Im currently running a 3 Blade Alloy Boat Propeller 436x4 on my genesis with the stock motor and a turnigy 180 esc. I use 2 turnigy nano-tech 6000 batteries in series and the boat seems fast. My temps are good but I want to change my prop to see if I can go faster. I'm some what new to boating but I have been in the Car, Truck and Heli hobby for the past ten years. I have a 4mm shaft on there now but I would like to convert it to 3/16 and upgrade my prop. I just dont understand what 1.4 or 1.6P means or any other measurments for that matter. I do know what diameter is but I dont know what would be to big for my set up. Can anyone suggest a prop size or explain it and also tell me how to upgrade my shaft size? Thanks