Securing the return on investment for commercial floating wind farms by a proper estimate of the Operation & Maintenance (O&M) downtime is a key issue to triggering final investment deci-sions. That is why Crew Transfer Vessel (CTV) weather stand-by issues should be assessed together with new floating wind floater concepts, to boost their cost attractivity. However, such issues as the numerical investigation of the landing manoeuvre of a service ship against a floater reveal complex to calculate. Based on similarities with seakeeping, we inves-tigate various floater geometries. To estimate the weather limitations associated to each configura-tion. Most recent works find that calculation compares with 5% accuracy to an experiment from a test tank at model scale. Method description Vessel seakeeping: • Assess vessel responses (amplitude and phase angles) • Compare them with vessel responses of available publications, as a benchmark Vessel berthing: • Model both vessel and floater • Account for the wave masking effect of existing floater designs. • Compare the ratio of wave vertical force over wave horizontal force and the grip coefficient at the interface between the vessel fender and the floater boat landing. Findings The wave masking effect calculation for a square floater is cross-checked favora-bly with an existing demonstrator.