I have sanded and sanded...and sanded some more. I added a thin coat of epoxy over some spots and then sanded and sanded and sanded. I have now washed the boat twice with dish washing liquid and am about to wipe her down with vinegar.
I have Interlux Pre-Kote primer and the Builder Tips say to put two coats on sanding between coats. I was reading some other threads on primer and ran across this one:
The last post has a photo showing most of the primer sanded off. Is this way everyone does it?