Re: fixing little holes thoughout aluminum boat
I know just what you mean. My current boat had holes all over the place for things like those swiveling drink holders that don't work, extra cleats in places that aren't helpful, and all kinds of other add-on accessories that went right into the trash when I bought it. All of those screw holes were above the water line so I just closed them off with regular aluminum pop-rivets. I repainted the boat as part of the renovation project so those within the painted areas blend in and those in the natural aluminum areas blend in as well.
It doesn't look GREAT, but it's much better than before and was a relatively cheap and easy way to improve the boat's appearance. It's the kind of thing that isn't noticed by those who aren't looking for it.
I used a body dolly and hammer to flatten the ugly side of the rivet in places where both sides can be seen. Once you do this they look very much like the factory rivets. In fact, a few of the panels on my boat were secured from the factory with pop-rivets so they look right at home for the most part.