I didn't know what a Jackline was. For anyone
else in this situation here's what I found via Google....


What is a Jackline?
It is a line running from the tack of the sail up the luff approximately the
distance of four slides. This line is secured to the sail at the top and
tied to the fitting at the tack. The jackline is threaded through pairs of
grommets that are on the luff of the sail. Hardware to attach the sail at
the intervals is threaded on the line between each thimble pair. When the
sail is hoisted, the line is tight and the hardware is pulled tightly
against the edge of the sail between the thimble pairs. When the sail is
lowered, this hardware falls away from the edge of the sail on the relaxed
line. It really is a very simple concept.


What does a Jackline do?
A jackline is used along the hoisted edges of a sail to make it possible to
pull the sail away from the mast or the stay while it is lowered. They are
especially useful in reefing mainsails that are secured to the mast with
slides or slugs trapped in the spar. As the hardware comes down the mast and
stacks up at the stopping point on the track or slot, the jackline permits
the sail to be pulled away from the mast and down to the boom where it
belongs.