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Following the excitement and publicity of recovery of artifacts from site, it is all too easy for it to seem that artifacts sink again, without trace, when conservation begins. Despite the impression that television may give, conservation of waterlogged archaeological material takes time, especially with limited resources, as well as equipment and expertise. Our conservation reports are one of the ways we keep the public informed of what's going on in the lab. Since our last conservation report in July 2008, we have made good progress on a number of fronts. The 2008 field season was a success, which saw the beginning of a long term project to investigate the corrosion status of an anchor still on the site, and ended with the recovery of our 12th cannon, Cannon 18 (C18). The frames from the wooden hull structure are moving along in the conservation process and we are implementing a new treatment to prevent bacterial/fungi growth on our sternpost. Artifacts have been transferred to the NC Maritime Museum as well as the Museum of History and we will give a brief overview of what you might expect to see on display. QAR Lab
Crew Valerie Grussing, who worked with uslast year as an illustrator,
briefly returned to the lab in September to complete the illustration
of the seat of ease before it was transferred to the museum. We also very much appreciate contributions to the conservation effort from our volunteer helpers. In July we were assisted by Laura Brown and Peter Campbell. Laura, a junior in high school, joined us for work experience before going on to the NC School of Math and Science in Raleigh. Jessica Smeeks has just started volunteering with us. Peter and Jessica are both Master's graduate students in East Carolina University's Program in Maritime Studies. Lerae Umfleet, NCDCR Chief of Collections Management, has also spent some of her time at the lab updating our database and assisting Myron with lead shot processing (see below). Cleaning Lead Artifacts Most recently Jon has been cleaning concretion from lead artifacts such as strips and bilge strainers. He has used a variety of techniques to clean up the lead strips including various sizes of air scribes and acidic poultices, taking great care to leave the hair encountered on the strips in place for future interpretation. Seeing how Jon is very familiar with the lead strips he has been set the task of creating a documentation template for recording the different features on the lead strips, determining which characteristics are recorded and how.
Lead Shot Processing 2008 Fall Field Season - Preparations at the Lab Before the 2008 field season began, Franklin was available
to help Myron, Jon and Lauren at the lab set up a carport provided by
ECU to make additional space available for artifact storage. Our 4000
square foot warehouse lab storage area is now almost full. Myron and
Jon were instrumental in completing the task of making artifact storage
tanks water tight and safe for storage. Project director Dr. Mark Wilde-Ramsing
acquired additional storage tanks from Harlan Summers, owner of the
Royal Forge and Trading Company located in Aurora, North Carolina. They
provided additional storage for artifacts recovered from the 2008 field
season. As luck would have it, Ed Talley of MVS Military Vehicle Equipment,
learned of our needs and has donated an additional 16 tanks to the project.
These tanks have held As excavations began, Lauren and Jon helped with processing the 2008 artifacts, making sure they were stored properly and inventoried. They spent many hours doing data entry and completed all the new records for this year's artifacts (c.700) by Christmas.
After field season, Franklin returned to the lab to carry on with the micro archaeology of the sluice sediment. He continues to extract glass beads, gold grains, lead shot/fragments, copper alloy straight pins, bone and the most frustrating, mercury. Mercury is difficult to remove from the sediment because it has to be done under the microscope to separate the sand grains from the small globules of mercury, down to 1/10mm. Mercury will also adhere to the surface of gold grains if it comes in contact with the gold. The mercury cannot be easily separated from the gold therefore discoloring & contaminating the gold grains. Franklin will elaborate fully on the different artifacts removed during sediment processing in his upcoming article about micro archaeology.
X-radiography of Interesting Artifacts from 2008 Field
Season The sword guard (QAR3082.000)
was found in unit 203 on the east side of the main ballast pile next
to the north-south baseline. At first glance you can tell the sword
guard is copper alloy with a missing iron blade and handle that may
have been wooden.
There is always something interesting recovered from the
last unit excavated in a field season and this season was no different.
A possible coin (QAR3233.001)
was found in the sluice box from the sediment of unit 207.
We have also made some progress with x-radiography of concretions recovered in 2007. Lauren has been tasked with identifying artifacts in x-ray films and in doing so has brought the inventory of our x-ray films up-to-date.
Iron is the most prevalent metal on the QAR site, from cast iron cannon and wrought iron anchors to a multitude of wrought iron fasteners and cask hoops. The presence of iron in salt water creates a galvanic cell and the seawater acts as an electrolyte, increasing the rate of corrosion. A calcium carbonate layer begins to form on the surface made up of sand, shell and sea life, encrusting the entire iron artifact as well as adhering to anything around it. The encrustation grows over time and becomes very solid resembling concrete, referred to as concretion. Even though concretion is very solid, it is a semi-permeable membrane, and there is still an exchange of ions going on between the metal and the seawater. The presence of concretion has actually preserved theiron artifacts; however, it also increases the concentration of chloride and hydrogen ions at the iron surface. According to MacLeod, the pH beneath the concretion at the surface of the metal is acidic (4-5); while outside the concretion in seawater the pH is neutral to basic (7-8) (MacLeod, 1996). The corrosion of metal is an electrochemical process and the rate of decay is sensitive to temperature, salinity, dissolved oxygen, marine life and water movement. An artifact that stands proud on the ocean floor will have a higher corrosion potential than an artifact that is buried in the sediment; the lower the corrosion potential the less the artifact will corrode. To test the corrosion potential, the voltage of the iron object must be measured with an inert platinum electrode in relation to a silver-silver chloride (Ag/AgCl) reference electrode, indicating the difference in potential between the reference electrode and the object. Obtaining these measurements over a period of time can reflect the stability of the object. A3 was chosen to monitor because this artifact has one half buried deep in the sand and the other half protrudes about 6 feet above the ocean floor where it is always exposed to harsher conditions. The test site was chosen at the crown of the anchor, which is about 2 feet from the seabed. A sample of the marine life was taken from the anchor for analysis because different types of organisms can promote corrosion even further if they are boring organisms.
After obtaining the corrosion potential and pH readings
The aluminum anode was placed on a PVC frame and buried so the aluminum was just above the sea floor.A copper wire was used to attach the anode to the anchor. A band clamp was used to attach the wire to the aluminum anode. A larger band clamp was modified by attaching an adjustable screw, which connected the wire to the anchor. Once the band clamp was in place a sealant that cures underwater was put on the anchor in the newly exposed area. The anchor and anode were observed throughout the field season and the setup seemed to be holding up well. The first test was when a large storm came through the area. Once the storm passed we checked on the anchor setup and the connection to the anchor was still solid, however, the sacrificial anode had tumbled 7' to the north and west. The anode frame had flipped over and was a bit deeper than originally buried, luckily extra wire was attached to the frame in case an instance like that happened. The wire was still secure to both anchor and anode.
There are many uses to in situ monitoring and the information
this study could provide will be useful to both conservators and archaeologists.This
is a long-term project and if respectable results come from A3, there
is a possibility other anchors and cannon will be monitored on the
For more information on the in-situ monitoring project
contact Wendy:
Bacteria/Fungi on the Sternpost: A Growing Concern
Bacteria
and fungi have been a growing concern at the lab, especially on larger
waterlogged wooden artifacts, such as the sternpost
recovered during the 2007 fall field season. This composite structure
we refer to as the sternpost is a 6-foot fragment of the ship's sternpost
and its associated curved knee that served to connect the post to the
keel. Other structural elements attached to the piece include fragments
of both white oak bottom planks and sacrificial pine planking designed
to prevent wood boring organisms from penetrating into the primary hull.
Also present is the heavily concreted lower wrought iron gudgeon that
would have connected and hinged the vessel's rudder onto the back of
the sternpost, a sheet of lead wrapped around the bottom of the sternpost
that could have functioned to prevent chaffing, as well as tar/pitch
and hair that was used as caulking. This composite artifact will be
very challenging to conserve and the growth of bacteria/fungi growth
may be just the start of our troubles, but the archaeological information
this structure provides is invaluable. QAR archaeologist, David D. Moore, describes the sternpost as undoubtedly the most significant section of the remaining hull structure recovered to date, however the most interesting feature would have to be the Roman numeral "VI" carved into the upper part of the post indicating the height above the bottom of the now missing keel. These numbers would have extended up the sternpost well above the waterline to indicate the draught of the vessel (i.e. how deep she sat in the water), allowing the crew to adjust the trim of the ship as well as revealing the depth of water the ship could sail in before running aground. At least two features on the sternpost assembly, including the distance between the visible draught marks, suggest a design and construction in France, supporting the probability that this ship was the French slaver Concorde, hence Blackbeard's flagship Queen Anne's Revenge. Until this year, our strategy to control fungal growth
in the wood conservation tanks was through regularly changing the water.
However, even with this approach, fungi were still growing in the tanks
and with the recovery of the sternpost it was decided to investigate
the possibility of using a biocide/fungicide. After a literature review,
a couple of products seemed promising, one of which was Kathon CG. However
when we tried to purchase it from Rohm & Haas we were told that
due to regulations proscribing Our investigations led us to a product similar to Kathon but with a benzyl group attached rather than chlorine, known as Proxel, manufactured by the Arch Chemical Inc. Arch Chemical's Tech Department very graciously helped us decide on Proxel BD20, as it most closely met our specifications of use. Jim Loricchio, Arch Chemicals Inc. Account Manager was instrumental in providing the Proxel BD20 we needed to begin experimental testing. The testing consisted of using Proxel BD20 in various solutions under environmental conditions ideal for growing bacteria or fungi. The experiment contained two controls and two test samples with Proxel BD20 for each solution tested. Weight, solution color, and visual appearance, such as presence or absence of growth, were monitored weekly over eight weeks. The results from our tests indicated that Proxel BD20 could be effective in controlling the growth of bacteria and fungi in our large wood storage tanks. Proxel BD20 breaks down naturally in 9 months and is then safe to dispose of as water. Having gained permission for its use from ECU Environmental Health & Safety, we have just begun full scale use of Proxel BD20 for the sternpost tank and will be monitoring it over the next few months. QAR Wooden Frames - Moving Forward In 2004 (March 2004
Report) (Watkins-Kenney, et al 2005) it was decided to use a bulking
agent known as polyethylene glycol wax (PEG). One of the most successful
treatments of wood has involved a two-stage treatment that uses a low
molecular weight PEG 400 followed by a higher molecular weight PEG 4000.
This two-stage treatment is particularly good for treating waterlogged
oak, which typically has a degraded outer layer and less degraded core.
The low molecular weight PEG 400 penetrates readily into the smaller
cellular spaces of the less degraded wood and that it may chemically
bond to the wood structure replacing chemically bound water. In November of 2005, the QAR frames were placed
in a 5% v/v solution of PEG 400 in water. The percentage of PEG 400
was slowly increased until it reached a concentration of 20% v/v solution
of PEG 400. It was decided to move forward with the conservation process
to the second part, immersing the frames in the higher molecular weight
PEG 4000. In September 2008, the QAR frames were placed in a 5% w/v
solution of PEG 4000. The percentage of PEG 4000 will slowly increase
over several months until it reaches a concentration of 23% PEG 4000.
Afterwards, it will be ready for the freeze-drying stage of conserving
wood. The progress of the QAR frames will be reported on in future
reports. For more information on the conservation of wood artifacts
contact Shanna Daniel at: shanna.daniel@ncdcr.gov
Set of Nesting Weights and the fleur-de-lis
Symbol Five weights have been removed from the set of seven and
the first two weights (QAR2590.001 & QAR2590.002) did not possess
any markings. In February, the third weight (QAR2590.003) was removed
from the set and a fleur de lis symbol was identified in the
bottom of the inside of the weight. The first three weights were relatively
easy to remove from the set by cleaning corrosion from in-between the
weights while in an acidic treatment. Once the third weight was removed another interesting marking in the next cup (QAR2590.004) was revealed. The mark in the fourth weight looked like an arrow with decorative flare on the sides. Unsure of the meaning of the marking in QAR2590.004, it made more sense once the weight was removed from the set and the markings in the fifth cup (QAR2590.005) were exposed. QAR2590.005 has two fleur de lis symbols, one on its own and another that appears to have the number "2" stamped over it. After seeing the marking in QAR2590.005, the marking in QAR2590.004 appeared to be a stylized arrow, possibly representing a "1" stamped over a fleur de lis symbol. You can clearly see the bottom of the fleur de lis on the right side of the "1" and a portion of the fleur de lis on the left side of the "1". From the sixteenth to the eighteenth century, Nuremburg, Germany practically held a monopoly on the production of nested weights. The weights were exported and adjusted to the local weight standard of the country to which they were sent (Deagan, 1987). Every weight removed from the QAR2590.000 set has file marks on the outside bottom of each weight. Perhaps these file marks are evidence of the adjustments made to the original weights to fit a particular system. Once all of the weights from the set are conserved we will attempt to figure out which weight system our weights follow. Even though there is a great deal of literature about nesting weights, we have recently found examples with markings similar to our weights from a 1747 British warship, Maidstone that was lost off the coast of Noirmoutier, France. Fortunately the example from the Maidstone has all the weights to the set. The illustration shows numbers marked in the base of the nesting weights that correspond with the numbers marked in our set; 1, 2, 4, 8 (de Maisonneuve, 1991). QAR2590.004 would actually be the fifth weight in an intact set and the fifth weight in the set from Maidstone possesses the stylized "1" that looks like an arrow. It is important to mention that there are no fleur de lis markings in the base of the weights from the Maidstone.
These nesting weights are the first artifacts we have
recovered from the site that have possessed fleur de lis symbols. The
fleur de lis or "flower of the lily" symbol has many
meanings and has been used by many countries such as France, England,
Portugal and Spain. The simple presence of the fleur de lis symbol does
not make it possible for us to pinpoint the origin of our set, however
when we figure out the weighing system and if there is an adjuster's
mark in the master cup, we may be able to narrow down where these weights
originated. *Deagan, Kathleen. Artifacts of the Spanish Colonies of Florida and the Caribbean 1500-1800. Smithsonian. 1987.
Cannon 2 (C2) was a topic in our last conservation report in which we discussed cleaning out the remaining concretion from inside the bore. After the bore was cleaned C2 continued desalination in electrolysis until that process was complete in September. Successive baths of RO water (water purified by reverse osmosis) rinsed out the sodium carbonate electrolyte and by December the cannon was dehydrated. C2 was taken through the same dehydration procedures as C4 (March/April 2005) & C3 (July-September 2006). Tannic acid was applied to all surfaces and the cannon is now being monitored in the main building for stability. Since dehydration in December the cannon has lost four pounds of water.
Artifacts Transferred to Museum
One featured artifact known as the seat of ease (QAR632.000)
was transferred to the NCMM in October 2008. For the officers, these accommodations were located at
the ship's stern in an area known as the quarter galleries. These galleries
or balconies were projected from the stern area allowing drainage downward
to the sea. Various tapered lead tubing labeled either 'pissdales' or
'seats of ease' have been recovered from other shipwrecks, Whydah
(1717), Henrietta Maria (1700), and Dartmouth (1690),
indicating these accommodations were available to the crew. The remains
of the seat of ease's wooden portion have only been recorded on one
shipwreck, Vasa (1628). The QAR lab has been working hard to get artifacts ready for loan to the NC Museum of History in Raleigh for the 'Knights of the Black Flag' exhibit which opened March 6th 2009. Approximately 80 artifacts, in varying stages of conservation, on loan include pewter plates, ceramic sherds, pipe stems, crown/window glass shards, wine bottle base shards, cannon apron, lead strips, gunflints, copper alloy buckles, nesting weights, chart dividers, spigot valve and hundreds of gold grains with 2 gold jewelry fragments. You will also see 11 concretions as they were recovered from the site and some will have an x-ray displayed to illustrate what type of artifact you are actually seeing. Artifacts will be on display from March 6th to January 2010. Visit www.ncmuseumofhistory.org for more information on the exhibit and museum.
Public and Professional Outreach
In August, Shanna traveled to Port Discovery in Elizabeth
City to speak to 3rd, 4th, & 5th graders (approx 60) who participated
in the 2nd Saturday Science Program coordinated by Wendy Pierce. These
lively and enthusiastic students were broken up into two groups and
Shanna gave a presentation about the
In January, Sarah attended the Society for Historical
Archaeology (SHA) conference held in Toronto. She presented a paper
titled, Sunk without Trace? Accessing the Artifact Assemblage
from the North Carolina Beaufort Inlet Shipwreck (31CR314) in the
conservation session. Sarah's presentation focused on the ways conservators
and archaeologists strive to maintain accessibility to the artifacts
for many different interested groups, as conservation and analysis proceeds.
They were very excited about the presentation and asked
very interesting questions.
For the past six years the Museum of Albemarle has put on an educational program titled "Students Day on the River" organized by educator, Lori Meads. This is an event where 4th grade students from surrounding schools come to the museum to gain a better understanding of the maritime heritage, both historical and natural, of the Albemarle Region. In March, Wendy attended the event and spoke about the QAR Project to the nearly 400 individuals from Pasquotank County including students from J.C.Sawyer Elementary, Weeksville Elementary, Pasquotank Elementary and Albemarle School. Lori conveyed that the teachers and students found the QAR presentation to be enjoyable, age appropriate and met curriculum goals set by the state of North Carolina.
ICOM-CC WOAM (Wet Organic Archaeological
Material) 2010 Visitors
ECU Class Visits Open Day Scheduled *Any comments, suggestions or questions
can be directed to the conservation report editor at wendy.welsh@ncdcr.gov |