|Alexander L. Kielland Semi-Sub|
|27 March 1980|
|Ekofisk Field, Norwegian Continental Shelf|
The Alexander L. Kielland was a Pentagon-type semi-submersible and, in 1980, was located in the Ekofisk Field for Phillips Petroleum. It was supporting the Edda rig, acting as a so-called flotel (a floating hotel) for workers who travelled between the two rigs via a bridge, although this bridge had been raised prior to the accident due to gale force conditions. Around 1830 hours on 27 March 1980, one of the main horizontal braces supporting one of the five legs failed. The failure of the brace was attributed to a fracture which had developed around a hole in which a hydrophone, used to aid the positioning of the rig, had been installed. After the failure of the first brace, the remaining five braces attached to the leg failed in quick succession causing the leg to break off. The rig almost immediately listed to one side at an angle of 35 degrees, partially submerging the main deck and accommodation block.
The initial collapse occurred within a minute but the Kielland remained floating for another 14 minutes or so after the initial failure. During this time, a number of attempts were made to launch lifeboats, with only two of the seven lifeboats launched successfully. Three of the lifeboats were smashed against the rig's legs as result of the storm winds and waves whilst being lowered, leading to a number of casualties. After around 15 minutes, as water flowed into another two of the rig's legs, the last anchor wire parted and the rig rolled over completely with only the undersides of its legs visible above the surface.
There were 212 men aboard: 123 perished and only 89 survived the accident. On top of the high winds and waves, the men also faced near freezing waters with little protection. While some men did manage to swim to the Edda Platform to save themselves, others were swept away by 10m waves and strong currents as they attempted to reach rescue boats or other rigs.
Attempts were made to right the rig in 1980 but were abandoned due to the rig's dangerous state. In 1983, the rig was successfully righted and investigated before being towed to Nedstrand Fjord, where the remains of the rig were deliberately sunk. While the official investigation concluded that the leg bracing broke as a result of fatigue in a weld, later evidence was put forward indicating that the rig had been deliberately sabotaged with explosives. No new official inquiry was undertaken but the sabotage theory can be read in detail at the F.A.L.K. website.
BBC News Website
HSE Review of issues associated with the stability of semi-submersibles
Stavanger Petroleum Museum
F.A.L.K. Sabotage Theory
See also: Scotsman article
View a detailed animation of the accident at Exponent.com
2. Kulturnett Norway
4. F.A.L.K website