dk nkf - Nordisk Konservatorforbund Danmark

Figure 10 Fox Talbot’s 1843 photograph
of the options showed that control of the relative
humidity (RH) around the original iron was likely
to be the most effective way of conserving the
maximum amount of original material. What was
less clear was the level of RH required and the
optimum physical arrangements for providing the
controlled environment.
Eventually, after considering all possible options
it was decided to recommend the installation of
a glass plate at the level of the ship’s waterline.
The glass plate would seal between the hull and
the walls of the dry dock, allowing environmental
Figure 11 Scuttled in Sparrow Cove
210
Figure 12. The ss Great Britain mid 1990s
control of the iron below the waterline. Iron surfaces
within the ship were environmentally controlled
by sealing corrosion holes, installing air locks on
doors, and sealing a new mild-steel deck to the
bulwarks of the ship. This left only the topsides (the
external area of the hull above the waterline) to be
treated. It was decided that these areas should be
treated conventionally. There were several factors
that lead to this decision. It was hard to envisage
any form of encapsulation other than a complete
building that would be more aesthetically pleasing
than the waterline plate. Although tests had shown
the presence of large quantities of chlorides in the
iron, they were significantly fewer in the iron of
the topsides, perhaps because the iron had been
washed with Bristol rain for 30 years. Furthermore,
significant areas of the topsides had been replaced
with mild steel or glass re-inforced plastics in the
1970s and 1980s. So although the majority of the ship
had not responded well to a cleaning and re-painting
regime since 1970 it was believed that with careful use
of conventional treatment, and careful maintenance,
the topsides could be effectively conserved.
A ‘hierarchy of intervention’ was agreed between the
conservator and the curator. All material dating from
before1970 was designated as’ precious’ and could
not be cut, drilled, or welded without their agreement.
All treatments were to be reversible. (In the event,
only two forms of non reversible treatment proved to
be necessary. One was the use of abrasive cleaning
to some parts of the topsides and the other was the
removal of a small part of a deck hatch to permit the
fitting of a lift to ensure complete access to all parts