Yes, I had exactly the same problem with water in the paddle shaft. Firstly put duct tape around the joints where the blades fit onto the shaft. This stops the water getting in. Then drill a very small hole in the centre of the paddle shaft, apparently the centre takes the least forces. (It should not weaken the paddle much, my paddle did snap evenutually but it snapped at my hand, not in the middle where the hole was.)
Now blow into the hole holding the paddle above your head so the hole faces down, release and tilt the paddle. If you do it right you should get a jet of water coming out the hole. Repeat this until all the water is gone or you pass out.
Keep the hole open to do this before every paddle. You'll get some strange looks standing in the beach kissing your paddle in the air - its OK
Alternatively take your paddle to an expert, the glue they generally use to fix the blades to the shaft can be molten with heat and the blades can be removed, the water drained and then re-glued sealing the leaks.