Yes "crazing" or the little spider cracks/webs type surface degradation is unavoidable in plexiglass (acrylic, lexan
, etc.) as time and UV exposure eats at the material. Covering the hatches, etc. with opaque material like sunbrella will stop the process - except - that the whole idea of having the hatch
is to let sunlight into the boat without having to open the hatch
- - I have successfully "polished" away the surface to remove the crazing, but any hand or machine polishing introduces distortions in the surface level which is visibly noticable. So the easy way is to just replace the old plexiglass with new. There are super strong coated plexiglass material that greatly resists the natural crazing, but the costs of the material is extremely high versus plain ole acrylic plexiglass. It is more cost-effective to replace with the ordinary material than go with the "super" stuff.