Safety Lessons from Marine Incident Investigation (AMSA Report) No.16 – February 2023

Planned maintenance failure leads to vessel sinking.


In the early afternoon of 30 May 2022, a hire and drive sailing catamaran began to take on water before sinking shortly after departing the marina. Onboard was the charterer, their family and a briefer who was in control of the vessel.

The investigation established that following recent maintenance, an inspection plate had not been replaced, allowing water ingress. It was further identified that the charter company’s maintenance procedures did not suitably document handing over and/or tagging of removed items during maintenance work.

What happened

A Class 4D hire and drive sailing catamaran reported rudder misalignment issues following a charter (28 May 2022). The company’s maintainer investigated the rudder with assistance from divers. This required removing the aft port duckboard inspection plate and locking bar which was stowed in the vessel’s cockpit. The issue could not be rectified at the time, and additional work was recommended for a later date.

The maintainer was also tasked with preparing another vessel for departure. The next day, a different maintainer conducted a mechanical check of the vessel, noted the rudder misalignment, but did not complete the work list or the checklist. Two days later (30 May 2022) a hydraulic company was brought in to fix the rudder.

Later that day, a briefing was conducted for the charterer and their family. Following the briefing, the vessel departed the marina with the briefer in control of the vessel. The briefer handed over the helm to the charterer at the exit to the marina, just inside the rock wall. The vessel began veering to port and could not be turned. The briefer retook control of the helm and engaged reverse propulsion to stop the vessel colliding with the rock wall. With water coming up over the duckboards, the vessel quickly started taking on water, began listing and subsequently sinking.

The charterer and their family abandoned the vessel. The briefer stayed with the vessel, attempting to manoeuvre it out of the marina entrance until instructed to abandon the vessel by the water police.

Investigation findings

The investigation identified the following contributory factors:

  • An inspection plate had been removed from the aft port duckboard above the rudder stock to investigate the steering alignment issues and was not replaced prior to the vessel’s departure. When the vessel engaged reverse propulsion, the open inspection port allowed water ingress into the void and filled non-watertight compartments, flooding the vessel quickly.
  • The first maintainer who removed the inspection plate failed to document and hand over this action to the next maintainer.
  • The charter company’s maintenance procedures did not provide for suitably documented procedures for handing over and/or tagging of removed items for multiple vessel maintenance work. Vessel briefers and maintenance crew verbally communicated the prioritisation of work required on multiple vessels each day. Work decisions and tasking were not documented, or checklists completed.
  • The vessel was designed with an inspection hatch 30mm from the waterline on the external aft area of the vessel and was hidden by a hinged step.

Safety message

Vessel owners/operators (the charter yacht company in this incident) must ensure an appropriate and well documented regular program of inspections and maintenance.

It is critical that they also ensure companies providing maintenance services for their charter operations and servicing multiple vessels on a regular basis have proper planning and procedures for the management of maintenance schedules in place.

Last updated: 

Thursday 23 February 2023