Section 197.334 - Open diving bellsEach open diving bell must-
(a) Have an upper section that provides an envelope capable of maintaining a bubble of breathing mixture available to a diver standing on the lower section of the platform with his body through the open bottom and his head in the bubble;(b) Have lifting equipment capable of returning the occupied open bell to the dive location;(c) Have an umbilical; and(d) Be-(1) Made of corrosion-resisting material; or(2) Protected against and maintained free from injurious corrosion.