Method for transferring fluid between a first offshore assembly located in a body of water and an assembly floating on the body of water, associated assembly and facility

A fluid transfer method to transfer fluid between an offshore assembly located in a body of water, the offshore assembly having a first fluid storage capacity, and a floating assembly on the body of water, having a second fluid storage capacity, the method comprising:

• positioning a lateral face of the floating assembly opposite a lateral face of the offshore assembly to place the floating assembly side by side with the offshore assembly;
• installing and mechanically tensioning a plurality of mooring lines between the offshore assembly and the floating assembly, each mooring line having a first attachment point on the offshore assembly, a second attachment point on the floating assembly and an active length under a mechanical tension between the first point and the second point;
• fluidically connecting the first fluid storage capacity and the second fluid storage capacity via a fluid transfer system, and transferring fluid between the first fluid storage capacity and the second fluid storage capacity;
• continuously measuring the mechanical tension applied to the active length of at least one mooring line of the plurality of mooring lines;
• controlling the active length of the at least one mooring line via a controller, to keep the mechanical tension applied to the at least one mooring line within a preset mechanical tension interval.