Is it necessary to isolate the grounding points in an aluminum-hulled boat?
ANSWER 4: No, to the contrary, isolating elements increases the likelihood for corrosion because we cannot control the potentials of the individual metals. To protect stainless steel or bronze you have to arrive at a reading of a minimum of -600mV. To protect steel you have to arrive at a reading of a minimum of -800mV. To protect aluminum you have to arrive at a reading of a minimum of -900mV (all measured using a silver reference electrode – silver chloride). If we unite all the metals and at the same time connect them to the negative of the battery we can situate the metals at the appropriate levels of protection of -900mV by sending positive current through the titanium anodes. This way all the metals will be protected; and this is controlled through a corrosion monitor incorporated in the system.
