Mooring Force Coefficients for First Order Motions of Floating Bodies

Abstract In a previous work of Chads and Esperança (2024)[1], titled Procedure to Include the Dynamic Loads of Catenary Shaped Risers on FPSO Roll Motion Assessments, expressions of added inertia and damping coefficients of riser force effects on a FPSO were given, which were based on a specific formulation for the dynamic top tension of risers in a context of restricted heave and roll first order motions in the frequency domain. However, considering the relevance of extending this discussion to a more general case, the present work describes the derivation of added inertia and damping coefficients that represent the effects of mooring line forces on floating bodies with 6 degrees of freedom in the first order frequency domain approach. Differently from the previous work mentioned, the derivations in the present work do not assume a specific formulation for the top dynamic tension of the lines connected to the body, since they can be assumed to be approximately sinusoidal. The assumptions and hypotheses that underlie the derivations in the present work are described and justified.