The excavation campaigns
(by years)
José Antonio Bettencourt (Centro de História d’Aquém et d’Além-Mar, University of Lisbon)
Underwater excavation
Recording
The 2015 field season took place from 23rd July to 18th September 2015. Several of sites were investigated.
Clearing and scale drawings of the most exposed parts of the 19th century Angra A wreck (a section of the keel to the east, elements of the frame and the hull to the south, as well as various elements of the frame, cabin and fittings in the central part of the mound). The scale drawings could be carried out once the study area had been cleared and the system of position fixing had been put in place. A comprehensive photographic survey of the wreck was conducted, along with the placing of reference points, in order to produce orthorectified images (Angra A mound: 50m x 20m). This data enabled an initial photogrammetric reconstruction of the wreck. The same process was carried out on part of the stern of the Lidador, a steam ship which sank in Angra in 1878.
Alongside these investigations, monitoring and systematic data collection was carried out on sites investigated in previous years. Rapid deterioration in the level of conservation of the sites was observed (in particular due to bioerosion by the naval shipworm teredo navalis which bores through wood, and the invasion of the plant species caulerpa taxifola). This encouraged us to strengthen pre-existing protection measures.
Topographic survey was carried out on 5 mounds recorded in the Bay of Angra (wrecks Angra A, Angra B, Angra I, Angra and Lidador), with the installation of fixed reference points and a network of temporary markers. This enabled the mapping of the distribution of the various wrecks in relation to each other.
Survey dives carried out around the site of wreck BH001 (18th century) led to the identification of a new elephant tusk associated with the wreck (O naufragio do marfim, 18th century). Survey dives were also conducted on the site of the Nossa Senhora da Luz, a merchant ship which sailed on the sea route to India, and which sank in the Bay of Porto Pim in 1615.