Finally got the boat off for trailer repairs. Back end of keel on tyres and slowly dragged out the trailer and put the stands under, have managed to keep the front end high so can slide the trailer back under easily. Replacing all the zinc plated U bolts with galv ones. Why they ever put these on is a mystery to me as they corrode quick once the coating is compromised and that affects the galv. All new rollers going on with stainless pins, the old ones will need to be cut off with a grinder as the steel pins have rust expanded in the roller tubes. I'll be double nutting everything too and readjusting the hull support slides as they were out of alignment and making the boat pull left when winching on.