Not sure exactly where the water is getting in in you case.. But one of my paddles got water in the blade section as i think i didnt glue/seal it properly..

I found that if i put it in the sun, with where the water is getting in at a low point, it heats up, expands and the water runs out.. You may need to untape or take off shrink rap to let the water out properly.. Then seal it up

Good Luck Belly..