Corrosion on tinner

[Chuck]

Have corrosion starting under vent. What is the best practice to repair this?

 

[ryanb]

Dissimilar metal started it causing paint to lift. As the paint lifts more moisture gets under the paint and it spreads. It won't be nearly as bad as you think once you remove the paint, but the bubbling paint will spread if you leave it. Sanding or acid wash to stop corrosion. Paint on an aluminum boat sucks. My next one will have no paint.

If you repaint after repair make sure you figure a way to avoid the dissimilar metal issue going forward. Mine is isolated from the hull with a gasket.