When I restored my H16 last year, I used two products to remove the oxidation on the hulls and to protect them. My boat had sat outside, unloved for a decade.
I started with a thorough cleaning using a good boat soap and a soft brush to remove the dirt. Once dry, I applied Yacht Brite Buff Magic to a small section at a time and then went over it with a random orbit buffer. The more you work this product with the buffer, the better the results. After buffing off the oxidation and smoothing the gel coat with the Buff Magic, I applied Yacht Brite Pro Polish to protect the gel coat from further oxidation. It also put a like new shine on it. The finish is still holding up nicely after a full season. I will put on a fresh coat of the Pro Polish this spring to maintain the gel coat protection and shine.
Put on some Jimmy Buffett sailing tunes, work slowly and patiently, and the results will be excellent. Here are links to the products that I used...http://shurhold.com/marine/yacht-brite- ... uff-magic/http://shurhold.com/marine/yacht-brite- ... ro-polish/
I bought these at West Marine, but have seen them available from other marine suppliers as well.