Here's the setup ...
ed, i don't see any responses to your question so maybe i can help a little bit.my 23.5 had all the hardware in place when i started and with crazy dave's help i got the assembly apart, replaced the sheaves, put a new divider between the main and jib halyards, and got it all back together again.when i took it apart, to my surprise i found that the 1/2" shaft was not secured at all. dave suggested that i would have dig out adhesive but there was none there. here's the setup:the shaft has a head, pin or other stop inside the deck to the aft of the sheaves (see diagram). when the shaft is pulled forward the head of the shaft stops it from pulling all the way through and coming out of the forward end of the support. in order to pull the shaft back into the forward position, i had to drill a hole in the end of the shaft, put in a SS screw and use a nylon line to pull it through the sheaves, washers, spacer, through the forward support and then daubed the end with a bit of adhesive/sealant. i'm wondering if perhaps what has happened on your boat is that the shaft fell inside the deck on the aft end, and is lost somewhere between the deck and cabin liner. i can't figure out how to access that area without undesirable major surgery.hope this helps some. - ed a.