A commercial diving crew performing regular field maintenance from a lift boat in 25 ft of water in the Gulf of Mexico experienced a potentially catastrophic near miss. Approximately 70 ft of the divers umbilical was pulled into the lift boat propeller before it was completely severed less than 20 ft from the diver.

The diver was working underwater on an offshore platform riser. The lift boat was stationed 20 ft from the work site, and was elevated from the surface of the water 2 ft, leaving the propeller and rudder assembly underwater. The configuration of the Lift boat was such that the dive station was above the propeller area (stern of vessel).

The lift boat's main engines (which turn the propeller shaft), and the lift boat crane, share a common hydraulic system. During crane operations, though the main engines are in neutral, there exists a possibility of partial clutch engagement causing a slow rotation of the propeller.

The dive crew's standard procedure on this type of vessel is to secure the shaft with a large pipe wrench, chain, binder, and lock-out/tag-out. For unknown reasons, this procedure failed, causing the shaft to turn the propeller slowly, grabbing the divers hose and pulling the diver toward the propeller. This action occurred during a timeframe of less than 60 seconds prior to the umbilical completely severing. The diver surfaced unharmed.