cracked plexiglas
If your hatch cover is made of Plexiglas you can repair it with methelmethacrilate available in hardware stores and hobbyshops or Plastics suppliers who sell sheet Plexiglas. In fact verify what I suggest here with plastic sheet plexiglas sellers (see yellow pages)for their experience will surely superceed mine...methelmethacrilate is the chemical used to "weld" Plexiglas pieces together. Hold the joints tightly together with clamps, rubber bands, whatever and apply the meth with a small brush. It will capillary into the break. Wherever you get it on the surface, it will cause dulling so care should be exercised. To correct surface flaws use a fresh single edged razor place and grently scrape the area to a flat plane then polish with tooth paste of the old fashioned type which has some grit in it. It will take a while, but the gloss can be restored eventually. If you try to save time by ising a power buffer be careful...heat buildup can melt the surface and you are really in trouble...if that doesn't work, remember, you didn't hear it from me...there's alway duct tape...and there's always the old standby--get a replacement. Good luck (I'd talk to a Plexiglas dealer if I were you)