This portion of the exhibit illustrates one typical commercial diving project in the Port of Los Angeles. In 1975, commercial divers constructed the sewer force main that transports sewage across the main channel to the Terminal Island Waste Treatment Plant. This project was a necessary response to an urgent need for improved waste treatment facilities.
The diving work required the installation of 1,542 lineal feet of ductile iron joined pipe laid under the main channel of the harbor. Divers laid the pipe in a trench excavated to a depth of 65 feet, and surrounded it with rock backfill for support and protection. Diving work within the trench had to be accomplished by feel because of zero visibility caused by mud particles suspended in the water – a typical diving condition when working in harbors and muddy bottoms. A Los Angeles City survey crew worked with the inspector diver to help maintain the grade and alignment of the pipe.
Attached to the fire hose is a jetting nozzle that the diver will use to fill voids and compact the bedding gravel under the pipe. This style of jet is called a T-nozzle. The T-nozzle is fitted with short pipe nipples on each side of the T to prevent back pressure when it is turned on. Although several hundred pounds of water pressure will be forced through the nozzle, it will stay balanced because the streams of water coming out of it will be equal and opposed. This allows the diver to manipulate the nozzle more easily.
When all the studs are in place, the diver will use the pneumatic impact wrench to torque (twist) up all the bolting. The spud wrench is used to line up the gasket. Other hand tools used here are in the diver’s tool bag, or lying next to him. Because of the muddy water conditions, the real-life divers would not have been able to use the light. The diver is wearing one of the four-light helmets originally used in this project.