A report from Stavanger Engineering
The Alexander L. Kielland was originally planned to be anchored with 10 anchors, but for practical reasons, only 8 were used. As a result, the angles of the anchor wires ended up slightly different than intended. Combined with the forces from wind, waves, and currents, this may have put more strain on the rig than it was designed for.
The Kielland Network commissioned a report from Stavanger Engineering to see if modern analysis methods could provide more precise answers. However, the results, published in 2024, were largely in line with previous conclusions. Read the report here
The Norwegian Investigation Commission claims that the anchoring had little impact on the accident, while the French report suggests a greater influence.
Stavanger Engineering identifies a significant increase in stress levels in the horizontal braces, with D6 rising from 3.4 MPa to 13.5 MPa and DE from 1.3 MPa to 11.0 MPa. This suggests that the reduced anchoring (eight anchors instead of ten), combined with four years of load and offload operations from fixed installations and severe deviations from the ballast procedure, contributed to the disaster.
None of the ten other Pentagon platforms developed similar cracks. “Drill Master” (P83, later Buchan A) operated for over 40 years without structural issues. Gundersen considers it highly serious that Norwegian authorities and the classification society allowed “Kielland” to operate far beyond its design criteria and operational manuals without addressing the deviations.
Gundersen has written several articles on this in the: Memory Bank – Alexander L. Kielland : Those of Us Who Saved, Rescued, and Investigated.