Re: 1986 spider cracks
Are you talking about the exterior cracks in the gel-coat? Mine was littered with them. I found, due to their location, that it was a result of rotten stringers and bulkheads. The boat was apparently in use while they were rotten. All the cracks in mine were along the length where the stringers are. Also, sideways across the boat in line with the bulkheads.
I used a grinder and "veed" them out through the gel-coat and into the 'glass then filled them with 'glass and sanded. It worked out pretty well. I figure after primer and paint you'll never know they were there.
That's how I did it. I'll be posting pics soon.
Jason