Why Divers Bell?

A diving bell is a cable suspended watertight chamber, open at the bottom that is lowered underwater to operate as a base or a means of transport for a small number of divers. Unlike a submarine it is not designed to move under the control of its occupants, or to operate independently of its tether.

Diving bells are used as underwater rescue vessels and by working divers doing underwater work and salvage. The bell is lowered into the water by cables from a crane attached to a ship or dock. The bell is ballasted so as to remain upright in the water and to be negatively buoyant so that it sinks even when completely full of air.