phil,
i'd be curious to hear what break tests showed about the stiff section of your rope compared to the normal part. granted it's a well used rope, so the break strength will be substantially diminished, but i think it would be interesting to break the stiff section and then break a section 30 ft away from that point on the rope. any place near you to do that? we have one in seattle i think, and if it's not too pricey i'd do the footwork to get it tested.
k.