Plymouth City Council and Orbis Conservation | The Box Naval Figureheads Collection

Stephen Conway

Conservator, The Box

Hans Thompson

Conservator, Orbis Conservation

Plymouth City Council (The Box)

Plymouth City Council (The Box) Tavistock Place Plymouth PL4 8AX United Kingdom

Museums + Heritage Award 2020 Restoration/Conservation Project


Conservation of the Box Naval Figureheads Collection




Description of the Project:

The Conservation and Display of The Box Naval Figureheads Collection was an ambitious and transformational project to conserve and restore fourteen degraded, nineteenth century, naval ships’ figurehead carvings and place them on prominent public display as a permanent exhibition suspended within the main entrance of The Box (a museum, gallery, archive and visitor attraction opening in central Plymouth in May 2020).

The carvings underwent restoration work in the 1950s using untried methods including coating the decorative carved and painted surfaces with glass fibre, which failed, leading to water ingress and decay to internal timbers. This put these important figurehead sculptures at major risk.

The Box proposed to restore the sculptures and suspend the 20 tonnes of figureheads in a huge sweep from the ceiling of the main entrance atrium, creating a memorable visual experience from both within and outside The Box.
Overall Objective:

The project aimed to secure the long-term future of 14 naval figureheads, through sensitive conservation and restoration. It also aimed to significantly widen public access to, and understanding of, the figureheads, in relation to their symbolic importance and Plymouth’s naval heritage.

By creating an audacious, dynamic and engaging display in the main entrance of The Box, it is hoped that the figureheads are re-understood by the viewer as substantial floating heritage, as opposed to floor mounted large scale wooden sculptures, helping to contextualise the pieces. The project also aimed to develop wider conservation and restoration techniques and processes that would enable these, and potentially other figureheads or large-scale wooden objects, to be conserved successfully.


The National Museum of the Royal Navy agreed to the figureheads being removed from storage in a former fire-shed at the Devonport Naval Heritage Centre (DNHC) to permanent display at The Box.
Orbis Conservation were appointed as primary conservation partner. They undertook the full conservation, consolidation and restoration of the figureheads. In addition, Orbis Conservation designed bespoke mounts and armatures, working alongside PCC’s structural engineers, to suspend each carving at the required angle for the dynamic ‘floating flotilla’ display.

Orbis led the de-installation and transportation of the structurally vulnerable sculptures, the largest of which is 4m tall and weighs 2.5 tonnes, from the DNHC to the conservation specialists. The six most severely degraded figureheads went to Orbis, seven to Mainmast Conservation and one to Hugh Harrison Conservation. EU Interreg funds supported method pilot testing on Topaze and Royal William, gleaning information to share with the other conservators.


Innovative analysis of the collection:

The immense scale of the sculptures restricted the feasibility of most structural analysis techniques. The exhibition’s challenging suspension requirements meant it was imperative to fully understand the condition of the internal timbers. Hugh Harrison Conservation used micro-drilling techniques to identify internal decayed timber, but these tests offered limited understanding about the extent of degradation throughout these huge objects.

Orbis identified and trialled a range of innovative solutions before deciding sonic tomography (usually used to measure the integrity of living trees) offered the potential for best understanding the internal condition of the figureheads. Sonic Tomography uses a system of sensors, placed around the circumference of the wooden sculpture, to measure sound waves passing through a structure. The presence of rotten timber or voids within the timber influence the speed of the sound wave transmission through the object and through analysing these transmission speeds a tomograph of the internal structure is produced. Software converts these into colour coded, cross-section maps that identify the locations of good timber, structurally compromised material and voids.

By applying this analysis technique, other hugely invasive and destructive techniques were avoided on most of the collection, allowing the treatments to be focused on only those figureheads with significant internal loss and decay.


Dismantling, Consolidating, and Rebuilding 2 tonne sculptures:

The analysis had indicated that the most degraded sculptures needed full deconstruction to remove decayed timber and install armatures to reinstate structural stability. The second significant challenge of the project therefore was developing a strategy for consolidation of those severely degraded figureheads that required extensive treatment.

In some case, such as HMS Topaze and HMS Tamar, the timber was so unstable internally (through the damage caused by rot) that only a thin outer shell of timber, approximately 5-20mm, remained. It was obvious that the challenge would be how to control the drying out and addition of consolidants to the fragments, so that dimensional changes would not occur, and that structural integrity of the pieces would not be breached. Conservators had to introduce a consolidant to the timber at the earliest point possible in the drying out process to re-establish structural integrity, whilst simultaneously controlling the drying and monitoring the fragments.

During testing some timber showed levels of up to 85% Moisture Content (MC). Most consolidants function up to levels of 25%MC so experimentation was required by Orbis until they found an epoxy based solution that worked at 40%MC (below this level, irreversible dimensional/structural deformation would occur). The fragments required drying out in purpose-built humidity chambers where the Relative Humidity (RH%) could be brought down in a controlled way, preventing timber distortion or shrinkage of component parts. When the appropriate MC was achieved a first round of consolidation took place, aiming to offer enough structural integrity to the fragment for it to reach a MC where the consolidant would work more effectively. This was followed by a second round of consolidation once 20% MC was reached.

Rot was removed to ensure structural integrity and avoid spore migration whilst 3D scans enabled a 3D milling machine to produce rough carvings of missing areas, finished by hand carving using traditional techniques.

Orbis worked closely with The Box’s structural engineers to design a system of internal mounts and armatures to facilitate the ambition for the figureheads to appear to float and sweep in a suspended arc. The mounts could be used to hoist them in place and connect into steel suspension cables.

Orbis’ 3D scans provided a more complete picture and could be used to ascertain the weight and centre of gravity of each figurehead.

Paint analysis was performed to understand the stratigraphy of the historic decorative schemes. Some figureheads had up to 50 layers of paint. They were repainted with a conservation grade acrylic system, following the results of historical analysis.

In October 2019 final delivery, hoisting and fixing into place was managed by Orbis, working with The Box Conservator and other specialist contractors.


Saving of 14 naval figureheads that were in greater danger of loss than originally known. Many similar naval figureheads in comparable condition could now be protected.

Hugely improved access from behind secure gates to a prominent 24/7 public experience.

Development of techniques, processes and understanding. Adapted use of sonic tomography has enabled the scanning of the entire sculpture, rather than reliance on spot analysis.

Techniques developed to measure the structural integrity of large wooden sculptures.

Paint analysis has confirmed the theory that originally the figureheads were painted lead white and were only painted in bright colours once displayed on shore. We chose an authentic, more subtle colour palette, using illustrations from a set of 1911 cigarette cards.


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