If they are in good condition, just old and oxidized, you have two choices.
Hard work method:
Use a chemical like Oxalic acid (Barkeepers Friend) to remove the oxidation, then wetsand the gelcoat, then use polishing compound, then wax or seal the finish.
Or the easier method: http://www.poliglow-int.com/poliglow.phtml
The kit includes the oxidation stripper and the sealer, everything goes on like water and is really pretty easy, if time consuming.
Let see some before and after pictures of your boat!
Is your boat a Stars and Stripes "Gunsmoke Blue" color like mine?
Do post some photo for us all to enjoy the fruits of your labor.
Thanks,
Bill 404 21SE