Wessex Archaeology (WA) was commissioned by Cadw to acquire, process and interpret marine geophysical data over a number of known and suspected wreck site locations off the coast of Wales. This survey was conducted under the Protection of Wrecks Act (1973) contract and the data is Crown Copyright©. The data were acquired and processed by Wessex Archaeology. The marine geophysical surveys targeted a total of nine suspected wreck locations in Milford Haven area, off the coast of South Wales, seven of which represent the locations for the remains of 19th century Welsh vessels associated with the coal mining industry. Additional survey data were acquired over two 20th century sites within the Milford Haven, the Thor and the Sunderland. The acquisition of these data aimed to assist RCAHMW maritime team and the Sunderland Trust with on-going archaeological research and fund-raising. The marine geophysical surveys also targeted a total of ten suspected and known wreck site locations off the coast of Lleyn peninsula in North Wales. These included eight unconfirmed positions of 19th century Welsh vessels associated with the slate mining industry, two designated sites the Diamond and the Tal-Y-Bont, and the marine hazard of St Patrick’s Causeway with the aim of discovering new wreck sites. The project aimed to acquire marine geophysical data consisting of high resolution sidescan sonar and magnetic gradiometer data over a total of total of 21 known and suspected wreck positions and along the known marine hazard of St. Patrick’s Causeway. Since the sites were located in two different areas, they were surveyed during two separate surveys from the Pembroke based vessel Blue Shark. The first session surveyed sites mostly off Milford Haven in south Wales between 17th and 18th April 2010. The second session surveyed sites off the coast of Lleyn peninsula and along St. Patrick’s Causeway in north Wales between 23rd April 2010 and 2nd May 2010 with a day of mobilisation and a day of demobilisation at the start and end of the survey session. The geology and geophysics component of the data are archived at British Geological Survey (BGS) MEDIN Data Archive Centre (DAC) for Geology and Geophysics. Data were also provided to other archive centres as appropriate.
