The locking mechanism I chose for Redwing is elegantly simple -- a piece of line from the keel cap to a self jamming horn cleat on the keel trunk. That's the way the original HMS 18's were set up. It takes about 3 seconds to lock or free the keel. You can leave a few inches of slack when sailing in shallow waters, to allow the keel to bump up. I've tried steel bolts, nylon bolts, and heavy-duty bungee cords. I think this is the best system!