Annual General Meeting December 2004: The s.v. Cutty Sark: Electrochemistry in Conservation

Abstract

The s.v. Cutty Sark is the last surviving example of an extreme clipper built for the profitable China Tea trade. Although expected to be in service for 30 years, the ship has survived to the present day with approximately 80% of the original structure remaining. However, the ship is now showing signs of deterioration, particularly chloride sponsored corrosion of the bolts used to secure the iron frame. As the s.v. Cutty Sark is one of three remaining vessels of composite construction, its preservation is vital for UK and World Marine Heritage. This paper describes an evaluation of the possibility of using an electrochemical method to remove the aggressive chloride ions from the wood/metal matrix structures on the ship. The presence of these species is a major problem associated with the conservation of marine artefacts and although studies have proven the usefulness of this technique for the conservation of large metal structures, e.g. the World War I gunboat M33, its effects on chloride-ion contaminated wood/metal composites had not been evaluated. The results from this work showed that by careful selection of the electrochemical and microbiological control parameters it is possible to successfully electrolyse wood and iron assemblies without degradation of the either the wood or the iron. A subsequent pilot study in the Aft Peak area of the ship further confirmed the feasibility of using electrolysis to remove chloride ions from the wood/iron matrix.