Engineer Amy Kukulya, left, watches engineer Robin Littlefield, center, both of the Woods Hole Oceanographic Institution, and Underwater Archaeologist George Schwarz, right, of the Naval History and Heritage Command, place a sonar unit in the water Wednesday for a second day of surveying in an area on Watch Hill Reef. Divers Craig Harger, background left, and Charlie Buffum, background right, think they discovered the 201-year-old wreck of the Oliver Hazard Perry ship the Revenge. The information gathered will provide video, acoustic images and metal data that will be analyzed back at the Woods Hole lab.