I've used autorelease clamcleats on wooden boats before. Not sure if it would work with the TI rudder line, what with all the pulleys and lines and such, but here's the product:http://www.duckworksbbs.com/hardware/cl ... /index.htm
If it were just a direct hauldown line to a cleat, it'd be a perfect solution.
I'm working two solutions - one for loss of steering line (happened to me three times so far in the last 6 outings) and one for a backup rudder. So it's either "carry a bunch of backup equipment" or "don't go more than a stone's throw away from the beach, and don't sail in offshore conditions, ever". Not real happy.
Hold everything! If you have broken steering lines THREE TIMES IN SIX OUTINGS, something is very wrong. That rate of failure is massively higher than anyone else has mentioned here.
There surely must be a reason for this, and I would be very interested to find out exactly where the line broke on each occasion, as this should give a pointer into the cure.
It seems to me that working around the problem with additional hardware like cleats etc should only be a last resort.
Having said that, for the rudder down-line, that cleat does exactly what is required, although it is hard to see how to incorporate it onto the Island without some work, given the large travel of the down line. I suspect the line would need replacing with thicker line at the cockpit end, removal of the existing cleat, and fixing of the "breakaway cleat" aft of the mesh pocket.