The objective of drifters is to monitor the movement of the 'bottom load' - how sediment and other materials (such as pottery shards) move in response to prevailing currents. Two types of drifter were used in this study, these had to have reproducible behaviour, but be built on a limited budget. The 'ultra-light' model, based on a golf practice ball, moves in response to very slight currents, while the heavier model based on a halved tennis balls require strong currents to get moving.
Bottom drifters did not move over the two weeks of study in 2002. Most deep-water drifters re-located in 2003 by RAF team, showing that they had not moved over the period of one year. On the basis of this observation, it appears that no movement of artefacts is to be expected in the deep-water part of this site. None of the shallow water drifters were recovered in 2003, though these need not have drifted far to be hidden in thick kelp.
The results indicate that materials, once deposited in the deep-water part of the site, will not move under normal conditions. In the shallow water section of the site, it is possible that storm waves may churn up sediments and any artefacts contained on or within them.
Pottery has only been recovered from the deep-water part of the site. Shards recovered show sharp breaks, and lack of erosion indicating very little post depositional disturbance. This confirms the drifter results, that material is not moving once it has been deposited within this environment.