I know this is an old thread, but I figured it worth adding to. We recently acquired a West Marine
RIB310 of the PVC variety. The boat is in very good shape (after a small fiberglass
repair and reinforcement), so I figured I'd build chaps to help save the PVC from the south Florida
I had a bunch of two and three yard sections of Sunbrella lying around from projects completed for others, so rather than buy new stuff, I used the extras. Yep, she has six - count em! - SIX colors. The beige patches on top are just for a light, cool place to sit, and extra reinforcement. Perhaps a bit of an eye full, but it sure is easy to recognize the dink at a dock
For patterning I used clear shower
curtains purchased at a dollar store: good, heavyish plastic that clings to the tubes. Heavy visqueen or paint
drop cloth would work. For the drawstring hold down, rather than make a hem in the sunbrella, I used some 3" folded dacron sail leach tape I had leftover (well, I still did a hem for strength, but I think the dacron is a better idea for the drawstring). On the inside, I sewed some 1" polyester webbing straps to hold oars, and a bunch of loops for attaching bags or pouches. I also put little loops on the exterior in such a way that we lace little finders along the exterior.
We patterned in the cool morning, sewed that evening and night, did a couple test fits and corrections the next morning, finishing that afternoon. About eight hours invested, and it was pretty easy. I highly suggest adding chaps to your dink!