Boat Hull Staining

[JohnSciacca]

I was looking at a used boat, about 4 years old. The hull was bare aluminum, no paint. Below the water line there were small white spots (staining) that wouldn’t come off when I rubbed them with my finger. I thought they might be oxidation marring but not sure. I forgot to take a picture so sorry about that.

Anyone have an idea as to what they are and are they removable? Thanks ahead for input. John

[Bill Kiene semi-retired]

It is probably just cosmetics but I think it can be buffed off with an electric buffer and buffing compound.

A friend buffed his aluminum boat to look shiny like chrome.

[JohnSciacca]

Thanks Bill for the timely feedback. John

[Mr T]

Galvanic corrosion is likely what you are seeing. if it is light not a problem if it gets really deep then it may enter the hull- That is extreme though.

If there is an outboard, make a point to check the anode(s) (zincs is another term used), and chances are it is covered in a similar white-ish coat. Clean it off with a wire brush so the zincs get destroyed and not the hull.


It's not uncommon at all to see some on a metal hull.

[JohnSciacca]

Thank you for the useful information Mr T.