Hi Dave,
I used Titebond exterior glue on my first greenland paddle. I finished the paddle with 4-5 coats of Helmsman satin poly. I've used the paddle for 2 seasons with no sign of weakening. I'm building a Euro paddle for my daughter's boat now. I used gorilla glue on this one. I agree with Paul, that you should use whatever is handy. Also,a good finish will keep moisture from weakening the glue. If you are doing a euro paddle, a little glass on the paddle face should make a tough paddle.