When replacing the dolphin striker in the endcap think about wrapping it in heat shrink tape ( for electrical wire) : it isolates the stainless steel rod from the aluminium. My endcap insides were completely eaten up by the corrosion caused by joining a weak and a strong metal in a seawater environement, I still consider this a design flaw in a otherwise superb boat ( I love my old 18 !)
Also : paint the end ( threaded) part of the rod with epoxy-paint, this end part cannot be shrink-wrapped ( the nut needs the threads) and the paint provides a measure of isolation.
It took me blood, sweat and tears to get the dolphin striker out of the end caps, but worth it : think what could happen when an end cap collapses during sailing....
Michel, sailing on Mana.