liquid oxygen.

The body of the S-IC had to be wide because the engines had to be wide, and the engines had to be wide because the rocket had to lift itself plus a Moon program. The propellant tanks had to be deep because the engines burned through 13 metric tons of fuel per second. Cut any of those measurements in half and the rocket runs out of fuel before it reaches orbital velocity. Make the casing thinner and it ruptures during max-Q.

It is a thing that exists at exactly the proportions it has to. There is no version of the Saturn V that is sleeker. A sleeker Saturn V doesn't reach the Moon.

Supertankers

The TI-class oil tankers, TI Europe, TI Oceania, TI Asia, TI Africa, are among the largest ships ever built. Each is 380 meters long, 68 meters wide, with a deadweight tonnage around 440,000. Fully loaded, they sit about 24 meters into the water. They cannot enter most of the world's ports.

The width is dictated by the cargo. To carry a usable amount of crude, the hull has to enclose a lot of volume. To enclose a lot of volume without flexing in heavy seas, the hull has to be deep, wide, and built from steel plates that are themselves thick enough to handle bending loads measured in tens of thousands of tons.

Up close, the hull plates of a supertanker are visibly proportionate to the ship: not just steel sheet, but inches-thick structural plate, ribbed and stiffened. The whole vessel is overbuilt by ordinary boat standards because ordinary boat standards do not survive at this scale.

Hoover Dam

Hoover Dam is a 221-meter-tall arch-gravity dam on the Colorado River. It contains roughly 2.6 million cubic meters of concrete, about 6.6 million tons. The base of the dam is 200 meters thick. The crest is 14 meters thick.

This taper is doing structural work. At the bottom, the dam has to resist the full hydrostatic pressure of Lake Mead, which at depth is many tons per square meter. At the top, the water is shallow and the pressure is low. The dam thickens toward the bottom for the same reason a tree trunk does. That is where the load is.

You cannot build a thin dam. You can build a short dam, or a narrow dam, or a dam in a different shape. But once you commit to holding back 35 cubic kilometers of water at this height, the bottom of the structure has to be 200 meters thick. No design choice gets you out of that. The dam is the shape the river requires.

What this means for a dictionary

A satirical dictionary of thiccc things has, until now, mostly catalogued objects whose proportions are a matter of taste. A Chesterfield sofa is thiccc because someone made it that way; a thinner version exists. A Boeing 747 is thiccc because Boeing chose a wide-body fuselage; narrow-body planes also fly. The category, in those cases, is aesthetic.

Industrial-scale thiccc is different. The Bagger 288 has the body it has because that is the only body that can move that much earth. Saturn V has the proportions it has because no other proportions reach the Moon. The supertanker has its width because the alternative is sinking. Hoover Dam tapers from 200 meters at the base to 14 meters at the crest because the river requires it.

These objects are not thiccc by choice. They are thiccc by physics, and we will be cataloguing more of them. Watch the archive.

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