New Zealand accident investigators publish report on containership loss of control in Wellington Harbour
The Transport Accident Investigation Commission of New Zealand (TAIC) has published its report on the investigation into the loss of control on the container vessel Shiling in Wellington Harbour on April 15, 2023.
On the said date, Shiling was turning into the Wellington Harbour entrance channel when the main engine stopped. The crew used both anchors to stop the ship from grounding and it was subsequently towed by harbour tugs back to its berth to be repaired.
After repairs, the ship departed Wellington again on May 12, 2023, and was sheltering from adverse weather off the New Zealand coast. The bilge tanks were full and when the ship entered the Tasman Sea and began to roll, bilge water entered the lube oil tanks, resulting in the main engine stopping.
A tow-capable vessel sailed from New Plymouth to tow Shiling to sheltered waters and eventually back to Wellington for repairs.
Maritime New Zealand detained the ship for repairs and survey until July, when it departed for Singapore.
Why it happened
The TAIC found that exhaust gases from a cracked cylinder liner in one of the generators entered the centralised system that supplied cooling water to all generators and the main engine. The cooling water temperature increased, tripping out the running generators, which caused the main engine to stop.
The commission said that, although the ship held valid statutory and classification society certificates, the generators and several other safety-critical systems were in a deteriorated condition.
The investigation revealed age had deteriorated rubber diaphragms intended to prevent water entering the lube oil tank.
The TAIC said that it is very likely the diaphragms had not been inspected for many years. This was despite insurance clubs and engine manufacturers issuing several bulletins warning of the critical importance of maintaining the diaphragms in good condition.
What can be learned
Ship owners carry the risk responsibility, according to the TAIC. The creators of risks are best placed to manage them.
A shipowner who offers a ship for service must remain responsible for its safe operation, regardless of any other entities involved in operating, inspecting and auditing the ship and its systems.
The commission emphasised that deferred ship maintenance, especially of critical equipment and systems, will significantly increase the risk of accidents and incidents.
The TAIC said it is imperative to fully investigate failures involving critical equipment and systems, establish causes, and resolve them before putting the systems back in service.
Safety issues and recommendations
Several safety issues relate to international and domestic systems for regulating international ships and the ability of shipowners to devolve their responsibilities for the safe operation of their ships to third parties without regulatory consequences.
The TAIC has made recommendations to Maritime New Zealand to address these matters through the International Maritime Organisation.
The commission has also recommended that the Ministry of Transport consider legislating to give Maritime New Zealand the authority to ban certain ships from entering the country's waters.
The TAIC said one safety issue relates to NZ tow salvage capability. The commission has therefore recommended that work continue to develop and implement a comprehensive maritime incident response strategy that will strengthen salvage and rescue capability.
