Originally Posted by Nos4r2
They are very useful in shallow water to push you along...
They're also quite useful for snagging the odd bit of trash in the water. Don't think I've ever used them for propulsion.
On my boat, I've two aluminum shaft platic paddles, the blade fits into a pocket made of hypalon (picture a square with three sides glued and you're pretty close), the shaft is secured with a velcro loop up near the handle. They sit on the lower inside of the tube, so they're really not noticeable in terms of being in the way.
If space is an issue, how about these:
At $16 a lot cheaper than Fred's link (but not carbon fiber, so not as sexy...)