3 weeks ago

NSIA report about Viking Sky vs reality

The Viking Sky cruise ship incident, which occurred on March 23, 2019, off the coast of Norway. A cruise ship carrying over 1,300 passengers and crew, encountered engine failure during a storm near Hustadvika, Norway. The loss of power rendered the ship unable to maintain its position, putting it at risk of running aground. A complex rescue operation involving multiple helicopters, tugboats, and other vessels successfully evacuated all passengers and some crew members before the ship was eventually anchored. Thankfully, there were no fatalities or serious injuries reported. The Viking Sky incident in 2019 ranked among significant cruise ship events of the 21st century.

NSIA final report

The Norwegian Safety Investigation Authority has compiled a final report and published on March 2024 for several key reasons:

  • Improve Safety at Sea: The primary objective of the NSIA is to enhance maritime safety. By investigating accidents and incidents, they can identify contributing factors and make recommendations to prevent similar occurrences in the future.
  • Identify Root Causes: The report delves into the Viking Sky incident to pinpoint the root causes of the engine failure and the challenges encountered during the emergency response. Understanding these root causes enables the implementation of targeted solutions.
  • Transparency and Accountability: The NSIA report fosters transparency by publicly outlining the events, findings, and recommendations. This can hold relevant actors accountable and encourage the cruise line, regulatory bodies, and other stakeholders to prioritize safety measures.
  • Learning from Experience: Every maritime incident presents a learning opportunity. The Viking Sky report disseminates valuable insights that can be used by the entire maritime industry to refine practices, training, and emergency procedures.

A review of the NSIA report reveals that several critical safety practices, once standard on cruise ships, are now being neglected. Our further view in comments will be highlighted.

Viking Sky 2019 incident paragraphs from summary report

In general what happen

“In the afternoon of 23 March 2019, the cruise vessel Viking Sky experienced a blackout, causing
loss of propulsion and steering, during a storm in the Hustadvika area of the Norwegian coast. The
vessel is estimated to have come within a ship’s length of running aground with 1,374 persons on
board, and the accident had the potential to develop into one of the worst disasters at sea in
modern times.”

Main findings

“Viking Sky suffered a blackout when all three operational diesel generators (DGs) were shut down
by their protection systems responding to low lube oil pressures. The low lube oil pressure was due
to low levels of lube oil in the sump tanks in combination with the vessel motion, causing the lube
oil suction pipe opening to be exposed to air.” – this appear to be a main cause of accident.

DG’s oil sump tank

“Since the departure from Tromsø two days before, no oil had been transferred into the DG sump
tanks even though low lube oil level alarms went off both for DG2 and DG4 during the voyage, and
the heavy weather checklist, that included an item requesting the lube oil sump tank levels to be
optimised, was logged as completed.”- Commonly the lub oil stock is counting only what you have in your storage tanks, not in engine sump. Therefore most of Chief Engineers are trying to keep a level in sump just above the alarm to hand over more oil in the end of month in perspective of economy.

“None of the vessels in the fleet of five sister vessels had been provided with instructions on correct
lube oil sump tank filling levels or alarm setpoints.”- very rarely any ship has. Usually information is generic to keep some percentage of oil sump capacity.

“The combination of economic considerations, underestimation of consumption, the lack of
confidence in the remote tank monitoring system and the lack of instructions regarding the correct
filling and alarm setpoints, probably resulted in the lube oil levels and alarm settings decreasing
over time.”- as we mentioned.

Ship’s construction issue

“The shipyard’s design process did not effectively ensure that the lube oil sump tanks complied with
all applicable rules, regulations, and recommendations. Likewise, the plan approval process of the
classification society was ineffective and did not ensure that the sump tank design, which is critical
to safe engine operation, was compliant.”- this is a commercial part of shipbuilding where shipowner trying to cut a cost of calculations for installation of engines. The new ship could be built on several different shipyards by parts and to be assembled on final one.

Technical automation and alarm system

“The alarm system in the engine control room did not differentiate between critical and less critical
alarms. Troubleshooting was therefore challenging when a total of approximately 1,000 alarms
sounded within the first 10 seconds after the blackout. Several issues related to design and
configuration of the alarm system are likely to have had a negative impact on the effectiveness and
efficiency of engineering officers on watch.”- it is an absolutely common for most of the ships and automation systems (Viking Sky was equipped with a Wärtsilä NACOS VALMATIC Platinum Integrated Automation System (IAS)). During black out all alarms starting from vacuum toilet system till main power generation are jumping on screen and it is challenging and time consuming to figure out a source of real trouble.

Black out

“During the 10 seconds following the blackout, approximately 1,000 alarms registered in the engine
room alarm system as a result of the blackout. The vessel’s emergency diesel generator started
within 4 seconds, and power was established to the emergency switchboard 16 seconds later.”

“In the engine department, the engineers focused on restarting the diesel generators, but the efforts
were unsuccessful. After some time, they realized that the shutdowns might be caused by low lube
oil pressure. At around 1412 they began transferring lube oil from the storage tank to the sump
tanks.”- as we mentioned above the troubleshooting is relatively time consuming due to amount of alarms, calls and stress.


“The blackout recovery was time consuming, and it took 39 minutes from the blackout until both
propulsion motors were operational and the ship had sufficient power available to maintain
between 1 to 5 knots ahead. Blackout drills had been carried out, but recovery from a full blackout
without a standby generator had never been drilled on board. The engineers were therefore faced
with a situation they were not practised in managing. The situation was stressful, the control
system was complex, and a specific sequence of actions was needed. Insufficient training likely
contributed to why the blackout recovery was time consuming.”- blackout training in 99% cases is a verbal discussion with providing safety operation procedures printed usually in ECR. Real drill require to stop the ship from all operations and off course it’s an expansive procedure due to faulty equipment onboard after any power spikes and due to tough schedule.

 Every maritime incident presents a learning opportunity. The Viking Sky report disseminates valuable insights that can be used by the entire maritime industry to refine practices, training, and emergency procedures. The Viking Sky incident, though fortunately not a disaster, serves as a crucial reminder for the cruise industry to prioritize passenger and crew safety through robust emergency preparedness and adherence to safety protocols.

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