Khasiat Fadhilat (Isnad) Doa Haikal - Majmu' Syarif

In terms of the design loads, the key functional differences are that tankers have the ability to avoid bad weather or alter heading, whereas the FPSO (floating production storage & offloading) is in a fixed location and may be subject to larger loads, depending on the environment. Again, the consequences of failure differ. Therefore, the maximum FPSO global design loads are based on a 100-year return compared with 20 years for a tanker [Classification Rules for Ships4 (+1A1) requirements]. In addition, turret-moored FPSOs will head into the extreme weather, particularly if passively moored. Consequently, FPSOs are more likely to be subjected to larger bow slamming, bow impact pressures, sloshing, and greenwater loads. A tanker normally operates in the fully loaded or ballast state, whereas an FPSO is in a constant state of load-unload. This influences fatigue loading design considerations, particularly for the side longitudinals located at intermediate drafts. FPSOs have components-topsides, turrets, flare towers, and riser porches, for example-not found on tankers. These create greater mass, higher centers of gravity, and large windage areas, all of which will alter vessel motion and response compared with a normal trading tanker. These elements, combined with some of the new barge-shaped FPSO designs, introduce specific differences between tanker and FPSO design. Barge and novel-shaped designs may suffer undesirable motion characteristics leading to mechanical downtime, crew discomfort, green sea problems, and slamming. The additional volume at the ends of the barge-shaped hulls, combined with limited ballast tanks, can create still-water bending moments significantly larger than for a traditional shaped vessel. In this circumstance, the still-water moments may exceed the rule still-water bending moment value by as much as 95%. Furthermore, the absence of water ballast tanks may cause large draft variations between the fully loaded and ballast conditions, compared with a normal trading tanker. This may impact the fatigue design of the side longitudinals located near the waterline, because intermittent wet and dry surfaces in the splash zone drive the fatigue life.