Bleaching panels?

[Wait & Sea]

I recently had some fiberglass work to a couple of hatches. They look great but they do not match the boat at all. Would you beach them to try to lighten them?

 

[seasick]

If paint or gel coat you can't bleach, that wont do anything. I suspect that whoever did your panels didn't do a good of matching matching. Was the color of the lids before the repairs correct?
If it were me and I specified I wanted the color matched and I paid a decent price for the work I would ask to have the panels re-coated and color matched. I suspect that won't go over well.

 

[SkunkBoat]

Depending on the age of your boat, even with perfect color matching its going to look different because the old gelcoat is not as shiny.
Bleach won't help. It will take years or a few beers before the difference doesn't stand out.

 

[Fishtales]

Either paint to match or live with. If a big deal to you, have a paint guy review.

 

[georgemjr]

Possible wet-sand/buff gel coat around the hatches to bring its luster back to match the new gel coat.

 

[seasick]

Depending on the age of your boat, even with perfect color matching its going to look different because the old gelcoat is not as shiny.
Bleach won't help. It will take years or a few beers before the difference doesn't stand out.

You and georgemjr make a point worth mentioning. Whenever you are matching gel coat color, the area that you want to match should be clean, polished and waxed.
The OP didn't say whether the repaired lids were painted or gel coated. If gel coated, they can be coated with another coat of color correct gel coat. Painted finishes are trickier