Bruce,
We have an awning on Rum Runner that I made a few years ago. I purchased a 
silver tarp at WM, but I can't remember the size.( Might be 8 x 10') There 
are three PVC pipes that support it on top of the boom. I capped the ends of 
the pipe and installed eyes in the caps before permanently gluing them on. 
The eyes also go through eyes on the tarp to keep it together with the PVC 
pipe. 
I unroll it and then bungee it in six locations. The sides are long enough 
that when it rains, the side flaps keep the cockpit dry. When not raining, 
they are folded over the top and tied from side to side. It's not rocket 
science, but it works and costs around $25.00 to build. It goes the full 
length of the boom and also protects the pop top and cabin area.

Rummy