.................. there really isn't a solution as the countless number of cracks appear to penetrate quite deeply into the acrylic. I'm assuming yours are acrylic, the same as I have on my 1999 Hunter 310.
This winter, I decided to see if I could replace the lenses on my two Lewmar and one Bomar hatches based on an article I had seen in DIY Boating. The article was supposedly written by an expert but was "rough

" in the finishing to put it mildly. I did the first hatch lens replacement using his grouting method and would up redoing it again after I worked out a few bugs myself. The finished products are identical in every way to the original ports when new. Problem is, most people at the marina just roll their eyes when I say that I just finished replacing the lenses. No one believes me :bang:.
Without going into great detail at this point, I will say that anyone with a small hobby woodworking shop and a reasonable knowledge of woodworking will find hatch lens repalcements to be a simple and enjoyable winter project. Actually, for what new hatches are worth these days, it would still be cheaper to buy the router, router bits, drill, drill bits, small drill press, etc, etc, do it yourself, and save loads of money.
I had figured on installing snap-on covers when the new hatch lenses were installed to protect the lenses against UV, but I think it's easier to replace the lenses every 7 - 8 years as required.
Maybe someday when I have the time (and ambition) like Maine Sail, I'll put together a pictorial on how to replace hatch lenses.