A sidescan anomaly picked up during the 2002 wreck survey is the wreck of HMS Impregnable, a 98 gun ship built in Deptford in 1786. The sidescan data shows a number of rectangular features on the seabed. The magnetometer data indicates that these features are of ferrous metal.

The site was not dived in 2002, but it was investigated by the Hampshire and Wight Trust for Maritime Archaeology.