UPDATED: Preliminary Findings Shed More Light on Brave Tern Collision in Esbjerg, Bonheur Names ‘Lack of Situational Awareness’ as Cause

NOTE: The article was updated on 31 July with information shared by Bunheur ASA, Fred. Olsen Windcarrier’s parent company.

Fred. Olsen Windcarrier’s wind turbine installation vessel (WTIV) Brave Tern was out of operation for three weeks after the incident in the Port of Esbjerg on 10 June, which was caused by a lack of situational awareness, according to information from Bonheur ASA.

In a presentation of its results for the second quarter of 2026, the parent company of Fred. Olsen Windcarrier said the direct cause of the incident was found to be a “lack of situational awareness on the bridge during pilotage, leading to too small clearance.”

Preliminary findings from an initial investigation by the Danish Maritime Authority (DMA) provided the sequence of events that led to the collision involving Brave Tern in the Port of Esbjerg.

It is worth noting that the DMA’s report followed an unannounced survey conducted shortly after the incident and does not represent the conclusions of the investigation, which was ongoing at the Danish Maritime Accident Investigation Board, an independent accident investigation authority.

DMA carried out the survey the day after Brave Tern collided with Cadeler’s WTIV Wind Keeper and quayside port equipment during a harbour manoeuvre on 10 June while transporting wind turbine blades for RWE’s 1.1 GW Thor offshore wind farm. There were no serious injuries reported, but the incident left all nine blades onboard the vessel damaged.

According to preliminary investigation documentation from the Danish Maritime Authority (DMA), accessed by offshoreWIND.biz, Brave Tern had completed a 180-degree turn and was proceeding through the port at a speed of around three to four knots when the incident occurred.

A member of the Brave Tern bridge team moved to the starboard bridge wing during the manoeuvre to assess the clearance between the vessel’s blade cargo and Wind Keeper, which was moored alongside the quay. Although the distance seemed close, the clearance was deemed to be sufficient at the time, according to the witness account included in the DMA report.

Moments later, however, the crew was alerted that the blades were getting dangerously close before the cargo struck Wind Keeper‘s starboard crane at approximately 07:41 local time.

The vessel subsequently experienced difficulties maintaining its heading and, according to the reported timeline, made contact with the quayside about six minutes later. Control was regained using the vessel’s dynamic positioning (DP) system, after which Brave Tern proceeded to a turning basin with tug assistance before returning to port.

The DMA survey report notes that all vessel certificates were valid, no violations of crew rest-hour requirements were identified, and no equipment alarms had been reported before the collision. Investigators also recorded that all equipment appeared to be functioning normally at departure and stated that it remained unclear exactly what caused the incident.

In its observations included in the report, the DMA also states that the windage effect of the cargo “may have had a greater influence on the vessel’s maneuvering performance than originally expected,” as Brave Tern was carrying vertically stowed tower sections on deck and turbine blades extending approximately 60 metres beyond the vessel’s starboard side.

The survey identified hull damage on the vessel’s starboard side covering an area of approximately 12 square metres. Following the inspection, the DMA set a requirement for a safety meeting with bridge personnel before the vessel departs from Esbjerg to discuss the incident and measures to prevent similar occurrences.

Meanwhile, cleanup operations in the Port of Esbjerg have been completed. According to Danish newspaper JydskeVestkysten, divers and specialist contractors have removed blade debris that fell to the seabed during the incident. The newspaper also reports that costs and damages following the collision are estimated to exceed DKK 1 billion (approximately EUR 134 million).

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