Re: gelcoat
dk
Depending on what type of resin was used to make the boat, catalyst level, temperature in the shop, how soon it went outside, gel coat thickness, or a few other things, you can get some post cure. This means the resin and/or gel coat was not cured well enough before the boat was removed from the mold. When it's still curing out of the mold there is nothing to keep it from changing shape as it continues to cure and shrink, this leaves a fiber pattern in the gel coat. When everything goes right, you will have little or no fiber print from the mat or chop used as a skin coat against the gel coat, when it goes wrong you can see every fiber.
Roving is not used in the skin coat but it can still print through to the gel coat, this is more common on older boats.
The layer that the roving is in is normally thicker than the skin coat, so if it's hot out, it can generate a lot of heat when curing and will shrink more than normal, when this happens you can get a roving pattern in the gel coat.
If the print is only on one side of the boat, it can be from being taken out side shortly after being made and the sun was shining on that side of the boat, causing it to finish curing faster and shrinking more than the other side. This is very common on dark colors, they get much hotter in the sun than whites or other light colors and tend to deform more.
The fix, start sanding and hope the reason for the print isn't thin gel coat.
