This should be the insert needed from Catalina Direct ($230 - enough for a full refit) https://www.catalinadirect.com/shop-by-boat/catalina-36/hull-deck/midship/rubrail/rubrail-c-320-c-36-open-transom-c-380-gray-vinyl/?SearchResults=1 Click on "more info" about installation. Dave Hupe 1994 Cat 320 (#32) "Mayan Sun" Holland, MI