Painting leg of Mariner 30efi outboard

[picardy]

I have recently purchased a RIB with a 2006/7 Mariner 30efi. Unfortunately the previous owner left the leg in the water for long enough to allow barnacles to grow. These were then scraped off leaving a real mess on the leg.

I would like to sand the rough areas down and re spray.

My question is how to do this. I was going to use wet and dry to achieve a smooth surface but what sort of paint do I use as a primer/undercoat?

Thanks

 

[northwind]

Etch primer, you can buy it in halfords.