RR83 - Margins of safety in FPSO hull strength

Instigated to collate available data on the range of variation of safety factors of currently used floating production, storage and off-loading (FPSOs), and to consider how more consistent margins of reserve strength for various FPSO configurations under various loading conditions might be achieved. Recent studies were carried out to determine the variation in safety factors (between the applied loading and the capacity) of FPSO's currently operating in the UK sector of the central North Sea, and designed using either a class rule type approach or a more advanced hydrodynamic - FE type approach. results seem to indicate that the safety factor in both cases is similar, since the advanced hydrodynamic F/E type approach tends to result in higher loadings but also higher capacities. However, it is not clear to what extent these results can be applied to other FPSO's, or to other areas. There is also an apparent variation of reserve strength against hogging and sagging bending moments, particularly for double hull FPSO's that tend to have a higher capacity at the bottom of the hull in comparison to the deck.

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Updated 2021-04-15