The Accident Investigation Board released a preliminary report yesterday. They also announced a hitherto unknown design flaw in the Nansen-class design in the shaft arrangement, which may also be present in other ships designed and built by Navantia (Australian Hobart class, Spanish Bazan class). Naturally, Navantia categorically denies that there are any flaws in the design.
For the benefit of our non-Norwegian reading friends, I have taken the liberty to translate the bulk of the official report to English. Any errors in translation are accidental and mine alone.
Source: https://www.aibn.no/Sjofart/Undersokels ... e&attach=1
Preliminary description of chain of events
On Thursday 8. November 2018, the frigate HNoMS Helge Ingstad was sailing south in inshore waters north of Bergen. As is common during a transit, navigational training was undertaken. Before the vessel arrived in Fedje VTS area of responsibility, the crew notified that they would enter the area from the north and stated the route they planned to navigate. This is logged at Fedje VTS at 0240. During the transit south, cruising at 17-18 knots, HNoMS Helge Ingstad had her AIS set to received move (reception only, no transmission of own ID data), the vessels running lights were lit, and the vessel was visible on radar. HNoMS Helge Ingstad established listening watch on VHF channel 80 which is the VTS working frequency for the area of responsibility.
A little before 0300 one of the Coastal Administration pilots embarked the Malta-flagged tanker Sola TS, which had loaded crude oil at Sture terminal and was preparing to get underway. Two tugs which were to assist during departure arrived shortly thereafter.
At 0313 the pilot on Sola TS hailed Fedje VTS and notified that Sola TS was started to single up moorings and preparing to get underway. Fedje VTS acknowledged this information. Around the same time, three other vessels were sailing north from the area south of Sture terminal.
At around 0340 the ongoing Officer of the Deck arrived on the bridge of HNoMS Helge Ingstad and reviewed the handover procedures, and was informed of traffic in the area by the offgoing Officer of the Deck. The three vessels heading north had been registered by HNoMS Helge Ingstad and were plotted on the vessels radar. During the handover, a heavily illuminated static object was observed at or directly outside Sture terminal.
At approximately 0345 the pilot on Sola TS reported departure from Sture terminal and [intention to proceed] out Fedjeosen in the west to Fedje VTS.
At approximately 0355 the ongoing Officer of the Deck on HNoMS Helge Ingstad assumed the watch, whereupon the offgoing Officer of the Deck departed the bridge.
Assisted by the two tugs, the tanker Sola TS started to move out from the quay at Sture terminal. The vessel was moored with starboard side alongside and the bow facing south. When Sola TS was sufficiently cleared of the quay, the vessel executed a port turn to steady up on course 350T up towards Fedjeosen. As Sola TS left Sture terminal, three vessels from the south passed and were on the tankers starboard quarter as she had completed her turn and steadied up on a northerly course. When Sola TS left quay, her running lights and deck lights were illuminated.
At approximately 0357 the pilot spotted the echo of a southbound vessel on the radar. The vessel was north of Sola TS. The pilot could see the vessel’s green lantern and that it would cross his navtrack, but they did not have AIS-signal on the vessel.
At approximately 0358 the pilot hailed Fedje VTS and asked for the name of the vessel that approached on the port side. VTS replied that they did not have any information on this vessel. The pilot and master of Sola TS then tried to establish contact with the vessel using different methods. They used morse with the Aldis light, and the pilot asked the master of Sola TS for a ten degree starboard course change to 000T.
At approximately 0400 Fedje VTS hailed Sola TS, and informed that the vessel was possibly HNoMS Helge Ingstad. Shortly after this, the pilot hailed HNoMS Helge Ingstad and asked that they turn starboard immediately. The bridge crew of HNoMS Helge Ingstad replied that they could not turn starboard until they had passed the object they had on their starboard side.
Shortly after 0400, HNoMS Helge Ingstad was approximately 400 meters from Sola TS. When HNoMS Helge Ingstad did not alter course, both the pilot and Fedje VTS hailed HNoMS Helge Ingstad and requested that the vessel do something. Shortly thereafter, Sola TS answered full astern bell and HNoMS Helge Ingstad attempted to maneuver, but it was too late and the two vessels collided.
The collision inflicted large damages on HNoMS Helge Ingstad. They lost control of helm and propulsion. This caused the vessel to continue uncontrollably in towards shore where it grounded at 0411, approximately 10 minutes after the collision. As the water intake increased, HNoMS Helge Ingstad suffered so poor stability and buoyancy that the vessel was evacuated.
The preliminary description of the chain of events is based on the Accident Investigation Boards initial investigation with interviews of operational crews and data from the vessels and the traffic central. The Accident Investigation Board consider the bridge crew of HNoMS Helge Ingstad, the bridge crew of Sola TS, and Fedje VTS as three main units in this investigation. Communication and cooperation between these three units and internally in each unit has influenced the chain of events. A thurrough examination and analysis of this is considerable work. The Accident Investigation Board can still give the following preliminary assessments of the chain of events:
It was a clear night when HNoMS Helge Ingstad sailed south in Hjeltefjorden, and the lights from Sture terminal would have been visible at long distances. When the terminal first became visible for HNoMS Helge Ingstad, Sola TS was moored at the terminal. Because the crew of the tanker were preparing for departure, the deck of Sola TS was considerably illuminated. There were no movements in the lights as the tanker was still moored. Both these factors have most likely contributed to the crew of HNoMS Helge Ingstad having early on been given the impression that the lights belonged to a static object.
After changing the watch crew on the bridge approximately 0340-0345, this was situational awareness [of the bridge team]. Even though Sola TS left quay roughly around this time, there were still little relative movement on the lights as the tanker turned from the southerly to a northerly heading. The vessels use of deck lights after departure also led to the crew of HNoMS Helge Ingstad not seeing the navigational lanterns of Sola TS.
When HNoMS Helge Ingstad at approximately 0400 reported that they could not turn to starboard, this was based on a lingering understanding that the lights they saw were stationary and that a starboard turn would lead them straight into the illuminated object. They also thought that they were communicating with one of the three northbound vessels they were tracking on radar. It was only just after this that the crew of HNoMS Helge Ingstad became aware that they were on a collision course, and it was at that point not possible to avoid the collision.
The Accident Investigation Board’s preliminary analysis is that no single action or event led to the accident, but that the accident can be explained with a series of complex factors and circumstances. The investigation group is working to uncover and understand these factors. The Accident Investigation Board have until not no indications that technical systems have not functioned as expected up until the collision.
The Accident Investigation Board has started the mapping of how the accident developed after the collision and until the entire crew were evacuated. In the course of this, the Norwegian Armed Forces, Defence Materiell Agency, Royal Norwegian Navy, the Military Materiell Administration, and the ship’s designer Navantia have been informed that they will receive a warning concerning a safety critical concern. The warning entails the frigate’s watertight sectioning.
Still a lot of unanswered questions, but at least we have a somewhat less murky picture of what went wrong. The answer: many things. Swiss cheese hole theory
seems to be an apt comparison.