If you have the RapidUp Kayak Sail from Advanced Elements on your kayak, you can take advantage of a tailwind to speed your paddling. The sail lays flat on your kayak's deck until you need it, then deploys quickly thanks to its non-corroding "spring" frame.
Compatible with any inflatable or hard-shell kayak, the sail is made of rip-stop fabric and comes with center and side windows so you can see where you're headed. Multiple adjustable attachment points make installation easy, and you can even use the sail if there's nothing to attach it to – it can be hand-held.