Just did this on my 23.5
I am sorry to say but the only way to SAFELY perform this operation is to have your boat hauled out and put on stands. Under the two access plates around the compression post there is a big bolt that holds the bracket that, in turn, holds the swing keel up under the boat. Once the boat is on stands it is a very simple process of unbolting the keel bracket, dropping the keel (held up by someone else while unbolting) and attaching the new uphaul line to the old one and re-snaking it up to the topside. When reinstlling the keel someon on othe forum recommended installing a 1 foot threaded rod into the bracket and then feeding the bracke up into the hole. This eliminates fighting to align the hole to reinstall the keel bolt. Not knowing the condition of any of the rollers, bushings, etc. I ordered all new stuff from Hunter. Actually, in my case, there was very little wear on any moving parts BUT I am glad to have had the spares in case something was bad and I wasn't stuck waiting on spares being overnighted to me. Look in the archives there is plenty of information.