I recently bought a used canoe that I’m repainting and making small repairs on. The aluminum gunwales are painted over with marine top side paint. I don’t know if I should remove the paint and refinish or just leave it and paint over it for cosmetic reasons.
If the paint is sound, not flaking or peeling , I’d degrease , lightly sand and paint.
My just acquired old canoe has bare aluminum gunnels. I’ve been advised just to polish them.
You also have the option of just removing the old paint if you’d prefer the look of aluminum gunwales.