Broaching has to be the least pleasant event in sailing. I experienced one of these death roll broaches in my old Potter 19 years ago and now I always rig a jibe preventer on the downwind leg on our M17 s/v cerulea by attaching a purchase near the end of the boom and clipping to the toe rail forward of the mast. By doing so, the wind should it cross over your quarter and get behind the mainsail it will prevent the dreaded wham of the booms violent crash across the boat and accompanying momentary mayhem.