From the iboats prop selection section:
3 blades... or 4?
We recommend 3-blade propellers for recreational boats with 3, 4, and 6 cylinder outboards and I/0 engines.
These propellers provide good "hole shot" and top-speed performance.
We recommend 4-blade propellers for bass boats and boats with high performance hulls running high horsepower outboard engines.
Compared to 3 blades, they provide better "hole shot" performance with less steering torque and less vibration at high speeds.
When switching from 3 to 4-blades, generally a 1" pitch decrease is required. So, a 21" pitch 3-blade prop is replaced with a 20" pitch 4-blade prop. Pitch is increased when switching from 4 to 3-blades.
Hope this helps a little
__________________
1987 V20 w/1987 150HP Yamaha on a Shoreland'r Trailer
1978 16.5 Airslot w/1996 120HP Force on a Four Winns trailer
1996 V21 w/1993 200HP Mercury on a Shoreline Trailer
All towed by a 5.7L Hemi Durango.
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