Timbo,

The line didn't break, a knot came undone. The way my boat is setup, there is a loop in the hull and the end of the stay is tied to a carabiner which is clipped on the loop. I think the idea was to make it easy to clip the poll on/off without having to worry about the chafing that you are concerned about. Instead the knot (a round turn and a few half-hitches) came loose. I should have inspected it more often and wrapped it in rigging tape.