Although it’s only been a few weeks since I looked at ‘what lies beneath,’ it feels like a lifetime as so much has happened to our blue whale skeleton in a relatively short space of time. The biggest challenge of de-installing the skeleton from the Mammals Hall has been completed with resounding success and the Conservators are now busy with the next phase of cleaning and conserving each individual bone.
We all knew that safely removing the bones from the 81 year old armature was not going to be easy. Add in the fact that it was suspended over a large model of a blue whale and several other specimens with very little room for manoeuvre and you start to appreciate the whale-sized nature of the project. This post outlines what happened during the de-install.
After careful planning and the labelling of the skeleton, we were ready to start with the smallest caudal vertebrae. The first task was to remove the plaster covering the very end of the tail section so we could release the initial vertebra.
Underneath the plaster the first challenge presented itself in the form of two steel metal rods embedded through the bone which had been fashioned into a loop at the end thus preventing the first vertebra from being removed.
After carefully applying a small hacksaw (which would come in handy throughout the project) the loop of metal was carefully cut away and the first bone was ready to be removed.
It’s worth noting at this stage that, in order to remove any of the vertebrae, the plaster modelled intervertebral discs had to be chiselled away so that the central armature could be seen and the vertebrae loosened from the mount. This was further complicated by the fact that underneath the plaster there was a large number of wooden splints and wedges holding each vertebra firmly in place. These were often nailed directly into the bone by our predecessors all those years ago. So some reverse engineering was needed to extract each bone from the armature.
The next 3 caudal vertebrae were even more challenging as the internal armature increased in size and complexity. This took the form of several steel metal rods, plus a rectangular iron bar bolted in sections, that was to run throughout the vertebral column.
As the vertebrae increased in size the armature became slightly more predictable but each bone was a challenge to remove as it was so firmly wedged onto the internal metal bar by the wooden wedges.
After the first 8 caudal vertebrae were removed the next problem had to be tackled in the form of the cable suspension metalwork which was bolted into the armature and effectively blocked the removal of more vertebra.
A support gantry was wheeled into place and a sling was placed under the exposed metal armature to support the structure and the first cable was uncoupled. More vertebrae could then be removed and each safe removal caused great joy amongst the Conservators.
As each vertebra was removed the team learned more about how the skeleton was articulated and mounted onto the armature and soon the process became more predictable. There seemed a certain elegance in the vertebrae as they waited to be removed. Anyone think of aeroplanes when they look at the image below?
Further along the vertebral column, other skeletal elements had to be removed to ensure progress towards the skull, including the chevrons, sternum, scapula, radius, ulna, phalanges and ribs. Each was bolted onto the armature or had additional armature attached and in some places the Conservators had no choice but to cut through some metal rods to ensure safe removal.
When the team reached the cervical vertebrae removal of the modelled intervertebral discs that had been inserted between the bones during the original installation, was more time consuming as the vertebrae were closer together. However the added bonus was that the team discovered that a large quantity of newspaper has been used as packing material.
The newspaper pieces , dating back to between 1932-1934 will be preserved where possible to add to the archive documentation for this project. One piece may well find its way back inside the specimen once it is re-suspended in the Hintze Hall in 2017. Watch this space.
As the vertebral column was taken down more space was created on the scaffolding to check, wrap and pack each bone. Conservation approved materials were used to protect the bone surface such as Tyvek (polyethylene sheet) and Plastazote (blown polyethylene foam sheeting).
The next stage involved removal of the two parts of the mandible. Blue whale mandibles are the largest single bones of any animal to exist and both sides have large cracks around their existing metal armature so extra care was needed to move them.
Once some of the scaffolding was re-built to allow easier access the first challenge was to excavate around each bolt connection and uncouple the mandibles from the skull whilst providing full support to each element.
Each mandible was then packed into a bespoke wooden frame so it could be carefully lowered down to the floor of the mammal gallery. The mandibles were too large to move internally to their new home in the Pop Up Conservation studio so they had to be hoisted out through a side exit in the wall of the gallery and down onto a HIAB (lorry with integral crane) waiting in the colonnade below.
This was no easy task and there was much manoeuvring to ensure they “landed” safely on the lorry. They were then driven around the perimeter of the Museum so that they could be taken in through our entrance in the Darwin Centre. Once they were transferred into the entrance by the wonderful and versatile HIAB crane, they were wheeled into the Pop up Conservation Studio that has been created for us there, ready for treatment. There was relief all round at this point, but everyone was aware that the greater challenge of removing the skull lay ahead.
After the 2015 festive break the team reassembled to spend a week taking down the skull. The skull is almost 6 metres in length and three metres at its widest point. It is highly complex in shape with over individual 40 elements fused or partly fused together.
The first challenge was to lift and move it without placing any strain on the bone. The second challenge was that, due to existing cable supporting the whale model underneath (which could not be moved or removed), the skull was going to need to be rotated as we moved it, so that it would fit through the gap between the cable and the side of the scaffolding to enable it to be lowered to the ground floor of the gallery without damaging anything.
This was the biggest challenge of all. A cradle had been designed to be placed underneath the skull and existing holes and bolted areas of the skull were used to attach it to the cradle. The Conservators were extra vigilant at this stage ensuring that as much support could be given to the skull to ensure it would stay attached to the cradle. Crack monitors had been placed at existing vulnerable parts of the skull to provide an additional recording mechanism for cracks opening up during the process.
Extra removable sides were then added to the cradle, to provide extra protection for the rotation and subsequent move. The team managed to decouple and move the skull down to the ground of the Mammals Hall and then onto the HIAB though, at times, there were literally centimetres to spare!
The skull is now safely stored in one of our off-site stores and will be undergoing treatment over the next few months as it was too big to treat at the Museum. Conservation methods and treatments will be covered in my next post but, in the meantime, why not pop along to the Darwin Centre in the Museum, to our newly created Pop up Conservation Studio. There, you can see how we are getting on with the conservation of the mandibles and other parts of our blue whale skeleton.
Amazing feat.keep up the fantastic work.worth all the toil and worry to all of the team.
Very interesting, gaining a huge appreciation of the work, skill and patience that’s involved to complete the move to its new home.