There are surf specific paddles that some companies make...
Lendal Mystic
Onno makes one called ~the New Wave (weird also because it is
symmetrical top-bottom).....
there is a whole bunch of wood paddles that the San Onfre guys use as
well....
i hear tell that a squirt paddle works well too....

in my surf boat i use:
a) Seven2 Airidium....this paddle has NO dihedral-it does flutter a bit
when paddling because of that....
b) Jackson Kayaks kids paddle....i am testing this one out....so far it
does VERY well...shorter because the deck of my boat is not that
wide....the hull is wide so you can have a hard edge to carve on but
the deck is thinner and you keep your knees almost completely together
(think of a pyramid shape without the top being pointy)....because of
that open area i can get away with a shorter paddle without banging my
knuckles on the boat....you only use 1/2 the paddle on the wave if that
anyway-so a shorter paddle is making sense.....
r