: How wide of a blade should I use? How long should the paddle be
: (roughly...in comparison)? If it helps I'm about 5'8"

I'm 5'7" and use a 220 for sea paddling (about the same length whether
Euro or GP), but have a 205 for white water. The blade area is comparable
to my biggest euro sea paddle, but obviously the blade has to be a lot
tougher - white water is a lot tougher on blades than even the most
aggressive rock-hopping on the sea ! You are also often paddling in water
which is very shallow - maybe even less than the draught of your boat,
so you are often pushing off rocks. To get the maximum amount of blade
in shallow water you need a wide blade and a fairly vertical stroke.
I started with an 80° paddle, but now use a 45° one - even lower feathers
are quite popular in W/W, down to 30°. Much lower than this and you will
start to miss braces when switching from a power stroke at one side to a
support stroke at the other (which you often have to do very quickly:).

Something like the paddles in Nick Schade's book would be good, with
glassed blades and something very tough around the blade tips. I'd choose
somewhere 195-205 for length, possibly make the blades a bit wider (but
pretty much the same length), go for 45° feather and make 'em tough !
Oh, it's also important that the paddles float and are not river-bottom
coloured. Unless you are absolutely great at not letting go the paddle
when you swim, paddles need to be easy to recover from a chase boat - a
paddle leash is not an option in white water because of the entanglement
risk.

Don't make the blades too spooned, suitability for bracing, sculling and
radical ruddering strokes and more important than absolute flat out forward
speed.... You want a blade that will slice cleanly out of the water when
you need to change sides in a hurry !

And, as mentioned, make sure the boat is filled out with buoyancy at both
ends, not only to make it easier to recover when swamped, but also to help
the rigidity. Oil-canning will lead to entrapment in a two-point pin, and
the higher the boat stays in the water, the less are the forces it will
suffer and the more chance you get out alive and with an intact boat !

Here's a typical pin on fairly easy whitewater (and the level was low so
not very powerful). The boat is packed out with buoyancy, and pretty tough,
but even so, I was very careful to get my knees loose under the spraydeck
before pulling the deck off, in case the boat collapsed as it filled. This
was one of the rare occasions when I did let go of my paddle - I used it for
support to stand up out of the cockpit and the blade was pushed under the
boat, threatening to rotate the whole thing upside down before I had got out,
so I binned the paddle and stood up in haste ! Took us about 30 minutes to
free the boat - eventually by having the biggest person jump on it :-(

Andy