Report on the capzise and sinking of the workboat Heidi in Sandebukta 16 February 2015

The mooring line broke while the workboat Heidi prepared for a diving operation in Bjerkøysundet on 16 February 2015. While waiting for a new mooring arrangement, the diving leader ran the boat slowly back and forth in the area with/against the waves in a circle formed pattern and conducted a starboard turn in each end.

The Accident Investigation Board Norway (AIBN) stability calculations show that the total deck cargo carried on board on the day of the accident made the stability of the boat marginal. Because of unsatisfactory bilging of observed bottom water, there was water in the hull at the time of departure in the morning. The low freeboard in the front allowed water from waves and ripples against the bow to come on to the deck. This led to water ingress in the hull from i.e. corrosion in air intake on deck and leaky deck-hatches. In practice this caused the absence of stability and stability-reserve for the boat. Supplied with an inclining energy from the use of the rudder, together with sideway displacement of bottom water, lead to capsizing and foundering.

The investigation has shown that the company OPD had not prepared any stability calculations for the boat based on established stability standards. The load limit of 6 tons, which was fixed by the company with background in information from the previous owner and from their own experience with freight of a 6 tons heavy excavator as deck cargo on board the workboat, resulted in marginal stability independent of any stability standard.

Consequently, a description giving the crew information about the operational limitations were absent. In addition the maintenance of the boat had deficiencies. The AIBN considers that this in total indicate deficiencies in the management of the boat safety in the company.

Please note: The full report is in Norwegian only.