A bell diving team will usually include two divers in the bell, designated the working diver and bellman, though they may alternate these roles during the dive. The bellman is a stand-by diver and umbilical tender from the bell to the working diver, the operator of the on-board gas distribution panel, and has an umbilical about 2 m longer than the working diver to ensure that the working diver can be reached in an emergency. This can be adjusted by tying off the umbilicals inside the bell to limit deployment length, which must often be done in any case, to prevent the divers from approaching known hazards in the water. Depending on circumstances, there may also be a surface stand-by diver, with attendant in case there is an emergency where the surface diver could assist. The team be under the direct control of the diving supervisor and will also include a winch operator, and may include a dedicated surface gas panel operator.