A number of different types of recording were used underwater: traditional survey; DSM or Direct Survey Measurement; various types of photography; and drawings, sketches and notes from the archaeologists and volunteer divers.
In l976 and again in 1979, Nigel Kelland used an acoustic rangemeter, developed by John Partridge of Sonardyne, to produce a series of fixed datum points on the structure of the ship that were used as a basis for future surveying. The section drawings of the ship and the plans of the decks were then produced by manual trilateration and offset measurements. This was carried out mainly with thirty metre tapes (left) and one metre rules. Given that conditions on site were far from perfect, with poor visibility, strong currents, cold numb hands and plenty of structure and equipment to tangle tapes around, the results were very satisfactory.
Where possible, the deck planks and half beams were surveyed, and drawings prepared from these surveys, including details such as the fastenings. Parts of these surveys were never completed, as they had to be done before parts of the deck, particularly near the starboard side, had been excavated.
One part of the orlop deck had been dislodged during the past, and
an in situ survey was not possible in the area affected.
The DSM system was developed by Nick Rule on the Mary Rose site. With this system an object is measured from four fixed points and the data is converted to x, y and z coordinates using custom-written software. The simplicity of the system allows divers who are inexperienced in survey techniques to produce useful data with a minimum amount of difficulty. It is particularly useful for measuring objects suspended in the silt that are not contiguous with the deck structures. The results can be shown on a conventional site plan with the depth in text, or can be modelled in 3D on a computer.
Both still and video photography (above) were used underwater, but there was one common problem, the Solent just isn't the Caribbean. Except on rare occasions, still photography of large areas of structure was rendered impossible by the limits of visibility.
Even if the lack of light could be resolved with lamps, suspended sediment tended to get in the way. Despite these problems, a great many useful pictures were obtained, particularly of structural features in close-up. The advantage of video was that by using panning and tracking shots it could show relationships between timbers that couldn't be seen in a single frame. In total, seventy hours of video footage was taken.
Some of the most useful information came from the divers and supervisors notes, drawings and sketches. The divers and supervisors logs and site-book entries fill approximately 31,500 A4 sheets. In many cases, a drawing of a feature or even a rough sketch possibly combined with a written description has proved invaluable in understanding it. At the end of each diving season the archaeological supervisors wrote reports on the areas of the ship they had been responsible for, summarising it while the information was still fresh.
The incomplete nature of the hull and the disintegration of some of the iron fastenings holding the deck structures in place made it imperative that all the internal structure, barring the main and orlop deck beams, some of the stanchions and carlings, and most of the knees, be removed before the ship was raised. Before this was done, each timber was given a unique number and tagged with a plastic label. The timbers were then removed and stored off-site to be lifted later.
Bolt holes in the ship - the bolts have totally corroded away.
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