Divers forcing a hydraulic probe into the seafloor.
Hydraulic Probe
Image courtesy of the Search for the Lost French Fleet of 1565 Expedition, NOAA-OER/St. Augustine Lighthouse & Museum. Download larger version (jpg, 85 KB).

Divers forcing a hydraulic probe into the seafloor. The probe is ten feet long and is connected by a hose to a water pump on the boat. It jets water out of the end being thrust into the sand.

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