I finally finished the rudder deciding to go with one 5x2 made from alum. With it mounted on the boat, I tried 7x6 prop along with a 6x5.5 and decided the 7x6 was much better. So to pond I went and tried it first with a 9.9v a123 battery. It ran quite well except for the hopping quite abit and my right turns weren't too well so need to work on the steering abit. I also tried a 11.1v lipo which did make it go faster, but I flipped it trying to steer too sharp at high speed. Before I could get it back it smoked the lipo. Don't know if everything else works or not yet, but we'll let it dry out & then see. I need to do some work on it anyway. Here are some pics of the boat, rudder, and interior damage after flipping.