Dynamic Response Influencing Factors of the LNG Offloading Hose String in Bow-Loading Operations

To ensure the safe operation of floating LNG offloading hoses in bow-loading systems, this study investigates the key factors affecting the dynamic response of an LNG offloading hose string. A fully coupled dynamic model of the hose string, the LNG carrier (LNGC), and the FLNG is established based on the lumped-mass method. The sensitivities of hose loads and deformation indicators to the hose-string length, vessel stand-off distance, tanker-heading offset, internal flow velocity, ocean current speed, and wave height are quantified. Based on these results, a low-load operating configuration is identified and a preliminary operational envelope is proposed. The results show that, under the considered operational sea state, a hose-string length of 170.6 m and an FLNG–LNGC distance of 80 m yield the minimum effective tension. The recommended limiting environmental conditions for safe operations are a surface current speed of 1.1 m/s and a maximum wave height of 7.0 m. The present study provides a practical basis for preliminary configuration design, response assessment, and operational-limit determination of floating LNG export hoses in bow-loading applications. The main contributions of this study are threefold. First, a coupled time-domain framework combining AQWA-based vessel motions and OrcaFlex hose dynamics is established. Second, the effects of key configuration and environmental parameters are systematically quantified. Third, a preliminary operating envelope and a recommended configuration are proposed based on effective tension, bending moment, and curvature. These contributions distinguish the present study from previous work focusing mainly on local hose mechanics or qualitative system description.