Originally Posted by Gorey
The bonding wire is like a belt and suspenders. On newer boats the thru hull's are bonded. My boat was made in 1985 and the thru hussl look good. I did replace the Marlon plastic valves with brass.
I would not assume that you need bonding on all thru-hulls; sometimes if there is a grounding problem you can create more problems if the thru-hulls are attached together and have a pathway to the electrical loop. If your thru-hulls are sound now and they are 20+ years old I would not add bonding to prevent them from suffering galvanic corrosion. If they had been corroding there would have been evidence of it by now.