Excuse my use of words as I am totally new to this, so my terminology is limited,
Okay here we go.
The genoa sail which I am fitting is to a Robbe Atlantis which whether you know or not has two masts, the genoa replaces the fore sail, and is approx 50% bigger in size, so to be able to move from one side to the other and avoid the fore mast, the sheet line is attached to a block which moves on a track which is in the shape of a horse shoe., the sail is attached to a boom at the front and in turn is attached to a winch which hauls the sail in and out to increase or decrease the sail area...phew I think that's it, don't know if anyone can explain further.
Steve.