The Norwegian Accidents Investigation Commission (SHT) has reported that it's detected a "critical" safety flaw in the frigate KNM Helge Ingstad, which collided with a tanker just off the coast three weeks ago. The Helge Ingstad was built in Galicia by Spanish firm Navantia.
The issue, according to the commission's preliminary report, is to do with the frigate's watertightness. It has sent alerts to the Norwegian navy and Navantia itself to carry out investigations.
SHT has called on Norwegian authorities to look into whether the construction flaw is also present in the other four vessels of the same class built by the Spanish company for Norway.
Recommendations for Navantia
The SHT recommends Navantia undertake a study "on the elements identified in this initial investigation" to determine whether the same problem is present in other vessels. It also suggests it notify the "relevant shipyards, owners and operators" and advises they take the "necessary measures to address safety".
The commission says their finding shows the Helge Ingstad didn't "conform with the required damage stability standards". It suspects the same could be true of the other four Nansen-class warships delivered by Navantia.
The issue was detected while the Commission worked on its initial report into the incident. The accident took place on 8th November this year on return from exercises when it collided with a Maltese-flagged tanker near Bergen. The ship was quickly grounded and the crew was evacuated before it sank.
The SHT believes the collision was due to a number of factors, for example, a confusion between the lights on the tanker and those of the nearby terminal. They warn, however, that more investigation is necessary.
Flooding
In an appendix to the preliminary report, the Commission says that the ship took on water in three watertight compartments: the aft generator room, some crew cabins and the storeroom.
Based on the damage and documents about the vessel's stability, the crew decided the frigate has a status of "poor stability" but that it could stay on the surface. However, when warned that water was falling from the generator room into gear room through the hollow propeller shaft, they decided to evacuate.
"It was discovered that water was entering through the shaft into another room. They weren't watertight", Kristian Haugnes of SHT said in a press conference. He emphasised that the investigation was still in the opening states and that "the circumstances could be subject to more investigations".
The SHT said that it isn't their aim to attribute blame or civil or criminal responsibility and that it's a complex situation, and that as such they need time and resources to continue their investigation.
The KNM Helge Ingstad is one of five Nansen-class frigates built last decade for the Norwegian Navy at Navantia's yards in Ferrol and Fene in Galicia. The total contract was worth 1.1 billion euros.
The frigate was returning from Nato exercises, Trident Juncture 18, at the time of the collision. Seven sailors were lightly injured and tanker operations were suspended in the area for several hours.