The Conservation Project in Detail

The Holland I Conservation Project in Detail

1. Introduction

Holland 1 the Royal Navy’s first submarine, built in 1901which is part of the Core Collection of the National Historic Ship Register, was originally recovered from the seabed in 1982. In 1993, after eleven years of open air display at the Museum, it became apparent that chloride sponsored corrosion was causing the rapid deterioration of the boat. The Museum recognized that a sophisticated conservation package was needed if the vessel was to be preserved for the long term. The conservation process outlined below began in 1995 and was completed in June 2001. At the outset the project was supported by the PRISM Fund and for the construction of the new gallery the Museum received an HLF grant of £671,000. The first phase of the project was led by the Director of RNSM, the second by the Curator. The principle conservator was Ian Clark. Conservation advice was received from the following people and institutions:

Peter Lawton & Alan Johnston, Hampshire County Museums Service; Hazel Newey, The Science Museum; Dr Des Barker, University of Portsmouth; the late Chris O’Shea, freelance conservator, formally of Portsmouth Museums Service. Additional corrosion analysis was also carried out by UMIST and Southampton University.

The project had two distinct phases:

• Remedial intervention, which involved soaking the submarine in a passive electrolytic solution in order to facilitate removal of chloride ions

• Preventative, through the preparation of the submarine for re-display and at the same time the construction of a de-humidified gallery in which to house the submarine in an environment of less than 40% R/H

Phase 1 - Remedial Treatment

The soaking of the Holland I took place between 1995 - 2000. The methodology of the process was well established with respect to archaeological and marine artifacts, however the treatment of an historic object the size of Holland I was a major departure from what had gone before. A process typically carried out on the laboratory workbench had to be literally scaled up thousands of times. Set out below is some of the key features of the process:

a. the submarine was deemed to be too fragile to move or dismantle without risking further damage, so a sophisticated purpose built GRP tank was constructed around the boat. This structure was a triumph of ingenuity and civil engineering skill.

b. solution circulation was recognized as essential to ensure the effective removal of as much chloride as possible. A tailor made fluid distribution system was designed to circulate all 800,000 litres of electrolyte around the submarine. This capillary system had to be kept free flowing at all times, and on one occasion required the insertion of Royal Navy divers into the tank to service it.

c. the tank had to be drained and re-filled with new solution on three occasions in order to maximize the amount of chloride being removed. Active electrolysis and core sampling were both used to measure progress within the tank, and after five years of treatment residual levels of chloride were deemed minimal and the submarine ready for the next phase.

2. The Gallery Building Project

. In 1993, after eleven years of open air display at the Museum, it became apparent that chloride sponsored corrosion was causing the rapid deterioration of the boat. The Museum recognized that a sophisticated conservation package was needed if the vessel was to be preserved for the long term. The soaking of the Holland I took place between 1995 - 2000. The methodology of the process was well established with respect to archaeological and marine artifacts, however the treatment of an historic object the size of Holland I was a major departure from what had gone before. A process typically carried out on the laboratory workbench had to be literally scaled up thousands of times. Set out below is some of the key features of the process:

(a) the submarine was deemed to be too fragile to move or dismantle without risking further damage, so a sophisticated purpose built GRP tank was constructed around the boat.

(b) solution circulation was recognized as essential to ensure the effective removal of as much chloride as possible.

A tailor made fluid distribution system was designed to circulate all 800,000 litres of electrolyte around the submarine. This capillary system had to be kept free flowing at all times, and on one occasion required the insertion of Royal Navy divers into the tank to service it.

(c). The tank had to be drained and re-filled with new solution on three occasions in order to maximize the amount of chloride being removed. Active electrolysis and core sampling were both used to measure progress within the tank, and after five years of treatment residual levels of chloride were deemed minimal and the submarine ready for the next phase.

3. Chloride Extraction

4. Preparation For Display

Working closely with the Client the Conservator devised a specification for mechanical surface preparation based on extensive test patches. Similarly the combination of wax sealers and paints eventually used on the boat was the result of considerable testing. All materials used were required as far as possible to be reversible with minimum damage to the object. The Client was particularly concerned that if in the future corrosion activity was identified, it could be treated without having the need of aggressive treatments simply to remove whatever protective coating had been applied. As a result up to 70% of accessible surfaces have been coated with SHELL ENSIS TX fluid in preference to paint. Not only is ENSIS TX relatively easy to remove, but also, while providing protection against moisture and physical touch, it is air permeable. However some surfaces both externally and internally have been repainted. The areas chosen had to be in exceptional condition. The painting was done in order to assist interpretation of the vessel to visitors. For example internally operational submarines past and present are painted white so as to maximize the working light. To wax the entire interior would have resulted in an impression of the submarine very different from that which prevailed during its period in commission.

5. Long Term Preservation

The gallery building, its specification and features should be seen as integral to the conservation of the object. As already stated above the long-term conservation depends on the maintenance of a dry air environment. The building not only delivers this environment but also provides first-rate access for visitors. Ramping allows wheelchair access right up to the main visitor hatch into the submarine. The visibility of the vessel for visitors inside the gallery is superb and includes access into the submarine. The building’s enormous glass window means that visitors can step back from the building and appreciate in one panoramic view the lines of the submarine hull.

6. Project Management

Financial and commercial factors meant that the construction of the new gallery building had to run in parallel with preparing the exhibit for display. Furthermore many parts of the conservation treatment would not have been desirable once the new building had enclosed the submarine. Establishing the best critical path for carrying out the conservation work was a crucial part of the project management process. The step-by-step preparation of the boat had to be fitted around the dynamics of the building construction work.

This project therefore necessitated an exceptional amount of co-operation between the various parties in order that both building and submarine progressed according to schedule.

By way of illustration the conservator had to apply a first class uncontaminated paint finish to a 63 feet long, 15 feet high object, while surrounded on all sides by wet plasterers and commercial decorators. This project therefore necessitated an exceptional amount of co-operation between the various parties in order that both building and submarine progressed according to schedule. By way of illustration the conservator had to apply a first class uncontaminated paint finish to a 63 feet long, 15 feet high object, while surrounded on all sides by wet plasterers and commercial decorators.

6. The wider community

A paper detailing the method of chloride extraction was given to the ICOM Metal Conservation Conference in 1995. The project has proved of interest to a number of other maritime conservation projects who have visited the site and discussed the project with Museum staff and the consultants e.g. the CSS Hunley submarine ( 1863) and the SS Great Britain.

7. Documentation

The project has been fully documented from the outset and will be the subject of consolidated reviews in the coming months (particularly with respect to the Museum’s website.

8. Cost Effectiveness

The time and money invested in the active conservation treatments are cost effective to the Museum because the overall sensitivity of the vessel to corrosion has been greatly reduced. This in turn means that R/H levels within the new gallery can be less dry, which means lower energy consumption by the dehumidification plant and therefore less cost in maintaining Holland I’s conservation environment. The above investment has also delivered far better access for visitors than would have been likely had the Museum chosen only to pursue a preventative environment strategy.