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Near-miss: Diver’s umbilical severed by propeller

A member has reported a high potential near-miss which occurred during a regular field maintenance operation which was taking place from a lift boat in 7½ metres of water, whereby a diver’s umbilical was pulled into the lift boat’s propeller before it was completely severed with the diver less than 6 metres from the propeller.

The diver was working underwater on an offshore platform riser. The lift boat was stationed 6 metres from the work site and was elevated 60cm from the surface of the water, leaving the propeller and rudder assembly underwater. The configuration of the lift boat was such that the dive station was above the propeller area at the stern of the vessel. The dive crew’s standard procedure on this type of vessel was to secure the propeller driveshaft with a large pipe wrench, chain, binder, and lockout/tag-out. For unknown reasons, this procedure failed, causing the driveshaft to turn the propeller slowly, grabbing the divers hose and pulling the diver toward the propeller. This action occurred very swiftly – in less than one minute over 20 metres of umbilical were drawn in, before it was completely severed. The diver surfaced unharmed.

The company involved has made the following recommendations:

  • A purpose-built clamp, which will not become disengaged, with padlock, is to be installed on lift boat propeller driveshaft(s) prior to any diving operations;
  • A lift boat must be elevated above the waterline enough to completely expose the propeller and rudder assembly;
  • Specific job hazard/safety analysis must be performed, involving both vessel and dive crews.

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