restoring painted gel coat

[fibersport]

As the title states, I'm trying to see if I can restore the gel coat on my Century Cardel. I'm finding that some parts are just heavily oxidized while other parts have been painted. I'm trying to sand off the paint with 400 grit but I'm wondering if I should go a little coarser to get to the gel coat then start going with finer grits. I don't have much experience with gel coat so I'm treading lightly. If I cut through it's not the end of the world as I'll just change plans and paint it. I've also noticed that I have some very fine cracks in the gel coat, some as long as 1/4" and straight but in a random pattern. Again I'm thinking I could go a little coarser to sand them out but could they be just on the surface and caused by years of exposure to the elements or might they go deeper? Thoughts and comments please?

 

[Scott Danforth]

400 will work, however your looking at 2 years of sanding

There is a reason it was painted. You will most likely find repairs below the paint

The gel is only about 0.020-0.030" thick from the factory

Most likely, you will have to sand the whole hull with 80 grit and re-spray, the gel. then sand with 320, 400, 600, and 800 grit, then polish and buff