A talk By Steve Allen given to AIM at Liston Hall on Thursday 16 May 2013
Steve Allen BA, MA, MIfA is a Wood Technologist at York Archaeological Trust and he came a long way to talk to Archaeology in Marlow about the Shottesbrooke log boat and also some more recent findings uncovered during the Hungate (York) project.
Steve gave us the background to how the log boat was found, apparently the Shottesbrooke estate workers were enlarging a pond on the estate, when they hit with the JCB, what we now know to be a log boat. They called in local archaeological units for advice and the River and Rowing Museum at Henley subsequently volunteered to fund its conservation.
In December 2003, having won the tender, York Archaeological Trust collected the boat to carry out the conservation work. Luckily the fragments that had broken when the JCB box hit the boat had been kept. The boat had in the meantime not been allowed to dry out.
As an example of what happens if wood is not conserved properly, Steve handed round two parts of the same medieval wooden stake, one part had been left to dry out and the other had been conserved. (not to worry, apparently there are very many medieval stakes where Steve works). The dried out piece had shrunk alarmingly and seemed to have broken up, whereas the conserved piece was well preserved.
Steve impressed on us the importance of recording everything, citing examples of some Victorian archaeologists who had not kept viable records as a bad example. The boat was recorded first by drawing, Steve showed us a slide of some of the drawings, which showed the boat had straight sides, about 12” deep, was flat bottomed, with two integral cross members to give it lateral stability and was cut from a single log of oak. It was probably used for personal transport. Steve explained that by looking at the pattern of the wood, the grain, the knots etc. he deduced the log was probably from managed woodland. There had been a nailed repair to the boat, but no artefacts were found with it. Radiocarbon dating showed the tree was cut down in 1075, but it is not known how long the boat was used for. A similar log boat had been found in Warrington.
Steve then went on to explain the conservation process that was carried out at the Trust. PEG (Polyethylene Glycol) which has a wax texture was used as a preservative and Steve explained with the aid of graphs the solution percentages and times of immersion. Once it had the PEG treatment, any excess was removed from the surface and then the water was removed from the boat under controlled conditions by spending 3 – 4 months in the freeze dryer at temperatures of -20ºC to -30 ºC. Very importantly records are meticulously kept and this information is added to the report given to the River and Rowing Museum.
Steve then showed us a picture of the boat on display and explained that as long as the temperature was stable the boat should be OK, it just needs dusting as PEG attracts dust.
Steve then went on to tell us about a discovery during the Hungate excavation. In 2008 they dug a sondage and found a late 12th century cellared building. The planking used to hold back the sides was found to be from a boat, this planking had been preserved because the site had been waterlogged. The planks were taken out and peg holes along each side of the plank were found, which suggested a clinker built boat i.e. partially overlapping planks, pinned with wooden (willow) pegs, with moss between the planks providing watertightness. Dendrochronology told them that the tree was cut down in AD965 and that the planks were from the London area and the boat had been constructed in the South East area before making its journey to York. The boat would have been a minimum of 36ft. If you go to the following web site, there is a YouTube video of the plank removal http://www.yorkarchaeology.co.uk/specialist/wood.htm. It is not possible to see the structure in York currently as it is behind hoardings, but it will eventually be opened for public viewing.
Our thanks went to Steve for his fascinating talk, which increased our knowledge of wood conservation and also gave us insight into a local artefact, as well as giving us information on part of an excavation at York.