FATIGUE ANALYSIS OF CATENARY MOORING SYSTEM DUE TO HARSH ENVIRONMENT IN FOLLOWING SEAS
Abstract
In the operation, Floating Production Unit (FPU) will get dynamic loads on the structure periodically
such as the mooring line responses. The aim of the present study to discuss fatigue life on catenary
mooring system refers to the comparison of using or without using the Single Line Freestanding Riser
(SLFR), the operational design and installation conditions at FPU Gendalo-Gehem and located in the
Makassar Strait using the six-strand wire rope with 0,115 meters outer diameter and 1.200 meters length
will be fatigue life analysed. The FPU motion observation shows the highest Response Amplitude
Operator (RAO) surge, sway, heave, roll, pitch, and yaw motion due to harsh environments are 0,615
m/m, 1,01x10-6 m/m, 1,048 m/m, 1,14x10-5 0/m, 2,23 0/m, and 9,08x10-8 0/m. It means that the
amplitude response will always be smaller than the wave amplitude coming up. Taking into RAO
motion calculation, the fatigue life on catenary mooring systems for following seas are 445 years in
mooring line 1 and mooring line 8 with using SLFR while without using SLFR for 5.461 years in
mooring line 1. The structure is still in safe condition because of the design safety factor about 300
years.
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