The USS Monitor Center Blog
This post is coming out a little later than I wanted it to, but we have had a very busy few weeks here in the lab. We had some outdoor projects to finish before the weather turned cold. Some of our activities in the last few weeks have included assembling and installing a new anode rig in the tank holding the pieces we used to test the dry ice blasting, winterizing the tank farm and having adventures in the skeg tank. The skeg tank adventures will get their own post after Thanksgiving, today I want to tell you about dry ice blasting.
We were fortunate enough to have the opportunity to try out a SDI Select 60 dry ice blaster from Cold Jet. The set up for this machine is not overly complicated. You hook it up to an air compressor; load the hopper with either dry ice pellets or blocks, in our case we found that pellets worked better, the block or pellets are pressed into an auger that shaves them and then the shaved pieces are fired down a hose and out a nozzle held by an operator. The system set up is not so different from other abrasive cleaning methods, but the unique thing about dry ice blasting is that there is no aggregate left at the end to clean up. If you are doing abrasive cleaning using glass beads, sand, ground walnut shell or any other medium you will have to clean bits of that medium off of your object when you’re done. You get to skip this step with dry ice blasting since your medium just sublimates away.
We will need to do more testing and Will has some samples to analyze, but after cleaning some lower hull plates I am willing to say that the results look pretty positive. The comment was made more than once that dirt and corrosion product flew off the surface of the objects. Hopefully this is a cleaning technique we will be able to use again in the future.
Check back soon for lab activity updates and Happy Thanksgiving from everyone here in the Monitor Lab.
Will adding dry ice pellets to the hopper.
Dave blasting away. Everyone got a turn. It was very fun.
Dave blasting and Will keeping an eye on the machine.
The act of moving USS Monitor artifacts during conservation or onto exhibit at The Mariners’ Museum often isn’t very simple. Factors like an artifact’s size, weight, fragility, and material composition must be considered before any move occurs in order to avoid damaging these precious artifacts. Minimizing movement during treatment and exhibition is critical to the overall health and long-term survivability of fragile artifacts. Often times the Monitor Conservation team spends days or even weeks planning and prepping for a move that may take no more than a few seconds or minutes. Better safe than sorry!
We use a variety of gear and equipment including overhead cranes, lifting straps and cables, shackles, chain hoists, lifting platforms, come-a-longs, pneumatic tires, dollies, forklifts, and good old-fashioned sweat and elbow grease. But sometimes even the best equipment and planning is no match for 140-years of exposure to a corrosive ocean environment. As a result, many of these treasured artifacts from USS Monitor are too unstable after deconcretion and conservation to move out of the exhibit.
There are very few facilities in the world that have developed an expertise in moving and conserving extremely large and fragile archaeological materials. The Mariners’ Museum is fortunate to be a leader in this field. Here are a few pictures of our efforts to move large, heavy, and complex artifacts recovered from the Monitor National Marine Sanctuary.
It generally goes without saying that we have a lot of metal artifacts to treat here at the Monitor Center. The term ‘ironclad’ does not exactly lend itself to images of wood or rope, but our collection of organic objects is not insubstantial. Thursdays have been devoted to survey of the organic objects in the walk-in refrigerator for the last couple of months, with a few breaks for other activities. This week we were doing something a little different, but still organic related. Some of you may recall that awhile ago one of the gun carriages was dissembled. The wooden sides still need to have their long iron bolts removed, an activity we hope to undertake soon, but for now those beautiful oak pieces are living in tanks with water, a corrosion inhibitor, and a biocide. The corrosion inhibitor helps to keep the iron bolts from corroding away until we can remove them, and the biocide prevents new ecosystems from growing in the lab. In addition to the corrosion inhibitor we are also using galvanic protection to prevent the iron bolts from corroding. The bolts are hooked up to magnesium blocks with electrical wire. Magnesium is less “noble” than iron in a galvanic series, which means that when it is connected to iron, magnesium will corrode faster than if it were unconnected. The other side of this is that the iron will corrode more slowly than if it were unconnected. So the magnesium will corrode into nothingness and the iron stays reasonably intact. The catch is that you periodically have to put in new magnesium blocks, an item we sometimes have difficultly tracking down. If anyone out there knows of a good source for magnesium blocks, please leave a comment or drop us an email.
So, as some of you may have gathered, Thursday was spent changing the solutions in these tanks and wiring in new magnesium blocks. Be sure to check back to the blog soon as we are testing dry ice blasting as a cleaning method this week. Hopefully there will be excellent results to share around this time next week.
Mike rinsing out the tank.
A newly rinsed oak gun carriage side.
Will and Mike in the wet lab.
Our good friend Dr. Francis DuCoin has been busy! Check out his new hi-def photo mosaics of the exterior and interior of USS Monitor‘s gun turret in the latest issue of Civil War Times.
Additionally, he wrote a brief update on the slow but steady progress being made by conservators in the lab to stabilize the 120-ton wrought iron turret.
Want to see Dr. DuCoin’s mosaics? Want to see new pictures of recently excavated artifacts? Pick up your copy today and let us know what you think!
It’s late Tuesday evening. The phone rings. It’s Dave Alberg, Superintendent of NOAA’s Monitor National Marine Sanctuary. “We’re taking our research vessel SRVX off the coast of Atlantic City to hopefully identify an old shipwreck. We have one empty spot on the boat. It’s yours if you want it.”
“I’m in!”, I excitedly yell into the phone. So much for staying calm and playing it cool…
As Dave continues to describe details about the trip, my mind starts swimming in a world somewhere between reality and fantasy. Visions of scientific exploration and shipwrecks morph into Jules Verne’s 20,000 Leagues Under the Sea. I imagine a giant squid’s massive life-sucking tentacles wrapped around the SRVX. Exploration and adventure. The stuff of legend.
“Where’s the boat docked and when do we leave?”
It’s now Thursday evening and Dave and I meet up with the rest of the crew at Little Creek in Norfolk. It’s a crew fit for a movie; equal parts brilliant and talented mixed with a dash of crazy. Russ Green, Deputy Superintendent of Thunder Bay National Marine Sanctuary and a veteran diver; Tane Casserley, Marine Archaeologist with NOAA and a descendent of a Maori chief; Pasquale DeRosa, a skilled captain who knows the SRVX inside and out; two other licensed captains from the National Marine Sanctuary Program round out the crew.
It’s nearly 10:00pm when we throttle out of the Chesapeake Bay Bridge. “The seas shouldn’t be too bad,” I think to myself. But even though the SRVX is almost 90-feet in length, she starts to rock and roll as soon as we get out into open water and head north. Dave, Tane, and I hold on for dear life as we go flying off our bunks in the forward berth. “Scratch that last thought, it’s gonna be a long night.”
After a sweaty night of fitful sleep, I awake early and walk out on deck. It’s bright and sunny, the New Jersey coastline is clearly visible on our port side, and Pasquale begins a long, slow turn toward Atlantic City. We pull up to the pier at the Coast Guard station expecting to meet our other divers and remote sensing experts. Instead, we are greeted by a 175-pound dog named Nucky. He is the Coast Guard station guard dog and he’s all business. He backs down but only after we toss him a few pizza crusts. He gobbles them up quickly, leaving behind nothing but crumbs and a puddle of drool.
The rest of the crew eventually arrives, including Jim Delgado and Dan Basta of NOAA. Everyone gathers in the main galley and Jim briefs us on the mission. Divers will be sent down on a wreck site located 12 miles off the beach in 90 feet of cold, dark water. The wreck is the only major site yet to be positively identified by the robust New Jersey recreational diving community. Our divers are to take photos and videos of the site for comparison with original plans and engineering drawings of the Robert J. Walker, a United States Coastal Survey ship that sank after colliding with another vessel in 1860, taking twenty of her crew to the bottom. It was the largest loss of life for the ancestor agency of modern-day NOAA.
During the briefing I show the team a high-resolution photo of a painting of the Robert J. Walker, part of the museum’s general collection. The image depicts the sinking but also reveals important details about the appearance of the vessel. Jim is excited to see the photo of the painting as he had recently funded its conservation with the goal of public display.
Tane, Russ, Dan, and Matt from Stellwagen Bank Sanctuary take notes and prep for the dive as we motor offshore. The SRVX is positioned directly above the wreck coordinates. Russ and Matt splash in the water first, followed by Tane and Dan. There is some visible frustration as they surface almost 30 minutes later. “We couldn’t see anything. We know it’s down there, but we just couldn’t find it!”
That’s when Vitad Pradith, a remote sensing wizard with the Coast Survey’s Navigation Response Branch, stepped up to the plate. He quickly reviews his recent survey data and recommends repositioning the vessel. Minutes later, divers splash again and are underwater for another 30 minutes. Dave and I stand watch on the bow and track the divers’ bubbles rising slowly from the seafloor. The divers re-appear on the port side. Both teams give a thumbs-up and climb aboard the stern of the SRVX. The divers are smiling and talking, and we can only assume they had a great dive.
The group assembles to review the pictures and film. Although visibility is generally poor and dark, their images are incredible. A badly corroded and concreted engine assembly is clearly visible, as are slightly canted paddle wheels. Matt shows video footage (http://oceanservice.noaa.gov/news/weeklynews/aug13/walker.html) of a mid-19th century glass bottle resting on the seafloor next to what appears to be a wool blanket or coat. The wool gently flutters back and forth in the light current. Tane and Russ compare measurements from their dive slates with original engineering drawings, and we review other data that NOAA has gathered from the site in prior days.
After careful consideration and evaluation, Jim and Dan confirm that the wreck is indeed the Robert J. Walker. Everybody aboard the SRVX shakes hands but remains somewhat somber, realizing that this is indeed the same vessel that took 20 of her crew to their deaths. We walk quietly to the bow and observe a brief moment of silence, followed by a few words of remembrance from Jim.
Soon we are underway again, and the smell of food wafts up from the galley. While we eat dinner around the cramped table, the mood lightens and we all trade a few laughs and stories. They ask me questions about conserving the Monitor; I ask them what it is like to dive beneath the waves in search of shipwrecks. During the meal, I can’t help but think about the amazing technical skills and abilities of the people around me and of the possibilities for future collaboration.
It has been almost three months since our successful expedition but the taste of adventure still remains. And so does my optimism that NOAA and The Mariners’ Museum will broaden our partnership and continue to explore the great depths of the ocean and her many mysteries in the coming years.
It occurred to me that most of our recent posts have been about exciting individual events, and while these are very interesting perhaps you would also like to hear about day-to-day adventures in the lab. However, as I have said before, there really is no such thing as a ‘normal’ day at the Monitor Center. So let me tell you about my week:
Currently I am working on cleaning the wooden components of a block, which would have been part of a pulley system. This particular block came out of the turret and may have been used as part of the system to maneuver the guns. So I spent all day Monday using the ultrasonic cleaner, much like the one in your dentist’s office, to remove the concretion from these pieces of wood.
Cleaning a wooden sheave, the circular center piece of a block.
Tuesday involved more of the same as Monday as far as lab work went. I am still cleaning wooden block pieces and will likely be doing so for some time. It is slow going, but the results will be well worth it. Tuesday evening, during their bimonthly meeting, the Newport New City Council presented a small contingent from The Mariners’ Museum and NOAA with a Resolution of Recognition in Honor the 40th Anniversary of the Discovery of the USS Monitor. This was an honor greatly appreciated by both the museum and NOAA.
Left to Right: Mayor Price, Dave Krop, Stuart Katz, Shannon Ricles, Elliot Gruber, Anna Holloway, and Kate Sullivan at the Newport News City Council meeting
Wednesday was a lab cleaning day, while not one of our more exciting days, definitely a necessity from time-to-time. Wednesday also saw the arrival of Fran DuCoin, aka ‘The Duke’, one of our long-time, out-of-town volunteers. Fran came bearing gifts in the form of the newly rendered 2012 Turret photo-mosaic. The turret photo-mosaics show the interior and exterior of the turret as one long image. Fran is currently researching the crew and the positioning of the turret awning stanchions after sinking.
On Thursday we continued on with our survey of the organic material in the walk-in refrigerator. The survey involves pulling out each container, writing a brief condition assessment of the artifact, taking its photograph, and changing its storage solution. Thursday evening the lab was host to members of the Bronze Door Society and their guests, who had the opportunity to see some newly conserved, never previously displayed artifacts.
Friday is pH survey day, a pH measurement of the solution in each tank in both the wet lab and tank farm is taken, just to ensure that all of our solutions are doing what they are supposed to be doing. Will was back in the lab and working on the Worthington pumps. He had been off earlier in the week having his own adventures. We also had to say good bye to Fran on Friday, hopefully he will be back soon.
So there you have some highlights of the week. Check back to the blog soon for more updates on lab activities.
Christmas came early to the Monitor Center this year. We were recently able to purchase a refurbished Bruker Tracer III-SD portable XRF (x-ray fluorescence). We have been able to borrow one of these devices from Bruker in the past, and it is a fabulous piece of analytical equipment. You may remember that we talked about using one on the condenser tank a few months ago. Through non-destructive testing, which conservators are a big fan of, this machine will tell you the elements present in your sample, or in our case, artifact. There are some limitations, but it works really well with identifying metals. I had the chance to use the XRF less than a week after its arrival in the lab for just this purpose on a spoon I am currently treating.
The spoon’s official during treatment photograph.
This particular spoon had been previously treated. The records for this object state that it was likely a silver spoon. We have other flatware in the Monitor collection that we know to be made of silver. Closely comparing this spoon visually to other spoons, one begins to have the sense that perhaps one of these things is not like the other. And this sets the conservation senses tingling, because if it’s not made of silver, than what it is? I admit I had a hunch, but while hunches are all well and good, analytical fact is another thing entirely. Enter our shiny, new XRF, which only mostly looks like a Star Trek phaser.
An Original Series Star Trek phaser vs. a Bruker portable XRF.
The Star Trek phaser in action, difference here: the XRF does not fire a red beam, nor do we have to hide behind rocks to use it.
Following a round of testing and examining the resulting spectra, I had my answers. The spoon in question was not made of silver. I can say that it is definitely a tin alloy. The other metals present, antimony, copper, and just a little bit of lead indicate that this is most likely a pewter spoon. It may have been a crew member’s personal belonging.
Check back to the blog soon for more updates from the lab.
Our origami Monitor contest wrapped up at the end of June. We didn’t quite get the fleet of Monitors we were hoping for, but the winning entry was very impressive. Mary-kate won with this entry.
Look how tiny it is!!!
We also received a link from Charles to an origami model he had designed a couple of years ago. It features both the USS Monitor and the CSS Virginia and is pretty impressive. Go check it out.
Check back to the blog soon for more updates from the lab.