Aluminum hull anodes

[GordMay]

Originally Posted by thaisail

I will go with zinc based on your advice...
... My boat is built in 1982 at Kanter Boat Yard in Ontario, Canada and they welded anode pads made of aluminum to the hull with threads in them and the old anodes were attached to those pads with two stainless steel bolts that hold the anodes firmly to the aluminum pads....

Kanter did it right.

For saltwater use, with an aluminum alloy hull, one should use a zinc anode.

Be aware that the zinc can oxidize over when exposed to air. This means if zincs are not cleaned when a boat has been out of the salt water, and the boat is returned to the water, the oxidized coating will protect the zinc, and it will not function as a sacrificial anode.

[thaisail]

Should the aluminum pads welded to the hull have bare aluminum under the zink anode so that the zink is in direct contact with the hull? The new zinks that I just got from Vetus had a coat of blue paint on them only on the surface where they make contact with the aluminum pads that are welded to the hull. The Vetus website recommends to have the electrical connection only through the bolts. But I have removed all the paint using a wire wheel from the aluminium pads and under the anodes so that the bare zink is held firmly against the bare aluminium hull. Should I follow the advise of Vetus and paint the bottom of the anodes and the aluminum pads?

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