said by Ostracus:
That's actually an interesting idea. Two things, could it be installed over a preexisting roof, and the other is how to deal with the cap?
I would suggest based upon this comment, you don't add anything over what is already there.
Heh, I know the picture isn't the best (and yes the structure underneath has issues)
It isn't going to be inexpensive but you need a full teardown, solve the problems with and below deck and then re-roof.