My preventer
I have a 23.5, and I modelled my preventer after what a regular here, George, has posted on his website for his 260 (see link below). One end has a shackle to attach to the mainsheet bale. He put a block on one of the shroud U-bolts (chainplates) and ran a line back to a stanchion to tie off. I didn't like the stanchion idea so I ran mine back to the cleat near the stern. To be fair, at least if his stanchion gave out it would fly up to the chainplate, not across the cockpit. ;-)I don't know if George set up both sides or just the starboard. I did both sides.I have snap shackles on the lines to attach to the mainsheet bail. The other ends of the lines are tied to the aft cleats and I don't undo them. There is enough slack such that the boom can by gybed (or tacked) without undoing either preventer. When not using the preventers, I tidy up the slack by running the shackle back towards the stern, attaching to a lifeline or stern rail sest. To set the preventer, I take up the slack and tie the line (in the middle) to the same stern cleat where its end is fixed.Have a look at George's pictures. Mine is the same except for being tied off at the stern cleat....RickM...