197.334—Open diving bells.
Each 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.