my friend wants me to clean his boat up a bit, it has been very neglected and the exterior feels like chalk, Im thinking its gonna take some muscle to cut through this stuff, should I start out with one of these (#4 or #84) and a LC purple foam or orange pad on a rotary? I have never done a boat so I really dont know what to expect



also, once its cleaned up should I hit it with a paint sealant or something like 303?