Brace yourself as we update you on U.S.S. Monitor mystery maker's mark and explain how two rods stabilized ironclad's remarkable revolving turret

Braces under, near guns in recovered turret (top); rendering of them with crew (MMP, Andy Hall)

The 600-page “Drawings of the U.S.S. Monitor, published in 1985, depicts the venerable Civil War ironclad from practically every angle. Scores of sketches demonstrate the exacting work of the draftsmen – with some components drawn to the inch.

“To the men who had the imagination, knowledge and skill to produce these drawings and the Monitor,” reads the dedication in the volume, written by Ernest W. Peterkin for the North Carolina and federal governments.

I continue to marvel at the design and engineering skills of those who made the vessel that changed naval warfare in a single battle with the CSS Virginia in March 1862. My recent foray into learning a bit more about the vessel’s circular, ingenious turret – and its supporting braces -- put me back in touch with experts on Monitor.

As I further studied the turret after communicating with them – I had an amusing observation.

A drawing (below) at the top of the publication – “transverse section through turret” -- features a cross-section of Monitor, with the turret resting on top of a spindle.

Oh my, I thought. The turret and rod combined look like a child’s spinning top!

Transverse section through turret shows spindle beneath (Drawings of the Monitor)

The revolving turret was no toy, however. It housed two XI-inch Dahlgren guns that could smash both ship and man. But to make the setup work, designer John Ericsson had to overcome challenges with the turret, dubbed a “cheesebox on a raft.”

“It was enormously heavy … (and) was designed to be turned by machinery rather than by hand,” Civil War naval expert Andy Hall told me in a recent email.

“To improve this efficiency, Ericsson recognized that it was necessary to relieve part of the weight of the turret on the rollers around its perimeter by ‘jacking up’ the turret a bit, temporarily placing much of its weight on its central vertical spindle. To prevent the turret structure from sagging, Ericsson included diagonal braces from the central roof beam to the base forward, aft and on either side of the turret that could be adjusted using enormous turnbuckles.”

Aft diagonal brace with ULSTER, highlighted at right, click to enlarge (Courtesy Mariners' Museum and Park)

Maker's mark 'Ulster' leaves questions

The two diagonal support braces (forward and aft) inside the turret have been of interest to me following the 2017 announcement by The Mariners’ Museum and Park in Newport News, Va., that Monitor conservators removing corrosion from the aft brace uncovered the word “ULSTER.” It’s the first time a maker’s mark was found in the turret.

Officials theorized the two wrought-iron braces – which have undergone conservation since 2016 -- were produced by Ulster Iron Works in Saugerties and added to the turret interior. The scenic city along the Hudson River is about 100 miles north of New York City, where Monitor was assembled in late 1861 and early 1862.

The company, which operated from 1827 to 1888 and took advantage of iron deposits in the area, was a Navy contractor.

Cannon damage on USS Monitor after clash with Virginia (Library of Congress)

“While this firm was never mentioned as a supplier during the Monitor’s construction at Continental Iron Works, it is now believed that Ulster provided materials for modifications to the ship while it was undergoing sea trials at the Brooklyn Navy Yard,” says the museum, which houses the USS Monitor Center, home to artifacts and items still being conserved after they were recovered off Cape Hatteras, N.C., more than two decades ago.

I have been mesmerized since the announcement by the mystery of the Ulster mark.

I reached out last month to Will Hoffman, Monitor project manager, to see whether conservators have since confirmed any link between the vessel and Ulster Iron Works.

The short answer: No.

Hoffman has cited papers from Ulster Iron Works in the collection of William L. Clements Library at the University of Michigan in Ann Arbor.

A summary of the collection includes this line: “Among the factors that contributed to the success of the Ulster Iron Works was the ability of the owners of the corporation to arrange for government contracts, especially contracts with the Navy, for providing iron products for use in rockets, ships, and other materials.” (At left, the forward and aft braces, courtesy of Mariners' Museum and Park.)

I reached out to the library to ask whether Ulster Iron Works records make specific mention of Monitor.

Terese Murphy, head of reader services, says a bound volume has entries through 1863 – a year after Monitor was lost in a storm.

Murphy wasn’t able to find mention of Monitor, but kindly sent me photos of the pages that would have mentioned the ironclad. I wasn’t able to make all the writing, but I, too, didn’t see the Monitor in the notes – many descriptions of technology and project summaries. It is possible that the names of the vessels for projects were not inscribed. The descriptions are very technical.

The manufacturer, which drew workers from as far away as England and Wales, was known for using European technology. A process called “double puddling” could produce appreciable amounts of high-grade bar iron.

1862 page from volume on Ulster Iron Works (Courtesy Clements Library, U. of Michigan)

Hoffman says, despite some research by his staff, he has not learned much more.

“It kind of went dead after that,” he says of the search for the Ulster connection. “We know these braces are additions.” They are not shown in original blueprints.

I reached back out to Audrey Klinkenberg, Saugerties town historian, about whether anyone there have come across any mention of the USS Monitor and Ulster Iron Works since the 2017 news. She said no.

A delicate balancing act during battle

With the Ulster mystery still out there, I asked Hoffman and Hall, who writes the Dead Confederates blog, about the six braces that reinforced the turret. (BTW, it’s possible the forward diagonal supporting brace also had an ULSTER mark and it was eaten by corrosion or is still covered.)

The diagonal braces were installed near the two guns in a claustrophobic space manned by an executive officer and 16 sailors. Like Hall, Hoffman says the 160-ton turret had a revolutionary design for the time.

 Braces highlighted, “U.S.S. Monitor: The Ship that Launched a Modern Navy” by Edward Miller

“The turret is like a suspension bridge,” with the diagonal braces providing balance to “keep it from tipping while firing the gun,” the lead conservator told me. One crew fired a Dahlgren while the other reloaded the second.

Hall says turnbuckles on the braces were a particular benefit at close quarters, as in the Monitor-Virginia battle in Hampton Roads.

“The crew in the turret adopted the practice of firing as the gun muzzles rotated past the target, rather than trying to rotate the turret, lock it in place, and then fire,” he says.

“With both ships maneuvering for advantage, almost at point-blank range, keeping Monitor’s turret moving during the action was essential. The officer commanding in Monitor’s turret, Samuel Dana Greene, described this as the turret’s ‘whirligig motion.’”

In a post on Dead Confederates, Hall describes the turret as “a very crowded and chaotic place.”

Clevis used in aft diagonal support brace (Courtesy The Mariners' Museum and Park)

The “Ulster” brace and its mate have undergone extensive conservation.

Hoffman says in 2016 both got their first round of dry-ice cleaning, followed by another round in 2018, and the aft “Ulster” braces was disassembled. Conservation of its aft clevis (fastener) was completed in 2019. Last year, the forward brace and remaining after-brace components received additional cleaning.

Unroll the turret for cleaning, or leave as is?

The turret currently rests on a lower support pad in a giant Mariners’ Museum and Park tank where it has undergone conservation for two decades.

The guns and braces have been treated in separate areas.

More than 50 maker’s marks associated with Monitor have been noticed over the years, says Hoffman. Roman numerals were spotted on the turret armor plates (the roof is upside down in the tank) and there are Roman numerals on sockets of the canopy stanchion.

The next big thing will be the full cleaning of the turret – but that is still a couple years off. (At right, dry-ice cleaning. Courtesy of Mariners' Museum and Park)

 And there are two considerations:

1. Should the turret be left in its current ring configuration for cleaning? While unrolling the plating might allow conservators to get into its curved layers, replacing rivets afterward may be impossible. Hoffman says the decision was to keep it as is.

2. The team has studied ways to treat wrought iron, which is forged and several inches deep. The turret is too big to clean by hand, so the likely scenario is dry ice, going from solid to gas. The whole idea is to remove ocean salt (chlorides) from the metal, to stem further corrosion.

The lab is working on a plan for the turret treatment, which could take up to eight months.

The turret will be turned right-side up, and the roof taken apart. “There are potentially artifacts still to be found” in the roof because some may be captured in concretion, according to Hoffman. (The remains of two sailors and numerous artifacts were found in the turret.)

Using scaffolding, conservators will clean the ring.

Turret bracing goes down in history, literally

Monitor and Virginia fought to a tactical draw at the 1862 Battle of Hampton Roads.

Hall, author of “Civil War Blockade Running on the Texas Coast,” says Monitor earned the strategic victory because the Confederate ironclad never ventured out again to attack the U.S. fleet.

“The U.S. Navy immediately contracted for new monitors, with several classes of the type entering service before the war ended in 1865. Each new class of monitor was built on the hard-won lessons of those before, with incremental technical improvements in armament, machinery and armor,” he says. (At left, part of the aft diagonal brace assembly. Courtesy of Mariners' Museum and Park)

Monitor sank in the Atlantic storm on Dec. 31, 1862, with the loss of 16 lives.

“The value of Ericsson’s bracing to keep the iron cylinder of the turret rigid proved to be beneficial to history as well, as it ensured that when Monitor capsized and sank in December 1862 after only a few months’ service, the turret fell off the ship but remained intact on the sea floor, from where it would be recovered in one piece in 2002,” says Hall.