The Weekly Reflektion 43/2022

The current energy crisis in Europe demonstrates how important power is to industrial and domestic users and to maintain the services society requires. Like many aspects of life, we only really appreciate them when we are close to losing them. We cannot afford to be complacent on essential services.

The Viking Sky cruise ship nearly aground off the Norwegian Coast

How vulnerable are your power generation systems?

In the late nineties I was working offshore in Norway. I was on my way back to my office after a routine inspection when I heard a loud bang and the platform started to shake. Suddenly the lights started to flicker, and I heard the process system shutdown and gas venting to the flare. The two turbines that were online had both tripped causing a black-out. A supply ship that was offloading diesel had inadvertently collided with the platform. The vibration from the collision initiated a wave in the lube oil tank for the gas turbines and when the trough on the wave hit the low-level switch (LSLL) on the lube oil tanks, both turbines tripped, as per design. Due to the limited emergency power systems, recovering from a black-out was challenging and there was a significant production loss. The LSLL on the lube oil tanks was later modified such that it had to be active for more than 5 seconds before initiating a trip. This prevented a similar incident while still providing adequate protection for the turbines.

On March 23, 2019, the cruise ship Viking Sky was en route from Tromsø in the north of Norway to Stavanger in the south. There were strong winds and rough sea, however the conditions were well within the operational capability of the ship.  At 13:50 the ship experienced a black-out and loss of propulsion. The master immediately sent out a mayday as the ship drifted towards shore. Anchors were deployed to help prevent the ship going aground and evacuation of the passengers by helicopter was initiated. Eventually the crew managed to start first one and then three of the four engines and the ship sailed to Molde under its own power.

The investigation into the incident pointed to three direct causes of the loss of propulsion.

One of the recommendations from the investigation was:

All vessel owners and operators are recommended to ensure that engine lubricating oil tank levels are maintained in accordance with engine manufacturer’s instructions and topped up in the event of poor weather being forecast.

We, in Reflekt, place this in the ‘remember to do what you are supposed to do’ category and it really has little value for learning without context. Why did the captain and crew believe the lube oil levels in the tank were OK for the planned journey in the forecasted weather conditions? Did the captain and crew actually make a conscious decision or was this an example of normalisation of deviance? We are still researching.

Reflekt AS