Bobby, hello, hope all is well. I'm repainting a 21 Chris Craft (Fiberglass) that has some spider/stress cracks. I'm not so concerned about it being like new but was curious if a primer would cover/fill these or would they have to be ground and filled, which I don't want to spend the time or money on. After all the research I plan on using Interlux perfection either paying someone or doing it myself. Any help is greatly appreciated. Thanks, SHB