Is uncertainty of wave induced fatiguing loading on FPSOs uncertain?

That FPSOs being permanently positioned offshore installations are continuously subjected to sea actions was known to the industry from the very begin of offshore exploration. This however has not prevented some new built and converted FPSOs from fatigue damage. Uncertainty in fatigue loading has been identified as one of potential causes. The paper demonstrates that the direct approach towards wave induced fatigue loading has a firm basis and concludes that other causes should be investigated. The approach has been verified based on an extensive full-scale monitoring campaign and model test program. The paper summarises the work on the subject carried out between 1996 and 2004 mainly within two JIPs: MARIN’s “FPSO Integrity I & II” and DNV’s “FPSO Capacity II”