Thats what i was thinking as I was reading it...I have that issue on the bottom of the boat on one of the strakes...i was filling in a nick with gelcoat (yea I know the color match isnt even close) and I was trying to get off this little gray spot and it started getting bigger....dont know if you can see it in the pic but to the left of the big gray spot the strake is sprinkled with gray coming through thin gelcoat....(dont mind the big black spots at the top of the phota thats just road schmutz)....would make sense that this area might have thin gelcoat as while spraying from the inside this surface would be kind of upside down and would need a good shot in there....not saying thats what you got skunkboat but take a close look .....
