yeah, basically a large genoa actually.
You hit on the problem precisely. The line has to be "crept" until it reaches the length of the luff of the sail so I am not tearing the new sail in half. I have heard of people tugging on the synthetic line with their car/truck to get some of the creep out. Wonder if a truck could break a 5k breaking load line (slowly of course, sure it could with a jerk)?