Conservation of the RMS "Big Piece": A Case Study and Critical Evaluation Author(s): JOSEPH SEMBRAT, PATRICIA MILLER and JUSTINE POSLUSZNY BELLO Source: APT Bulletin: The Journal of Preservation Technology, Vol. 43, No. 4, SPECIAL ISSUE ON IRON AND STEEL (2012), pp. 41-50 Published by: Association for Preservation Technology International (APT) Stable URL: https://www.jstor.org/stable/41827038 Accessed: 28-01-2019 17:30 UTC

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This content downloaded from 38.125.11.94 on Mon, 28 Jan 2019 17:30:22 UTC All use subject to https://about.jstor.org/terms Conservation of the RMS Titanic "Big Piece": A Case Study and Critical Evaluation

JOSEPH SEMBRAT, PATRICIA MILLER, AND JUSTINE POSLUSZNY BELLO

The salvage and treatment of a Introduction the central section of the (Fig. I).1 significant section of the Titanic The RMS Titanic is one of the most Following recovery, the fragment was subdivided into two pieces of unequal illustrate the great logistical and storied sea vessels in history. Despite size, which are known anecdotally as the sinking a century ago, this massive ship technological challenges associated "Big Piece" and the "Little Big Piece." continues to captivate the curious pub- with the conservation of a The Big Piece is a 17-ton artifact that lic and vested professionals alike. As the measures 25 feet by 12 feet and consists monumental iron artifact recovered now-familiar history goes, while en of three steel plates, each approximately from a marine environment. route from Belfast to New York, the 1 inch thick, riveted to each other and to Titanic struck an iceberg. The impact eight segments of the original steel compromised rivet seams in a section of frame. Four bronze portholes, three of the hull, creating a 32-foot-long gash below the waterline. Under substantial which retain glass, and a lead methane pipe are part of the piece. In some loca- stresses, rivets failed, seams parted, tions original paint still survives.2 plates cracked, and compartments filled This paper discusses how the treat- with water, ultimately leading to the ment of the Big Piece evolved over the sinking of the ship on April 15, 1912. course of nearly a decade, a period Lost for decades, the wreck site was during which the authors had several discovered in 1985, miles below the surface of the North opportunities to reevaluate and re-treat and more than 300 miles southeast of the artifact. The discussion is placed Newfoundland. The hull fractured into within the context of several larger two main sections and sank to the themes, including the emergence of new iron and steel materials and fabrication ocean floor, landing nearly 2,000 feet methods at the turn of the twentieth apart. As they spiraled downwards, century; substantial metallurgical and their contents scattered, forming what is referred to as the debris field. forensic testing performed on this arti- fact; and the challenges associated with In 1998 a 20-ton fragment of the hull was recovered from the wreck site. The recovery of this and similar large-scale marine artifacts. The paper summarizes fragment was subsequently identified as the treatments performed, which in- shell plating from two empty first-class cluded both traditional and novel meth- suites, C-79 and C-81, just forward of

Fig. 1 . Diagram illustrating the approximate location of the Big Piece on the RMS Titanic. All images by Joseph Sembrai, unless otherwise noted.

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Fig. 2. Timeline of milestones in the recovery and treatment of the Big Piece.

ods, and the reasons for which they The hull of the Titanic was con- wrought-iron to steel rivets for the were, selected (Fig. 2). Finally, the au- structed of more than 2,000 rolled mild- greater strength of the steel rivets. Inno- thors evaluate the efficacy of select steel plates VI 2 inches thick, 30 feet vations in the manufacturing of steel treatments with the advantage of hind- long by 6 feet wide, triple-layered, and meant that its prices were falling at a sight, given the curatorial and conserva- stitched together with more than 3 time when the cost of wrought iron was tion parameters specific to this project.3 million rivets in distinct configurations. increasing. Unlike wrought-iron rivets, The design specified double-riveted lap which had to be installed by hand, steel Turn-of-the-Century Shipbuilding: and butt joints for seams at the bow and rivets could be installed by machine, Materials and Fabrication stern sections. Triple- and quadruple- which reportedly increased construction riveted overlapping joints added strength rates twelve-fold. Although labor was The Titanic was one of three White Star in the central section, where the ship generally cheap, a sufficient and reliable Line "Olympic-class" liners constructed had to withstand the greatest stresses. pool of skilled labor needed to construct by Harland &; Wolff in Belfast in the Specifications called for hydraulic- these ships was hard to come by. There- first decade of the twentieth century. machine-driven mild-steel rivets to be fore, a mechanical innovation such as Each was touted as having the best the used throughout the ship wherever this appealed to shipbuilders working on world could offer in a passenger sea possible; hand-hammered wrought-iron compressed timelines with limited re- vessel: speed, luxury, modernity, and rivets were to be used in construction of sources, further accelerating the techno- safety. The Titanic boasted a length of all frames and anywhere machine rivet- logical migration to steel. 883 feet and a gross weight 46,329 ers could not be used due to restricted tons; contained 3 engines, 29 boilers, clearance. In general, steel rivets were Recovery and Research and 159 furnaces; and carried more used in the central hull and deck plates, than 2,100 passengers on her maiden and wrought-iron rivets were used in the The discovery of the Titanic in 1985 voyage. bow and stern plates.6 renewed a flurry of interest in the ship, The Olympic class was conceived The various types and mixed use of both in popular culture and in scientific during a period of intense competition rivets in the construction of the Titanic communities. Nearly all shared an in- terest in what sank the Titanic . A series between Great Britain, Germany, and is an indication of how this ship strad- America for domination in transatlantic dled a metallurgical and technological of early expeditions by various parties transport.4 Shipbuilding technology was frontier and illustrates a number of com- recovered thousands of artifacts, which in the midst of being transformed from peting industrial and economic forces fueled some early independent research, an industry of manpower to one domi- that were at play. Although steel had conservation, and metallurgical testing.7 nated by the machine. Materials were become the primary hull-plate material However, in an attempt to answer the also changing: wrought iron, used only in the first years of the twentieth cen- question as to the cause of the catas- to clad wooden hulls in the early part of tury, wrought iron still held onto a place trophe, as well as to meet numerous the nineteenth century, was being used in shipbuilding. Due in large part to its other goals in a more comprehensive with steel in all parts of shipbuilding by ductility, wrought iron was reasonably way, RMS Titanic, Inc. - the salvor-in- the late nineteenth century. Steel-built easy to hammer, shape, and form by possession - and other invested parties hull design was common to the industry hand. This workability, combined with led an expedition to recover a substan- tial section of the hull in 1996. 8 In this by the late 1880s; the British Standards its tensile strength, made it a favorable Institute followed this trend and offi- material for rivets in all types of con- first recovery attempt, the piece was raised to within 200 feet of the surface cially approved open-hearth steel for struction of the time, from ships to when retrieval had to be aborted. rivets and plates in 1906. 5 bridges to buildings. However, ship- builders had begun transitioning from

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Fig. 3. The Big Piece shortly after it emerged from the sea aboard Fig. the 4. A surviving bronze porthole and rusticles, which remained intact on recovery ship, 1 998. the surface of the Big Piece, shortly following recovery, , Mass., 1998.

Although the desired hull piece could rivets; this effort was led by Tim Foecke cause of this substantial initial invest- not be raised at that time, iron and steel (National Institute of Standards and ment, recovery also necessitates a com- recovered from the wreck site enabled Technology, Gaithersburg, Md.) and mitment to conservation, management, the first authorized forensic testing on Prof. Timothy Weils and then-doctoral storage, and long-term care of the arti- the Titanic. The team returned to the student, Jennifer Hooper McCarty fact, so that the vast efforts expended at wreck site in 1998 for a second recovery (Johns Hopkins University, Baltimore, the outset yield fruitful long-term re- attempt, tantalized by the opportunities Md.). Their research is documented in sults for the future study and display of for the continued research that a portion McCarty's doctoral thesis and in Foecke the artifact. It is imperative that the of the hull would allow. On August 10, and McCarty's book, What Really Sank condition of the artifact be adequately 1998, the artifact was successfully raised the Titanic.11 Due in large part to their assessed and stabilization efforts be by attaching diesel-filled lift bags and research, the quality of the rivets and implemented prior to and after its re- towlines to the element and carefully riveting procedures have recently come covery. Failure to do so can lead to ca- floating it to the surface, where it was under scrutiny and have been faulted tastrophic structural failure during the winched aboard a waiting vessel (Fig. with the rapid sinking of the vessel. recovery and the immediate and irre- 3).9 Researchers also collected hull versible deterioration of the object if it debris10 and 48 rivets, including exam- Challenges Posed by Large-Scale is not properly stabilized and stored ples of the four different rivet types: Marine Artifacts after it is recovered. hull, bulkhead, deck, and porthole. A Recovery is complicated by a number sample of the hull was subsequently Excavation, removal, or the raising of a of variables. Foremost is the location of removed for testing and also yielded five shipwreck and its associated artifacts the wreck site, including its depth and intact steel rivets. poses many ethical issues that must be remoteness. For example, the H. L. It is difficult to overstate the impor- addressed prior to any recovery opera- Hunley , a Confederate , sank tance of the Big Piece and the expedi- tion. Not only may ownership of the in 1864 in the waters of Charleston tions associated with it. These recovery site be disputed, but these vessels can be Harbor in South Carolina. It was re- ventures have provided the physical considered gravesites, serve as memori- discovered in 1995 and subsequently re- materials necessary to undertake the als, and/or may still contain human covered in 2000. The Hunley was found analyses that have provided not only a remains. The discovery of the Titanic in harbor waters only 27 feet deep; by greater understanding of the role mate- famously sent the question of ethics contrast, the deep-ocean location of the rial failures played in the sinking, but before the U.S. Congress, which in turn Titanic (approximately 350 miles south- have also yielded information that has recognized the sanctity of the wreck site east of Newfoundland at a depth of been valuable in promoting the future and developed standards to prevent 12,460 feet) meant that expeditions to preservation of the ship. Initial metallur- wanton looting and, through the Titanic the wreck-site were arduous and report- gical testing and chemical analyses Maritime Memorial Act (1986), fos- edly cost upwards of $300,000 per day. sought to measure the metal's strength, tered cooperative scientific and cultural Recovery is also contingent on the rela- fracture behavior, chemistry, and mi- research among various countries.13 tive fragility or stability of the artifact.14 crostructure to understand the relation- Recovery. Recovery combines enor- Despite its location in shallow waters, the fragility and sensitivity of the Hunley ship between the behavior of the mate- mous feats of engineering, foresight, presented particularly complex engineer- rial and the sinking of the ship.11 Subse- planning, funding, and determination to ing issues, which necessitated the design quent analysis focused largely on the further significant research goals. Be-

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and fabrication of a dedicated lifting recognizing that full chloride removal actually remains within the shell. In the frame.15 Prior to recovery, the Big Piece may not be able to be achieved, or to case of the Big Piece, no imaging was was assessed and determined to be a even accurately measure.19 performed, due to the fact that selective sturdy artifact that could withstand the The Titanic is well known for its dis- probes and test areas demonstrated that stresses of the deep-ocean recovery. tinctive bio-concretions known as "rus- the substrate was stable and that no ticles." This term was coined by Robert portion of the artifact had become fully Post-recovery treatment: methodol- Ballard, based on their appearance re- encapsulated. Further, rusticles are softer ogy and logistics. Once successfully sembling a rust-colored "icicle." Rusti- than typical concretions, and it was pos- recovered and situated in a suitable cles are composed of up to 35 percent sible to remove this material with much environment, the overall treatment of iron compounds, including iron oxides, less effort than a concretion; thus, me- such a large artifact can be very com- iron carbonates, and iron hydroxides, chanical cleaning and crust removal plex. Manipulation of and access to the and inhabited by colonies of bacteria posed less of a risk to the artifact over- artifact will likely involve aerial man- and fungi that are intertwined with cor- all. lifts, scaffolding, forklifts, cranes, or rosion products from the ship and car- Passive soaking is a desalination even specially engineered tanks. Manag- bonates from the surrounding water method whereby the artifact soaks in an ing each of these variables requires a (Fig. 4). While typical ocean concretions alkaline bath, which neutralizes the significant commitment in time and may act much like an impermeable shell metal surface, significantly slowing the money. For example, the conservative around an artifact, inhibiting ion ex- corrosion rate. Chlorides diffuse out of estimate for completion of conservation change and slowing corrosion rates, the artifact and into the electrolyte solu- of all artifacts recovered from the USS rusticles are, by contrast, quite friable, tion. Sodium carbonate (Na2C03) is the Monitor is not expected to occur until extremely porous, and hygroscopic.20 preferred electrolyte (5 to 10 percent).22 2029, although conservators do "hope The shell can create a microclimate over Alternate solutions of sodium bicarbon- we can beat that by a good number of the surface, allowing the substrate to ate (baking soda) and sodium sesquicar- years."16 For the Big Piece, once the continue to corrode unseen. Further, the bonate have also been used, with vary- challenge of raising the artifact had presence of sulfate-reducing bacteria ing results. Passive soaking is a slow been conquered, the next hurdle of (SRB) can create locally corrosive condi- process that may take several years to stabilizing and conserving it began. tions that aggravate attack: SRB can The treatment to stabilize metal arti- complete, require regular monitoring of lower the pH of seawater from 8 to as the artifact and bath water, and refresh- facts recovered from seawater is typi- low as 4, thus significantly increasing ing of the solution. As discussed below, cally focused on removing concretions the rate of corrosion.21 the efficiency of passive soaking can be and removing chlorides (desalination) as increased through the use of sacrificial a means of arresting the electrochemi- Stabilization methods. In the planning anodes and electrolysis. cally induced corrosion process. Concre- of appropriate stabilization methods to The installation of sacrificial anodes tions represent a calcium carbonate be used for the Big Piece, conservators is a low-impact treatment meant to precipitate that forms on the surface of began with the evaluation of the most arrest ongoing corrosion of an artifact, an artifact and may also include silt, traditional methods used to treat similar either in situ or during passive soaking shells, and other sea matter. Concretions large iron artifacts. The majority of (Fig. 5). To that end, a more highly re- may hold chlorides themselves and may methods below were employed in the active piece of metal (anode) is attached also prevent access to the underlying initial treatment program from 1998- to the artifact (cathode), in the presence artifact, which has also been permeated 2000 and/or re-treatment in 2004. of an electrolyte. In situ, the electrolyte by chlorides over the course of the pe- Mechanical cleaning constitutes is seawater itself; in passive soaking, the riod of submersion. Because the concre- manual de-concretion of the artifact electrolyte is typically sodium carbonate. tion shell is fairly impermeable, the both prior to other cleaning methods In this system, the anode deteriorates physical presence of concretions can and intermittently throughout the stabi- hinder the success of chloride extraction preferentially, thereby providing protec- lization process. Mechanical cleaning is tion to the artifact. from an artifact. However, concretions likely to involve a variety of hand tools, Electrolysis is a method of desalina- can also preserve essential information including stainless-steel scalpels, picks, tion that operates on principles similar for the archaeologist and conservator, chisels, etc. Such cleaning is time- and to those of sacrificial anodes, but it and therefore should be removed only labor-intensive and has the potential to introduces an applied electrical current once they have been thoroughly exam- result in accidental damage to the under- ined.17 from a direct-current (DC) power supply lying substrate. Although the extent of to the cell. Chlorides and other anions The presence of chlorides has been de-concretion can vary, some degree of are drawn from the artifact toward the identified as "the major corrosion accel- mechanical cleaning will likely be neces- positively charged anode (usually type erator within archaeological iron."18 sary before any other treatment occurs. 316 stainless-steel mesh) by electrolytic Chlorides must be removed to limit fur- Non-destructive imaging (film radio- attraction. One of the advantages of this ther corrosion of the metal. Numerous graphy, digital radiography, etc.) is studies have demonstrated that chloride system is that the externally applied sometimes performed on a concreted electrical current can be controlled to reduction is essential to promoting the artifact prior to mechanical cleaning to effect different results, such as to pro- long-term stability of an artifact, while determine how much of the artifact mote more or less aggressive cleaning.23

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Fig. 5. Sacrificial anodes (indicated by arrow) attached to Fig. the 6. Big The Piece interior to of the Big Piece, following completion of initial treat- help facilitate the extraction of chlorides during the soaking ment process in 2000, of Frontthe Royal, Va. compromised artifact, Boston, Mass., 1998.

However, despite the applied current, try are generally designed to assist in RMS Titanic, Inc., as to how long it months or, more commonly, years degreasing, of removing chlorides and should take to properly desalinate and closely monitored electrolysis are chloride often compounds, and preventing conserve the artifact. Although other necessary to stabilize an artifact flash satisfac- rust. The active agents in industrial Titanic artifacts had gone through simi- torily.24 CRAs may consist of patented mixtures lar treatments, the client was extremely Steam, low-pressure (<2,000 psig), of amines, surfactants, and acids. CRAs eager to display and capitalize on its and medium-pressure (2,000-4,000 should be used on artifacts only follow- greatest find. As a result, extensive psig) water-jetting are often used by ing extensive testing. The authors have discussions arose concerning the client's conservators for rinsing, cleaning, and worked directly with chemical manufac- wish that the piece(s) be on display corrosion removal. All methods can be turers to select and modify material- during the desalinization process; about useful to assist in the removal of concre- appropriate CRAs. how the pieces were to be displayed; and tions. The flooding of microscopic sur- about the fact that it would be necessary face pits using medium-pressure water Initial Treatment Period: 1998-2000 to remove them from their alkaline envi- can also assist in flushing away surface ronment during times of transport from contaminates, such as soluble salts.25 Investigating a range of potential treat- venue to venue in an unclimatized vehi- Ultra-high-pressure (UHP) water- ment techniques was only one of several cle. There were also points of contention jetting is a technique that the authors significant hurdles involved with devel- regarding the sacrificial anodes that and other conservators have extensively oping a comprehensive plan for the con- were necessary to help expedite the researched and demonstrated as a viable servation of the Big Piece. Logistically, chloride-extraction process but that method for the removal of both existing treatment posed several challenges from were considered unsightly. Ultimately, the time it was received at the Boston coatings and surface soluble salts with- the parameters set by the client and out damaging the underlying metal or harbor. Because the Big Piece was so presented to the conservators were that necessitating use of additional chemi- difficult to handle and maneuver, it was the piece(s) would be placed on a dis- cals. UHP is an optional tool that may decided to separate the artifact into play stand; that the sacrificial anodes be used in combination with other what were to be two more manageable could be visible; and that caustic water treatment methods to augment chloride sections. Determining how, when, and sprays would be needed to keep the removal.26 where to perform this separation was pieces continually wet instead of fully another hurdle that needed to be over- The authors have also investigated immersing them in a soaking tank. the use of ultrasonic cleaning methods come. This decision proved successful in Given these stipulations, conservators to facilitate concretion removal and terms of facilitating handling, display, proceeded with desalination. They es- chloride extraction, performed most and treatment. Treatment was imple- tablished baseline chloride levels, both recently and successfully on select ob- mented on the Big Piece and Little Big on the surface and internally. Filings jects recovered from the wreck site of Piece as separate artifacts, but in an collected when sacrificial anodes had the RMS Carpathian the very ship that identical manner, during this initial been attached to the artifact were ana- rescued survivors from the Titanic F phase. Each piece subsequently fol- lyzed to determine the depth of chloride Cleaning may be further facilitated lowed a separate exhibition trajectory, penetration. Findings from these tests through the use of chemical rinse aids and it is unfortunate that they were determined that the salts were contained (CRAs), which are simply additives to never again displayed together. to the rusticle crust layer, outer surface wash water used to assist in cleaning. The second-biggest challenge encoun- pits of the metal, and crevices, and that Industrial CRAs used in the steel indus- tered was the expectations of the client,

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they had not migrated deeply into the port and display. Iron stains on the glass substrate. were removed or reduced using multiple Even given the fact that the presence applications of a 3-5 percent solution of of chlorides was, fortunately, concen- ethylene diamene tetraacetic acid (also trated near the metal surface, the use known of as EDTA).28 All metal surfaces water sprays proved to be an ineffectual were treated with a protective barrier method of desalination; it also posed coating a of thermally applied microcrys- safety risk to the viewing public, since talline wax. Once the metal cooled, the the fine caustic mist generated by the waxed surfaces were polished using spray heads drifted with the slightest Tampico natural-needle buffing wheels breeze. This approach was abandoned fitted on an electric drill (Fig. 6). shortly after it was implemented (ap- A custom-built skid was constructed, Fig. 7. An area of rusticle crust delamination, proximately one month), and the pieces and the hull fragments were set on revealing the metal surface that had continued were placed in a large soaking vessel Ethafoam (an blocks to help prevent chafing to corrode underneath, Chicago, III., December above-ground swimming pool) filled and reduce the effects of vibration dur- 2003. with a 4- to 5 -percent solution of so- ing transport. A wooden frame was dium carbonate and allowed to soak constructed around the piece, and rub- which the artifact was subjected proba- intermittently for a total of 16 months. ber tarps were used to protect it from bly destabilized the crusts through cycli- During this time the pieces traveled to the environment. No other attempt was cal swelling and shrinking and that the several different venues, which required made to climatize the environment constant vibration of the flatbed truck within the enclosure. that the pool be drained and that the likely caused rusticle crusts to detach pieces be transported on an unclimatized from the substrate. Further, when sam- flatbed truck. Towards the end of this A Reassessment and Réévaluation: ples were removed for analysis, it readily time the pieces were transported to a 2002-2003 became apparent that although the wax conservation facility in Virginia, where had penetrated the porous rusticle crust, After several years of cyclical trans- they were allowed to remain in the soak- it had not saturated sufficiently through portation and display, conservators ing vessel undisturbed for four months. to protect the underlying steel, which Chloride concentrations were monitored were asked to reexamine the Big Piece continued to corrode. Chloride activity in December 2002. This request was using an Orion conductivity meter and was found to be localized around rivets prompted by client observations that Merck Quantab titrators throughout the and in multi-plate construction. rusticle crusts had been delaminating soaking process. Make-up water and The conservation treatment that was and that white deposits were forming sodium carbonate levels were adjusted performed in 2000 should be considered as needed. around some of the rivet heads. Where a limited success in light of some of the rusticle crusts had become detached, At the end of the soaking period, the obstacles and restrictions that the con- active corrosion was seen on the under- pieces were removed from the vessel; the servators encountered in the design and sacrificial anodes were removed; and all lying metal (Fig. 7). A thorough surface implementation of the work. It pro- examination was performed, and sam- surfaces were treated using waterjets duced relatively stable and sturdy arti- ples of rusticle/crust, corrosion prod- operating at 3,000 psig. Rusticles were facts that were of excellent material ucts, and the white deposits were re- removed to the pre-determined extent, quality and capable of withstanding the moved for qualitative analysis. Results using pressurized water and rotating environmental changes to which they of the testing revealed that the white nozzles down to a stable layer but not were subjected. However, both the down to the metal substrate. Crevices deposits consisted of carbonates (resi- conservative preservation approach and due from the electrolyte) and low levels and interstitial areas were mechanically aesthetic requirements mandated by the of chlorides and were most likely ema- cleaned using picks and scalpels and client meant that the unstable rusticle nating from between the steel plates. then cleaned again with the waterjets. At materials had to be retained; because the The active corrosion appeared to be this point in the treatment, the pieces rusticles are somewhat delicate forma- contained to the surface of the metal should have been returned to the caustic tions with a tenuous hold to the under- bath and allowed to soak for an addi- and did not possess chlorides. lying metal, this necessarily put the Conservators initially believed that tional period of time, but the client artifact at risk of rusticle loss due to the unclimatized transport likely played a decided that the pieces should be pre- less-than-ideal transport, storage, and significant role in causing the conditions pared for exhibition immediately. display environments to which it was observed. Oversized as the piece is, the In order to protect and stabilize the subjected. most cost-effective and practical way of metal surfaces, the iron components of In hindsight there are certain aspects transporting a large, heavy, and cumber- the pieces were heated and treated with of the treatment that could have been some artifact was on a flatbed truck. a 5 -percent tannic acid solution to help performed differently and might have This scenario made it nearly impossible convert iron-corrosion products to a better promoted the long-term stability and cost prohibitive to climatize its more stable state. Loose fragments of of the pieces. This includes the following environment. Conservators suspected the hull were fastened with ferrous alternatives: that the environmental fluctuations to hardware to help secure them for trans-

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• The pieces should have been returned sive blasting medium - might remove to the soaking bath after the water- the crusts efficiently, but it was consid- jetting and detailed cleaning pro- ered too aggressive and would still not cesses. have accomplished the necessary flush- • The addition of impressed current ing and toremoval of salts. For these reasons, conservators looked to alterna- the soaking bath would most likely have made the desalinization tiveprocess cleaning methods. more effective and efficient. Ultra-high-pressure (UHP) water- jetting was considered because of its • More of the rusticle crust should have ability both to offer controlled removal been removed during the initial of rusticle con- crusts and to mobilize and servation treatment. The long-term Fig. 8. Ultra-high-pressure water-jetting being remove soluble chlorides (Fig. 8). UHP retention of the rusticle crust was performed on the Big Piece, Houston, Tex., July emerged as an industry standard for 2004. Courtesy of Steve Dunne. largely contingent upon the artifact metal-surface preparation in the second being transported, stored, or dis- half of the twentieth century. UHP Performing UHP according to these played in a climate-controlled envi- water-jetting technology consists of ronment. The client and conservators parameters greatly reduced the amount highly specialized pumps, hoses, nozzles, of time conservators had to spend re- should have realistically acknowl- and accessories necessary to create and moving the remaining crusts by hand.31 edged that this might not always deliver water at a pressure up to 35,000 Fine picks were still used to remove occur; accordingly, the client should psig.29 Pressurized water has two work- have allowed some rusticle removal crust and corrosion material within pits ing components: direct impact (shear at the outset. and especially between plates around force) or erosion effect, which is con- rivet heads. The result was that some • If more of the rusticle crust could trolled principally by the pressure of the rivets became loose in their hole, though have been removed, ultra-high-pres- stream, and hydraulic or lifting effect, not entirely free, a change that actually sure (UHP) water-jetting could have which is controlled principally by the became beneficial later in the process, as been used to reduce soluble salts volume of the stream. the entire rivet and the exposed edge of more effectively than the 3,000 psig The effective design of a proper UHP the plate could be coated with wax. pressure that had been used. cleaning protocol must balance a num- After cleaning, the hull piece re- • A conservator should have been ber of variables, including pressure as mained uncovered for two days, allow- engaged to provide oversight during measured at the gauge (psig), nozzle de- ing it time to "flash rust." This was the many rigging and moving cam- sign, the diameter of the opening in the done in part to allow the corrosion paigns to limit avoidable damage. nozzle for the water stream (orifice size), converter to achieve a uniform and dark the angle at which the water stream • Once the pieces were on display, (near black) oxidized finish, at the re- meets the artifact surface (angle of in- regularly scheduled inspections by a quest of the client. The oxide layer was cidence), the working distance between competent conservator would have then stabilized with a new proprietary the artifact and nozzle tip, and dwell identified problems earlier so that solution of tannic and phosphoric acids time.30 corrective measures could have been (Fertan). Use of this product effectively The conservators partnered with a implemented in a timely manner. converted the corrosion and generated a team of industrial-corrosion profession- uniformly black surface color. A chemi- • Regular maintenance would have als to quantify the concentration of salts cal rinse aid (Cortee Corporation) was greatly improved the aesthetic ap- on the surface and to develop a proper used near the end of the cleaning to re- pearance of the pieces. cleaning methodology that could be move excess tannic acid solution while safely used to achieve the intended preventing flash rust. Re-treatment: 2003-2004 goals. Through testing mock-ups, it was Following cleaning, it was necessary determined that the hull could be cleaned Although the treatment in 2000 pre- to remove any remaining moisture be- using water jets at 10,000-20,000 psig, served as much of the rusticle crust as fore the final protective coating could be depending upon the thickness of the possible, by 2003 it was agreed that the applied. The approach was two-fold: crusts to be removed. Utilizing a rotat- crust should be removed down to stable first, surface moisture was driven off ing nozzle at a standard surface-to-tip metal. Conservators also decided to using heat from propane torches, after distance of 2 to 4 inches, the high- flush all accessible interfaces between which the Big Piece rested in a dehumid- pressure water rapidly and safely re- ification chamber (40-50% RH) for sev- plates and around rivets to the greatest moved crusts and crust residue and un- eral weeks. When the artifact was once extent possible in order to remove stable corrosion products. It also flushed residual chlorides. It became clear that again reintroduced to unclimatized con- pores, cracks, and interstices between ditions, some salts did appear again manual scraping, picking, or pneumatic plates with heated, filtered water. Spe- tools would not be a viable method for around rivet heads, but the incidence cialty tips were utilized to introduce full crust removal, as their use was was extremely minor. These salts were pressurized water into tight spaces and neither time- nor cost-effective. Micro- allowed to dry and were removed by between plates. abrasion - cleaning using a fine abra- vacuum, and the surrounding area was then wiped clean with ethanol. Finally,

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Fig. 9. A torch being used to heat the surface in order to apply a protective Fig. 10. The wax coating was applied by both spray and brush, Houston, wax coating, Houston, Tex., July 2004. July 2004.

the surface was treated again with two In 2003 the piece was stored out- foil bag with desiccant and crated for coats of a thermally applied microcrys- doors unprotected for several months, shipment. talline wax (Figs. 9 and 10). The for- resulting in significant failure of the Thus far, only maintenance of the mula had been modified since 2000 and protective coatings, loosening of the Little Big Piece has been required since now included a solvent-based blend of concretion layers, and active corrosion re-treatment. In 2007 the surface was contact and vapor-phase corrosion in- in the presence of the residual salts. washed with sponges, the protective hibitors (VpCI) (M-238, Cortee Corpo- Failures were extensive enough to war- wax coating refreshed and buffed, and ration).32 A series of minor salt blooms rant re-treatment over maintenance. loose paint was stabilized. The Little Big developed on the surface shortly after Conservators opted for a treatment that Piece continues today to travel in North the piece had been waxed; however, the went further towards removal of all America and Europe. period of salt activity was extremely existing rusticle crust in an attempt to The overall success of this treatment brief and was understood to be part of remove all potential for chloride activity in 2003 was a key factor in the decision the initial acclimation of the newly in the future. to completely re-treat the Big Piece in exposed steel surface to the coating. Steam was used at a temperature of 2004. Many of the materials and tech- Aside from the long-term benefit of 300°F to assist in the removal of existing niques, including water-jetting, were improved material stability imparted by wax. Medium-pressure water-jetting at seen as significant improvements upon this treatment, practical benefits were 3,000 psig using 180°F water was used the initial treatment. realized in the short-term, as well. For to assist in the removal of rusticle crust instance, the surface was now easier to and to help solubilize and flush away Critical Evaluation: 2008-2011 clean and maintain; no rusticle crust sodium chloride salts. Mechanical clean- losses were sustained during transit; ing was performed using dental picks The Big Piece was exhibited at three different locations between 2004 and and, due to the darkened surface ap- and wooden skewers to remove harder pearance, one could more readily iden- rusticle accretions and debris from 2008. The first opportunity for inspec- tify fresh corrosion if it did occur (Fig. crevices. The surface was again water- tion and maintenance of the Big Piece was in 2008. The conditions observed II).33 jetted at 3000 psig using 180°F water and a 2 percent solution of a chemical were overwhelmingly stable, requiring only surface cleaning and rewaxing. In The Little Big Piece: 1998-2003 and rinse aid (Chlor*Rid) to help remove 2008 the Big Piece was installed at the 2007 loose areas of the rusticle crust and to help solubilize and flush away sodium long-term exhibition space at the Luxor Although it is not the focus of this chloride salts. Areas of loose or flaking casino in Las Vegas. The artifact was study, the treatment of the Little Big paint were consolidated with a dilute inspected again in September 2011; this Piece should also be considered for the (10 to 15 percent) solution of Paraloid investigation confirmed the soundness purposes of comparison, both today B-72. Conservators then treated the of the artifact. The only notable condi- and in the future. The Little Big Piece surface with a solution of tannic and tion observed at that time was an accu- mulation of dust. was initially treated at the same time phosphoric acids (Fertan) and applied The soundness of the artifact as seen and using the same methods and mate- multiple coats of a microcrystalline wax rials as the Big Piece. As it was smaller containing VpCI to a heated surface. in both 2008 and 2011 is likely to be a in size and weight, it was easier to Because its size allowed for it, the Little testament to improvements in the treat- transport and was exhibited throughout Big Piece was hermetically sealed in a ment design and execution, improved Europe and Asia. storage conditions, and a significant

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and conservators at the Warren Lasch conservation process to preservé the Big Conservation Center at Clemson Uni- Piece and make it available foi: exhibit versity, in Charleston, South Carolina, to the public has led to significant ad- where this research was driven by the vancements in treatment design and H. L. Hunley project. Subcriticai water technology that can now be evaluated is heated and pressurized to a tempera- by other conservators for use in the ture between 100°C (normal boiling large-scale metal maritime artifacts. point) and 374°C (critical point). As JOSEPH SEMBRAT is a Fellow of the Ameri- water temperature increases, its viscos- can Institute for Conservation (AIC) and holds ity decreases, while the rate of chloride a master's in historic preservation from Colum- diffusion increases. Research to date bia University. He conducts research and pub- demonstrates that the use of subcriticai lishes on topics in the preservation field, with special emphasis on technology-sharing among water solutions dramatically increases various areas of industrial research and its the rate and efficiency of chloride ion applicability to conservation treatments. Fig. 1 1 . The Big Piece following treatment, Houston, July 2004. removal, significantly reducing treat- PATRICIA MILLER is a Professional Associate ment times of both cast and wrought of the AIC and holds a master's in historic iron. This effect may be further acceler- reduction in the amount that the artifact preservation from Columbia University. She ated by the use of an alkaline solution. was senior conservator at Conservation Solu- is handled and transported. The oppor- However, because treatment requires tions, Inc., and was involved in the assessment, tunity for the same conservators to testing, and treatment of artifacts from the submersion in a suitable pressure vessel, reassess and re-treat these artifacts be- Titanic and Carpathia. She was shipboard there are strict limits to the size of the conservator at the Titanic wreck site in 2004. tween 2000 and 2004 led to significant artifact that can be treated. Expanding improvements in treatment design and this technology to treat large-scale metal JUSTINE POSLUSZNY BELLO is a Profes- technological innovation. The 2004 sional Associate of the American Institute for artifacts remains daunting. Challenges treatment was one of the first examples Conservation and holds a master's in historic are myriad and include the financial and preservation from Columbia University (2007). of ultra-high-pressure water-jetting that logistical issues associated with building, As a senior conservator, she performs and was used successfully in a conservation housing, and maintaining a sufficiently directs condition assessments, treatments, treatment of a marine archaeological materials testing, and analysis and construction large treatment vessel. There may also artifact. Additionally, the use of vapor- management of a variety highly significant be difficulties associated with handling historic and artistic works. phase corrosion inhibitors in the 2004 and manipulating such large, heavy treatment seems to have provided an artifacts, particularly those whose stabil- added level of protection to the artifact. Notes ity may be questionable or compromised 1. Susan Wels, Titanic : Legacy of the World's The decision to substantially remove due to theadvanced deterioration.34 If sub- rusticle crust eliminated a condition that Greatest (New York: Time-Life critical water treatment can successfully Books, 1997), 152-169. would have continued to be problematic be scaled up to treat larger artifacts, the had it been allowed to remain on this 2. Joseph Sembrai, Patty Miller, and Lydia potential for reducing treatment times as Frenzel, "Use of Waterjetting in Conservation artifact. Lastly, understanding the practi- compared to passive soaking or even of Historic Structures," The Society for Protec- cal limitations of the environments to tive Coatings and Painting & Decorating Con- electrolysis is enormous. Until that time, which these artifacts would be subjected tractors of America (SSPC) presentation for the proper treatment of similar large- PACE 2005 Expo (Jan. 23-26, 2005, Las Vegas, to during transport, storage, and display scale artifacts is likely to remain a fairly Nev.). helped tailor the treatment design to one 3. Since its recovery, the Big Piece has received that would be successful in these slowcircum- process. maintenance by conservators other than the stances. authors; the results will not be addressed at this Conclusions time due to a lack of familiarity with that work and a lack of published documentation of the New Frontiers in Treatment The desire to recover a significant por- treatments. Because the authors were primarily Methodology tion of the hull of the RMS Titanic , for responsible for the two most substantial treat- both study and exhibit, was finally ment campaigns, these form the basis of the One of the greatest challenges to the discussion. realized in 1998. Through the combined conservation of recovered marine ar- 4. John P. Eaton and Charles A. Haas, Titanic: efforts of hundreds of professionals, the chaeological artifacts is the time neces- Triumph and Tragedy ; 2nd ed. (New York: W. retrieval and conservation of the Big W. Norton and Co., 1994), 12-18. sary to properly conserve them - and, Piece has been a source of the physical by extension, the human resources 5. Jennifer Hooper McCarty and Tim Foecke, material for analyses that have provided What Really Sank the Titanic (New York: and money that need to be sustained a greater understanding of the tragedy Kensington Publishing Corp., 2008), 36-38. throughout this process. Thus, one of of her sinking. It is an important arti- 6. The central portion of the ship afforded the most exciting advancements in the fact that illustrates history in a way that much more space in which to operate the conservation of marine artifacts is that hydraulic riveting machines than did the bow both inspires and humbles the viewer. of subcriticai water treatment, which and stern (more confined spaces where a person However, the Big Piece has acquired itscould fit but a machine might not be able to), has the potential to significantly reduce own complicated history of challenges another possible reason why different rivets treatment times. This methodology is were chosen. along the way. The multi-campaign currently being developed by scientists

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7. McCarty and Foecke, 15-16. Lasch Conservation Center Clemson Univ., tural Conservation 11, no. 3 (Nov. 2005): 121- Charleston, S.C., May 2006, pp. 14-15. 146. 8. Numerous parties teamed to achieve these expeditions, including RMS Titanic Inc. 16. Scott C. Boyd, "USS Monitor's Turret Has 26. Ibid. (RMSTI), co-supported by the Discovery Surprises for Conservators," Civil War News 27. Treatment of objects recovered from the Channel; the Marine Forensics Panel of the (Sept. 2011), http://www.civilwarnews.com/ RMS Carpathia was performed in 2007-2008. Society of Naval Architects and Marine Engi- archi ve/articles/201 l/sept/monitor-091 102.html These objects are also currently owned man- neers (SNAME) was also consulted on these (accessed Feb. 2, 2012). aged by Premier Exhibitions, Inc./RMSTI. missions. Recovery efforts had to be aban- 17. Although the formation of new concretions doned when the artifact was just 200 feet shy 28. A heated solution of 3 percent EDTA in will be slowed or stopped once the artifact has warm water was applied to the glass by cotton of the surface, due to an oncoming hurricane. been removed from the ocean, the existing shell The artifact drifted back to the ocean floor, swab and carefully scrubbed with natural creates a microenvironment on the surface of bristle brushes. Additional EDTA solution was fracturing into two pieces. the iron object that can allow complex corro- injected into cracks in the glass using a syringe sion mechanisms to continue to occur unno- 9. William J. Broad, "Effort to Raise Part of to promote cleaning in inaccessible areas. Titanic Falters as Sea Keeps History," New ticed. In the case of the Big Piece, the crust was York Times , Aug. 31, 1996. found to be hygroscopic (attracting water) and 29. PSI, pressure measured in pounds per kept the surface moist, i.e., provided a means square inch, is referred to in the water-jetting 10. The right to access, recover, and profit from for corrosion to occur. Additionally, the non- industry more specifically as PSIG, the pressure the Titanic and its artifacts has been highly porous calcium carbonate shell can inhibit ion as it is measured at the pump gauge (pounds litigated and contentious since its discovery. exchange, which may hinder and prolong treat- per square inch at gauge) where the operator Multiple laws and regulations were generated controls are located. ments such as electrolysis. Bradley Rodgers, out of early court proceedings, including the The Archaeologist's Manual for Conservation Titanic Maritime Memorial Act, designating 30. Sembrat et al., 123-124. (New York: Kluwer Academic/Plenum Publish- the wreck as international maritime memorial, 31. Sembrat et al., 130-131. ers, 2004), 79-80. legally maintained and protected by the United 32. M-238 product data sheet, Cortee Corpo- States, Canada, France, and the UK, with the 18. D. Watkinson, "Chloride Extraction from ration, http://www.cortecvci.com/Publications/ U.S. National Oceanic and Atmospheric Asso- Archaeological Iron: Comparative Treatment PDS/M238.pdf (accessed Feb. 20, 2012). ciation (NOAA) named environmental steward Efficiencies," in Archaeological Conservation of the wreck site. NOAA went on to publish and Its Consequences , Copenhagen Congress , 33. The treatment methods used on the Big "Guidelines for Research, Exploration and 26-30 August 1996 , ed. A. Roy and P. Smith Piece in 2000 were also applied to other large Salvage of RMS Titanic" explaining these (London: International Institute for Conserva- artifacts from the collection around the same international standards. At the time of writing, tion, 1996), 208. time. Despite better transport conditions, climate-controlled trucking, and dedicated RMSTI, a subsidiary of Premier Exhibitions, 19. Mardikian, 72. Inc., currently retains its status as "salvor-in- crates with silica packs, these elements also possession" of the wreck site and artifacts. 20. D. Roy Cullimore, Charles Pellegrino, and displayed similar loss of the rusticle crust. It Lori Johnston, "RMS Titanic and the Emer- was determined that the lack of wax penetra- 11. Metallurgical testing on the hull steel was gence of New Concepts on Consortial Nature tion to the steel-and-cast-iron substrate that directed by H. P. Leighly, of the University of of Microbial Events," Reviews of Environmen- allowed these crusts to detach. Several large Missouri-Rolla, assisted by Tim Foecke, of the tal Contamination and Toxicology 173 (2002): artifacts, including the Bollard, D-Deck Door, National Institute of Standards and Technol- 117-41. and Eccentric Strap, were similarly re-treated ogy. Chemical analyses were performed by with waterjets, chemical rinse aids, and wax Prof. Leighly and Dr. Harold Reemsnyder of 21. Rodgers, 89-90. after the 2004 treatment of the Big Piece. This the Homer Laboratories of Bethlehem Steel in 22. Mardikian, 97-100. treatment yielded similarly successful results, Bethlehem, Penn. 23. Texas A & M University files: File 1 OA and far fewer salt breakouts were observed. Iron Conservation Part I: Introduction and 12. Jennifer Jo Hooper, "Analysis of the Rivets 34. Mardikian, 107. from the RMS Titanic using Experimental andEquipment and File lOB: Iron Conservation Theoretical Techniques" (doctoral dissertation, Part II: Experimental Variables and Final Steps, Johns Hopkins University, Materials Science http://nautarch.tamu.edu/class/anth605/Filel0a and Engineering, 2003). Foecke and McCarty. .htm and http://nautarch (accessed Feb. 19, 13. Kieran Hosty, "A Matter of Ethics: Ship- 2012). I Association of Preservation Technol- wrecks, Salvage, Archaeology, and Museums," 24. Al Kazunias, Kathy Pearl, and Rolf ■ ogy International, an interdisciplinary Bulletin of the Australian Institute for Maritime Schlake, "Metal Artifact Preservation Using ■■ I ■ I The ogy organization I organization Association dedicated International, to the APTprac- Bulletin of dedicated Preservation is an published interdisciplinary to the Technol- prac- by the Archaeology 19, no. 1 (1995): 33-36. the Subcriticai Water Extraction Technique," iNTiRM atonal ^cal application of the principles and techniques necessary for the care and wise use of 14. Martin Weaver, "Heritage Conservation presentedof at Pittcon 2010 (Feb. 28-Mar. 5, the built environment. A subscription to the ," APT Bulletin 35, no. 2-3 (2004): 2010, Orlando, Fla.). Bulletin and free online access to past articles are 51-59. 25. J. Sembrat, P. Miller, J. Skavdahl and L. member benefits. For more information, visit www.apti.org. 15. Paul Mardikian, "H. L. Hunley Conserva- Frenzel, "Conservation of Historic Metals by tion Plan." Unpublished internal document, Waterjetting Techniques," Cleaning Techniques copyright by Friends of the Hunley, Inc./Warren in Conservation Practice , Journal of Architec-

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