0.33 disc area ratio blades. (This means 33% of the "disc" area of prop dia is blades)
Rules of thumb.
One inch diameter = 2.5 inches of pitch.
Two inches extra pitch will cut engine rpm by 450.
If you can't fit the indicated diameter due to clearance, or have plenty room left, the rules
of thumb above will be a useful guide.
NEVER, EVER use these rules of thumb to specify a pitch that is lower than the pitch calculated from required speed and propeller RPM, as doing so will mean that the vessel will NEVER reach required speed under power.
