Tayla van Ingen is an archaeology undergraduate student at the University of Groningen. In this blog she gives an update on her work placement experiences with the Rooswijk project.
In September 2017, I had the opportunity to participate in the Rooswijk project during the first excavation season. It is safe to say that the Dutch East Indiaman, subject of my very first maritime archaeological excavation, holds a special place in my heart. While I am currently an undergraduate archaeology student at the University of Groningen, The Netherlands, I spent the last five months in Southampton to focus on maritime archaeology. I was therefore absolutely thrilled to return to the project at Historic England’s conservation laboratory at Fort Cumberland to work on the conservation of the finds of the Rooswijk and experience the post-excavation part of the project. Together with Angela Middleton, a conservator for Historic England, Kim Roche, a conservator for MSDS Marine, and Nicole Schoute, a maritime archaeologist for MSDS Marine, I worked on various aspects of the conservation process.
After a tour through the conservation lab and meeting the staff, Nicole and I started the first day with changing the water in the tanks that included the big and heavy finds, like a cauldron and a barrel. The water is changed every month, because fresh water improves the desalination process of the objects. Changing the water of the numerous small boxes containing concretions took some heavy lifting, and kept us busy for a whole day. The following week we cleaned and refilled the largest tank, which contains the large concretions excavated from the site, and sorted the finds according to their priority for conservation treatment. Taking care of finds is hard work sometimes: I can still feel it in my muscles!
The iron finds from the ship, such as cannonballs, bar shot and other objects, pose a challenge to conserve. Due to the salty environment these objects have been in, chlorides are causing heavy corrosion in these iron objects. Controlling this process post-excavation requires a very low humidity level, and in most environments this is difficult to achieve. Therefore the iron is desalinated in an alkaline solution, which slowly removes the chlorides, to prevent further corrosion. Kim and I checked the pH-level of the solutions to see if the solutions were caustic enough, and we checked the chloride levels to measure the effectiveness of the desalination process.
The Rooswijk has been under water for almost 280 years, and many of the objects have corroded and concreted together. The concretions that are brought up are all x-rayed to determine what might be inside. Kim and I x-rayed several concretions from the site. When the x-rays are taken, they become directly visible on a computer screen, so we could assess the finds directly. Most of the concretions contained tool handles and rings, and we could even make out a corroded key. On one particular x-ray, we encountered glass (beads), coins, copper rings and other metals, that appear bright white. Other objects, like tool handles, ceramics and organic materials, which are less dense, are often visible too, but to a lesser extent than the dense metals. Sometimes, a concretion has formed around an iron object which has now disintegrated and left a void. This is also visible on the x-ray.
Concretions have to be mechanically de-concreted by a pneumatic air scribe that slowly chips away the tough lump of corrosion, sand and sea life in order to retrieve the objects inside. I started cleaning a concretion that appeared to contain beads, glass, ceramics and copper rings. The process is lengthy and precise. Certainly the beads, that are no bigger than a pin’s head, are difficult to find and clean without losing them. It is, however, extremely rewarding to finally come upon the artefact you’ve been looking for!
Of course, for every x-ray that is taken, every assessment that has been made, every concretion that has been cleaned and every object you find in it, there is paperwork to do. It is very important to precisely describe what find is connected to which x-ray and documentation photographs, and which conservation treatment was applied to it. Everything receives its own find, photo or x-ray number, and every find is measured, weighed and its condition established. To keep track of the thousands of Rooswijk finds, this data is all meticulously inserted into the many spreadsheets of the project. Data management may not sound exciting, but it’s necessary to keep track of an artefact’s condition, conservation treatments undertaken, and other archaeological data.
Although I was in Portsmouth for a fairly short period, I deeply enjoyed my placement in the conservation lab at Fort Cumberland and wish I could have stayed longer. To return to the same project I worked on a year and a half ago, with some of the same team members, was an absolute pleasure. Many archaeology students don’t experience the post-excavation part of the projects they work on, and I found it to be very educational. I learned what happens with finds after they’re taken off site: the different chemical and scientific methods used to analyse and stabilise them, the time-consuming and sometimes painstaking aspects of conservation treatment, and how to maintain the archaeological database. I’m grateful for having had the opportunity to work on the Rooswijk again, and I definitely hope to return one day.