Ancient remotely-operated instruments recovered under water off the Israeli coast

Underwater archaeological investigations in Israel have recovered instruments intended to be operated under water from a vessel on the surface, at depths and times beyond the ability of free divers. Some of these remotely-operated devices, including salvaging-rings, coral-harvesting devices, and grapnels, are described, classified and discussed. These humble but efficient instruments, the prototypes of sophisticated modern instruments, fulfilled necessary tasks in antiquity and are still being used today by traditional fishermen.