I need to replace the boom end cap, and Catalina Yachts no longer stocks the part for my 1977 boat. They have redesigned the gooseneck three times since my sliding gooseneck fitting. The part I have doesn't have a sheave attached, and is only compatible with the sliding gooseneck fitting on this boat. I need to replace it as the small cylinder inside is partly corroded and no longer holds the pin going into it which attaches to the gooseneck fitting. Does anyone know which of the later 3 designs of fixed gooseneck fittings I should get to replace it with, and how hard is it to do this? Any other ideas on what to do???--Thank-you!!! Laurie Miller