Get a rotary buffer and use a wool pad. I picked one up on sale at a local auto parts store for $45. I beat it like a dead horse but use this. Notice it will get 1200 grit scratches out. I use 1500 to 2500 to be safe:
It's an amazing chemical compound. Slow speed to use the compound, press firmly, then as the compound starts to dry speed up a bit and lighten the pressure the more it dries. It turns into a polish, no joke. Wipe residual away with microfiber towel. Pick your best wax to finish.
If you really want to do it right, wet sand the oxidation away with 1500, then follow by wetsanding for awhile with 2500 to get the 1500 scratches out. Then use the compound/polish on the entire boat, then Mequiars tech wax 2.0 paste. Follow instructions on the wax. Apply, let dry, then wipe off with micro-fiber towel. The results will be stunning!