One inch in prop diameter absorbs the torque of two to three inches of pitch. On a fishing boat I do not want too large a prop because of exposure to rocks in the shallows. I believe my prop is 9-7/8 x 10-1/2. WOT limit is 6000 rpm. If you go on the Yamaha website and look at your motor they have Performance Bulletins for the motor on different boats. If you find a boat like yours they show the prop pitch and diameter..
