I used Hypalon for a
water catching foredeck awning, which doubled as a water catcher & a
wind scoop for the forward
hatch. Hypalon will stand the
Queensland sun for years. We used it for the
hood of the Happy Bay Shark cat. I had to resew it twice in 9 years as the terylene sail cloth thread deteriorated full time in the sun, but the Hypalon
fabric was still perfect.
The important thing is to use beverage hose, definitely not garden hose. I used a couple of inches of 1/2" brass threaded tube in the approximate center of the awning, which weighed it down enough for the water to gather, & ran the beverage hose back to the water tank. Just a couple of minutes rain cleared any
salt, then the water was good.
In 6 years in the Pacific islands I did not once have to carry water. I did sometimes on the reef as rainfall is not that regular in
winter.