Boat is a 1992 13 SS with a Yamaha 40 2-stroke (year 2000). Prop is aluminum and is perfectly matched (5500 WOT) but has no markings I can find. Does anyone know either how I figure out what the prop I have is or does anyone know the appropriate size prop for this boat and engine? What prop size is working for others with this boat / engine combo? I have tried the prop-finder tools online but numerous sizes are given.