That would indeed be an interesting case for the geometric multiscale mapping (you would need a radial mapping to map the 1D ropes on the 3D fluid and the reverse), but I would not expect this to work out of the box without some tinkering.
I assume you want to do FSI, where you have the fishing net immersed into water. You still need to define some surface on which to compute forces. I would rather try to implement this conversion (3D to 1D and defining a coupling mesh) in the 1D code for now. Note also that preCICE does not yet support 1D meshes (but working on it).
See also: