Layline: straight line indicating the course a boat should be able to sail on the one tack in order to pass to the windward side of the mark. The layline is not necessarily the same as the proper course to the next mark simply because the skipper may need to factor such variables as wind shifts, stream, tide and obstructions into the process for deciding upon a proper course. In short, a metaphor for the spiritual experience of many a contemporary lay Catholic.