Clear dome in this bell allows scientists to record observations in midwater. In the air-filled bell dome, divers can talk to each other and the surface. Stable on the pool bottom, a bell bobs when hanging from a pitching ship. 1984 July 254. A dive bell support ship must be in a multi-point mooring to avoid dragging.
Surface supplied air is used in polluted water to avoid contact or ingest.
Compared to old hard hat diver, Exo mask diver doesn't need lead boots. A dome for talking to the surface and other divers. Early hard hats were heavy in air, but buoyant underwater. Surface-supply and dive bells greatly extend the time divers could stay down. North Carolina 1984 July 261.