MAST archaeological conservation
MAST’s Archaeological Centre in Poole, Dorset, is the only seabed to museum maritime archaeological facility in the UK capable of handling artefacts excavated directly from the seabed through the recording and conservation process to be passed on to the receiving museum. It is currently assessing the conservation requirements of the collection of artefacts acquired from the Shipwreck Centre in Charlestown. This will be a major conservation project. It has recently completed the conservation of the 9-tonne cutwater from HMS Invincible, pictured below arriving in the Centre and now cleaned and ready to return the Royal Navy Museums in Portsmouth.
The Archaeological Facility, which it shares with Bournemouth University’s maritime team, is a robust industrial unit of 330 square metres converted after purchase in 2016. Vehicle access is via a 5 metre high and 4.5 metre wide roller doors. The site has full disabled access to the ground floor.
Property particulars:
- 366m² overall area
- max 7.9m and min 6.0m eave height
- 276m² available for finds processing & passive storage
- 15m² first floor office with kitchen & teleconferencing facilities
- 30m² dive store
- 36m² general storage
- Goods access via a 5m high x 4.5m wide roller doors
- 7.2m² dive support container c/w a 195 litres/min air compressor and 135m³ air bank.
Storage volumes, the unit is capable of storing and processing
- Up to 150m² of wet finds storage
- Up to 17.5m³ of environmentally controlled storage
- 0.326m³ of cold storage
- 0.1 m³ Eurograde 2 security (max total value £175k)
Material handling. The unit is capable of handling loads / material of the following sizes
- 3,000kg @ 5.5m length
- 5,000kg @ 4.0m length
- 1,500kg palletised loads
Freeze Drier
We have a new Frozen in Time very versatile freeze drier, a D6/14, with a new semi-automated control system (chamber cylinder dimensions 600mm by 1400mm)
HMS Invincible CUTWATER: from seabed to complete conservation
The 9 tonne cutwater is one of the largest artefacts we have conserved to date.
Other sizeable projects have included Invincible’s rope and mainstay.
Below photos from our deck to display in Chatham Historic Dockyard.
The team raised c.3 tonnes of rope (157 metres from the orlop deck) and c. 2,000 pieces of wadding from different bored guns (the largest collection of wadding found on any shipwreck site). These were desalinated and washed, some then air-dried whilst brushing off excess sand. The rope was conserved by consolidation in diluted PEG wax solutions* and freeze-dried**. Other delicate finds include a glass bottle (intact with cork), several leather shoes.
Swivel gun conservation
The conservation of the five swivel guns raised in 2018 is now complete. They spent two years soaking in a 2% sodium hydroxide, a solution which prevents corrosion. Following this they were deconcreted them - including the bore. Whilst cleaning one of the guns a Broad Arrow was found indicating it was indeed British government property.
Once complete, we used electrolysis to remove the harmful salts from the iron. Electrolysis took 3-4 months, followed by a period of soaking in sodium hydroxide solutions to reduce the chloride levels to an acceptable level of less than 50ppm. Once desalinated the guns were air dried and cleaned and coated in tanic acid to protect them. They will need to be displayed now in a very dry environment, of less than 15% relative humidity.
Our next puzzle to come is SS Eastfield’s gun. In 1917 Britain there were no spare guns so an old 19th century trench land artillery gun – a French de Bange 90 mm land artillery piece originally made in 1877 - was repurposed and a recoil system was added and placed on SS Eastfield. It was basically a piece of scrap and obsolete, but the country had to use everything it could. Eastfield was sunk in November 1917 off the coast of Cornwall by a U-Boat, ending her WW1 service. The gun suffered physical damage during the sinking and now exhibits active corrosion to both iron and copper alloy components. In addition, small flakes have dropped off the barrel during removal from the museum. Until conservation begins, the gun is under a temporary cover to ensure it remains as dry as possible. help stabilise it in the short-medium term.
And from the very large to the very small, our specialised conservation laboratory allows us to conserve the smallest, most delicate finds. Here, Ian Panter is preparing HMS Anson artefacts for exhibition in Chatham Historic Dockyard, where they are currently.
And sometimes conservation is simply a large puzzle. Here’s Tom Cousins reassembling multiple pieces to reinstate a large vase. This work took over a week to complete.
*PEG, Polyethylene Glycol is a water-soluble wax, a by-product of the petroleum industry, that is used in the conservation treatment of waterlogged timbers. Once the timber is desalinated, cleaned and recorded, the object is placed in an aqueous PEG solution whose strength is increased over time until sufficient wax has penetrated into the wood cell structure to act as a scaffold, and prevent deformation of the wood during drying.
**PEG impregnated objects are dried in a freeze-dryer. Here the items are frozen to around -30 °C and a vacuum applied to the drying chamber. Under these conditions of reduced temperature and pressure the solid water – ice – is converted directly to a vapour which is then removed from the wood. This technique is a very gentle procedure as removing the water as a vapour reduces the forces applied when water is in its liquid form.
For further information on our conservation work at MAST, please call 07768 080105 or 07733 206272.
How to find us
If you would like to visit, please make an appointment at mast@thisismast.org. The address is:
MAST
19 Cowley Road
Nuffield industrial Estate
Poole
BH17 0UJ