Throwback Thursday: Rebuilding Old Ironsides

Imagine a ship is docked at your local port, and it towers over nearly every building in the neighborhood. That was the awesome sight of the USS Constitution in the 1790s, as it was under construction off Boston’s North End. Even without its masts, the frigate was the height of a four-story building. Only the steeple of the Old North Church could compete with that on the local skyline then.

We bring this up not only because the Tall Ships just visited Boston, but also because if you think about it, shipbuilding is a sister industry to our own land-based form of construction. Like a city high-rise, a ship is a unique, standalone structure (with its own name) that can take years to design and build. This feat was all the more impressive in the age of sail, when the endeavor relied largely on human brain and brawn.

And yet, in the case of Constitution—the last ship standing of the U.S. Navy’s original six, and the world’s oldest commissioned warship afloat—what might be more impressive is the dedication to re-building. Since she first put to sea in 1797 to protect Yankee merchant voyages, every American generation has produced engineers, architects, carpenters, and other builders who pitched in to patch up a national treasure. That holds true today, as the current crop of restorers apply high-tech tools to the preservation of “Old Ironsides.”

To see for ourselves, we descended into the dry dock.

The eagle of the sea

Undefeated in the War of 1812, Constitution was already a legend when she entered the brand-new, Quincy-granite dry dock in Charlestown, Massachusetts, on June 24, 1833. (That’s 184 years from this Saturday.)

That’s where and when the story of Constitution’s repeated extensive overhauls begins in earnest. At minimum, the frigate needed new planking, masts, rigging, decking, stem, head, and quarter galleries. After an erroneous report got out that the Navy planned to scuttle her, a young Oliver Wendell Holmes published an ode to “the eagle of the sea,” which rallied Americans to her defense and assured her survival. The Navy decided Old Ironsides would be the first ship to get a new treatment.

dry dock design

USS Constitution Section in Dry Dock No 1 (Rendering courtesy of the Naval History & Heritage Command Detachment Boston)

After six years of construction, the Charlestown Navy Yard’s Dry Dock One opened a week after its twin in Norfolk, Virginia. Both designed by Bay Stater Loammi Baldwin, Jr., they were the first large-scale dry docks in the States. Now the Navy could repair its fleet without resorting to the arduous process of “careening” a ship—that meant using weights to tip it over, first on one side then the other.

dry dock expansion

Dry Dock One’s 1940s expansion. (Photo courtesy of Charlestown Navy Yard Boston National Historical Park)

The dry dock was considered a marvel of engineering even decades later, and it was still used to service vessels during WWII. Although the dock had to be lengthened twice—from 341 feet to, eventually, 415—its width has remained the same, 86 feet at its widest point. “The interior of this dry dock was so well designed in the late 1820s,” said Margherita Desy, the official historian of the Navy’s Boston detachment, “that with the right shoring, you can put a flat-sided vessel in here, you can put a submarine in here—you can put vessels in this dock that could not have been conceived of by Loammi Baldwin 184 years ago.”

The coolest thing about the dry dock is how it works. Start by thinking of it as an artificial inlet. After a ship is towed in, another vessel called a caisson is towed to the entrance. (It’s not unlike other kinds of caissons you may have read about, here and here.) The caisson is filled with water and sunk into place.

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Your fearless blogger drops in to the dry dock. (Photo by Patrick Kennedy)

Then the dock is drained—slowly, so as to ease the ship onto its keel blocks. While the ballast water at the bottom of the caisson weighs it down, the pressure of the harbor beyond holds it at the dock’s seaward end, creating a watertight door.

When repairs are finished, the dock is flooded again, the caisson is emptied and floated out of the way, and the ship is towed back out into the harbor.

The operation requires a complex system of reservoir, tunnels, culverts, valves, and gates. In the 1830s, a steam engine powered eight pumps that could empty the basin in four to five hours. The caisson itself took 24 men working hand pumps 90 minutes to drain.

That old wood caisson is long gone, and even its 1901 steel replacement was replaced in 2015. And today’s pumps are diesel-powered. But though the dock’s technology has changed over 184 years, its basic principles remain the same. “It’s like with any tools,” Desy said. “We still use planes and saws; it’s just that we plug them in.”

Check out the time-lapse video of Constitution entering the dry dock in 2015:

Plugging in

Just as the pumps have been updated, the means and methods of restoring the ship itself have kept pace with the times. For Constitution’s current round of renovation, a naval architect used computer-assisted drawing (CAD) software to redraw plans for the work, make precise measurements, and document the project.


This CAD drawing shows the spar and rigging plan for Constitution as she will be rigged at the end of the 2015-2017 restoration. (Photo courtesy of the Naval History & Heritage Command Detachment Boston)

The 3D virtual model is a far cry from the quill pen that Joshua Humphreys used to design the Navy’s first six frigates in the 1790s. (A frigate, by the way, is a war vessel with at least three masts and one covered gun deck. It’s also a fun thing to say aloud, especially when you’ve given up on something.)

And whereas 18th-century loggers seemed to have their pick of trees from an infinite supply—the thick wild woods that covered most of the East Coast—modern timber concerns know to practice sustainable forestry. Indeed, there’s a grove in Indiana devoted solely to timber for the Constitution. To procure the white oak timber for the ship’s hull planking, the Navy set aside 150 white oak trees in the forest around a naval facility in Crane, Indiana. “Constitution Grove” was dedicated in 1976.


White oak delivery in Charlestown. (Photo courtesy of the Naval History & Heritage Command Detachment Boston/Margherita M. Desy)

“It’s a managed forest,” said Desy. “As the trees grow, their lower branches are trimmed and each tree is allowed a lot of sunlight. Because, to qualify as trees for Constitution, they have to be at least 45 feet in length from base to crown, and at least 40 inches in diameter at the base.” In 2015, thirty-five of the trees were felled, and eventually 350,000 pounds of white oak were delivered to Charlestown.

Here we should point out that “Old Ironsides” is just a nickname, earned when cannon balls bounced off her hardwood hull. It was sturdy New England white oak and dense, rot-resistant live oak from Georgia—not iron—that repelled the attacks. However, below the water line, the frigate’s hull has always been sheathed in copper, to keep out wood-eating shipworm. In fact, master metalworker Paul Revere imported an innovation from England (by way of a little industrial espionage) when he opened our nation’s first copper rolling mill to provide the Constitution’s second copper coating, in 1803.

Another innovative tool used in today’s restoration work is the Gemini Universal Carving Duplicator in the Charlestown Navy Yard’s restoration workshop. The decorative carvings along the ship’s bow—like much of the ship—have been replaced time and again. The most recent set (based on earlier drawings and models) dated to 1930. To produce a new set, carpenter Josh Ratty used the Gemini duplicator to trace the 1930 carvings with a blunt stylus hooked up to a router that mimics its motion, making the real cuts in fresh planks.

“It’s like a manual 3D printer,” said USS Constitution Museum spokesman David Wedemeyer. Check out Ratty and the duplicator in action:

The Constitution wraps up its current phase of restoration next month. Still seaworthy, still officially in service, she’s the oldest vessel in the world still capable of sailing under her own power. But rather than sail off into the Atlantic after leaving dry dock, she’ll stay at the Charlestown Navy Yard, where generations of Americans can continue to enjoy visiting her and hearing her stories.

Special thanks to the U.S.S. Constitution Museum and the Naval History & Heritage Command Detachment Boston. There’s plenty more info about the restoration work on the detachment’s blog. And consider a visit to the Charlestown Navy Yard this summer. (Note to our readers in California: you get your own dose of tall ships in September! See

P.S. Safety being a prime focus here at Suffolk, we especially appreciated the following PSAs posted at the Charlestown Navy Yard…

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This post was written by Suffolk Construction’s Content Writer Patrick L. Kennedy. If you have questions, Patrick can be reached at You can connect with him on LinkedIn here or follow him on Twitter at @PK_Build_Smart. 

Our preference for detail? It’s by design

The case for basing buildings on biometrics

A developer caused a minor uproar late last month when he criticized the Boston Seaport’s “uninspiring architecture.” Of course, it’s common for ordinary citizens across the country to air complaints about plain, boxy towers—for example, Curbed readers rated their choices for the ugliest buildings in San Francisco and New York. But in the February incident, an audience of architects found it jarring to hear an industry insider speak ill of their work.

Yet nobody seemed to notice back in November when architect Ann Sussman made even stronger comments about the corridors of glass boxes built lately in the Seaport, which is sometimes called the Innovation District. People just don’t like sheer walls, Sussman said in a talk at last fall’s ABX conference. “That’s one reason why the Innovation District fails. Too many blank facades.” The district’s streetscape even poses a “health issue,” she said. “Our cortisol level goes up” in such bland environments.

Maybe builders and designers should start paying attention to this argument. Sussman wasn’t merely expressing an opinion. A growing body of research suggests that humans are hard-wired to prefer lush details over clean lines, thanks to millennia of evolution in the wild. And Sussman says there’s nothing architects can do about that preference, except design to it.

Mind over matter

When she lived in Paris for a time, amidst the Mansard roofs and street-level cafés, Sussman noticed that her fellow visiting Americans walked everywhere. Back in the States, the same people would rather drive everywhere. She began to wonder: Why is that, really?

Sussmann sought real data on why people seem to prefer some kinds of buildings over others. Last year, relying on biometric-measuring software, Sussmann and co-researcher Justin Hollander analyzed eye movements and unconscious response to a variety of images. Their findings were eye-opening.

In one test, two sets of volunteers were shown two different photos of the Stapleton Library in Staten Island, New York—one with the windows Photoshopped out, and one unretouched. See the images side by side below. The dots indicate what parts of the building one subject looked at in each. (The human eye can make four to five rapid movements between fixation points per second.) Notice that the de-windowed walls got hardly a glance.

Stapleton Library

The researchers found the same preference in test after test. Subjects barely registered the blank or sheer walls of a library in Queens and a museum in Brooklyn, focusing instead on billboards, cars, and pedestrians.

This raises two immediate questions: First, how the heck does the eye-tracking software work? And why do people unconsciously avert their gaze from plain facades?

Programs that measure people’s reactions to images have been around for years, Sussman pointed out in her ABX talk and in a later e-mail exchange. At multi-billion-dollar companies, the designers of packaging and automobiles use the insights they gain from biometric testing to determine a look that will have mass appeal.

Fortunately, the cost of such software has come down recently, to the point where curious architects can get in on this research. For her study, Sussman used a program called iMotions to measure eye movement as well as facial recognition—e.g., picking up on our barely perceptible lip and forehead movements that indicate joy, fear, or surprise. (Other features of iMotions include tools to measure heartbeat and electromagnetic activity in the brain.)

As a test subject looks at an image on a computer, an infrared light shines on her eye. A high-resolution camera records the eye’s rapid movements, capturing the flashes of infrared as the light bounces off the eye. If the eye is looking up and to the left, a burst of red will appear on the lower right part of the eye. (At least, that’s the broad-strokes explanation.) That data is linked to the photo being shown, and the software spits out a graphic representation. For example, the below video shows the gaze path of one subject viewing an image of the Villa Rotunda in Italy.

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Embracing sea level rise with resilient design

With sea levels rising fastest on the East Coast, the Gulf of Mexico and in California, finding ways to stem the tide is increasingly difficult because shrinking glaciers continue to add water to the world’s oceans and increased global temperatures are expanding seawater. That’s why some of the brightest and most creative architects, designers and engineers from around the world are now innovating solutions that embrace water by integrating infrastructure that works with the ocean’s projected rise rather than just trying to stop it.

In fact, some notable examples of this emerging philosophy known as resilient design are currently on display at the Boston Society of Architects (BSA) gallery. The winning submissions from the Boston Living with Water competition are being shown through June.

A Google Earth image of the Fort Point Channel and Boston Seaport shows what the landscape looks like today. The artist's rendering above shows the same landscape after the 100-acre neighborhood is raised about 12 feet to combat sea level rise. Both images courtesy of Architerra.

A Google Earth image of the Fort Point Channel and Boston Seaport shows what the landscape looks like today. The artist’s rendering above shows the same landscape after the 100-acre neighborhood is raised about 12 feet to combat sea level rise. Both images courtesy of Architerra.

Similar to the Jacques Rougerie Foundation’s International Architecture Competition and San Francisco’s Rising Tides competition, Boston’s version challenged members of the international AEC industry to design ways to shield the city from sea level rise. These competitions are evidence that the seeds of innovation are being planted right now, to account for sea level rise and that cities such as Boston and San Francisco are giving this crisis the attention it deserves. After all, a report released last year said that Boston could see its harbor rise by as much as seven feet by the year 2100. Just last week, city officials announced that they might allow developments in coastal floodplains to build taller than is currently permitted so that electrical, mechanical and HVAC systems can be designed into the midsection of buildings rather than in the basements. This would not only protect mechanical systems against flooding, but it would mean owners don’t have to sacrifice valuable square footage.

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