As others have said, to keep dry, sitting in the center is your best bet.
In general, it's not a ride designed or made to get you wet. However, with some of the "explosions" in the water, as well as shark swim by's, Water may splash into the boat. If you do get wet, it's likely to just be some general splash type damage.
honestly, normally the wettest I've gotten the past couple times I've ridden came from sitting in a wet seat. (Of course, i enjoy sitting on the edge so I can be "closest to the action")