Norwegian Maritime Authority (NMA) published March 19, 2024 a response to the report on the almost-catastrophic incident involving the cruise vessel VIKING SKY off the coast of Norway in March 2019.
Read the response on NMA’s webpage
NOTE: I remember that the potentially catastrophic engine failure made a big impression on me. Primarily, because of the seriousness of the incident, but also because it involved a modern passenger vessels, built according to the Safe-Return-to-Port regulations. The following text is based on the preliminary accident report, which was published eight months after the incident, and lists some of the key times in the sequence of events leading up to the accident:
When the cruise vessel VIKING SKY on March 23rd 2019 lost propulsion in weather conditions with wind speeds between gale force and storm and a significant wave height of nine to 10 meters in the waters off Hustadvika on the Norwegian west coast, it was due to the ship’s engines shutting down as a result of low lubricating oil levels. The incident is considered potentially the most serious near-catastrophe in maritime history. When VIKING SKY regained some propulsion, the vessel with 1,373 people on board was within a ship’s length of hitting skerries off the coast.
Departure from Tromsø
VIKING SKY had embarked on the last of six “Northern Light” cruises from Bergen on March 14th. The cruise included calls in Narvik, Alta, Tromsø, Bodø, and Stavanger. The ship had left Tromsø at 22:10 on March 21st and was scheduled to arrive in Bodø on March 22nd. The plan was then to call at Stavanger on March 24th.
When VIKING SKY departed Tromsø, there were two Norwegian coastal pilots on board. The use of pilots is mandatory on this route, and both pilots had sailed on VIKING SKY and with the current bridge crew several times before. The route to Bodø was reviewed by the captain and the two pilots before departure from Tromsø.
The southbound passage through Tjeldssundet towards Bodø proceeded as planned. According to the weather forecast, the wind would increase during the afternoon and into the evening, leading the captain to anticipate that the ship might have trouble leaving the quay in Bodø. He therefore, in consultation with the shipping company, decided to cancel the call at Bodø and instead proceed directly to Stavanger.
Around 13:40 on March 22nd, the captain instructed the staff captain to initiate the crew in preparing the ship for the deteriorating weather conditions ahead.
The ship’s propulsion
VIKING SKY’s propulsion system is diesel-electric. It consists of four generator sets from MAN: Two small generator sets, number 1 and 4, each with 5,040 kW, as well as two large sets, number 2 and 3, each with 6,720 kW. Since VIKING SKY is built according to the rules of Safe-Return-to-Port, the four generator sets are distributed with one large and one small set in each of two separate engine rooms. Each engine room has its own electrical switchboard. However, the two panels were typically connected with a switch to operationally create a combined main panel.
Problems had arisen with the turbocharger on generator set number 3 on March 16th. Therefore, a repairman from MAN was on board to disassemble the turbocharger and prepare for repair with spare parts that would arrive in Stavanger. VIKING SKY thus had only three of its four generator sets in operation.
18 alarms
On the morning of March 23rd between 05:00 and 09:04, there were 18 alarms indicating low lubricating oil level on the three functioning generator sets. Each alarm was accepted and cleared within a few seconds.
No further alarms were recorded until 13:37:04, when an alarm indicated that generator set 4 lost momenta. A few seconds later, an alarm warned of low lubricating oil level from generator set 4.
At 13:39:52, there was an alarm indicating that generator set 1 had a low lubricating oil level in the oil tank. Just over five minutes later, at 13:45:26, generator set 4 shut down – a few seconds later, generator set 2 also shut down.
Generator set 2 was restarted after 11 minutes but shut down again at 13:58:31, parallel to generator set 1, leaving the ship in a complete blackout with no propulsion whatsoever.
“Mayday” at 14:00
The bridge team immediately contacted the engine control room, where at that time there was no overview of the cause – or causes – of the blackout. Therefore, it was not possible to estimate when propulsion could be restored. The officer of the watch on the bridge notified the captain, who promptly arrived on the bridge.
After assessing the situation, the captain issued a “mayday” at 14:00. He then ordered both anchors dropped. However, the anchors were unable to hold the ship, which was drifting sternwards towards the coast at a speed of six to seven knots.
The ship’s general alarm was activated at 14:13, after which the assembly of passengers and crew at muster stations began. At this point, VIKING SKY had 915 passengers and 458 crew members on board. The Southern Norway Joint Rescue Coordination Centre immediately launched an extensive rescue operation upon receiving the mayday, including mobilizing resources, notably helicopter capacity.
Slow ahead
About 30 seconds after the blackout, the emergency generator started. The engine crew then transferred 10.8 cubic meters of lubricating oil to the sumps under the three functioning diesel engines. It was then possible to start generator set 2 and thus supply power to the main switchboard in manual load-sharing mode at 14:22.
At 14:29, the port propulsion motor could therefore be started, and about five minutes later, also the starboard propulsion motor. Together, this provided sufficient propulsion for the ship to maintain a slow forward speed.
Over the next hour, generator sets 1 and 4 were also started in automatic load-sharing mode, and the starboard propulsion motor was restarted, allowing for propulsion between slow ahead and half ahead. Although all three functioning diesel engines were now restarted, the engine crew had to continuously balance the electrical load manually while the ship maneuvered towards open water with both anchors lowered.
Lifeboats and rafts are ruled out
Around 15:00, the first rescue helicopter arrived. VIKING SKY was maneuvered towards the sea to minimize the ship’s rolling as much as possible to reduce the risk during helicopter evacuation. The captain had considered evacuation using the cruise ship’s lifeboats and rafts but ultimately deemed it too risky given the wave height and wind strength.
The first vessel with towing capacity arrived at VIKING SKY position at 16:40, but the weather conditions at that time were too extreme to transfer a towline between the two ships. It was only the following morning, on March 24th at 06:30, when the weather had considerably improved and several ships with towing capacity had arrived, that a towline was successfully established both fore and aft.
This, coupled with VIKING SKY still having propulsion, led the captain to call off the evacuation. At that point, 479 passengers had been evacuated by helicopter to an emergency centre on land. At 16:25, VIKING SKY was moored at the quay in Molde. 18 passengers sustained injuries during the incident and evacuation.
The preliminary accident report concluded that the lubricating oil level in all lubricating oil tanks for the four diesel engines was maintained at a level of 28 to 40 percent of capacity. The engine manufacturer’s recommendation is a level between 68 and 75 percent. Furthermore, the report concluded that the engines shut down as a result of insufficient lubricating oil being sucked up due to the low level. This condition was exacerbated by the ship’s movements in the rough sea, which caused a shutdown of all three functioning generator sets within 19 minutes, resulting in a blackout. Finally, the report concluded that the VIKING SKY was within a ship’s length of touching the rocks off the coast when a part of the propulsion was successfully restored.
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