The multibeam data acquired over the 2km x 2km area was not able to detect the Thomas Lawrence or any of the other small or ephemeral sites. This is perhaps surprising given that this data set was collected using the highest possible resolution system available and with archaeological considerations as a primary concern.

Therefore, marine surveys for detecting small or ephemeral sites of archaeological interest are best conducted using a sidescan and magnetometer with the closest line spacing considered to be affordable. The sidescan sonar used should be a high frequency system and the range setting should be as short as possible to still allow at least 200% coverage when run at the line spacing considered to be affordable.

Multibeam surveys do add information to such investigations but it is not advisable to use multibeam systems on their own or as a means for prospecting for archaeological sites. Where they are used, though, then the system should be a high resolution system with the narrowest beamwidth affordable. Also, any wreck sites should be surveyed with the vessel at low speed and the ping rate of the multibeam system as high as possible. The archaeological geophysicist should then review all the data and not just the filtered data produced for hydrographic interpretation.