I purchased a 1990 PII without a motor and knowing it was it rough shape. I was going to have some glass work done and fix scatches with Marine-tex. We lifted the boat off the trailer the other day and under the bunks were round blisters in the gel. Is this going to be a total, sand down and re-gelcoat project. Or can I run the Marine-tex down the blisters and seal it off good enough. The boat is white if that matters.