Two weeks before the diver groundtruthing portion of the investigation, project sponsor Subnauta conducted one leg of a remote-sensing survey in the Bay of Martinhal. As there is some evidence of concreted cannon ( possibly 4-5 pounders) submerged in the bay, the objective was to create a map of magnetic anomalies in the survey area. The survey provided over two dozen possible man-made anomalies, which were prioritized for diver investigation.
