Failure of chamber door spindles and seals

A member’s diving support vessel (DSV) had recently completed a period of maintenance with some minor work on the saturation chamber system, which included door hinge realignment.

During pressurisation of the divers, a leak was identified from the lock between the two occupied chambers. Pressurisation was halted at 5 msw and the system surfaced for repair. On completion of the repair the system was again pressurised when a different leak on the same door caused the pressurisation to be halted at 8 msw.

Both leaks were identified as being at the seals in the door spindle shafts that passed through the chamber doors to enable the retaining ‘dogs’ to be operated from both sides of the chamber door. The two leakages prompted an inspection of all the door spindles in the system, identifying the following:

• There was no history available on the spindles or seals, as they were not part of the planned maintenance system.
• Almost 70% of the door spindles were found to be unserviceable due to surface damage in the sealing area or bending of the shafts and required replacement.

The following points are highlighted to members who have diving systems configured with spindles through chamber doors:

• The door spindles and associated seals should be identified as critical components.
• Inspection and replacement of the door spindles and seals should be included in the planned maintenance system.