Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Research on the Arrangement Method of Docking Block for 400,000-ton Super-large FPSO
Xianyin Chen1, Wenyuan Zeng1, Qingchun Zhu1, Chao Zhao1
1 Dept. of Military Ship Design& Research, Marine Design & Research Institute of China

Shanghai, China(Paik, Thayamballi, 2007). Therefore before the significant
improvement of docking block load capacity, it is necessary to propose
a docking block arrangement method to fulfill the demand of modernlarge ships.

ABSTRACTWith the reviving demand for deep-sea oil and gas development, thedesign of FPSO is aiming at its enlargement. Super-large FPSO, asbuilt in docking state, need to be concerned about its yielding strengthand the loading capacity of the dockings under FPSO. The bearing
reaction force should be taken into consideration when dockings are to
be arranged. This paper chose a 400,000 tons deadweight FPSO as theresearch object, whose molded lines of bow, stern and bilge partchanged rapidly and the flaring part of structure was comparatively
more than other FPSOs, which resulted in more concentration ofweight on the dockings at knuckle points. Therefore particular attention
should be paid to the arrangement of heavy docking blocks. In thispaper, the influence factors of the docking block bearing reaction force
were explored. Based on finite element method, a set of optimized
arrangement method could be summarized by the docking block
reaction force analysis of different arrangement directions and different
modules attached to the bottom, which could be used for reference fordesign and construction of super-large FPSO.

According to the CB/T 3677-2015 Standard, the space between keel
blocks should be 0.5m to 2.5m. More additional blocks were supposed
to be arranged at bow and stern areas, and the space between themshould be 0.5m to 0.8m. All the docking blocks should be laid close to
the longitudinal and transversal bulkhead or web frame (Guan, Zhu,Sun, Sun, 2012). In this research, a super-large 400,000-ton FPSO wasselected as the research example to study the factors influencing thedocking block reaction force. The variation of docking block reaction
force were explored under different block arrangement directions andadditional block positions. As for the software simulation method, thedocking block reaction force respectively under the simulation ofSpring element and MPC element were calculated and compared.

1.
INFLUENCE FACTORS OF DOCKING BLOCKREACTION FORCEFirstly, the bow area of the example 400,000-ton FPSO was selected toanalyze the optimal reaction force of docking block under ballast waterloading and without ballast water loading. The weight distributions of
the bow area, both with and without ballast water loading, were shownin Fig. 1.

KEY WORDS: Super-large FPSO; Docking blocks arrangement;
Bearing reaction force; Docking block group; Structural rigidity.

INTRODUCTION
With the gradual rise of oil price and the recovery of oil and gas
industry in recent years, FPSO has attracted more and more attention
than it ever had before. With the rapid technological innovation, ships
and other marine structure have been experiencing a new trend ofupsizing. Due to the long service in a certain sea area and the high costof round-trip, FPSO also followed the development process of ships
and moved towards larger scales.
However, the upsizing of floating structures had led to a serious
problem. The docking block, who had a limited carrying capacity,
could not be laid out for the bow, stern or bilge side part of the ship dueto the irregular molded lines (He, Xue, 2011). With the unstoppabledeveloping towards upsizing of ships, the traditional docking blockarrangement method had been gradually unable to meet the demand forgeneral assembly of large ship in dockyard (Hwang, Roh, Lee, 2010)

Fig. 1 Weight distribution of FPSO bow
According to the standard above, the docking blocks of the preliminary

811