Excavation techniques

Environmental conditions at the site, in particular the very short slack tide periods, led to a strategy of using a large team of divers who would simultaneously carry out a number of archaeological tasks. Starting in 2000, a very powerful motor-pump was put into service. It provided power for a single, large-calibre water column that was connected to a satellite with six outlets. This arrangement made it possible to connect six hoses and suction heads of six water dredges simultaneously, and prevented the hose lines from getting tangled in the swirling currents.
Several factors hampered the recording of vestiges and architectural structures, including the disorderly topography of the wrecks, the endless chains of seaweed brought in by the current, the limited diving time and the reduced – and even mediocre – visibility at low tide. And yet, this was the only way to register the shipbuilding techniques and methods that were used, and to reconstruct the hull shapes. The planimetry was carried out on a 1:20 scale for the entire site, and was completed by cross and longitudinal sections. Every diver had to use a standardised drawing technique for both the partial and scale drawings.
As the excavation progressed, extensive photographic and video documentation was collated in order to preserve the memory of the wrecks.

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