I'm probably nuts, but to keep hardware at the masthead to a minimum, I rigged my M15 topping lift to adjust at the boom. I dead-ended a line at the masthead connected by a small stamped d-shackle (I agree with Bones--the stamped d spreads the load on the pin). That line ends, oh, three feet short of the boom end. I have a little 3:1 that connects the line to the boom end, and run I the working end of the 3:1 through a cheek block and the end of the boom and forward a couple feet to a clam cleat w/integrated fairlead (so I don't lose the bitter end). I get three feet of adjustment with this setup. It's probably too elaborate, but I had fun thinking about it and building it. t Tom Smith and Jane Van Winkle M15--345 Chukar M17--064 Unnamed