A June day finds us once again diving around the battleship USS Arizona, whose sunken remains lie in Pearl Harbor. Larry Nordby surfaces beside me clasping his large plexiglass slate; a piece of mylar taped to it is covered with scribbled notations from his dive. “Navy’s here,” he announces. I look toward the boat ramp where a small landing craft full of “mudzoos” is tying up to the dock of the memorial building that straddles the wreck. Mudzoos are navy divers assigned to the Mobile Diving and Salvage Unit (MDSU) based at Pearl Harbor. We have a symbiotic relationship with these men, whose primary mission is as far from science and historic preservation as ours is from ship husbandry and underwater construction. Our allegiance instead is to the Submerged Cultural...