Grounding thru-hull fittings

[Scott]

Otto ...Who made that thru hull?? I would ask them why its there.
I know of no reason to ground them above the water line ... If fact I've never seen that, a grounded thru hull for your bilge discharge [img]/images/graemlins/confused.gif[/img]. Underwater would be different like Rodney mentions. But that’s when sacrificial anodes come into place. Bronze is meant for U/W but isn't immune from trouble either ... We busted a blade off a wheel and found out that electrolysis was most likely the problem ...

If your in a marina with boats around you using shore power, the stray current can chew up U/W metals on your boat if not protected.

EDIT:
I think I answered my own question ...FishJack with the manufacturer name. I believe that SS when used U/W is highly susceptible to corrosion more so than Bronze... so maybe thats why the bonding bolt??