Skylight replacement

[dieselclacker]

I am getting ready to replace the skylight over the shower in our Allegro motorhome. It has some cracks, and the caulking leaked during a recent rain.
Is there a skylight available that is made from a different material than the original plastic type material. I was thinking maybe Lexan, or something similar.
What would be the best to use for sealing it to my fiberglass motorhome roof? It is attached with 1/4 inch hexhead self tapping screws thru a flange that is molded into the skylight. I was thinking of trying Eternabond. Pros, Cons for this product for this job.
I should mention that this is not a vent, but just a skylight, approx 22 X 22 inches, opaque in color.
Thanks for any input on the subject

Dieselclacker

[Rick Long]

This is the place where everyone in my Bounder Group goes.. Good prices, fast delivery most of the time and good products all the time.
http://www.cleardomes.com/index.htm

[JC2]

We replaced a skylight several years ago when we owned a 5ver. Used new screws, put a strip of butyl tape under the edge, run a very small bead of caulk around the edge(probably optional) and finished by applying Eternabond. Would use it again in a heartbeat if/when needed on our MH. You can purchase the Eternabond here at IRV2 upgrades.
Go to the search box and type in Eternabond.http://www.rvupgradestore.com/
Eternabond and the butyl tape can also be purchased here along when a small roller to better seal the tape with.http://www.bestmaterials.com/roof_repair.aspx Last but not least, it might be usefull to have this website available if you make a mistake and have to remove the tape.How to remove Eternabond Tape