It emerged at the marine accident inquiry that the sheath on the hawser holding the ship to the buoy was observed 30 minutes before the accident to have slipped down so that the white core was visible.
The hawser comprised two layers, with the external sheath designed for safety reasons to break under a certain load. Pumps and the loading hose were then supposed to have been disconnected, but this was not done. Half-an-hour later, the hawser parted with a bang and fell into the water.
Positioned in the bow control room on Polytraveller, the first officer heard the bang and assumed the hawser had parted. He reacted swiftly by pressing the button which caused the loading hose to disconnect quickly. Oil flooded over the deck and caught fire. The whole bow was wreathed in smoke.
When the hose disconnected, it swung from side to side and sprayed crude over the whole deck. At the same time, the chain at the end of the mooring hawser rushed over the steel plates in a shower of sparks which ignited the oil.
Two methods were prescribed for disconnecting the ship quickly from the loading buoy in an emergency – either a staged process which took 25 seconds and prevented oil being spilt from the hose, or an immediate disconnection which risked spilling some 250 barrels of oil into the sea.
The first officer opted for the second of these. An investigation indicated that a failure in the hawser between ship and buoy was the indirect cause of the accident, but that a communication failure between Statfjord A and Polytraveller led to more oil than expected being spilt from the hose. This spillage was probably ignited by sparks from the chain.
Just over an hour after the fire started, the two injured mariners arrived at Bergen’s Haukeland Hospital. A fully equipped search and rescue helicopter from the joint rescue coordination centre (JRCC) was stationed by chance on Statfjord A.
It was there because the Norwegian rig Norskald – which was drilling for Statoil on what became the Gullfaks field – had encountered a gas pocket earlier the same day and come close to sinking. The injured could thereby be got to hospital quickly.
The fire had been brought under control after 15 minutes and completely extinguished after 40. This was accomplished with the ship’s own equipment.
Polytraveller suffered only minor damage and was able to sail under its own power to the refinery at Sola outside Stavanger in order to discharge. With a gross tonnage of 65 000 tons, the tanker was specially outfitted at its bow to take on crude via the loading buoy. It was almost fully laden when the accident occurred.
Extraordinary measures were adopted after the fire for buoy-loading of shuttle tankers, which would remain in place until new procedures had been developed.
The mooring hawser had to be monitored continuously during loading, and the maximum permitted load on it was reduced. Extra fire guards were required and, to avoid the threat of sparks, the bow area was to be covered by water spray during loading. Nor was it permitted to deviate from the rules on full communication between platform and ship.
But the hawser threatened to part once again when sister ship Polytrader was loading just six weeks later. On this occasion, however, everything functioned as it should. The pumps were shut down and the loading hose disconnected without any oil spillage.
Lindøe, John Ove. From Sea to Shore . 2009. P 115.
Norges Handels og Sjøfartstidende, 22 August 1980. “Oljespill på Polytraveller kan være antent av kjetting-gnister”.
Norges Handels og Sjøfartstidende, 4 September 1980. “Brannen på Polytraveller fører til nye prosedyrer for oljelasting i Nordsjøen”.
Rogalands Avis, 23 August 1980. “Var olje-pumpa steng?”
Stavanger Aftenblad, 22 August 1980. “To ble brannskadet under oljelasting”.
Stavanger Aftenblad, 28 August 1980. “Brannen oppsto i en slange”.
Interview with Arne Evensen by Trude Meland, Norwegian Petroleum Museum, 7 July 2011.