USS Monitor: How was it modified during its brief service? How did it sink? Remarkable 3D images, animation will add to our appreciation of ironclad, crew

View of the bow and forward section, with armor belt section nearby; 3D model of USS Monitor as it appeared in July 1862; another view of the inverted hull, captured last fall. (Northrop Grumman)

New breathtaking, high-resolution images of the USS Monitor wreck are available on a government website that includes animation of the famous ironclad’s sinking and 3D models of how it appeared at various times during its brief life.

NOAA’s Monitor National Marine Sanctuary rolled out the page – which includes a four-part timeline about the vessel – on Saturday after a presentation on the results of a September 2025 mapping of the wreck site off Cape Hatteras, N.C.

Sanctuary research coordinator Tane Casserley told an audience at Mariners’ Museum and Park in Newport News, Va., that the ironclad, despite damage from its March 1862 fight with CSS Virginia, its sinking ninth months later and artifact recovery projects 25 years ago, looks great.

“It is in fantastic shape, so the same armor belt that was built to repel cannonballs in the Civil War is now holding that cultural heritage together today,” he said. “I was surprised by just how intact things were.”

NOAA and its partners Northrop Grumman and Stantec showed off some of the sonar-produced images of USS Monitor, which was discovered in 1973. A Northrop Grumman unmanned underwater vehicle was equipped with a micro synthetic aperture sonar (µSAS) system during the expedition. The system is a big upgrade over old side-scan sonar.

The system penetrated low-visibility conditions to generate extraordinary imagery of the wreck and its surrounding debris field, including detailed views of hull remains and internal structure, according the museum.

The website features a 41-second animation of the Monitor’s sinking during a storm on Dec. 31, 1862. The clip shows the doomed ironclad bobbing in heavy seas and the “glub glub” of water as it dips beneath the surface and turns before slamming into the sea floor 240 feet down. The turret tumbles away upon collision.

John Broadwater (photo below), a maritime archaeologist who has been on numerous Monitor expeditions and is a former superintendent of Monitor Marine National Sanctuary, was among those attending Saturday’s program and his name was mentioned when the unveiling turned to the animation.

“Two of the developers of that animation came up to me and enthusiastically said they were glad to meet me," Broadwater told the Picket. "One said that when she was working on the sinking sequence, she had my Monitor book ('USS Monitor: A Historic Ship Completes Its Final Voyage'] in her lap, trying to follow my description of the sinking, which was based on archaeological evidence and long discussions with naval engineers, salvage experts and my colleagues at the Marine Forensics Committee of the Society of Naval Architects and Marine Engineers. From my perspective, Northrop Grumman and NOAA got it right."

Sixteen men, including four officers, perished when the Monitor went down. The remains of two sailors were found in the turret when it was recovered in 2002. The turret and hundreds of other Monitor artifacts have been or are being conserved at Mariners’ Museum and Park.

The vessel’s stern and part of the starboard side struck the sand as it landed upside down. The bow and forward section are still intact.

The new images shows the stern is gone, with some of that displaced by the recovery of the turret, anchor and other components from 1998-2002. (Image at left, Northrop Grumman)

The Picket asked Casserley for his thoughts on how the animation was done.

 “When the wreck was discovered in 1973, we observed damage at the stern and starboard side, as well as rudder missing from the site. From these observations and damage found to some of the aft bulkheads we recovered, we can theorize how the vessel sank -- which is reflected in the animation.”

Images on the website show a detached part of the ironclad’s armor belt and some wire rigging used during salvage operations. Navy divers had to remove a section of the belt and some hull plating during the recovery of the turret, which rested beneath the vessel.

The sonar imagery is so precise you can see an automobile tire or two that somehow came to be in the area.

Mariners’ Museum and Park -- which houses thousands of Monitor artifacts -- said the aim is to improve interpretation and perhaps protection of the wreck, which is slow deteriorating.

Those interested in 3D modeling can turn to the NOAA website and Sketchfab to see three reconstructions of USS Monitor produced by Northrop Grumman, a defense contractor. Viewers can use their mouse to see the vessel from different perspectives.

Built as a prototype for a brand new type of warship, Monitor was continually improved during its brief life afloat in 1862. These improvements included different deck layouts.

3D deck view of the Monitor as it appeared during the Battle of Hampton Roads (Northrop Grumman)

The first image shows the ironclad as it appeared for the March 8-9, 1862, Battle of Hampton Roads against the CSS Virginia (Merrimack). In July 1862, the Monitor got a modified pilot house at the bow and extended air intake vents and smoke boxes toward the stern.

The third model is an artist’s interpretation of work in November 1862 at the Washington Navy Yard. Repairs and further improvements were undertaken. A telescoping smokestack and taller air ventilation boxes were fitted, which improved efficiency, according to NOAA.

Saturday morning’s presentation also heralded the Monitor’s role as an artificial reef and thriving ecosystem. A Northrop Grumman “Wreck to Reef” visualization shows how the wreck hosts fish, invertebrates and plant life.

Kelly Swindle, a senior marine biologist with Stantec, said the team took environmental DNA sampling from the water around the wreck and identified several fish, including the lancer dragonet, largehead hairtail, pearly razorfish and the twospot flounder.

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

Casserley told the audience people can learn so much new about the ironclad from the comfort of their armchair. “We can now bring Monitor to you virtually.”

“It's one thing to read a historical account and it's a whole other experience seeing it come to life before your eyes,” he told the Picket in the email.

The sonar images help the agency track changes over time “by showing the hull and armor belt integrity with hyper-accuracy. It will provide the sanctuary with a valuable baseline for future monitoring and inspire the next generation of marine scientists and archaeologists alike,” Casserley wrote in the email.

Broadwater said he was impressed by Northrop Grumman’s technology and the educational products developed in cooperation with the museum.

 “I only wish we'd had that technology back before we recovered the engine and turret. I tried hard to get an accurate 3D image of the Monitor before we disturbed the hull.”

Wow factor: Hi-res views of USS Monitor will be unveiled March 7 at Battle of Hampton Roads event. The aim is to promote education, protection in a new way

Monitor has been on the sea floor163 years (NOAA/GFOE); sonar vehicle used in 2025 (Tane Casserley/NOAA)

The public will have its first opportunity March 7 to see new “groundbreaking” sonar-produced images of the USS Monitor wreck and a 3D reconstruction of what the famous Union ironclad looked like before it sank during a storm off Cape Hatteras, N.C.

Monitor National Marine Sanctuary and Northrop Grumman officials will make the 10 a.m. presentation during the annual Battle of Hampton Roads event at the Mariners’ Museum and Park in Newport News, Va.

About 60 people will be able to attend the program at the museum’s Explorers Theater. Those unable to attend can register here to watch the presentation online.

A Northrop Grumman unmanned underwater vehicle created scans of the December 1862 wreck site during high-resolution mapping in September 2025. The vehicle is equipped with a micro synthetic aperture sonar (µSAS) system.

A Northrop Grumman vessel deployed the technology last September (Tane Casserley/NOAA)

The system penetrated low-visibility conditions to generate extraordinary imagery of the wreck and its surrounding debris field, including detailed views of hull remains and internal structure, according the museum.

Discovered in 1973 and designated as the nation's first national marine sanctuary in 1975, USS Monitor rests nearly 240 feet below the ocean's surface.

“Along with these scans, Northrop Grumman created several new visualizations of Monitor for us to help interpret its historic legacy and its role now as a thriving reef,” sanctuary research coordinator Tane Casserley told the Picket.

The museum is hosting the daylong event remembering the March 8-9, 1862, clash between the innovative Monitor and the Confederacy’s Virginia.

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

The venue -- which houses thousands of Monitor artifacts -- said the aim is to improve interpretation and perhaps protection of the wreck, which is slow deteriorating.

Officials have been finalizing speakers for the program and have declined to release any of the sonar images ahead of the unveiling. Among those joining in the presentation are NOAA, museum and Northrop Grumman officials and technical experts.

The day’s activities (see details here) are aimed at inspiring young visitors to explore engineering, science and cutting-edge technology.

"By unveiling this new technology alongside hands-on STEM activities, we’re showing the community that history and innovation go hand-in-hand,” said Will Hoffman, director of conservation and chief conservator at the Mariners’ Museum. “These experiences provide visitors a new window into the past, enabling people to engage with USS Monitor through a different lens, and potentially, drawing in new audiences of all ages to learn about the little ship that saved the nation.”

According to a sanctuary article, all data products from the project -- including 3D models, visualizations, and animations -- will be transferred to NOAA and made available for public use, “supporting transparency, education and long-term stewardship of the site.”

Casserley said images and more details on the project will be released March 7 at the sanctuary website.

Cathryn Newton, then 16, was on watch when the USS Monitor was found. The project was an amazing collaborative effort, she writes

Cathryn R. Newton on Eastward in 1973 (Courtesy of MIT Museum). Her mother,
Sunny, asked her father whether they found the wreck. He whispered, 'We think so'

Cathryn R. Newton found her career calling while sailing as a teen on the RV Eastward with her father, John G. Newton, and other scientists. They located the Civil War ironclad USS Monitor on Aug. 27, 1973. Since then, the Syracuse University dean emerita and professor has conducted extensive research on shipwrecks and marine fauna and environments. Newton, who was raised in Beaufort, N.C, recently led a scientific team that traveled to Newfoundland. The Civil War Picket asked for her recollections of the Monitor expedition and she submitted this essay.

50 years ago: Just after noon, we found the wreck of the USS Monitor, the most famous missing ship in America, on Aug. 27, 1973. Four investigators conducted this two-week, blue-water expedition organized and funded through the work of my father, John G. Newton, a Duke oceanographer and marine superintendent of the oceanography program; Harold "Doc" Edgerton, strobe pioneer, inventor, and longtime MIT engineering faculty who’d invented many of the instruments we used; Bob Sheridan of Delaware (later Rutgers), accomplished and hard-charging marine geophysicist who had a nearby seismic survey funded; and Gordon Watts, the brand-new marine archeologist at the state of North Carolina (the inaugural one).

Duke University's research vessel Eastward

Our team decided to take Monitor’s (+ towship USS Rhode Island’s) mariners at their word --and search near the edge of the continental margin 16 miles off  Hatteras. {All but one of many other Monitor searches in summer 1973 were near shore). My father, Bob Sheridan and Doc Edgerton wrote the proposals that had secured funding for the E-12-73 cruise from NSF and National Geographic Society (NGS).

My father had mapped the NC continental margin in a recent geological atlas and, with Orrin Pilkey, published the first work on the Hatteras Submarine Canyon. This background elevated our odds of success, but did not guarantee it.

I was a 16-year-old Duke sophomore who’d worked all summer making cross sections and assembling geological/bathymetric data for the upcoming cruise; my friends Paul Kelly and Bob Springle were deployed in parallel. Shy, hardworking and unconfident, I logged many hours at the Duke Marine Lab preparing cruise materials, and had expressed an interest.

Yet the expedition consisted principally of towering figures in ocean sciences, with a few doctoral students. Then came a surprise: 24 hours pre-departure, a space held for a woman member of the NGS Explorers Club came vacant. This young girl leapt into the air with joy.

1973: Gordon Watts, front left, behind him John Harris; on right, from back,
Robert Sheridan, John Newton, Cathryn Newton and Harold Edgerton (NOAA)

Following the one best piece of advice ever from my mother Sunny Newton, I kept a journal of the expedition, the only one extant. When my father died without notice at 52 of heart failure in 1984, I inherited every bit of planning material for the expedition and all the files amassed while they (Dad, artist Sandy Belock and Gordon Watts) tried to figure out what we were seeing in this complex shipwreck. I have written a book manuscript on all this, with input from many, and sent it to my superb editor.

As I write, it is noon on August 27. Fifty years ago to the minute, our 12-4 midwatch came on duty. My watch was headed by get-it-done geophysicist Bob Sheridan. Second mate Tom Stout, a veteran Navy captain on loan from University of Rhode Island, was on the bridge. The other three investigators were having lunch in the galley. I was deployed to the Simrad recorder in the wet lab -- a basic depth recorder, not as refined a view of things as on the vertical PDR (portable diver recall) in the electronics lab.

Just after noon, it recorded something that looked like a smudge. I was trying to figure it out when veteran electronics technician Fred Kelly, one of my father’s closest colleagues, was coming in to put his fishing gear away and told me this could be it.

Bob and Tom Stout instantly reacted, and Stout remarkably brought the ship about immediately over the wreck. A high-contrast target appeared on the vertical PDR up above -- with the intensity expected for a metal wreck. It could be Monitor! Doc Edgerton’s side-scan sonar disclosed an arcuate piece that might be the turret, but in the wrong orientation.

We spent several days documenting the wreck, as the ship time ended on August 31. The target was not what we’d expected -- rather than atop the wreck, the turret was underneath, and had landed slightly to one side. But working with artist Sandra Belock, a recent Rhode Island School of Design graduate, and replaying the underwater television tapes again and again, and gaining input from Gordon Watts, the three figured it out.

By January 1974, Gordon confirmed their collective view that the ship had “turned turtle” as Doc said aboard E-12-73. The turret, which was only loosely articulated to the hull (in part to support the rotation) had fallen off as the ship inverted, and the upside-down hull fell only partly atop the turret.

We announced the find at a press conference at Duke University with then-president Terry Sanford, one that Dad, Gordon and I attended in early March 1974. But that is a story for another day. Walter Cronkite (CBS evening news broadcast) and The New York Times (front page) covered the story -- not bad for a group of ocean scientists out of Beaufort, North Carolina!

For my dear friends and students, you now see the origins of my impassioned commitment to undergraduate research. Being part of this changed my life. That is likely true of everyone involved -- all 60 people on three research vessels, including those of us on Duke’s RV Eastward. (Cathryn R. Newton at left)

There were more than 60 or us at sea and dozens more on land. John Newton would be the first to mention the tremendous contributions to finding Monitor from the remarkable people of Eastward, as well as boatswain (bosun) Curtis Oden Sr. of Beaufort or the stunning seamanship of Capt. Harold Yeomans of Down East in deploying both underwater television and two cameras simultaneously. He would mention the core contributions of historical cartographer Dorothy Nicholson of NGS, and would note with pride that the first woman ship’s mate at Duke, Susan Barker, was also part of this team.

These ocean scientists and Eastward's professional crew, both highly accustomed to mapping at sea, acted in an interdisciplinary way to find something that no marine archeologists at the time could have found -- they just were not yet using these techniques of swath mapping that are now standard.

Moreover, I remain sincerely and deeply grateful to every person who contributed -- both in E-12-73 and especially the stunning sanctuary, recovery and museum processes to follow. Let's honor the full expedition as well those who've done such a tremendous job to keep Monitor alive.

PICKET COVERAGE OF USS MONITOR

-- John Harris: He became a hang glider pilot and founded Kitty Hawk kites. But first, he ran the 1973 expedition's underwater camera system.
-- Gordon Watts: Young archaeologist confirmed location of shipwreck.
-- Go deep for 50th anniversary of USS Monitor discovery: Printable 3D artifacts, webinar and a 360-degree video of ironclad's resting place
-- USS Monitor: Navy recognizes Virginia museum for cleaning of ironclad's two Dahlgren guns, which are still being conserved
-- The USS Monitor overcame doubters. Its crew trusted the ironclad, even during the terrible storm that sank the famous ironclad.
-- What do USS Monitor, Jimmy Fallon have in common? Saugerties, NY. This town morphed from industrial 'Inferno' to a cool tourist spot

Picket exclusive: These two sailors went down with the USS Monitor. Now you can see items they carried or were found near them

(Civil War Picket photos)

They are the kinds of things one might carry in a pants pocket: A rubber comb to tame a lock of hair, a small pocketknife, a wisp of string and a stray button that needs reattaching.

While seeming so ordinary, two dozen artifacts under glass at The Mariners’ Museum and Park in Newport News, Va., tell an incredible story filled with mystery, hope and terror -- a very human story.

Sixteen crew members perished when the Federal ironclad USS Monitor sank during a storm off Cape Hatteras, N.C., on Dec. 31, 1862. At the time, it was being towed to a new duty station -- nine months after its famous clash with the CSS Virginia a few miles from the museum. Nearly 50 men were rescued.

The exhibit, which opened last year, showcases items found in the turret. “These objects were found in context with human remains,” says Tina Gutshall, conservation administrator with the museum’s USS Monitor Center. The exhibit is in a gallery that includes two large replicas of the turret; one depicts how the inside looked 140 years later.

The turret was raised by U.S. Navy and other divers in 2002 and brought to Newport News. The museum and the National Oceanic and Atmospheric Administration, or NOAA, removed tons of silt and made the discoveries.

Despite advanced forensics testing and physical descriptions of sailors noted during their Civil War service, the identities of the two crew members remain unknown. Sailor 1 is believed to be William H. Eagan or Jacob Nicklis (Nickles). Sailor 2 is likely either William Bryan or Robert Williams.

“They all speak to me,” USS Monitor Center director emeritus John Quarstein said of the items, which are accompanied by facial and skull reconstructions made during the federal government’s quest to find descendants through a DNA match.

Image courtesy of Mariners' Museum and Park, Newport News, Va.

(Civil War Picket photo)

At top and center in the small exhibit are two pieces of footwear (above). Sailor 1 was found with a mismatched boot and shoe.

“At the moment leading up to the sinking, my hunch is these men were putting anything on that was dry,” said David Alberg, superintendent of the Monitor National Marine Sanctuary.

In the chaos, crew members scrambled out of the turret, with the goal of being rescued by the USS Rhode Island. They left a jumble of clothing, shoes and items.

Among the artifacts is a bent spoon that has the initials “JN.” It likely belonged to Nicklis, a 21-year-old sailor from Buffalo, New York. Quarstein believes the utensil was struck by a heavy object – perhaps two Dahlgren guns -- when the Monitor plunged 236 feet and hit bottom.

“There are a lot of spoons and other objects found in the turret. You can imagine the chaotic situation. Some are desperately trying to keep the Monitor afloat, and the last pump of the Worthington pump was the death knell.”

Image courtesy of Mariners' Museum and Park, Newport News, Va.

Almost immediately after the Monitor hit bottom, the coal stores gave way and sealed in those who could not escape. The two skeletal remains include bone breaks caused by the cannon striking them.

“They died very swiftly, though the ride down was clearly a terrifying 20 to 30 seconds,” Alberg told the Picket.

Officials spent more than a decade studying the bones and trying to determine to whom they belonged. They asked the public to look at photos, go through the attic and review family histories. “Trying to get people to come forward with a match with maternal DNA, didn’t happen,” Alberg said.

The two remains were buried in March 2013 at Arlington National Cemetery in Virginia. While it may be a long shot, there’s a chance their identities may be known one day.

For Alberg, who was present at the burial, it might be better that they remain unknown.

“They belong all of us together.”

The Picket visited the museum in March and conducted interviews during and after that visit. Here are summaries of the items, based on museum descriptions and those conversations. Artifact photos are courtesy of The Mariners' Museum and Park, Newport News, Va. The description of each artifact is below or next to the photograph. Please click each image to enlarge:

Image courtesy of The Mariners' Museum and Park, Newport News, Va.

WELLINGTON LEATHER BOOT, LEFT FOOT

The brown boot, found on the feet of Sailor 1, is in fragile condition. The upper portion of the boot was not attached. “It is possible that the detachment is contemporary with its original use and not related to deterioration after the wreck.” This crew member was wearing two different shoes at the time of the sinking. Remnants of a sock were found in the boot.

Image courtesy of The Mariners' Museum and Park, Newport News, Va.

LEATHER SHOE, RIGHT FOOT

This was the other piece of footwear worn by Sailor 1, showing he may have grabbed what was nearest while trying to escape. “The shoe is made of leather, brown in color with heavy iron staining and in fragile condition yet structurally stable in general." There may be residue of human tissue on the item.

Image courtesy of The Mariners' Museum and Park, Newport News, Va.

RUBBER HAIR COMB

This comb was found by the tibia of Sailor 2. It was made by India Rubber Company, with a May 1851 Goodyears patent. One side has a U.S. Navy inscription. 

GOLD RING

This is possibly a wedding band and is in excellent condition. It was found on the third finger of the right hand of the sailor, possibly worn by Jacob Nicklis. The gold ring has a sealed joint at the back and is decorated with a pattern of swirls, lines and crescents. “Some of the decoration is fairly crude indicating that the ring may have been decorated by the crewman himself or a non-professional jeweler.” Nicklis never married. “There is no way we can really know is it a wedding ring or not,” said Quarstein.

SILVER SOUP SPOON

This Rogers & Bros. decorative spoon bears the initials “JN,” indicating it is more than likely the property of ordinary seaman Jacob Nicklis, 21, of Buffalo, New York.Nicklis came on board the USS Monitor on Nov. 7, 1862, when it was undergoing repairs at the Washington Navy Yard. In a letter to his father, Nicklis said while he did not care for his accommodations on the Monitor's berth deck, he conceded that he at least had "plenty to eat and drink" including rations of sea biscuits and "what they call coffee." 

The bent spoon has a significant dent on one edge, indicating it may have been smashed when the Monitor struck the bottom and heavy objects were dislodged. The spoon was found near the left femur. The location, according to the museum, suggests placement in the front left pocket.

Image courtesy of The Mariners' Museum and Park, Newport News, Va.

SPOON STANDARD SIZE

Rogers Bros. is stamped on the back of the handle, and the front has the initial “S.” After treatment, the shiny silver utensil is free of all debris and in excellent condition. 

BRASS BUTTON

The copper alloy button with four recessed holes is in excellent condition. It was found near the wrist of Sailor 1.

The button was likely a part of the uniform worn by crew members aboard Monitor. There is no textile associated with the button.

Images courtesy of The Mariners' Museum and Park, Newport News, Va.

SKELETON KEY

This was found among pockets for Sailor 2. The main key body is tubular with outstanding rings and detail. The tooth of the key, which was made of copper alloy, is perpendicular to the key body. This object is in extremely fragile condition. 

FLYING EAGLE COIN

This coin was with other items in Sailor 2’s pocket. It is a Flying Eagle coin, one of the first small pennies made in the US. It is made of German silver and is in fair and stable condition.

The edge of the coin is uneven and irregular and no design is discernible on either face. The surface of this coin is eroded beyond recognition of any design or lettering.

LIBERTY HEAD HALF PENNY

This corroded/eroded coin may have been minted in 1813. It is made of copper and is in extremely fragile condition. The edge of the coin is jagged, uneven and irregular.

Although details are difficult to discern, the coin has a decorative serration around the front edge. On the back is what remains of the words HALF PENNY. The coin and other items were together in a pocket.

WOOL FIBERS

This wool string fragment was recovered from the mouth of Sailor 1 in 2002. The string appears to be braided in some areas and frayed throughout. The string is approximately 8” long when laid out straight. The dark brown string is in good condition after treatment.

Image courtesy of The Mariners' Museum and Park, Newport News, Va.

SILK FIBERS

Three separate masses are made of wool, silk and another unidentified vegetal fiber such as linen, flax or hemp.

BONE BUTTON

This is one of nine buttons recovered from the dredge spoil around Sailor 1‘s hand area. The button is dark brown in color and in good, yet fragile, condition. The button has a concave center with four thread holes and is made of bone. 

MOTHER OF PEARL BUTTON

This four-hole mother of pearl button was found with other items in what was the pocket of one of the crew members. The button holes are filled with green concretion and may contain traces of thread. It at one point was concreted to a bone button.

Image courtesy of The Mariners' Museum and Park, Newport News, Va.

WOOD KNIFE HANDLE

These wooden pieces appear to have belonged to a knife rather than a fork or spoon due to the flat shape. Each half of the handle has a 3/16" diameter hole in the butt, as well as four small pin holes. There is no metal remaining and the two halves have separated. 

Image courtesy of The Mariners' Museum and Park, Newport News, Va.

POCKETKNIFE HANDLE

These knife handle parts are made of bone and still have some visible iron staining from the blade. “The exterior faces of the handles, those that were not against the bolster lining, have a gnarled, uneven surface, similar to antler. The interior faces of the handles are mostly smooth with visible saw marks related to manufacturing.” The museum says the artifact was concreted with other contents from one of the sailor’s pockets.

(Picket photo)

Coming soon: When it was launched, many didn’t think the USS Monitor would meet success. They were wrong. A closer look at the crew and the ironclad’s history.

3-D mapping allows viewers to 'swim' through Civil War wreck off Galveston

A three-dimensional map provides fascinating new details of the largely-intact wreckage of the only Union vessel sunk in combat in the Gulf of Mexico.

The CSS Alabama (background) battles the USS Hatteras. (Copyright, Tom Freeman)

The National Oceanic & Atmospheric Administration on Friday released 3D sonar images of the USS Hatteras, which rests about 60 feet below the surface. Publication of the findings coincide with observances of the 150th anniversary of the Battle of Galveston, Texas.

The Confederate raider Alabama sank the gunboat about 20 miles off Galveston on Jan. 11, 1863.

This three-dimensional sonar scan shows a top view of remains of the USS Hatteras. (Credit: NOAA)

"Most shipwreck survey maps are two-dimensional and based on observations made by sight, photographs or by feeling around in murky water while stretching a measuring tape," said James Delgado, director of maritime heritage for NOAA's Office of National Marine Sanctuaries. "Thanks to the high-resolution sonar, we have ... the ability for researchers and the public to virtually swim through the wreck's exposed remains and even look below the surface at structure buried in loose silt."

A diver examines the Hatteras' paddlewheel in September 2012 (Credit: Jesse Cancelmo)

Recent storms allowed for divers and researchers to survey the Hatteras. In a statement released by NOAA, Delgado said the sonar survey showed survival of most of one paddlewheel, and revealed most of the ship's stern and rudder are emerging from the sand.

The survey plots damage to the paddlewheel shaft and damage to engine room machinery.

"The engine room spaces were a dangerous place in the battle," Delgado said. "Cannon fire severed steam lines and filled these spaces with scalding steam. Fires broke out, and yet the crew stayed at their post to keep the ship running and fighting, and in here, two of them paid the ultimate price."

• Watch sonar video of USS Hatteras